Changes in Astigmatism in Children With Congenital Nasolacrimal Duct Obstruction Undergoing Probing and Irrigation

Changes in Astigmatism in Children With Congenital Nasolacrimal Duct Obstruction Undergoing Probing and Irrigation | 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 Article Changes in Astigmatism in Children With Congenital Nasolacrimal Duct Obstruction Undergoing Probing and Irrigation OFIRA ZLOTO, Itay Shavit, Omer Lev Ari, Hillah Levy Berkowitc, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7854321/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background Congenital nasolacrimal duct obstruction (CNLDO) is a frequent condition during infancy. While it is often self-limited, persistent cases may require probing and irrigation (P&I). Because this disorder affects the critical period of visual development, concerns have been raised about its potential role in amblyopia through induced refractive changes, particularly astigmatism. Methods A Retrospective, single-center cohort study. Medical records of children with CNLDO treated at Sheba Medical Center (2009–2024) were reviewed. Inclusion required P&I and paired cycloplegic refractions before surgery and 6–36 months postoperatively. Pre- and postoperative spherical equivalent (SE) and cylinder were compared using paired t-tests, stratified by age at last procedure (< 24 vs ≥ 24 months). Proportions with any measurable cylinder were tested with McNemar’s test. Results Of the 401 children screened, 25 met the inclusion criteria. Fourteen were treated before 24 months of age, and 11 at or after 24 months. SE showed a nonsignificant myopic shift (Δ = -0.43D, p = 0.065). In contrast, cylinder values increased from − 0.39 ± 0.70D to -0.87 ± 0.98D (p = 0.040). The proportion of measurable cylinder rose from 32% to 68% (p = 0.012). Later treated children had a greater mean increase (to -1.20 ± 1.14D), and among those with baseline cylinder, the mean reached − 1.47D, which is a borderline amblyogenic value. Conclusion CNLDO is associated with increased cylinder and astigmatism, with children treated later in life showing an even higher risk of progression toward amblyogenic levels. These findings support structured postoperative refractive follow-up and early surgical intervention whenever possible. Health sciences/Diseases/Eye diseases/Refractive errors Health sciences/Diseases/Eye diseases/Lacrimal apparatus diseases Nasolacrimal Duct Obstruction Cylinder Amblyopia Probing and Irrigation Introduction Congenital nasolacrimal duct obstruction (CNLDO) is a common pediatric condition, affecting up to 20% of newborns. The main cause is an incomplete canalization of the nasolacrimal duct at the valve of Hasner ( 1 ). Presentation typically includes epiphora, mucous discharge, conjunctival irritation or infection. Although spontaneous resolution mostly occurs within the first year, persistent symptomatic obstruction may require surgical intervention, such as probing and irrigation (P&I)( 2 , 3 ). CNLDO, which occurs during a tremendously sensitive window of visual development, raises concern about its potential contribution to amblyopia risk, due to an asymmetric or chronically impaired visual input ( 4 – 6 ). Several studies have shown an increased rate of astigmatism and anisometropia in children with unresolved or late-treated CNLDO ( 7 – 9 ). In addition, Kilic et al. found significantly higher astigmatic amblyopia risk factors (ARFs) in children that underwent the first P&I intervention after the age of 24 months ( 7 ). It is common for healthy infants to have mild with-the-rule (WTR) astigmatism, which usually decreases over time, as part of the emmetropization process ( 10 , 11 ). Several studies have shown that the mean cylinder values decrease from approximately 1.00-1.50 diopters (D) in infancy to around 0.50D by age 3–5 ( 11 – 13 ). Values exceeding 1.50D are considered pathological beyond infancy and are related to an increased risk of amblyopia, particularly when oblique or asymmetric between eyes ( 4 , 14 , 15 ). Despite the above, prior studies mostly focused on amblyopia prevalence or general refractive status. Cycloplegic refractive error measurements before and after probing were not specifically researched. Similarly, a few studies tracked the cylinder magnitude or the axis changes over time ( 7 – 9 ). Therefore, the effect of both obstruction