{"paper_id":"086129fe-e4ae-43b7-a96d-865ce54f309a","body_text":"Combined viscocanalostomy and retrabeculotomy versus retrabeculotomy for management of refractory primary congenital glaucoma: A Comparative study | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Combined viscocanalostomy and retrabeculotomy versus retrabeculotomy for management of refractory primary congenital glaucoma: A Comparative study Zakieh Vahedian, Ghasem Fakhraie, Mahsan Samadi This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9539983/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 8 You are reading this latest preprint version Abstract Background: To compare the outcomes of combined viscocanalostomy (VCO) and repeat trabeculotomy (retbo) versus retbo alone in primary congenital glaucoma (PCG) with prior failed trabeculotomy. Methods: This prospective study enrolled 164 PCG eyes with insufficient response to initial angle surgery, equally divided into VCO+retbo and retbo groups (n=82 each). Success was defined as intraocular pressure (IOP) between 6–21 mmHg with ≥20% reduction from baseline, classified as 'complete' (no medications) or 'qualified' (with medications). Results: Mean follow-up was 30.36±13.38 months. In successful eyes, IOP decreased from 28.52±6.06 to 16.2±2.94 mmHg in VCO+retbo and from 27.35±5.29 to 17.67±4.35 mmHg in retbo; medication use changed from 2.70±0.78 to 2.04±1.03 and 2.69±0.97 to 0.98±1.10, respectively (all p<0.001). Final IOP did not differ between groups, but retbo required fewer medications (p<0.001). Failure rates were 31.7% (VCO+retbo) and 37.8% (retbo) (p=0.219). Complete success was achieved in 9.8% (VCO+retbo) versus 32.9% (retbo), while qualified success was 58.5% versus 29.3% (p<0.001). IOP >30 mmHg before second surgery predicted higher failure risk (HR=2.33, 95% CI: 1.33–4.11, p=0.003). Conclusions: Adding VCO to retbo in PCG with prior failed trabeculotomy offers no additional benefit over retbo alone. Trial registration: The study was approved by the local ethics committee of Tehran University of Medical Sciences (IR. TUMS. FARABIH. REC. 1402.009). The online version of the decree is publicly available at: https://ethics.research.ac.ir/IR.TUMS.FARABIH.REC.1402.009 viscocanalostomy retrabeculotomy primary congenital glaucoma combined viscocanalostomy and retrabeculotomy Figures Figure 1 Background Because primary congenital glaucoma (PCG) is fundamentally a problem of angle development—specifically, maldevelopment of the trabecular meshwork [ 1 ]—it makes sense that the first line of defense is angle surgery, which generally works very well [ 2 , 3 ]. The real difficulty for surgeons arises when that first surgery fails, leaving them to manage complex cases that do not respond adequately. Several options remain for managing these challenging cases. Surgeons may attempt angle surgery again at a different site, or they may opt for filtering procedures like trabeculectomy or the implantation of a drainage device. One strategy to improve outcomes has been to combine different surgical approaches. For instance, trabeculectomy has been combined with trabeculotomy [ 3 ]. However, because trabeculectomy is a penetrating procedure that creates a full-thickness opening into the eye, it carries inherent risks. These can include vision-threatening complications such as shallow anterior chamber [ 4 , 5 ], hypotony, retinal detachment [ 5 ], choroidal effusion [ 4 ], and hemorrhage. Additionally, because it relies on the formation of a filtering bleb, patients are also at risk for bleb-related issues like leaks, infection [ 6 ], overhanging blebs, and dysesthesia [ 4 , 6 – 8 ]. In contrast, nonpenetrating glaucoma surgeries (NPGS) were developed to avoid many of these complications. Procedures like viscocanalostomy (VCO) aim to lower intraocular pressure by enhancing the eye's natural outflow pathways [ 9 ]. Given their better safety profile [ 10 ], combining NPGS with trabeculotomy is a logical approach for congenital glaucoma [ 11 , 12 ]. In our experience, unroofing Schlemm's canal during these procedures facilitates trabeculotomy. Based on this rationale, we compared VCO+retrabeculotomy (VCO+retbo) versus retrabeculotomy alone (retbo) in PCG patients with prior failed angle surgery. Unlike previous studies limited to virgin eyes, this is the first to evaluate this combination in truly refractory cases. Methods This interventional comparative investigation comprised a cohort of pediatric patients with PCG who had previously undergone inferotemporal trabeculotomy utilizing a Harms metal probe and had demonstrated an insufficient therapeutic response. The study protocol was approved by the institutional ethics committee and conformed to the principles outlined in the Declaration of Helsinki. Written informed consent was secured from the guardians of all participants prior to enrollment. All eyes in the study had undergone inferotemporal trabeculotomy utilizing a Harms metal probe as their primary surgical intervention. Failure of this initial procedure was defined as the persistence of IOP above the predetermined target level despite maximal tolerable topical therapy, typically in conjunction with persistent corneal edema and/or deterioration of the cup-to-disc ratio. The duration between the primary trabeculotomy and the subsequent surgical intervention was recorded for each case. Assignment to the second surgical method—either viscocanalostomy combined with retrabeculotomy (VCO+retbo) or retrabeculotomy alone (retbo)—was performed sequentially. The initial trabeculotomies were conducted by one of two surgeons (ZV or GF), and continuity of care was maintained such that each patient's second procedure was performed by the same surgeon who had performed the primary surgery. The diagnosis of PCG was established according to the following criteria: an intraocular pressure (IOP) of 21 mmHg or greater; glaucomatous optic disc neuropathy, defined as a cup-to-disc (C/D) ratio exceeding 0.6 or the presence of notching when fundal examination was feasible at presentation; and corneal enlargement, which may or may not have been accompanied by Haab striae. At initial presentation, corneal clouding was observed in the majority of patients, and a significant proportion also presented with epiphora, photophobia, and blepharospasm. Owing to the prevalence of corneal opacity, gonioscopic examination was not possible in most cases. The following criteria led to exclusion from the study: the presence of anterior segment anomalies consistent with developmental disorders such as Axenfeld-Rieger syndrome, aniridia, or Sturge-Weber syndrome; diagnosis of secondary glaucoma; a history of any ocular surgical intervention other than trabeculotomy; and cases in which guardians did not provide written informed consent for the procedure. Regarding follow-up duration, eyes with less than one year of postoperative observation after the second surgery were excluded from the final analysis. However, any case that met the criteria for failure within that initial twelve-month period was included in the analysis. For young children and those unable to cooperate during examination, sedation was achieved using oral chloral hydrate, and tonometry was carried out immediately following the onset of sleep [ 13 ]. Cooperative children were examined using standard clinic-based procedures. Pre-Operative Examinations The baseline ophthalmic evaluation comprised the following assessments: IOP measurement using the TONO-Pen AVIA (Reichert, NY, USA); horizontal corneal diameter determined with callipers; documentation of corneal status with respect to opacification or edema; identification of Haab striae; evaluation of anterior chamber depth, iris configuration, lens status, and pupillary characteristics (reactivity and shape). In cases where corneal clarity was sufficient to permit visualization, optic nerve head examination was conducted via indirect ophthalmoscopy using a 30D lens to determine C/D ratio, and cycloplegic refraction was also performed. Surgical Procedure and Follow- Up A 7 − 0 Vicryl corneal traction suture was placed to facilitate inferior rotation of the globe, thereby exposing the superonasal quadrant. This positioning ensured that the second surgical site was situated 180 degrees from the location of the initial trabeculotomy. A fornix-based conjunctival peritomy was subsequently performed. In retbo group, a half-thickness scleral flap measuring 3×3 mm was created. Following identification of the Schlemm canal, its outer wall was incised. A Harms trabeculotome was then introduced into the canal, advanced carefully, and gently rotated into the anterior chamber. In VCO+retbo group, a superficial rectangular scleral flap (4×4 mm) of approximately one-third scleral thickness was dissected, extending 1.5-2 mm into clear cornea. A deep scleral flap was then dissected anteriorly until the Schlemm canal was unroofed and approximately 0.5-1 mm of Descemet's membrane was exposed. High-molecular-weight sodium hyaluronate (Healon GV, Pfizer, New York) was injected into both ostia of the Schlemm canal using a 30-gauge cannula. A Harms metal trabeculotome was subsequently inserted into the canal openings, advanced with care, and rotated into the anterior chamber. The deep scleral flap was then excised. In both groups, the overlying scleral flap and conjunctiva were meticulously closed with 8 − 0 Vicryl suture. The anterior chamber was finally irrigated and reformed with balanced salt solution. The postoperative pharmacological regimen was standardized across both treatment groups. This consisted of topical Betamethasone administered for one month, Chloramphenicol for one week, and Pilocarpine 1% for two weeks. Supplementary anti-glaucoma medications were prescribed as clinically indicated. Postoperative assessments were done on day one; at 1, 3, 6, and 12 months; and then annually, with additional visits as needed. At each evaluation, IOP, C/D ratio, corneal clarity, and diameter were recorded. All complications were documented and managed. Eyes with inadequate IOP control despite maximal therapy underwent Ahmed valve implantation by the same surgeon. Complete success was defined as IOP 6–21 mmHg with ≥ 20% reduction without medication; qualified success met the same IOP criteria with medication. Statistical Analysis Descriptive statistics (mean, SD, median, range, frequency, percentage, 95% CI) were used. Group comparisons employed Chi-square/Fisher's exact tests for categorical variables and t-test/Mann-Whitney U for continuous variables. Longitudinal changes were assessed via paired t-test or Wilcoxon signed-rank test; time-group interactions were evaluated using linear mixed models. Time-to-event analysis was conducted employing the Kaplan-Meier method to estimate the mean survival time of IOP control. The relationship between potential prognostic factors and surgical failure was investigated using both univariate and multivariable Cox proportional hazards regression models. The covariates included in the regression analysis were: type of second procedure (VCO+retbo versus retbo), gender, age at disease onset, age at second surgery, and intraocular pressure at the time of second surgery (dichotomized as ≤ 30 mmHg or > 30 mmHg). Recognizing the potential non-linear relationship between age and surgical outcomes, age at onset and age at surgery were stratified into four ordinal categories: less than 1 month, 1 to 6 months, 6 to 12 months, and greater than 12 months. The strength of association between these variables and failure was expressed as hazard ratios (HR) from univariate analysis and adjusted hazard ratios from multivariable analysis, each with corresponding 95% confidence intervals. All statistical computations were performed using SPSS software (Version 27.0, IBM Corp., Armonk, NY, USA). A probability (p) value of less than 0.05 was deemed to indicate statistical significance. Results A total of 164 eyes with PCG were enrolled in this study, comprising 82 eyes in each treatment arm. All eyes completed a minimum follow-up period of 12 months and were included in the final analysis. The baseline demographic and clinical characteristics of the study population are summarized in Table 1 . Of note, there were no statistically significant differences between the VCO+retbo and retbo groups with respect to baseline IOP or the number of glaucoma medications. Mean follow-up time was 30.36 ± 13.38 months (31.52 ± 10.61 in VCO+retbo and 29.07 ± 15.91 in tbo p = 0.281). In successful eyes, IOP dropped from 28.52 ± 6.06 to 16.2 ± 2.94 mmHg and from 27.35 ± 5.29 to 17.67 ± 4.35 mmHg in VCO+retbo and retbo and the number of medications changed from 2.70 ± 0.78 to 2.04 ± 1.03 and 2.69 ± 0.97 to 0.98 ± 1.10 in the two groups respectively (all p-values < 0.001 for pre-post operative changes). Last visit IOP was not significantly different in successful eyes in the 2 groups, whereas the retbo eyes required less medications for IOP control (p < 0.001). Because the final follow-up time was highly variable among patients, for ease of analysis, patients were divided into three groups based on the time of the last visit: less than two years (50 eyes), two to three years (71 eyes), and more than three years (43 eyes). There was a marginally significant difference in last visit IOP, in favor of VCO+retbo, in eyes followed up for 2–3 years but no difference in those followed up less than 2 or more than 3 years (Table 2 ). Eyes that underwent VCO+retbo showed greater pressure reduction than retbo in patients with less than two years of follow up (-15.63 ± 8.26 vs -8.70 ± 8.26 mmHg, p = 0.018) (Table 2 ). Table 1 Demographic and clinical characteristics of the patients Group VCO + retbo retbo Mean ± SD Mean ± SD p-value Age at the time of first operation (week) 11.2 ± 28.5 8.9 ± 28.5 0.604 Interval between the two operations (month) 9.43 ± 12.08 17.03 ± 14.46 0.000 Age at the time of second operation (month) 12.19 ± 15.95 19.11 ± 15.72 0.006 CCT (micron) 593 ± 74 559 ± 51 0.005 Mean SE RE (Diopter) -3.20 ± 3.97 -1.90 ± 2.78 0.037 Corneal diameter (mm) 13.3 ± 0.8 13.1 ± 1.1 0.766 Cup/Disc ratio 0.58 ± 0.17 0.64 ± 0.20 0.159 Baseline IOP (mmHg) 29 ± 7 28 ± 6 0.124 Baseline medication number 2.63 ± 0.76 2.72 ± 0.89 0.290 Gender (N(%)) Male Female 41 (50%) 41 (50%) 43 (52.4%) 39 (47.6%) 0.755 Age at Diagnosis (N (%)) ≤ 1m 1-6m 6-12m > 12m 10 (12.2%) 55 (67.1%) 2 (2.4%) 15 18.3%) 7 (8.5%) 58 (70.7%) 9 (11%) 8 (9.8%) 0.063 IOP= Intraocular pressure, VCO= viscocanalostomy, retbo= repeat trabeculotomy, CCT= central corneal thickness, SE= spherical equivalent, RE= refractive error Table 2 Last visit IOP, IOP change, number of medications and its change in successfully treated eyes. VCO + retbo retbo Follow up time (months) Mean ± SD Mean ± SD p-value ≤ 24 Last visit IOP 15.9 ± 2.4 18.2 ± 5.2 0.121 Last visit IOP change -15.63 ± 8.26 -8.70 ± 8.26 0.018 25–36 Last visit IOP 15.9 ± 3.4 17.5 ± 3.6 0.047 Last visit IOP change -11.65 ± 6.04 -10.58 ± 6.19 0.531 ≥ 37 Last visit IOP 16.3 ± 3.0 16.6 ± 4.5 0.436 Last visit IOP change -10.85 ± 6.26 -9.43 ± 6.13 0.470 ≤ 24 Last visit medication number 2.06 ± 1 0.90 ± 1.0 0.002 Last visit medication number change -0.31 ± 0.87 -1.1 ± 1.0 0.034 25–36 Last visit medication number 2.1 ± 1.1 1.08 ± 1.2 0.007 Last visit medication number change -0.60 ± 1.4 -2.1 ± 1.4 0.002 ≥ 37 Last visit medication number 2.0 ± 1.0 0.86 ± 1.1 0.027 Last visit medication number change -1.0 ± 1.1 -2.1 ± 1.8 0.131 IOP= Intraocular pressure, VCO= viscocanalostomy, retbo= repeat trabeculotomy At last follow-up visit, 26 eyes [31.7%, (95% CI 22.4–42.3%(] of VCO+retbo and 31 eyes [37.8%, (95% CI 27.9–48.6%(] of retbo group met failure criteria (p = 0.219); iatrogenic cyclodialysis leading to hypotony occurred in one eye from each group, both of which required surgical closure. Overall, complete success was achieved in only eight eyes [9.8%, (95% CI: 4.7–17.6%)] of VCO+retbo and 27 eyes [32.9%, (95% CI: 23.5–43.6%)] of retbo group and qualified success rate was 58.5% (48 eyes) (95% CI: 47.7–68.8%) in VCO+retbo and 29.3% (24 eyes) (95% CI: 20.3–39.7%) in retbo group at last follow-up (p < 0.001). Using Kaplan-Meier analysis, the mean survival time for surgical success was estimated at 51.1 (95% CI: 44.3–57.8) and 73 (95% CI: 54.4–91.6) months (p = 0.290). The average time of failure was 9.8 ± 8.5 (range 1–39) months in VCO+retbo and 11.2 ± 9.9 (range 1–38) months in retbo group (p = 0.729) Also, in VCO+retbo the survival rates were 1 (95% CI: 1 to 1), 0.750 (95% CI: 0.645 to 0.873) and 0.435 (95% CI: 0.322 to 0.590) in 1, 2 and 3 years respectively. In retbo, the survival rates were 0.905 (95% CI: 0.836 to 0.980), 0.847 (95% CI: 0.759 to 0.945) and 0.511 (95% CI: 0.373 to 0.699) in 1, 2 and 3 years respectively (p = 0.290 based on Long Rank test) and remained relatively constant thereafter. Kaplan-Meier survival analysis results are depicted in Fig. 1Patients were stratified into four subgroups according to age at disease onset: less than one month, one to six months, six to 12 months, and greater than 12 months. The number of eyes within each age category is detailed in Table 3 . It should be noted that all patients were older than one month at the time of the second surgical intervention.For calculating the predictive ability of type of second surgery (VCO+retbo vs retbo), gender, age at disease onset, age at second surgery and IOP at time of second surgery (≤ 30 vs > 30 mmHg) in failure rate, univariable and multivariable cox regression analysis was done. The results are presented in Table 3 . In summary, only patients with IOP greater than 30 at the time of the second surgery faced a higher failure risk (HR = 2.33, 95% CI: 1.33–4.11, P = 0.003). No other variables emerged as significant predictors of failure. Table 3 Results of univariate and multivariable regression analyses (failure as dependent variable) Variable Levels N (%) Univariable Multivariable HR 95% CI P HR 95% CI P Lower Upper Lower Upper Second surgery type VCO+retbo 82 (50) 1 1 retbo 82 (50) 1.321 0.782 2.231 0.297 1.364 0.744 2.501 0.315 Sex Male 84 (51.2) 1 1 Female 80 (48.8) 0.679 0.400 1.154 0.152 0.607 0.351 1.050 0.074 Age at onset (month) < 1 118 (72) 1 1 1–6 36 (22) 1.076 0.456 2.539 0.868 1.386 0.567 3.389 0.474 6–12 4 (2.4) 1.406 0.429 4.611 0.574 2.104 0.578 7.665 0.259 > 12 6 (3.6) 0.690 0.222 2.140 0.520 0.694 0.200 2.410 0.565 Age at the time of second surgery (month) 1–6 67 (40.8) 1 1 6–12 29 (17.7) 0.844 0.405 1.758 0.651 0.678 0.311 1.477 0.327 > 12 68 (41.5) 0.780 0.440 1.384 0.396 0.665 0.337 1.313 0.240 IOP at time of second surgery (mmHg) ≤ 30 120 (73.2) 1 1 > 30 44 (26.8) 1.802 1.064 3.053 0.029 2.329 1.321 4.106 0.003 HR= Hazard Ratio, CI= Confidence Interval, VCO = Viscocanalostomy, retbo=repeat trabeculotomy Hyphema was present in the majority of eyes on day one but resolved spontaneously in all cases. One eye in each group developed iatrogenic cyclodialysis, which was surgically repaired after one month of cycloplegic therapy. No other major complications—such as shallow anterior chamber, choroidal effusion or hemorrhage, cataract, or infection—occurred. No filtering bleb formation was observed in any patient. Discussion We previously reported mid-term results of VCO+retbo in PCG with prior failed angle surgery [ 14 ]. To our knowledge, all other NPGS studies in PCG involved virgin eyes. This is the first to investigate retbo alone and compare it with VCO+retbo in eyes with one prior failed trabeculotomy. Therefore, it is not possible to compare and contrast our results with other studies. After about 30 months of follow up, 31.7% of the VCO+retbo and 37.8% of retbo patients had IOP greater than 21mmHg despite medications and required AGV implantation. This difference is neither statistically nor clinically significant. After failure of traditional trabeculotomy in PCG, it can be repeated in quadrants that are still intact. NPGS including deep sclerectomy (DS) and viscocanalostomy (VCO) either alone or combined with angle surgery are also slowly making their way into the literature for the treatment of PCG [ 3 , 15 ]. Tamcelik et al in 2007 have compared 3 year results of VCO + tbo with tbo in untreated PCG eyes. Using a success criterion of IOP less than 18 mmHg, viscotrabeculotomy yielded a significantly higher success rate than trabeculotomy alone (91.3% vs. 68.6%). The authors concluded that viscodilation of Schlemm's canal substantially improves trabeculotomy outcomes in PCG patients [ 16 ]. However, we could not confirm a beneficial effect of adding VCO to trabeculotomy in previously treated eyes. In patients resistant to angle surgery, dilating Schlemm's canal or collecting channels with OVD may not sufficiently reduce intrinsic resistance to effectively lower IOP. Tamçelik et al., in a later investigation, again integrated 360-degree viscodilation with conventional trabeculotomy with the aim of improving surgical outcomes in both primary and secondary congenital glaucoma.Their reported success rate (IOP < 18 mmHg) was 94.4% after about 28 months [ 17 ]. Elwehidy, A and colleagues have reported 3 year results of an RCT in PCG eyes comparing combination of VCO with either circumferential or rigid probe tbo. IOP was significantly lower at almost all follow-up visits in eyes that underwent complete angle treatment (P < 0.001). The 1-, 2-, and 3-year cumulative success rates were 100%, 95%, and 90% for VCO+circumferential trabeculotomy, and 100%, 97.7%, and 84% for VCO+rigid probe trabeculotomy. The more extensive the treated angle, the better [ 18 ]. In contrast, the success rate of VCO with rigid probe tbo in our study was lower (1 (95% CI: 1 to 1), 0.750 (95% CI: 0.645 to 0.873) and 0.435 (95% CI: 0.322 to 0.590) in 1, 2 and 3 years). This is probably because our patients had previously undergone failed trabeculectomy and were therefore more resistant to treatment. The same group, in another study, reported the results of combining VCO with circumferential tbo or rigid probe tbo in neonatal PCG. VCO + tbo was successful in 43.5% of the eyes in 4 years (near to our results) [ 19 ]. This was probably because neonatal PCGs are usually more resistant to treatment and may be more similar to our population group. In a recent study by our group, we compared VCO + tbo with tbo in virgin eyes of young (< 20 year old) patients with late-onset primary congenital, juvenile open-angle, steroid-induced, and pigmentary glaucoma. At the last visit, we had a better success rate in the combination group (complete and qualified success rate was 43.9% and 34.1% in the VCO + tbo and 46.8% and 10.6% in the tbo (p = 0.04)(, but the number of medication used was similar [ 20 ]. Qian et al., performed VCO + tbo using adjuvant mitomycin C in untreated PCG eyes. IOP dropped to less than 21mmHg with or without medications in 100%, 95.5% and 68.6% of cases 1, 2, and 2.5 years [ 12 ]. Liang et al. combined viscocanalostomy with nearly 360-degree suture trabeculotomy in PCG eyes, all of which were virgin eyes with no previous surgery. At 9 months, all eyes achieved IOP < 21 mmHg, with 87.5% being medication-free.[ 11 ] In our study, just 8 eyes (9.8%) of VCO+retbo and 27 eyes (32.9%) of retbo group were successfully controlled without medication while 58.5% (48 eyes) in VCO+retbo and 29.3% (24 eyes) in retbo group had medically controlled IOP at last follow-up (p < 0.001). Final IOP was similar between groups, but the retbo group required fewer medications at all time points. Medication initiation was at the physician's discretion based on IOP and disease progression signs (C/D ratio, myopia, corneal edema), with no standardized protocol. Thus, had the retbo group received the same medication amount as the VCO+retbo group, they might have achieved even lower IOP. However, this remains an unverified assumption. In both univariable and multivariable analysis, only IOP at second surgery predicted outcome; eyes with IOP > 30 mmHg responded less favorably. Higher IOP at second surgery reflects poorer initial surgical response and inherently greater treatment resistance. Age at onset was not a predictive factor, probably due to the predominance of neonatal-onset cases and the small sample sizes in the remaining age groups. Our study has limitations. The small number of patients in each age group reflects the rarity of PCG and the even rarer occurrence of non-response to initial angle surgery. Furthermore, corneal opacity precluded gonioscopic examination in most cases, preventing documentation of detailed trabecular meshwork and ciliary body findings. Conclusions In summary, it can be said at least that in terms of success, adding VCO to retbo in PCGs that have not responded adequately to a single traditional trabeculotomy does not have additional benefit. It is conceivable, however, that dissecting a deep flap, despite being technically difficult, may make it easier to find Schlemm's canal in the sometimes unusual anatomies of PCGs and their wide limbus. Abbreviations IOP Intraocular pressure PCG Primary Congenital Glaucoma retbo repeat trabeculotomy (retrabeculotomy) VCO Viscocanalostomy NPGS nonpenetrating glaucoma surgery VCO+retbo viscocanalostomy combined with retrabeculotomy C/D cup-to-disc Declarations Ethics approval and consent to participate: This study was done in Glaucoma Service, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran. The study was approved by the local ethics committee and adhered to the Declaration of Helsinki, with written consent from all guardians. The online version of the decree is publicly available at: https://ethics.research.ac.ir/IR.TUMS.FARABIH.REC.1402.009 Consent for publication: Not Applicable Availability of data and materials: The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request. Competing interests: The authors declare that they have no competing interests. Funding: No funding was received. Authors' contributions: GF and ZV performed the surgeries and examinations. MS Collected data and entered it into SPSS. MS and ZV analysed the data with the help of a statistician. MS prepared the primary draft. ZV and GF revised and wrote the final draft. Acknowledgements: Mehdi Yaseri, PhD from the department of epidemiology and biostatistics, school of public health, Tehran university of medical sciences, Tehran, Iran helped with the analysis. Ethics approval and consent to participate: The study was approved by the local ethics committee of Tehran University of Medical Sciences (IR. TUMS. FARABIH. REC. 1402.009). The online version of the decree is publicly available at: https://ethics.research.ac.ir/IR.TUMS.FARABIH.REC.1402.009. Written informed consent was secured from the guardians of all participants prior to enrollment. Funding: No funding was received for this study. Authors' contributions: GF and ZV performed the surgeries and examinations. MS Collected data and entered it into SPSS. MS and ZV analysed the data with the help of a statistician. MS prepared the primary draft. ZV and GF revised and wrote the final draft. Clinical trial number: Not applicable. References Allingham RR, Damji K, Freeman S, Moroi S, Shafranov G. Congenital glaucomas and developmental glaucomas with associated anomalies. In: Allingham RR, Damji KF, Freedman S, Moroi AE, Rhee DJ, editors (2005) Shields Textbook of Glaucoma. 