and its resolution on astigmatic development remains incompletely understood. This study aims to assess the impact of surgical treatment of CNLDO on astigmatism in children compared to refractive outcomes of healthy children. Our findings will potentially help guide future recommendations for monitoring and intervention in children with CNLDO. Materials And Methods Study Design and Population This retrospective study included children (ages 0–18) that were diagnosed with CNLDO and treated at Sheba Medical Center between January 2009 and December 2024. Inclusion criteria were a clinical diagnosis of CNLDO, at least one surgical P&I intervention. Exclusion criteria were lack of cycloplegic refraction measurements prior to the procedure or within 6 months up to 3 years postoperatively, incomplete clinical records, or indications unrelated to CNLDO for the procedures. This study was approved by the local institutional review board (IRB) of the Sheba Medical Center. Data Collection Demographic and clinical data were extracted from electronic medical records, including birth date, follow-up dates, type and timing of surgical interventions, side of intervention, obstruction severity, preoperative symptoms (epiphora, discharge and infection), and relevant medical/family history. The closest cycloplegic refraction prior to the last intervention and the most recent postoperative refraction obtained within 6–36 months were analyzed. Diagnosis and Follow-up Protocol CNLDO was diagnosed clinically based on the presence of persistent epiphora, mucopurulent discharge, or recurrent ocular infections. Initial treatment included lacrimal sac massage. If symptoms persisted beyond 12 months of age, interventional procedures were considered. Follow-up typically included visits in the postoperative clinic and repeat refraction and visual acuity testing. If the symptoms persisted or reoccurred, further follow-up or additional surgical interventions were performed. Statistical Analysis Paired pre- and postoperative refractions were analyzed in minus-cylinder convention. Spherical equivalent (SE = sphere + ½·cylinder) and cylinder power were compared within patients using paired t-tests, with results reported as means ± SD, mean change (Δ) with 95% confidence intervals, and p-values (α = 0.05). The age at last procedure (< 24 vs ≥ 24 months) was examined as a stratifying factor, with between-group differences tested using Welch’s t-test. Two-cylinder outcomes were prespecified: ( 1 ) the proportion of patients with any measurable cylinder (|cylinder| >0 D), tested with McNemar’s test and compared between age groups with a z-test; and ( 2 ) the change in mean cylinder (diopters), with a sensitivity analysis restricted to eyes with non-zero cylinder at either time point. Figures included kernel density plots of cylinder distributions (Fig. 1 ) and line plots of mean ± SD cylinder by age group (Fig. 2 ). Exploratory analyses evaluated whether refractive change related to baseline features (family history, laterality, symptoms, or surgical details) using McNemar’s test, z-tests, or permutation tests as appropriate, with false-discovery rate control. Analyses were performed in Python (v3.13.6). Results Out of the 401 patients for whom data were collected, a total of 25 patients were included in the statistical analysis after applying the exclusion criteria. Among them, 14 undergoing their last procedure before the age of 24 months, and 11 at or after 24 months. Table 1 summarizes the demographic, perioperative schedule and clinical characteristics of the two groups. Baseline demographics, surgical history, and refraction-related parameters for both groups are summarized in Table 1 . Notably, children in the late-treatment group were significantly older at the time of their last procedure and at follow-up, and more frequently required repeat probing or silicone intubation. Table 1 Demographic, perioperative, and clinical characteristics of children undergoing probing and irrigation (P&I), stratified by age at last procedure. N = 25 Last procedure before the age of 24 months (N = 14) Last procedure after the age of 24 months (N = 11) Male (%) 11 (78.6%) 5 (45.5%) Family History of Refraction Error (%) 3 (21.4%) 2 (18.2%) More Than One P&I (%) 0 (0.0%) 4 (36.4%) Tube Inserted (%) 0 (0.0%) 4 (36.4%) Last Follow Up Age (Months) 37.4 ± 23.4 72.4 ± 52.3 Last Procedure Age (Months) 16.4 ± 2.7 54.7 ± 29.4 Pre-Operative Cylinder (D) -0.39 ± 0.81 -0.39 ± 0.56 Pre-Operative Age in Refraction Measurement (Months) 13.8 ± 3.7 34.5 ± 28.8 Pre-Operative Refraction Time Difference from Last Operation (Months) 1.9 ± 2.1 19.7 ± 15.1 Post-Operative Age in Refraction (Months) 42.2 ± 12.8 86.7 ± 46.9 Post-Operative Refraction Time Difference from Last Operation (Months) 22.6 ± 9.6 18.8 ± 9.0 Values are presented as n (%) or mean ± standard deviation (SD). D = diopters; P&I = probing and irrigation. Spherical equivalent Across all patients, the mean SE shifted toward more myopia from 1.72 ± 2.11D to 1.29 ± 2.56D (Δ = −0.43 D; 95% CI − 0.89 to 0.03; p = 0.065; d_z = 0.39). In children < 24 months (n = 14), SE changed from 2.55 ± 1.63D to 2.21 ± 1.23D (Δ = −0.34D; 95% CI − 0.79 to 0.11; p = 0.124; d_z = 0.44). In children ≥ 24 months (n = 11), SE changed from 0.65 ± 2.23D to 0.10 ± 3.31D (Δ = −0.55D; 95% CI − 1.53 to 0.44; p = 0.247; d_z = 0.37). Overall, SE tended to become more negative after surgery, but the pre-post change did not reach statistical significance in the whole cohort or within either age stratum. Proportion with any cylinder Among 25 children with paired refractions, the proportion with any cylinder rose from 8/25 (32%) preoperatively to 17/25 (68%) postoperatively (exact McNemar p = 0.0117). By age, children < 24 months (n = 14) increased from 4/14 to 8/14 (Δ_prop = + 28.6%; p = 0.2188), and those ≥ 24 months (n = 11) from 4/11 to 9/11 (Δ_prop = + 45.5%; p = 0.0625). The between-age difference in Δ_prop was not significant (Δ difference = − 0.17; z = − 0.78; p = 0.438; 95% CI − 0.60 to 0.26). Mean cylinder For the whole cohort, the mean cylinder increased from − 0.39 ± 0.70D to − 0.87 ± 0.98D (paired t-test p = 0.0398; Fig. 1 ). Overall, within each age group, the < 24-month group (n = 14) changed from − 0.39 ± 0.81D to − 0.61 ± 0.78D (p = 0.38), and the ≥ 24-month group (n = 11) from − 0.39 ± 0.56D to − 1.20 ± 1.14D (p = 0.063); the between-group difference-in-differences was not significant (p = 0.204). In the analysis restricted to children with non-zero cylinder at either time, the < 24-month group (n = 9) changed from − 0.61 ± 0.96D to − 0.94 ± 0.79D (p = 0.391), and the ≥ 24-month group (n = 9) from − 0.47 ± 0.59D to − 1.47 ± 1.09D (p = 0.0615); the between-group difference in mean Δ was not significant (p = 0.275; Fig. 2 ). Exploratory categorical analyses Across the clinical features examined, within-level McNemar tests and between-level comparisons did not show consistent associations with the change in proportion after false-discovery-rate correction. Detailed per-level and across-level tables are provided in the accompanying spreadsheets. Discussion Our study evaluated the refractive outcomes of children with CNLDO before and after P&I. Using paired cycloplegic refraction measurements, we found that astigmatism tended to increase following surgery both in the early and the late treatment groups, with a significantly greater rise in children whose final procedure occurred after 24 months of age. Spherical equivalent remained stable, with a trend toward mild myopic shift that did not reach statistical significance. Across all patients, SE decreased from 1.72 ± 2.11D to 1.29 ± 2.56D (p = 0.065). These changes are consistent with physiological emmetropization in early childhood and likely reflect natural refractive development ( 10 – 14 ). According to the literature, our cohort falls slightly below the typical range of -0.8D to -1.2D at baseline ( 14 – 16 ). Interestingly, cylinder values showed a significant increase postoperatively, rising from − 0.39 ± 0.70D to -0.87 ± 0.98D in the overall cohort (p = 0.0398), as seen in Fig. 1 . After stratifying by age at last procedure, children treated before the age of 24 months had a smaller and nonsignificant increase from − 0.39 ± 0.81D to -0.61 ± 0.78D (p = 0.38), while those treated later showed a more pronounced increase from − 0.39 ± 0.56D to -1.20 ± 1.14D (p = 0.063). Notably, when considering only children with measurable cylinder in the late-treatment group, the mean cylinder after 24 months reached 1.47D, a value at the borderline amblyogenic threshold (Fig. 2 ). This trend was also reflected in the proportion of children with any astigmatism, which increased from 32% (8/25) preoperatively to 68% (17/25) postoperatively (p = 