5 ed. 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Journal of American Association for Pediatric Ophthalmology and Strabismus 3(2):117–24. Morales J, Al Shahwan S, Al Odhayb S, Al Jadaan I, Edward DP (2013) Current surgical options for the management of pediatric glaucoma. Journal of Ophthalmology 2013(1):763735. Mendrinos E, Mermoud A, Shaarawy T (2008) Nonpenetrating glaucoma surgery. Survey of ophthalmology 53(6):592–630. Rulli E, Biagioli E, Riva I, Gambirasio G, De Simone I, Floriani I, et al (2013) Efficacy and safety of trabeculectomy vs nonpenetrating surgical procedures: a systematic review and meta-analysis. JAMA ophthalmology 131(12):1573–82. Liang Y, Yu Q, Ji F, Sun H, Yuan Z. Viscocanalostomy combined with nearly 360-degree suture trabeculotomy for the treatment of primary congenital glaucoma: a preliminary report of a novel technique for trabeculotomy (2020) Graefe’s Archive for Clinical and Experimental Ophthalmology 258(2):379–86. Qian CX, Zong Y, Chen Q, Yuan ZL (2017) Viscocanalostomy combined with trabeculotomy and mitomycin C in the treatment of primary congenital glaucoma. International Journal of Ophthalmology 10(6):919. Varadaraj V, Munoz B, Karaoui M, Collins ME, Aljasim LA, Al Naji E, et al (2018) Effect of Chloral Hydrate Sedation on Intraocular Pressure in a Pediatric Population. American Journal of Ophthalmology 1;194:126–33. Vahedian Z, Fakhraie G, Ahmed AH (2022) Viscocanalostomy combined with trabeculotomy for management of refractory primary congenital glaucoma. Journal of American Association for Pediatric Ophthalmology and Strabismus 26(3):121-e1. Abdelrahman AM (2024) Non-penetrating Glaucoma Surgery. In: El Sayed YM, Elhusseiny AM, editors. Childhood Glaucoma: Current Trends and Future Prospects [Internet]. Cham: Springer International Publishing 289–97. Available from: https://doi.org/10.1007/978-3-031-61073-8_21 Tamcelik N, Özkiris A (2008) Long-term results of viscotrabeculotomy in congenital glaucoma: comparison to classical trabeculotomy. British journal of ophthalmology 92(1):36–9. Tamçelik N, Capar O, Atalay E (2019) Modified viscotrabeculotomy with microcatheter: our technique and experience in the surgical management of glaucoma. Journal of Current Glaucoma Practice 13(3):88. Elwehidy AS, Bayoumi NH, Abd Elfattah D, Hagras SM (2022) Surgical outcomes of visco-circumferential-suture-trabeculotomy versus rigid probe trabeculotomy in primary congenital glaucoma: a 3-year randomized controlled study. Journal of Glaucoma 31(1):48–53. Elwehidy AS, Bayoumi NHL, Elzeini RM, Abdelkader A (2023) Visco-Circumferential-Suture-Trabeculotomy Versus Rigid-Probe Viscotrabeculotomy in Neonatal-Onset Primary Congenital Glaucoma. Journal of Glaucoma 2023;32(9). Fakhraie G, Ansari S, Tabatabaei SM, Hamzeh N, Vahedian Z, Beikmarzehei A (2025) Modified viscotrabeculotomy versus modified trabeculotomy in late-onset primary congenital, juvenile, and secondary open-angle glaucoma. European Journal of Ophthalmology 1;35(2):618–26. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Reviewers agreed at journal 23 May, 2026 Reviewers agreed at journal 22 May, 2026 Reviewers agreed at journal 22 May, 2026 Reviewers invited by journal 07 May, 2026 Editor invited by journal 30 Apr, 2026 Editor assigned by journal 29 Apr, 2026 Submission checks completed at journal 29 Apr, 2026 First submitted to journal 27 Apr, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {\"props\":{\"pageProps\":{\"initialData\":{\"identity\":\"rs-9539983\",\"acceptedTermsAndConditions\":true,\"allowDirectSubmit\":false,\"archivedVersions\":[],\"articleType\":\"Research Article\",\"associatedPublications\":[],\"authors\":[{\"id\":641659137,\"identity\":\"bfe36646-11d5-4eff-a648-df816b6a38a0\",\"order_by\":0,\"name\":\"Zakieh Vahedian\",\"email\":\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA3ElEQVRIiWNgGAWjYFACHiAyADGYDwAJCRlStLAlgLTwEKkFwjCAcgkAg+NnDz54U2CXx8B/5vOrGzUWPAzsh49uwKvlTF6y4RyD5GIGhrPbrHOOAR3Gk5Z2A58WyYYcM2keA+bEBsbebcY5bEAtEjxm+LX0vzH/zWNQn9jAzPPMOOcfEVr4JXLMmHkMDic2sPEwP85tI0rLG2PJOQbHE9t42MyYc/skeNgI+YWNP8fww5s/1Yn9/Icff875VifHz374GF4tCL1AJAFlEA+YP5CiehSMglEwCkYOAABgGz7mxRXLkgAAAABJRU5ErkJggg==\",\"orcid\":\"\",\"institution\":\"Farabi Eye Hospital\",\"correspondingAuthor\":true,\"prefix\":\"\",\"firstName\":\"Zakieh\",\"middleName\":\"\",\"lastName\":\"Vahedian\",\"suffix\":\"\"},{\"id\":641659138,\"identity\":\"b7345517-37e3-4aae-b39b-79d9f1baaae4\",\"order_by\":1,\"name\":\"Ghasem Fakhraie\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Farabi Eye Hospital\",\"correspondingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Ghasem\",\"middleName\":\"\",\"lastName\":\"Fakhraie\",\"suffix\":\"\"},{\"id\":641659140,\"identity\":\"f37fd425-5887-413f-bbcf-a16f7d4024c3\",\"order_by\":2,\"name\":\"Mahsan Samadi\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Farabi Eye Hospital\",\"correspondingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Mahsan\",\"middleName\":\"\",\"lastName\":\"Samadi\",\"suffix\":\"\"}],\"badges\":[],\"createdAt\":\"2026-04-27 10:09:39\",\"currentVersionCode\":1,\"declarations\":\"\",\"doi\":\"10.21203/rs.3.rs-9539983/v1\",\"doiUrl\":\"https://doi.org/10.21203/rs.3.rs-9539983/v1\",\"draftVersion\":[],\"editorialEvents\":[],\"editorialNote\":\"\",\"failedWorkflow\":false,\"files\":[{\"id\":109435313,\"identity\":\"d3ed2a3a-d417-4153-8a7a-e343c9a8bddd\",\"added_by\":\"auto\",\"created_at\":\"2026-05-18 06:01:43\",\"extension\":\"png\",\"order_by\":1,\"title\":\"Figure 1\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":107034,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003eKaplan-Meier curve representing probability of total success of viscocanalostomy combined with trabeculotomy and retrabeculotomy after one failed trabeculotomy\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"figure1.png\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-9539983/v1/3254deb60354301b652e2b5d.png\"},{\"id\":109799749,\"identity\":\"173957ad-b0fc-4392-bd26-a675abf9125f\",\"added_by\":\"auto\",\"created_at\":\"2026-05-22 15:33:45\",\"extension\":\"pdf\",\"order_by\":0,\"title\":\"\",\"display\":\"\",\"copyAsset\":false,\"role\":\"manuscript-pdf\",\"size\":372631,\"visible\":true,\"origin\":\"\",\"legend\":\"\",\"description\":\"\",\"filename\":\"manuscript.pdf\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-9539983/v1/b494cad0-73ef-463f-b69c-ccadb966703a.pdf\"}],\"financialInterests\":\"No competing interests reported.\",\"formattedTitle\":\"Combined viscocanalostomy and retrabeculotomy versus retrabeculotomy for management of refractory primary congenital glaucoma: A Comparative study\",\"fulltext\":[{\"header\":\"Background\",\"content\":\"\\u003cp\\u003eBecause primary congenital glaucoma (PCG) is fundamentally a problem of angle development\\u0026mdash;specifically, maldevelopment of the trabecular meshwork [\\u003cspan citationid=\\\"CR1\\\" class=\\\"CitationRef\\\"\\u003e1\\u003c/span\\u003e]\\u0026mdash;it makes sense that the first line of defense is angle surgery, which generally works very well [\\u003cspan citationid=\\\"CR2\\\" class=\\\"CitationRef\\\"\\u003e2\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR3\\\" class=\\\"CitationRef\\\"\\u003e3\\u003c/span\\u003e]. The real difficulty for surgeons arises when that first surgery fails, leaving them to manage complex cases that do not respond adequately.\\u003c/p\\u003e \\u003cp\\u003eSeveral options remain for managing these challenging cases. Surgeons may attempt angle surgery again at a different site, or they may opt for filtering procedures like trabeculectomy or the implantation of a drainage device. One strategy to improve outcomes has been to combine different surgical approaches. For instance, trabeculectomy has been combined with trabeculotomy [\\u003cspan citationid=\\\"CR3\\\" class=\\\"CitationRef\\\"\\u003e3\\u003c/span\\u003e]. However, because trabeculectomy is a penetrating procedure that creates a full-thickness opening into the eye, it carries inherent risks. These can include vision-threatening complications such as shallow anterior chamber [\\u003cspan citationid=\\\"CR4\\\" class=\\\"CitationRef\\\"\\u003e4\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR5\\\" class=\\\"CitationRef\\\"\\u003e5\\u003c/span\\u003e], hypotony, retinal detachment [\\u003cspan citationid=\\\"CR5\\\" class=\\\"CitationRef\\\"\\u003e5\\u003c/span\\u003e], choroidal effusion [\\u003cspan citationid=\\\"CR4\\\" class=\\\"CitationRef\\\"\\u003e4\\u003c/span\\u003e], and hemorrhage. Additionally, because it relies on the formation of a filtering bleb, patients are also at risk for bleb-related issues like leaks, infection [\\u003cspan citationid=\\\"CR6\\\" class=\\\"CitationRef\\\"\\u003e6\\u003c/span\\u003e], overhanging blebs, and dysesthesia [\\u003cspan citationid=\\\"CR4\\\" class=\\\"CitationRef\\\"\\u003e4\\u003c/span\\u003e, \\u003cspan additionalcitationids=\\\"CR7\\\" citationid=\\\"CR6\\\" class=\\\"CitationRef\\\"\\u003e6\\u003c/span\\u003e\\u0026ndash;\\u003cspan citationid=\\\"CR8\\\" class=\\\"CitationRef\\\"\\u003e8\\u003c/span\\u003e].\\u003c/p\\u003e \\u003cp\\u003eIn contrast, nonpenetrating glaucoma surgeries (NPGS) were developed to avoid many of these complications. Procedures like viscocanalostomy (VCO) aim to lower intraocular pressure by enhancing the eye's natural outflow pathways [\\u003cspan citationid=\\\"CR9\\\" class=\\\"CitationRef\\\"\\u003e9\\u003c/span\\u003e]. Given their better safety profile [\\u003cspan citationid=\\\"CR10\\\" class=\\\"CitationRef\\\"\\u003e10\\u003c/span\\u003e], combining NPGS with trabeculotomy is a logical approach for congenital glaucoma [\\u003cspan citationid=\\\"CR11\\\" class=\\\"CitationRef\\\"\\u003e11\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR12\\\" class=\\\"CitationRef\\\"\\u003e12\\u003c/span\\u003e]. In our experience, unroofing Schlemm's canal during these procedures facilitates trabeculotomy. Based on this rationale, we compared VCO+retrabeculotomy (VCO+retbo) versus retrabeculotomy alone (retbo) in PCG patients with prior failed angle surgery. Unlike previous studies limited to virgin eyes, this is the first to evaluate this combination in truly refractory cases.\\u003c/p\\u003e\"},{\"header\":\"Methods\",\"content\":\"\\u003cp\\u003eThis interventional comparative investigation comprised a cohort of pediatric patients with PCG who had previously undergone inferotemporal trabeculotomy utilizing a Harms metal probe and had demonstrated an insufficient therapeutic response. The study protocol was approved by the institutional ethics committee and conformed to the principles outlined in the Declaration of Helsinki. Written informed consent was secured from the guardians of all participants prior to enrollment.\\u003c/p\\u003e \\u003cp\\u003eAll eyes in the study had undergone inferotemporal trabeculotomy utilizing a Harms metal probe as their primary surgical intervention. Failure of this initial procedure was defined as the persistence of IOP above the predetermined target level despite maximal tolerable topical therapy, typically in conjunction with persistent corneal edema and/or deterioration of the cup-to-disc ratio. The duration between the primary trabeculotomy and the subsequent surgical intervention was recorded for each case.