0.0117). Among children < 24 months, the proportion rose from 29% (4/14) to 57% (8/14), and in those ≥ 24 months, from 36% (4/11) to 82% (9/11), although the changes within each group were not statistically significant. The isolated effect on the cylindrical component may suggest that prolonged obstruction has a localized impact on corneal shaping. Chronic ocular irritation, frequently observed in CNLDO, may lead to subsequent eye rubbing. Eye rubbing is associated with astigmatic shift, as supported by prior studies in pediatric populations ( 17 , 18 ). When treatment is delayed, corneal changes may become less reversible, resulting in sustained alterations in curvature even after successful probing. According to that, habitual eye-rubbing can be a reasonable explanatory mechanism for the predominant effect of CNLDO on the cylindrical component. This finding is in line with earlier studies reporting an association between persistent CNLDO and amblyopia risk factors such as astigmatism and anisometropia ( 7 – 9 , 19 ). Importantly, while previous work often relied on single-timepoint assessments or binary categorizations of amblyogenic risk ( 6 – 9 ), our study assesses longitudinal data, demonstrating how cylinder values evolve in relation to the timing of intervention. The amblyogenic threshold for astigmatism in children decreases with age, ranging from ≥ 3.00D in infancy to ≥ 1.50D by age 3–4, with lower thresholds children with for anisometropia ( 14 ). Although the mean postoperative cylinder, measured at a mean age of 7 years, was below the amblyogenic threshold (1.50D), 2 out of 14 (14%) in the early intervention group, and 4 out of 11 (36%) of the children in the late intervention group, had amblyogenic cylinder values. Since these refractions were performed after the age of four, when refractive stability is considered to be generally established ( 14 ), the observed increase in cylinder is unlikely to reflect transient developmental variability. The direction and consistency of change can underscore a potential clinical impact of delayed intervention. These findings suggest a clinically meaningful alteration in corneal curvature associated with late resolution of obstruction. While probing effectively resolves symptoms and prevents tear stasis, it may not prevent the refractive consequences of prolonged obstruction, thereby emphasizing the importance of early intervention ( 17 , 18 ). The main limitations of our study are its retrospective design and the relatively small cohort, especially after stratification by age. Still, the consistency and novelty of the observed trends supports their clinical relevance. In conclusion, our findings suggest that delaying CNLDO intervention is linked with greater astigmatic progression, often toward amblyogenic levels. Early treatment combined with structured postoperative refractive monitoring may help reduce the risk of amblyopia. Declarations Acknowledgement This research did not receive any grant from funding agencies in the public, commercial, or other sectors. The authors declare that they have no conflicts of interest. This article have not been presented in a conference before. Conflict of Interest Statement The authors declare no conflict of interest. Funding Statement This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. Author Contribution Statement IS was responsible for data curation, study planning, literature search, and manuscript drafting. HLB contributed to data curation. OLA participated in data curation and study planning. OR performed the statistical analysis and contributed to manuscript editing and writing refinements. OZ conceptualized and planned the study, supervised all stages of the work, and contributed to editing and writing refinements. All authors reviewed and approved the final version of the manuscript References Bagheri A, Safapoor S, Yazdani S, Yaseri M. Refractive state in children with unilateral congenital nasolacrimal duct obstruction. J Ophthalmic Vis Res. 2012;7(1):29-33. Sathiamoorthi S, Frank RD, Mohney BG. Spontaneous resolution and timing of intervention in congenital nasolacrimal duct obstruction. JAMA Ophthalmol. 2018;136(12):1281-6. Morrison DG, Wallace DK, Freedman SF, et al. Office- or facility-based probing for congenital nasolacrimal duct obstruction. Ophthalmology. 