\\u003c/p\\u003e \\u003cp\\u003eAssignment to the second surgical method\\u0026mdash;either viscocanalostomy combined with retrabeculotomy (VCO+retbo) or retrabeculotomy alone (retbo)\\u0026mdash;was performed sequentially. The initial trabeculotomies were conducted by one of two surgeons (ZV or GF), and continuity of care was maintained such that each patient's second procedure was performed by the same surgeon who had performed the primary surgery.\\u003c/p\\u003e \\u003cp\\u003eThe diagnosis of PCG was established according to the following criteria: an intraocular pressure (IOP) of 21 mmHg or greater; glaucomatous optic disc neuropathy, defined as a cup-to-disc (C/D) ratio exceeding 0.6 or the presence of notching when fundal examination was feasible at presentation; and corneal enlargement, which may or may not have been accompanied by Haab striae. At initial presentation, corneal clouding was observed in the majority of patients, and a significant proportion also presented with epiphora, photophobia, and blepharospasm. Owing to the prevalence of corneal opacity, gonioscopic examination was not possible in most cases.\\u003c/p\\u003e \\u003cp\\u003eThe following criteria led to exclusion from the study: the presence of anterior segment anomalies consistent with developmental disorders such as Axenfeld-Rieger syndrome, aniridia, or Sturge-Weber syndrome; diagnosis of secondary glaucoma; a history of any ocular surgical intervention other than trabeculotomy; and cases in which guardians did not provide written informed consent for the procedure.\\u003c/p\\u003e \\u003cp\\u003eRegarding follow-up duration, eyes with less than one year of postoperative observation after the second surgery were excluded from the final analysis. However, any case that met the criteria for failure within that initial twelve-month period was included in the analysis.\\u003c/p\\u003e \\u003cp\\u003eFor young children and those unable to cooperate during examination, sedation was achieved using oral chloral hydrate, and tonometry was carried out immediately following the onset of sleep [\\u003cspan citationid=\\\"CR13\\\" class=\\\"CitationRef\\\"\\u003e13\\u003c/span\\u003e]. Cooperative children were examined using standard clinic-based procedures.\\u003c/p\\u003e \\u003cp\\u003ePre-Operative Examinations\\u003c/p\\u003e \\u003cp\\u003eThe baseline ophthalmic evaluation comprised the following assessments: IOP measurement using the TONO-Pen AVIA (Reichert, NY, USA); horizontal corneal diameter determined with callipers; documentation of corneal status with respect to opacification or edema; identification of Haab striae; evaluation of anterior chamber depth, iris configuration, lens status, and pupillary characteristics (reactivity and shape). In cases where corneal clarity was sufficient to permit visualization, optic nerve head examination was conducted via indirect ophthalmoscopy using a 30D lens to determine C/D ratio, and cycloplegic refraction was also performed.\\u003c/p\\u003e \\u003cdiv id=\\\"Sec3\\\" class=\\\"Section2\\\"\\u003e \\u003ch2\\u003eSurgical Procedure and Follow- Up\\u003c/h2\\u003e \\u003cp\\u003eA 7\\u0026thinsp;\\u0026minus;\\u0026thinsp;0 Vicryl corneal traction suture was placed to facilitate inferior rotation of the globe, thereby exposing the superonasal quadrant. This positioning ensured that the second surgical site was situated 180 degrees from the location of the initial trabeculotomy. A fornix-based conjunctival peritomy was subsequently performed.\\u003c/p\\u003e \\u003cp\\u003eIn retbo group, a half-thickness scleral flap measuring 3\\u0026times;3 mm was created. Following identification of the Schlemm canal, its outer wall was incised. A Harms trabeculotome was then introduced into the canal, advanced carefully, and gently rotated into the anterior chamber.\\u003c/p\\u003e \\u003cp\\u003eIn VCO+retbo group, a superficial rectangular scleral flap (4\\u0026times;4 mm) of approximately one-third scleral thickness was dissected, extending 1.5-2 mm into clear cornea. A deep scleral flap was then dissected anteriorly until the Schlemm canal was unroofed and approximately 0.5-1 mm of Descemet's membrane was exposed. High-molecular-weight sodium hyaluronate (Healon GV, Pfizer, New York) was injected into both ostia of the Schlemm canal using a 30-gauge cannula. A Harms metal trabeculotome was subsequently inserted into the canal openings, advanced with care, and rotated into the anterior chamber. The deep scleral flap was then excised.\\u003c/p\\u003e \\u003cp\\u003eIn both groups, the overlying scleral flap and conjunctiva were meticulously closed with 8\\u0026thinsp;\\u0026minus;\\u0026thinsp;0 Vicryl suture. The anterior chamber was finally irrigated and reformed with balanced salt solution.\\u003c/p\\u003e \\u003cp\\u003eThe postoperative pharmacological regimen was standardized across both treatment groups. This consisted of topical Betamethasone administered for one month, Chloramphenicol for one week, and Pilocarpine 1% for two weeks. Supplementary anti-glaucoma medications were prescribed as clinically indicated.\\u003c/p\\u003e \\u003cp\\u003ePostoperative assessments were done on day one; at 1, 3, 6, and 12 months; and then annually, with additional visits as needed. At each evaluation, IOP, C/D ratio, corneal clarity, and diameter were recorded. All complications were documented and managed. Eyes with inadequate IOP control despite maximal therapy underwent Ahmed valve implantation by the same surgeon.\\u003c/p\\u003e \\u003cp\\u003eComplete success was defined as IOP 6\\u0026ndash;21 mmHg with \\u0026ge;\\u0026thinsp;20% reduction without medication; qualified success met the same IOP criteria with medication.\\u003c/p\\u003e \\u003c/div\\u003e \\u003cdiv id=\\\"Sec4\\\" class=\\\"Section2\\\"\\u003e \\u003ch2\\u003eStatistical Analysis\\u003c/h2\\u003e \\u003cp\\u003eDescriptive statistics (mean, SD, median, range, frequency, percentage, 95% CI) were used. Group comparisons employed Chi-square/Fisher's exact tests for categorical variables and t-test/Mann-Whitney U for continuous variables. Longitudinal changes were assessed via paired t-test or Wilcoxon signed-rank test; time-group interactions were evaluated using linear mixed models.\\u003c/p\\u003e \\u003cp\\u003eTime-to-event analysis was conducted employing the Kaplan-Meier method to estimate the mean survival time of IOP control. The relationship between potential prognostic factors and surgical failure was investigated using both univariate and multivariable Cox proportional hazards regression models. The covariates included in the regression analysis were: type of second procedure (VCO+retbo versus retbo), gender, age at disease onset, age at second surgery, and intraocular pressure at the time of second surgery (dichotomized as \\u0026le;\\u0026thinsp;30 mmHg or \\u0026gt;\\u0026thinsp;30 mmHg). Recognizing the potential non-linear relationship between age and surgical outcomes, age at onset and age at surgery were stratified into four ordinal categories: less than 1 month, 1 to 6 months, 6 to 12 months, and greater than 12 months. The strength of association between these variables and failure was expressed as hazard ratios (HR) from univariate analysis and adjusted hazard ratios from multivariable analysis, each with corresponding 95% confidence intervals.\\u003c/p\\u003e \\u003cp\\u003eAll statistical computations were performed using SPSS software (Version 27.0, IBM Corp., Armonk, NY, USA). A probability (p) value of less than 0.05 was deemed to indicate statistical significance.\\u003c/p\\u003e \\u003c/div\\u003e\"},{\"header\":\"Results\",\"content\":\"\\u003cp\\u003eA total of 164 eyes with PCG were enrolled in this study, comprising 82 eyes in each treatment arm. All eyes completed a minimum follow-up period of 12 months and were included in the final analysis. The baseline demographic and clinical characteristics of the study population are summarized in Table\\u0026nbsp;\\u003cspan refid=\\\"Tab1\\\" class=\\\"InternalRef\\\"\\u003e1\\u003c/span\\u003e. Of note, there were no statistically significant differences between the VCO+retbo and retbo groups with respect to baseline IOP or the number of glaucoma medications. Mean follow-up time was 30.36\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;13.38 months (31.52\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;10.61 in VCO+retbo and 29.07\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;15.91 in tbo p\\u0026thinsp;=\\u0026thinsp;0.281). In successful eyes, IOP dropped from 28.52\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;6.06 to 16.2\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;2.94 mmHg and from 27.35\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;5.29 to 17.67\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;4.35 mmHg in VCO+retbo and retbo and the number of medications changed from 2.70\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;0.78 to 2.04\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;1.03 and 2.69\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;0.97 to 0.98\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;1.10 in the two groups respectively (all p-values\\u0026thinsp;\\u0026lt;\\u0026thinsp;0.001 for pre-post operative changes). Last visit IOP was not significantly different in successful eyes in the 2 groups, whereas the retbo eyes required less medications for IOP control (p\\u0026thinsp;\\u0026lt;\\u0026thinsp;0.001). Because the final follow-up time was highly variable among patients, for ease of analysis, patients were divided into three groups based on the time of the last visit: less than two years (50 eyes), two to three years (71 eyes), and more than three years (43 eyes). There was a marginally significant difference in last visit IOP, in favor of VCO+retbo, in eyes followed up for 2\\u0026ndash;3 years but no difference in those followed up less than 2 or more than 3 years (Table \\u003cspan refid=\\\"Tab2\\\" class=\\\"InternalRef\\\"\\u003e2\\u003c/span\\u003e). Eyes that underwent VCO+retbo showed greater pressure reduction than retbo in patients with less than two years of follow up (-15.63\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;8.26 vs -8.70\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;8.26 mmHg, p\\u0026thinsp;=\\u0026thinsp;0.018) (Table \\u003cspan refid=\\\"Tab2\\\" class=\\\"InternalRef\\\"\\u003e2\\u003c/span\\u003e).\\u003c/p\\u003e \\u003cp\\u003e \\u003cdiv class=\\\"gridtable\\\"\\u003e\\u003ctable float=\\\"Yes\\\" id=\\\"Tab1\\\" border=\\\"1\\\"\\u003e \\u003ccaption language=\\\"En\\\"\\u003e \\u003cdiv class=\\\"CaptionNumber\\\"\\u003eTable 1\\u003c/div\\u003e \\u003cdiv class=\\\"CaptionContent\\\"\\u003e \\u003cp\\u003eDemographic and clinical characteristics of the patients\\u003c/p\\u003e \\u003c/div\\u003e \\u003c/caption\\u003e \\u003ccolgroup cols=\\\"4\\\"\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c1\\\" colnum=\\\"1\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"char\\\" char=\\\"\\u0026plusmn;\\\" class=\\\"colspec\\\" colname=\\\"c2\\\" colnum=\\\"2\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c3\\\" colnum=\\\"3\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"char\\\" char=\\\".\\\" class=\\\"colspec\\\" colname=\\\"c4\\\" colnum=\\\"4\\\"\\u003e\\u003c/div\\u003e \\u003cthead\\u003e \\u003ctr\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c1\\\" morerows=\\\"1\\\" rowspan=\\\"2\\\"\\u003e \\u003cp\\u003eGroup\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003eVCO\\u0026thinsp;+\\u0026thinsp;retbo\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003eretbo\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c4\\\"\\u003e\\u0026nbsp;\\u003c/th\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003eMean\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;SD\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003eMean\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;SD\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003ep-value\\u003c/p\\u003e \\u003c/th\\u003e \\u003c/tr\\u003e \\u003c/thead\\u003e \\u003ctbody\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eAge at the time of first operation (week)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\"\\u0026plusmn;\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e11.2\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;28.5\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e8.9\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;28.5\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e0.604\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eInterval between the two operations (month)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\"\\u0026plusmn;\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e9.43\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;12.08\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e17.03\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;14.46\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e0.000\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eAge at the time of second operation (month)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\"\\u0026plusmn;\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e12.19\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;15.95\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e19.11\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;15.72\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e0.006\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eCCT (micron)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\"\\u0026plusmn;\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e593\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;74\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e559\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;51\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e0.005\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eMean SE RE (Diopter)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\"\\u0026plusmn;\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e-3.20\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;3.97\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e-1.90\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;2.78\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e0.037\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eCorneal diameter (mm)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\"\\u0026plusmn;\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e13.3\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;0.8\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e13.1\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;1.1\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e0.766\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eCup/Disc ratio\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\"\\u0026plusmn;\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e0.58\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;0.17\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e0.64\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;0.20\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e0.159\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eBaseline IOP (mmHg)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\"\\u0026plusmn;\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e29\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;7\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e28\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;6\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e0.124\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eBaseline medication number\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\"\\u0026plusmn;\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e2.63\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;0.76\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e2.72\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;0.89\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e0.290\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eGender (N(%))\\u003c/p\\u003e \\u003cp\\u003eMale\\u003c/p\\u003e \\u003cp\\u003eFemale\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e41 (50%)\\u003c/p\\u003e \\u003cp\\u003e41 (50%)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e43 (52.4%)\\u003c/p\\u003e \\u003cp\\u003e39 (47.6%)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e0.755\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eAge at Diagnosis (N (%))\\u003c/p\\u003e \\u003cp\\u003e\\u0026le;\\u0026thinsp;1m\\u003c/p\\u003e \\u003cp\\u003e1-6m\\u003c/p\\u003e \\u003cp\\u003e6-12m\\u003c/p\\u003e \\u003cp\\u003e\\u0026gt;\\u0026thinsp;12m\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e10 (12.2%)\\u003c/p\\u003e \\u003cp\\u003e55 (67.1%)\\u003c/p\\u003e \\u003cp\\u003e2 (2.4%)\\u003c/p\\u003e \\u003cp\\u003e15 18.3%)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e7 (8.5%)\\u003c/p\\u003e \\u003cp\\u003e58 (70.7%)\\u003c/p\\u003e \\u003cp\\u003e9 (11%)\\u003c/p\\u003e \\u003cp\\u003e8 (9.8%)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e0.063\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003c/tbody\\u003e \\u003c/colgroup\\u003e \\u003ctfoot\\u003e \\u003ctr\\u003e\\u003ctd colspan=\\\"4\\\"\\u003eIOP= Intraocular pressure, VCO= viscocanalostomy, retbo= repeat trabeculotomy, CCT= central corneal thickness, SE= spherical equivalent, RE= refractive error\\u003c/td\\u003e\\u003c/tr\\u003e \\u003c/tfoot\\u003e \\u003c/table\\u003e\\u003c/div\\u003e \\u003c/p\\u003e \\u003cp\\u003e \\u003cdiv class=\\\"gridtable\\\"\\u003e\\u003ctable float=\\\"Yes\\\" id=\\\"Tab2\\\" border=\\\"1\\\"\\u003e \\u003ccaption language=\\\"En\\\"\\u003e \\u003cdiv class=\\\"CaptionNumber\\\"\\u003eTable 2\\u003c/div\\u003e \\u003cdiv class=\\\"CaptionContent\\\"\\u003e \\u003cp\\u003eLast visit IOP, IOP change, number of medications and its change in successfully treated eyes.\\u003c/p\\u003e \\u003c/div\\u003e \\u003c/caption\\u003e \\u003ccolgroup cols=\\\"6\\\"\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c1\\\" colnum=\\\"1\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c2\\\" colnum=\\\"2\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c3\\\" colnum=\\\"3\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c4\\\" colnum=\\\"4\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c5\\\" colnum=\\\"5\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c6\\\" colnum=\\\"6\\\"\\u003e\\u003c/div\\u003e \\u003ctbody\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003eVCO\\u0026thinsp;+\\u0026thinsp;retbo\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003eretbo\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\" morerows=\\\"12\\\" rowspan=\\\"13\\\"\\u003e \\u003cp\\u003eFollow up time (months)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003eMean\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;SD\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003eMean\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;SD\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003ep-value\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\" morerows=\\\"1\\\" rowspan=\\\"2\\\"\\u003e \\u003cp\\u003e\\u0026le;\\u0026thinsp;24\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003eLast visit IOP\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e15.9\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;2.4\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e18.2\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;5.2\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e0.121\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003eLast visit IOP change\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e-15.63\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;8.26\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e-8.70\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;8.26\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003e0.018\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\" morerows=\\\"1\\\" rowspan=\\\"2\\\"\\u003e \\u003cp\\u003e25\\u0026ndash;36\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003eLast visit IOP\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e15.9\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;3.4\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e17.5\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;3.6\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003e0.047\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003eLast visit IOP change\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e-11.65\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;6.04\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e-10.58\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;6.19\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e0.531\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\" morerows=\\\"1\\\" rowspan=\\\"2\\\"\\u003e \\u003cp\\u003e\\u0026ge;\\u0026thinsp;37\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003eLast visit IOP\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e16.3\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;3.0\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e16.6\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;4.5\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e0.436\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003eLast visit IOP change\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e-10.85\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;6.26\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e-9.43\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;6.13\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e0.470\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\" morerows=\\\"1\\\" rowspan=\\\"2\\\"\\u003e \\u003cp\\u003e\\u0026le;\\u0026thinsp;24\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003eLast visit medication number\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e2.06\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;1\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e0.90\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;1.0\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003e0.002\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003eLast visit medication number change\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e-0.31\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;0.87\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e-1.1\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;1.0\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003e0.034\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\" morerows=\\\"1\\\" rowspan=\\\"2\\\"\\u003e \\u003cp\\u003e25\\u0026ndash;36\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003eLast visit medication number\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e2.1\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;1.1\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e1.08\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;1.2\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003e0.007\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003eLast visit medication number change\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e-0.60\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;1.4\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e-2.1\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;1.4\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003e0.002\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\" morerows=\\\"1\\\" rowspan=\\\"2\\\"\\u003e \\u003cp\\u003e\\u0026ge;\\u0026thinsp;37\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003eLast visit medication number\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e2.0\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;1.0\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e0.86\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;1.1\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003e0.027\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003eLast visit medication number change\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e-1.0\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;1.1\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e-2.1\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;1.8\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003e0.131\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003c/tbody\\u003e \\u003c/colgroup\\u003e \\u003ctfoot\\u003e \\u003ctr\\u003e\\u003ctd colspan=\\\"6\\\"\\u003eIOP= Intraocular pressure, VCO= viscocanalostomy, retbo= repeat trabeculotomy\\u003c/td\\u003e\\u003c/tr\\u003e \\u003c/tfoot\\u003e \\u003c/table\\u003e\\u003c/div\\u003e \\u003c/p\\u003e \\u003cp\\u003eAt last follow-up visit, 26 eyes [31.7%, (95% CI 22.4\\u0026ndash;42.3%(] of VCO+retbo and 31 eyes [37.8%, (95% CI 27.9\\u0026ndash;48.6%(] of retbo group met failure criteria (p\\u0026thinsp;=\\u0026thinsp;0.219); iatrogenic cyclodialysis leading to hypotony occurred in one eye from each group, both of which required surgical closure. Overall, complete success was achieved in only eight eyes [9.8%, (95% CI: 4.7\\u0026ndash;17.6%)] of VCO+retbo and 27 eyes [32.9%, (95% CI: 23.5\\u0026ndash;43.6%)] of retbo group and qualified success rate was 58.5% (48 eyes) (95% CI: 47.7\\u0026ndash;68.8%) in VCO+retbo and 29.3% (24 eyes) (95% CI: 20.3\\u0026ndash;39.7%) in retbo group at last follow-up (p\\u0026thinsp;\\u0026lt;\\u0026thinsp;0.001).