2021;128(7):920-7. Harvey EM, Dobson V, Clifford-Donaldson CE, Miller JM. Optical treatment of amblyopia in astigmatic children: the sensitive period for successful treatment. Ophthalmology. 2007;114(12):2293-301. Sims DT, Silbert DI, Matta NS, et al. Anisometropia and amblyopia outcomes in early versus late resolution of congenital nasolacrimal duct obstruction. Ophthalmic Plast Reconstr Surg. 2024;40(1):39-42. Badakere A, Veeravalli TN, Iram S, Naik MN, Ali MJ. Unilateral congenital nasolacrimal duct obstruction and amblyopia risk factors. Clin Ophthalmol. 2018;12:1255-7. Kilic D, Aydin I, Sirem MR, Birgin H, Guven S. Congenital nasolacrimal duct obstruction and refractive amblyopia risk factors: effect of age at the time of probing. Beyoglu Eye J. 2022;7(1):30-4. Ozgur OR, Sayman IB, Oral Y, Akmaz B. Prevalence of amblyopia in children undergoing nasolacrimal duct irrigation and probing. Indian J Ophthalmol. 2013;61(12):698-700. Matta NS, Singman EL, Silbert DI. Prevalence of amblyopia risk factors in congenital nasolacrimal duct obstruction. J AAPOS. 2010;14(5):386-8. Wen G, Tarczy-Hornoch K, McKean-Cowdin R, et al. Prevalence of myopia, hyperopia, and astigmatism in non-Hispanic white and Asian children: the multi-ethnic pediatric eye disease study. Ophthalmology. 2013;120(10):2109-16. doi:10.1016/j.ophtha.2013.06.039. Margines JB, Huang C, Young A, Yu F, Coleman AL. Epidemiological characteristics associated with astigmatism in a population of 3- to 5-year-old children in Los Angeles, CA. Ophthalmic Epidemiol. 2025;32(4):437-42. doi:10.1080/09286586.2024.2410302. Huynh SC, Kifley A, Ip J, Mitchell P. Distribution and heritability of cylinder power in 6-year-old children: the Sydney childhood eye study. Invest Ophthalmol Vis Sci. 2007;48(2):556-63. Chou YS, Tai MC, Chen PL, Lu DW, Chien KH. Impact of cylinder axis on the treatment for astigmatic amblyopia. Am J Ophthalmol. 2014;157(1):174-80. Hutchinson AK, Morse CL, Hercinovic A, et al. Pediatric eye evaluations preferred practice pattern. Ophthalmology. 2023;130(3):P222-70. doi:10.1016/j.ophtha.2022.10.030. Cowen L, Bobier WR. The pattern of astigmatism in a Canadian preschool population. Invest Ophthalmol Vis Sci. 2003;44(10):4593-600. doi:10.1167/iovs.02-0730. Yahya AN, Sharanjeet-Kaur S, Akhir SM. Distribution of refractive errors among healthy infants and young children between the age of 6 to 36 months in Kuala Lumpur, Malaysia: a pilot study. Int J Environ Res Public Health. 2019;16(21):4234. Satilmaz MF, Aslan MG, Besenek M. Evaluation of ocular parameters in newly diagnosed obsessive-compulsive disorder children with eye-rubbing compulsion. Clin Pediatr (Phila). 2025;64(6):877-86. doi:10.1177/00099228241304469. Scotto R, Vagge A, Traverso CE. Eye rubbing and transient corneal ectasia detected by topography in a pediatric patient. Cornea. 2021;40(2):251-3. doi:10.1097/ICO.0000000000002497. Piotrowski TJ, Diehl NN, Mohney BG. Neonatal dacryostenosis as a risk factor for anisometropia. Arch Ophthalmol. 2010;128(9):1166-9. 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10:16:53","extension":"png","order_by":9,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":24729,"visible":true,"origin":"","legend":"","description":"","filename":"OnlineFigure2.png","url":"https://assets-eu.researchsquare.com/files/rs-7854321/v1/2de8f77c3e782e7281b7bdfb.png"},{"id":95529653,"identity":"d2964eb4-a159-494c-bb8f-cccb0120b49b","added_by":"auto","created_at":"2025-11-10 10:17:21","extension":"xml","order_by":10,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":57990,"visible":true,"origin":"","legend":"","description":"","filename":"EYE2529050structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-7854321/v1/8912c5c1481deac0153423ee.xml"},{"id":95502767,"identity":"323b67f6-a0f2-44a6-af25-142dbf188995","added_by":"auto","created_at":"2025-11-10 05:37:51","extension":"html","order_by":11,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":67221,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-7854321/v1/cae400fef165dfcb2a9d2fa0.html"},{"id":101431556,"identity":"ea83f881-e66a-4505-9c74-976c1be24671","added_by":"auto","created_at":"2026-01-29 15:42:40","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":494247,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7854321/v1/7ed316b5-0c23-4113-9a4b-51a2a68c3151.pdf"}],"financialInterests":"There is no conflict of interest","formattedTitle":"Changes in Astigmatism in Children