\\u003c/p\\u003e \\u003cp\\u003eUsing Kaplan-Meier analysis, the mean survival time for surgical success was estimated at 51.1 (95% CI: 44.3\\u0026ndash;57.8) and 73 (95% CI: 54.4\\u0026ndash;91.6) months (p\\u0026thinsp;=\\u0026thinsp;0.290). The average time of failure was 9.8\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;8.5 (range 1\\u0026ndash;39) months in VCO+retbo and 11.2\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;9.9 (range 1\\u0026ndash;38) months in retbo group (p\\u0026thinsp;=\\u0026thinsp;0.729)\\u003c/p\\u003e \\u003cp\\u003eAlso, in VCO+retbo the survival rates were 1 (95% CI: 1 to 1), 0.750 (95% CI: 0.645 to 0.873) and 0.435 (95% CI: 0.322 to 0.590) in 1, 2 and 3 years respectively. In retbo, the survival rates were 0.905 (95% CI: 0.836 to 0.980), 0.847 (95% CI: 0.759 to 0.945) and 0.511 (95% CI: 0.373 to 0.699) in 1, 2 and 3 years respectively (p\\u0026thinsp;=\\u0026thinsp;0.290 based on Long Rank test) and remained relatively constant thereafter. Kaplan-Meier survival analysis results are depicted in Fig.\\u0026nbsp;1Patients were stratified into four subgroups according to age at disease onset: less than one month, one to six months, six to 12 months, and greater than 12 months. The number of eyes within each age category is detailed in Table\\u0026nbsp;\\u003cspan refid=\\\"Tab3\\\" class=\\\"InternalRef\\\"\\u003e3\\u003c/span\\u003e. It should be noted that all patients were older than one month at the time of the second surgical intervention.For calculating the predictive ability of type of second surgery (VCO+retbo vs retbo), gender, age at disease onset, age at second surgery and IOP at time of second surgery (\\u0026le;\\u0026thinsp;30 vs\\u0026thinsp;\\u0026gt;\\u0026thinsp;30 mmHg) in failure rate, univariable and multivariable cox regression analysis was done. The results are presented in Table \\u003cspan refid=\\\"Tab3\\\" class=\\\"InternalRef\\\"\\u003e3\\u003c/span\\u003e. In summary, only patients with IOP greater than 30 at the time of the second surgery faced a higher failure risk (HR\\u0026thinsp;=\\u0026thinsp;2.33, 95% CI: 1.33\\u0026ndash;4.11, P\\u0026thinsp;=\\u0026thinsp;0.003). No other variables emerged as significant predictors of failure.\\u003c/p\\u003e \\u003cp\\u003e \\u003cdiv class=\\\"gridtable\\\"\\u003e\\u003ctable float=\\\"Yes\\\" id=\\\"Tab3\\\" border=\\\"1\\\"\\u003e \\u003ccaption language=\\\"En\\\"\\u003e \\u003cdiv class=\\\"CaptionNumber\\\"\\u003eTable 3\\u003c/div\\u003e \\u003cdiv class=\\\"CaptionContent\\\"\\u003e \\u003cp\\u003eResults of univariate and multivariable regression analyses (failure as dependent variable)\\u003c/p\\u003e \\u003c/div\\u003e \\u003c/caption\\u003e \\u003ccolgroup cols=\\\"11\\\"\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c1\\\" colnum=\\\"1\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c2\\\" colnum=\\\"2\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c3\\\" colnum=\\\"3\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c4\\\" colnum=\\\"4\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c5\\\" colnum=\\\"5\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c6\\\" colnum=\\\"6\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c7\\\" colnum=\\\"7\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c8\\\" colnum=\\\"8\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c9\\\" colnum=\\\"9\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c10\\\" colnum=\\\"10\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c11\\\" colnum=\\\"11\\\"\\u003e\\u003c/div\\u003e \\u003ctbody\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eVariable\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\" morerows=\\\"2\\\" rowspan=\\\"3\\\"\\u003e \\u003cp\\u003eLevels\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\" morerows=\\\"2\\\" rowspan=\\\"3\\\"\\u003e \\u003cp\\u003eN (%)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colspan=\\\"4\\\" nameend=\\\"c7\\\" namest=\\\"c4\\\"\\u003e \\u003cp\\u003eUnivariable\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colspan=\\\"4\\\" nameend=\\\"c11\\\" namest=\\\"c8\\\"\\u003e \\u003cp\\u003eMultivariable\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\" morerows=\\\"1\\\" rowspan=\\\"2\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\" morerows=\\\"1\\\" rowspan=\\\"2\\\"\\u003e \\u003cp\\u003eHR\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colspan=\\\"2\\\" nameend=\\\"c6\\\" namest=\\\"c5\\\"\\u003e \\u003cp\\u003e95% CI\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\" morerows=\\\"1\\\" rowspan=\\\"2\\\"\\u003e \\u003cp\\u003eP\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c8\\\" morerows=\\\"1\\\" rowspan=\\\"2\\\"\\u003e \\u003cp\\u003eHR\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colspan=\\\"2\\\" nameend=\\\"c10\\\" namest=\\\"c9\\\"\\u003e \\u003cp\\u003e95% CI\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c11\\\" morerows=\\\"1\\\" rowspan=\\\"2\\\"\\u003e \\u003cp\\u003eP\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003eLower\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003eUpper\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c9\\\"\\u003e \\u003cp\\u003eLower\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c10\\\"\\u003e \\u003cp\\u003eUpper\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\" morerows=\\\"1\\\" rowspan=\\\"2\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003eSecond surgery type\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003eVCO+retbo\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e82 (50)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e1\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e1\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c9\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c10\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c11\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003eretbo\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e82 (50)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e1.321\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e0.782\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e2.231\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003e0.297\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e1.364\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c9\\\"\\u003e \\u003cp\\u003e0.744\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c10\\\"\\u003e \\u003cp\\u003e2.501\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c11\\\"\\u003e \\u003cp\\u003e0.315\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\" morerows=\\\"1\\\" rowspan=\\\"2\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003eSex\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003eMale\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e84 (51.2)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e1\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e1\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c9\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c10\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c11\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003eFemale\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e80 (48.8)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e0.679\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e0.400\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e1.154\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003e0.152\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e0.607\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c9\\\"\\u003e \\u003cp\\u003e0.351\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c10\\\"\\u003e \\u003cp\\u003e1.050\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c11\\\"\\u003e \\u003cp\\u003e0.074\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\" morerows=\\\"3\\\" rowspan=\\\"4\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003eAge at onset (month)\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003e\\u0026lt;\\u0026thinsp;1\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e118 (72)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e1\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e1\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c9\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c10\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c11\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003e1\\u0026ndash;6\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e36 (22)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e1.076\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e0.456\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e2.539\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003e0.868\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e1.386\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c9\\\"\\u003e \\u003cp\\u003e0.567\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c10\\\"\\u003e \\u003cp\\u003e3.389\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c11\\\"\\u003e \\u003cp\\u003e0.474\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003e6\\u0026ndash;12\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e4 (2.4)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e1.406\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e0.429\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e4.611\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003e0.574\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e2.104\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c9\\\"\\u003e \\u003cp\\u003e0.578\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c10\\\"\\u003e \\u003cp\\u003e7.665\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c11\\\"\\u003e \\u003cp\\u003e0.259\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003e\\u0026gt;\\u0026thinsp;12\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e6 (3.6)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e0.690\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e0.222\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e2.140\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003e0.520\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e0.694\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c9\\\"\\u003e \\u003cp\\u003e0.200\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c10\\\"\\u003e \\u003cp\\u003e2.410\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c11\\\"\\u003e \\u003cp\\u003e0.565\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\" morerows=\\\"2\\\" rowspan=\\\"3\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003eAge at the time of second surgery (month)\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003e1\\u0026ndash;6\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e67 (40.8)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e1\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e1\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c9\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c10\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c11\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003e6\\u0026ndash;12\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e29 (17.7)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e0.844\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e0.405\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e1.758\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003e0.651\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e0.678\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c9\\\"\\u003e \\u003cp\\u003e0.311\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c10\\\"\\u003e \\u003cp\\u003e1.477\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c11\\\"\\u003e \\u003cp\\u003e0.327\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003e\\u0026gt;\\u0026thinsp;12\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e68 (41.5)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e0.780\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e0.440\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e1.384\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003e0.396\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e0.665\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c9\\\"\\u003e \\u003cp\\u003e0.337\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c10\\\"\\u003e \\u003cp\\u003e1.313\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c11\\\"\\u003e \\u003cp\\u003e0.240\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\" morerows=\\\"1\\\" rowspan=\\\"2\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003eIOP at time of second surgery (mmHg)\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003e\\u0026le;\\u0026thinsp;30\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e120 (73.2)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e1\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e1\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c9\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c10\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c11\\\"\\u003e\\u0026nbsp;\\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003e\\u0026gt;\\u0026thinsp;30\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e44 (26.8)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e1.802\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e1.064\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003e3.053\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003e0.029\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e2.329\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c9\\\"\\u003e \\u003cp\\u003e1.321\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c10\\\"\\u003e \\u003cp\\u003e4.106\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c11\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003e0.003\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003c/tbody\\u003e \\u003c/colgroup\\u003e \\u003ctfoot\\u003e \\u003ctr\\u003e\\u003ctd colspan=\\\"11\\\"\\u003eHR= Hazard Ratio, CI= Confidence Interval, VCO\\u0026thinsp;=\\u0026thinsp;Viscocanalostomy, retbo=repeat trabeculotomy\\u003c/td\\u003e\\u003c/tr\\u003e \\u003c/tfoot\\u003e \\u003c/table\\u003e\\u003c/div\\u003e \\u003c/p\\u003e \\u003cp\\u003eHyphema was present in the majority of eyes on day one but resolved spontaneously in all cases. One eye in each group developed iatrogenic cyclodialysis, which was surgically repaired after one month of cycloplegic therapy. No other major complications\\u0026mdash;such as shallow anterior chamber, choroidal effusion or hemorrhage, cataract, or infection\\u0026mdash;occurred. No filtering bleb formation was observed in any patient.\\u003c/p\\u003e\"},{\"header\":\"Discussion\",\"content\":\"\\u003cp\\u003eWe previously reported mid-term results of VCO+retbo in PCG with prior failed angle surgery [\\u003cspan citationid=\\\"CR14\\\" class=\\\"CitationRef\\\"\\u003e14\\u003c/span\\u003e]. To our knowledge, all other NPGS studies in PCG involved virgin eyes. This is the first to investigate retbo alone and compare it with VCO+retbo in eyes with one prior failed trabeculotomy. Therefore, it is not possible to compare and contrast our results with other studies. After about 30 months of follow up, 31.7% of the VCO+retbo and 37.8% of retbo patients had IOP greater than 21mmHg despite medications and required AGV implantation. This difference is neither statistically nor clinically significant. After failure of traditional trabeculotomy in PCG, it can be repeated in quadrants that are still intact. NPGS including deep sclerectomy (DS) and viscocanalostomy (VCO) either alone or combined with angle surgery are also slowly making their way into the literature for the treatment of PCG [\\u003cspan citationid=\\\"CR3\\\" class=\\\"CitationRef\\\"\\u003e3\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR15\\\" class=\\\"CitationRef\\\"\\u003e15\\u003c/span\\u003e]. Tamcelik et al in 2007 have compared 3 year results of VCO\\u0026thinsp;+\\u0026thinsp;tbo with tbo in untreated PCG eyes. Using a success criterion of IOP less than 18 mmHg, viscotrabeculotomy yielded a significantly higher success rate than trabeculotomy alone (91.3% vs. 68.6%). The authors concluded that viscodilation of Schlemm's canal substantially improves trabeculotomy outcomes in PCG patients [\\u003cspan citationid=\\\"CR16\\\" class=\\\"CitationRef\\\"\\u003e16\\u003c/span\\u003e]. However, we could not confirm a beneficial effect of adding VCO to trabeculotomy in previously treated eyes. In patients resistant to angle surgery, dilating Schlemm's canal or collecting channels with OVD may not sufficiently reduce intrinsic resistance to effectively lower IOP. Tam\\u0026ccedil;elik et al., in a later investigation, again integrated 360-degree viscodilation with conventional trabeculotomy with the aim of improving surgical outcomes in both primary and secondary congenital glaucoma.Their reported success rate (IOP\\u0026thinsp;\\u0026lt;\\u0026thinsp;18 mmHg) was 94.4% after about 28 months [\\u003cspan citationid=\\\"CR17\\\" class=\\\"CitationRef\\\"\\u003e17\\u003c/span\\u003e]. Elwehidy, A and colleagues have reported 3 year results of an RCT in PCG eyes comparing combination of VCO with either circumferential or rigid probe tbo. IOP was significantly lower at almost all follow-up visits in eyes that underwent complete angle treatment (P\\u0026thinsp;\\u0026lt;\\u0026thinsp;0.001). The 1-, 2-, and 3-year cumulative success rates were 100%, 95%, and 90% for VCO+circumferential trabeculotomy, and 100%, 97.7%, and 84% for VCO+rigid probe trabeculotomy. The more extensive the treated angle, the better [\\u003cspan citationid=\\\"CR18\\\" class=\\\"CitationRef\\\"\\u003e18\\u003c/span\\u003e]. In contrast, the success rate of VCO with rigid probe tbo in our study was lower (1 (95% CI: 1 to 1), 0.750 (95% CI: 0.645 to 0.873) and 0.435 (95% CI: 0.322 to 0.590) in 1, 2 and 3 years). This is probably because our patients had previously undergone failed trabeculectomy and were therefore more resistant to treatment. The same group, in another study, reported the results of combining VCO with circumferential tbo or rigid probe tbo in neonatal PCG. VCO\\u0026thinsp;+\\u0026thinsp;tbo was successful in 43.5% of the eyes in 4 years (near to our results) [\\u003cspan citationid=\\\"CR19\\\" class=\\\"CitationRef\\\"\\u003e19\\u003c/span\\u003e]. This was probably because neonatal PCGs are usually more resistant to treatment and may be more similar to our population group. In a recent study by our group, we compared VCO\\u0026thinsp;+\\u0026thinsp;tbo with tbo in virgin eyes of young (\\u0026lt;\\u0026thinsp;20 year old) patients with late-onset primary congenital, juvenile open-angle, steroid-induced, and pigmentary glaucoma. At the last visit, we had a better success rate in the combination group (complete and qualified success rate was 43.9% and 34.1% in the VCO\\u0026thinsp;+\\u0026thinsp;tbo and 46.8% and 10.6% in the tbo (p\\u0026thinsp;=\\u0026thinsp;0.04)(, but the number of medication used was similar [\\u003cspan citationid=\\\"CR20\\\" class=\\\"CitationRef\\\"\\u003e20\\u003c/span\\u003e]. Qian et al., performed VCO\\u0026thinsp;+\\u0026thinsp;tbo using adjuvant mitomycin C in untreated PCG eyes. IOP dropped to less than 21mmHg with or without medications in 100%, 95.5% and 68.6% of cases 1, 2, and 2.5 years [\\u003cspan citationid=\\\"CR12\\\" class=\\\"CitationRef\\\"\\u003e12\\u003c/span\\u003e]. Liang et al. combined viscocanalostomy with nearly 360-degree suture trabeculotomy in PCG eyes, all of which were virgin eyes with no previous surgery. At 9 months, all eyes achieved IOP\\u0026thinsp;\\u0026lt;\\u0026thinsp;21 mmHg, with 87.5% being medication-free.[\\u003cspan citationid=\\\"CR11\\\" class=\\\"CitationRef\\\"\\u003e11\\u003c/span\\u003e]\\u003c/p\\u003e \\u003cp\\u003eIn our study, just 8 eyes (9.8%) of VCO+retbo and 27 eyes (32.9%) of retbo group were successfully controlled without medication while 58.5% (48 eyes) in VCO+retbo and 29.3% (24 eyes) in retbo group had medically controlled IOP at last follow-up (p\\u0026thinsp;\\u0026lt;\\u0026thinsp;0.001). Final IOP was similar between groups, but the retbo group required fewer medications at all time points. Medication initiation was at the physician's discretion based on IOP and disease progression signs (C/D ratio, myopia, corneal edema), with no standardized protocol. Thus, had the retbo group received the same medication amount as the VCO+retbo group, they might have achieved even lower IOP. However, this remains an unverified assumption.\\u003c/p\\u003e \\u003cp\\u003eIn both univariable and multivariable analysis, only IOP at second surgery predicted outcome; eyes with IOP\\u0026thinsp;\\u0026gt;\\u0026thinsp;30 mmHg responded less favorably. Higher IOP at second surgery reflects poorer initial surgical response and inherently greater treatment resistance. Age at onset was not a predictive factor, probably due to the predominance of neonatal-onset cases and the small sample sizes in the remaining age groups. Our study has limitations. The small number of patients in each age group reflects the rarity of PCG and the even rarer occurrence of non-response to initial angle surgery. Furthermore, corneal opacity precluded gonioscopic examination in most cases, preventing documentation of detailed trabecular meshwork and ciliary body findings.\\u003c/p\\u003e\"},{\"header\":\"Conclusions\",\"content\":\"\\u003cp\\u003eIn summary, it can be said at least that in terms of success, adding VCO to retbo in PCGs that have not responded adequately to a single traditional trabeculotomy does not have additional benefit. It is conceivable, however, that dissecting a deep flap, despite being technically difficult, may make it easier to find Schlemm's canal in the sometimes unusual anatomies of PCGs and their wide limbus.\\u003c/p\\u003e\"},{\"header\":\"Abbreviations\",\"content\":\"\\u003cdiv class=\\\"DefinitionList\\\"\\u003e \\u003cdiv class=\\\"DefinitionListEntry\\\"\\u003e \\u003cdiv class=\\\"Term\\\"\\u003eIOP\\u003c/div\\u003e \\u003cdiv class=\\\"Description\\\"\\u003e \\u003cp\\u003eIntraocular pressure\\u003c/p\\u003e \\u003c/div\\u003e \\u003c/div\\u003e \\u003cdiv class=\\\"DefinitionListEntry\\\"\\u003e \\u003cdiv class=\\\"Term\\\"\\u003ePCG\\u003c/div\\u003e \\u003cdiv class=\\\"Description\\\"\\u003e \\u003cp\\u003ePrimary Congenital Glaucoma\\u003c/p\\u003e \\u003c/div\\u003e \\u003c/div\\u003e \\u003cdiv class=\\\"DefinitionListEntry\\\"\\u003e \\u003cdiv class=\\\"Term\\\"\\u003eretbo\\u003c/div\\u003e \\u003cdiv class=\\\"Description\\\"\\u003e \\u003cp\\u003erepeat trabeculotomy (retrabeculotomy)\\u003c/p\\u003e \\u003c/div\\u003e \\u003c/div\\u003e \\u003cdiv class=\\\"DefinitionListEntry\\\"\\u003e \\u003cdiv class=\\\"Term\\\"\\u003eVCO\\u003c/div\\u003e \\u003cdiv class=\\\"Description\\\"\\u003e \\u003cp\\u003eViscocanalostomy\\u003c/p\\u003e \\u003c/div\\u003e \\u003c/div\\u003e \\u003cdiv class=\\\"DefinitionListEntry\\\"\\u003e \\u003cdiv class=\\\"Term\\\"\\u003eNPGS\\u003c/div\\u003e \\u003cdiv class=\\\"Description\\\"\\u003e \\u003cp\\u003enonpenetrating glaucoma surgery\\u003c/p\\u003e \\u003c/div\\u003e \\u003c/div\\u003e \\u003cdiv class=\\\"DefinitionListEntry\\\"\\u003e \\u003cdiv class=\\\"Term\\\"\\u003eVCO+retbo\\u003c/div\\u003e \\u003cdiv class=\\\"Description\\\"\\u003e \\u003cp\\u003eviscocanalostomy combined with retrabeculotomy\\u003c/p\\u003e \\u003c/div\\u003e \\u003c/div\\u003e \\u003cdiv class=\\\"DefinitionListEntry\\\"\\u003e \\u003cdiv class=\\\"Term\\\"\\u003eC/D\\u003c/div\\u003e \\u003cdiv class=\\\"Description\\\"\\u003e \\u003cp\\u003ecup-to-disc\\u003c/p\\u003e \\u003c/div\\u003e \\u003c/div\\u003e \\u003c/div\\u003e\"},{\"header\":\"Declarations\",\"content\":\"\\u003cul\\u003e\\n \\u003cli\\u003eEthics approval and consent to participate: This study was done in Glaucoma Service, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran. The study was approved by the local ethics committee and adhered to the Declaration of Helsinki, with written consent from all guardians. The online version of the decree is publicly available at: https://ethics.research.ac.ir/IR.TUMS.FARABIH.REC.1402.009\\u003c/li\\u003e\\n \\u003cli\\u003eConsent for publication: Not Applicable\\u003c/li\\u003e\\n \\u003cli\\u003eAvailability of data and materials: The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.\\u003c/li\\u003e\\n \\u003cli\\u003eCompeting interests: The authors declare that they have no competing interests.\\u003c/li\\u003e\\n \\u003cli\\u003eFunding: No funding was received.\\u003c/li\\u003e\\n \\u003cli\\u003eAuthors\\u0026apos; contributions: GF and ZV performed the surgeries and examinations. MS Collected data and entered it into SPSS. MS and ZV analysed the data with the help of a statistician. MS prepared the primary draft. ZV and GF revised and wrote the final draft.\\u003c/li\\u003e\\n \\u003cli\\u003eAcknowledgements: Mehdi Yaseri, PhD from the department of epidemiology and biostatistics, school of public health, Tehran university of medical sciences, Tehran, Iran helped with the analysis.\\u003c/li\\u003e\\n\\u003c/ul\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eEthics approval and consent to participate:\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eThe study was approved by the local ethics committee of Tehran University of Medical Sciences (IR. TUMS. FARABIH. REC. 1402.009). The online version of the decree is publicly available at: https://ethics.research.ac.ir/IR.TUMS.FARABIH.REC.1402.009. Written informed consent was secured from the guardians of all participants prior to enrollment.\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eFunding:\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eNo funding was received for this study.\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eAuthors\\u0026apos; contributions:\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eGF and ZV performed the surgeries and examinations. MS Collected data and entered it into SPSS. MS and ZV analysed the data with the help of a statistician. MS prepared the primary draft. ZV and GF revised and wrote the final draft.\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eClinical trial number:\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eNot applicable.\\u003c/p\\u003e\"},{\"header\":\"References\",\"content\":\"\\u003col\\u003e\\n \\u003cli\\u003eAllingham RR, Damji K, Freeman S, Moroi S, Shafranov G. Congenital glaucomas and developmental glaucomas with associated anomalies. In: Allingham RR, Damji KF, Freedman S, Moroi AE, Rhee DJ, editors (2005) Shields Textbook of Glaucoma. 5 ed. Philadelphia, PA: Lippincott Williams \\u0026amp; Wilkins 235\\u0026ndash;71.\\u0026nbsp;\\u003c/li\\u003e\\n \\u003cli\\u003ePapadopoulos M, Edmunds B, Fenerty C, Khaw PT (2014) Childhood glaucoma surgery in the 21st century. Eye 28(8):931\\u0026ndash;43.\\u0026nbsp;\\u003c/li\\u003e\\n \\u003cli\\u003eTan YL, Chua J, Ho CL (2016) Updates on the surgical management of pediatric glaucoma. The Asia-Pacific Journal of Ophthalmology 5(1):85\\u0026ndash;92.\\u0026nbsp;\\u003c/li\\u003e\\n \\u003cli\\u003eBeck AD, Wilson WR, Lynch MG, Lynn MJ, Noe R (1998) Trabeculectomy with adjunctive mitomycin C in pediatric glaucoma. American journal of ophthalmology 126(5):648\\u0026ndash;57.\\u0026nbsp;\\u003c/li\\u003e\\n \\u003cli\\u003eMandal AK, Prasad K, Naduvilath TJ (1999) Surgical results and complications of mitomycin C-augmented trabeculectomy in refractory developmental glaucoma. Ophthalmic Surgery, Lasers and Imaging Retina 30(6):473\\u0026ndash;80.\\u0026nbsp;\\u003c/li\\u003e\\n \\u003cli\\u003eSidoti PA, Belmonte SJ, Liebmann JM, Ritch R (2000) Trabeculectomy with mitomycin-C in the treatment of pediatric glaucomas. Ophthalmology 107(3):422\\u0026ndash;9.\\u0026nbsp;\\u003c/li\\u003e\\n \\u003cli\\u003eFreedman SF, McCormick K, Cox TA (1999) Mitomycin C-augumented trabeculectomy with postoperative wound modulation in pediatric glaucoma. Journal of American Association for Pediatric Ophthalmology and Strabismus 3(2):117\\u0026ndash;24.\\u0026nbsp;\\u003c/li\\u003e\\n \\u003cli\\u003eMorales J, Al Shahwan S, Al Odhayb S, Al Jadaan I, Edward DP (2013) Current surgical options for the management of pediatric glaucoma. Journal of Ophthalmology 2013(1):763735.\\u0026nbsp;\\u003c/li\\u003e\\n \\u003cli\\u003eMendrinos E, Mermoud A, Shaarawy T (2008) Nonpenetrating glaucoma surgery. Survey of ophthalmology 53(6):592\\u0026ndash;630.\\u0026nbsp;\\u003c/li\\u003e\\n \\u003cli\\u003eRulli E, Biagioli E, Riva I, Gambirasio G, De Simone I, Floriani I, et al (2013) Efficacy and safety of trabeculectomy vs nonpenetrating surgical procedures: a systematic review and meta-analysis. JAMA ophthalmology 131(12):1573\\u0026ndash;82.\\u0026nbsp;\\u003c/li\\u003e\\n \\u003cli\\u003eLiang Y, Yu Q, Ji F, Sun H, Yuan Z. Viscocanalostomy combined with nearly 360-degree suture trabeculotomy for the treatment of primary congenital glaucoma: a preliminary report of a novel technique for trabeculotomy (2020) Graefe\\u0026rsquo;s Archive for Clinical and Experimental Ophthalmology 258(2):379\\u0026ndash;86.\\u0026nbsp;\\u003c/li\\u003e\\n \\u003cli\\u003eQian CX, Zong Y, Chen Q, Yuan ZL (2017) Viscocanalostomy combined with trabeculotomy and mitomycin C in the treatment of primary congenital glaucoma. International Journal of Ophthalmology 10(6):919.\\u0026nbsp;\\u003c/li\\u003e\\n \\u003cli\\u003eVaradaraj V, Munoz B, Karaoui M, Collins ME, Aljasim LA, Al Naji E, et al (2018) Effect of Chloral Hydrate Sedation on Intraocular Pressure in a Pediatric Population. American Journal of Ophthalmology 1;194:126\\u0026ndash;33.\\u0026nbsp;\\u003c/li\\u003e\\n \\u003cli\\u003eVahedian Z, Fakhraie G, Ahmed AH (2022) Viscocanalostomy combined with trabeculotomy for management of refractory primary congenital glaucoma. Journal of American Association for Pediatric Ophthalmology and Strabismus 26(3):121-e1.\\u0026nbsp;\\u003c/li\\u003e\\n \\u003cli\\u003eAbdelrahman AM (2024) Non-penetrating Glaucoma Surgery. In: El Sayed YM, Elhusseiny AM, editors. Childhood Glaucoma: Current Trends and Future Prospects [Internet]. Cham: Springer International Publishing 289\\u0026ndash;97. Available from: https://doi.org/10.1007/978-3-031-61073-8_21\\u003c/li\\u003e\\n \\u003cli\\u003eTamcelik N, \\u0026Ouml;zkiris A (2008) Long-term results of viscotrabeculotomy in congenital glaucoma: comparison to classical trabeculotomy. British journal of ophthalmology 92(1):36\\u0026ndash;9.\\u0026nbsp;\\u003c/li\\u003e\\n \\u003cli\\u003eTam\\u0026ccedil;elik N, Capar O, Atalay E (2019) Modified viscotrabeculotomy with microcatheter: our technique and experience in the surgical management of glaucoma. Journal of Current Glaucoma Practice 13(3):88.\\u0026nbsp;\\u003c/li\\u003e\\n \\u003cli\\u003eElwehidy AS, Bayoumi NH, Abd Elfattah D, Hagras SM (2022) Surgical outcomes of visco-circumferential-suture-trabeculotomy versus rigid probe trabeculotomy in primary congenital glaucoma: a 3-year randomized controlled study. Journal of Glaucoma 31(1):48\\u0026ndash;53.\\u0026nbsp;\\u003c/li\\u003e\\n \\u003cli\\u003eElwehidy AS, Bayoumi NHL, Elzeini RM, Abdelkader A (2023) Visco-Circumferential-Suture-Trabeculotomy Versus Rigid-Probe Viscotrabeculotomy in Neonatal-Onset Primary Congenital Glaucoma. Journal of Glaucoma 2023;32(9).\\u0026nbsp;\\u003c/li\\u003e\\n \\u003cli\\u003eFakhraie G, Ansari S, Tabatabaei SM, Hamzeh N, Vahedian Z, Beikmarzehei A (2025) Modified viscotrabeculotomy versus modified trabeculotomy in late-onset primary congenital, juvenile, and secondary open-angle glaucoma. European Journal of Ophthalmology 1;35(2):618\\u0026ndash;26.\\u0026nbsp;\\u003c/li\\u003e\\n\\u003c/ol\\u003e\"}],\"fulltextSource\":\"\",\"fullText\":\"\",\"funders\":[],\"hasAdminPriorityOnWorkflow\":false,\"hasManuscriptDocX\":true,\"hasOptedInToPreprint\":true,\"hasPassedJournalQc\":\"\",\"hasAnyPriority\":false,\"hideJournal\":false,\"highlight\":\"\",\"institution\":\"\",\"isAcceptedByJournal\":false,\"isAuthorSuppliedPdf\":false,\"isDeskRejected\":\"\",\"isHiddenFromSearch\":false,\"isInQc\":false,\"isInWorkflow\":false,\"isPdf\":false,\"isPdfUpToDate\":true,\"isWithdrawnOrRetracted\":false,\"journal\":{\"display\":true,\"email\":\"info@researchsquare.com\",\"identity\":\"bmc-ophthalmology\",\"isNatureJournal\":false,\"hasQc\":true,\"allowDirectSubmit\":false,\"externalIdentity\":\"boph\",\"sideBox\":\"Learn more about [BMC Ophthalmology](http://bmcophthalmol.biomedcentral.com/)\",\"snPcode\":\"\",\"submissionUrl\":\"https://www.editorialmanager.com/boph\",\"title\":\"BMC Ophthalmology\",\"twitterHandle\":\"BMC_series\",\"acdcEnabled\":true,\"dfaEnabled\":false,\"editorialSystem\":\"em\",\"reportingPortfolio\":\"BMC Series\",\"inReviewEnabled\":true,\"inReviewRevisionsEnabled\":true},\"keywords\":\"viscocanalostomy, retrabeculotomy, primary congenital glaucoma, combined viscocanalostomy and retrabeculotomy\",\"lastPublishedDoi\":\"10.21203/rs.3.rs-9539983/v1\",\"lastPublishedDoiUrl\":\"https://doi.org/10.21203/rs.3.rs-9539983/v1\",\"license\":{\"name\":\"CC BY 4.0\",\"url\":\"https://creativecommons.org/licenses/by/4.0/\"},\"manuscriptAbstract\":\"\\u003cp\\u003eBackground: To compare the outcomes of combined viscocanalostomy (VCO) and repeat trabeculotomy (retbo) versus retbo alone in primary congenital glaucoma (PCG) with prior failed trabeculotomy.\\u003c/p\\u003e\\n\\u003cp\\u003eMethods: This prospective study enrolled 164 PCG eyes with insufficient response to initial angle surgery, equally divided into VCO+retbo and retbo groups (n=82 each). Success was defined as intraocular pressure (IOP) between 6–21 mmHg with ≥20% reduction from baseline, classified as 'complete' (no medications) or 'qualified' (with medications).\\u003c/p\\u003e\\n\\u003cp\\u003eResults: Mean follow-up was 30.36±13.38 months. In successful eyes, IOP decreased from 28.52±6.06 to 16.2±2.94 mmHg in VCO+retbo and from 27.35±5.29 to 17.67±4.35 mmHg in retbo; medication use changed from 2.70±0.78 to 2.04±1.03 and 2.69±0.97 to 0.98±1.10, respectively (all p\\u0026lt;0.001). Final IOP did not differ between groups, but retbo required fewer medications (p\\u0026lt;0.001). Failure rates were 31.7% (VCO+retbo) and 37.8% (retbo) (p=0.219). Complete success was achieved in 9.8% (VCO+retbo) versus 32.9% (retbo), while qualified success was 58.5% versus 29.3% (p\\u0026lt;0.001). IOP \\u0026gt;30 mmHg before second surgery predicted higher failure risk (HR=2.33, 95% CI: 1.33–4.11, p=0.003).\\u003c/p\\u003e\\n\\u003cp\\u003eConclusions: Adding VCO to retbo in PCG with prior failed trabeculotomy offers no additional benefit over retbo alone.\\u003c/p\\u003e\\n\\u003cp\\u003eTrial registration: The study was approved by the local ethics committee of Tehran University of Medical Sciences (IR. TUMS. FARABIH. REC. 1402.009). The online version of the decree is publicly available at: https://ethics.research.ac.ir/IR.TUMS.FARABIH.REC.1402.009\\u003c/p\\u003e\",\"manuscriptTitle\":\"Combined viscocanalostomy and retrabeculotomy versus retrabeculotomy for management of refractory primary congenital glaucoma: A Comparative study\",\"msid\":\"\",\"msnumber\":\"\",\"nonDraftVersions\":[{\"code\":1,\"date\":\"2026-05-18 06:01:39\",\"doi\":\"10.21203/rs.3.rs-9539983/v1\",\"editorialEvents\":[{\"type\":\"communityComments\",\"content\":0},{\"type\":\"reviewerAgreed\",\"content\":\"17677440446174711034190618932972457716\",\"date\":\"2026-05-23T09:54:25+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"reviewerAgreed\",\"content\":\"90850994443059323952965607745660678855\",\"date\":\"2026-05-22T23:41:35+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"reviewerAgreed\",\"content\":\"247136649027205702557689276001879579175\",\"date\":\"2026-05-22T08:35:37+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"reviewersInvited\",\"content\":\"\",\"date\":\"2026-05-07T12:19:05+00:00\",\"index\":\"\",\"fulltext\":\"\"},{\"type\":\"editorInvited\",\"content\":\"\",\"date\":\"2026-04-30T10:16:56+00:00\",\"index\":\"\",\"fulltext\":\"\"},{\"type\":\"editorAssigned\",\"content\":\"\",\"date\":\"2026-04-29T08:48:32+00:00\",\"index\":\"\",\"fulltext\":\"\"},{\"type\":\"checksComplete\",\"content\":\"\",\"date\":\"2026-04-29T08:48:23+00:00\",\"index\":\"\",\"fulltext\":\"\"},{\"type\":\"submitted\",\"content\":\"BMC Ophthalmology\",\"date\":\"2026-04-27T10:04:07+00:00\",\"index\":\"\",\"fulltext\":\"\"}],\"status\":\"published\",\"journal\":{\"display\":true,\"email\":\"info@researchsquare.com\",\"identity\":\"bmc-ophthalmology\",\"isNatureJournal\":false,\"hasQc\":true,\"allowDirectSubmit\":false,\"externalIdentity\":\"boph\",\"sideBox\":\"Learn more about [BMC Ophthalmology](http://bmcophthalmol.biomedcentral.com/)\",\"snPcode\":\"\",\"submissionUrl\":\"https://www.editorialmanager.com/boph\",\"title\":\"BMC Ophthalmology\",\"twitterHandle\":\"BMC_series\",\"acdcEnabled\":true,\"dfaEnabled\":false,\"editorialSystem\":\"em\",\"reportingPortfolio\":\"BMC Series\",\"inReviewEnabled\":true,\"inReviewRevisionsEnabled\":true}}],\"origin\":\"\",\"ownerIdentity\":\"0a405efb-0adf-43e5-8208-6cb5c103ddca\",\"owner\":[],\"postedDate\":\"May 18th, 2026\",\"published\":true,\"recentEditorialEvents\":[{\"type\":\"reviewerAgreed\",\"content\":\"17677440446174711034190618932972457716\",\"date\":\"2026-05-23T09:54:25+00:00\",\"index\":160,\"fulltext\":\"\"},{\"type\":\"reviewerAgreed\",\"content\":\"90850994443059323952965607745660678855\",\"date\":\"2026-05-22T23:41:35+00:00\",\"index\":159,\"fulltext\":\"\"},{\"type\":\"reviewerAgreed\",\"content\":\"247136649027205702557689276001879579175\",\"date\":\"2026-05-22T08:35:37+00:00\",\"index\":157,\"fulltext\":\"\"},{\"type\":\"reviewersInvited\",\"content\":\"102\",\"date\":\"2026-05-07T12:19:05+00:00\",\"index\":\"\",\"fulltext\":\"\"}],\"rejectedJournal\":[],\"revision\":\"\",\"amendment\":\"\",\"status\":\"under-review\",\"subjectAreas\":[],\"tags\":[],\"updatedAt\":\"2026-05-18T06:01:39+00:00\",\"versionOfRecord\":[],\"versionCreatedAt\":\"2026-05-18 06:01:39\",\"video\":\"\",\"vorDoi\":\"\",\"vorDoiUrl\":\"\",\"workflowStages\":[]},\"version\":\"v1\",\"identity\":\"rs-9539983\",\"journalConfig\":\"researchsquare\"},\"__N_SSP\":true},\"page\":\"/article/[identity]/[[...version]]\",\"query\":{\"redirect\":\"/article/rs-9539983\",\"identity\":\"rs-9539983\",\"version\":[\"v1\"]},\"buildId\":\"8U1c8b4HqxoKbykW_rLl7\",\"isFallback\":false,\"isExperimentalCompile\":false,\"dynamicIds\":[84888],\"gssp\":true,\"scriptLoader\":[]}","source_license":"CC-BY-4.0","license_restricted":false}