With Congenital Nasolacrimal Duct Obstruction Undergoing Probing and Irrigation","fulltext":[{"header":"Introduction","content":"\u003cp\u003eCongenital nasolacrimal duct obstruction (CNLDO) is a common pediatric condition, affecting up to 20% of newborns. The main cause is an incomplete canalization of the nasolacrimal duct at the valve of Hasner (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e). Presentation typically includes epiphora, mucous discharge, conjunctival irritation or infection. Although spontaneous resolution mostly occurs within the first year, persistent symptomatic obstruction may require surgical intervention, such as probing and irrigation (P\u0026amp;I)(\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eCNLDO, which occurs during a tremendously sensitive window of visual development, raises concern about its potential contribution to amblyopia risk, due to an asymmetric or chronically impaired visual input (\u003cspan additionalcitationids=\"CR5\" citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e). Several studies have shown an increased rate of astigmatism and anisometropia in children with unresolved or late-treated CNLDO (\u003cspan additionalcitationids=\"CR8\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e). In addition, Kilic et al. found significantly higher astigmatic amblyopia risk factors (ARFs) in children that underwent the first P\u0026amp;I intervention after the age of 24 months (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eIt is common for healthy infants to have mild with-the-rule (WTR) astigmatism, which usually decreases over time, as part of the emmetropization process (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e). Several studies have shown that the mean cylinder values decrease from approximately 1.00-1.50 diopters (D) in infancy to around 0.50D by age 3\u0026ndash;5 (\u003cspan additionalcitationids=\"CR12\" citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e). Values exceeding 1.50D are considered pathological beyond infancy and are related to an increased risk of amblyopia, particularly when oblique or asymmetric between eyes (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eDespite the above, prior studies mostly focused on amblyopia prevalence or general refractive status. Cycloplegic refractive error measurements before and after probing were not specifically researched. Similarly, a few studies tracked the cylinder magnitude or the axis changes over time (\u003cspan additionalcitationids=\"CR8\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e). Therefore, the effect of both obstruction and its resolution on astigmatic development remains incompletely understood.\u003c/p\u003e\u003cp\u003eThis study aims to assess the impact of surgical treatment of CNLDO on astigmatism in children compared to refractive outcomes of healthy children. Our findings will potentially help guide future recommendations for monitoring and intervention in children with CNLDO.\u003c/p\u003e"},{"header":"Materials And Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003eStudy Design and Population\u003c/h2\u003e\u003cp\u003eThis retrospective study included children (ages 0\u0026ndash;18) that were diagnosed with CNLDO and treated at Sheba Medical Center between January 2009 and December 2024. Inclusion criteria were a clinical diagnosis of CNLDO, at least one surgical P\u0026amp;I intervention. Exclusion criteria were lack of cycloplegic refraction measurements prior to the procedure or within 6 months up to 3 years postoperatively, incomplete clinical records, or indications unrelated to CNLDO for the procedures. This study was approved by the local institutional review board (IRB) of the Sheba Medical Center.\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eData Collection\u003c/h3\u003e\n\u003cp\u003eDemographic and clinical data were extracted from electronic medical records, including birth date, follow-up dates, type and timing of surgical interventions, side of intervention, obstruction severity, preoperative symptoms (epiphora, discharge and infection), and relevant medical/family history. The closest cycloplegic refraction prior to the last intervention and the most recent postoperative refraction obtained within 6\u0026ndash;36 months were analyzed.\u003c/p\u003e\n\u003ch3\u003eDiagnosis and Follow-up Protocol\u003c/h3\u003e\n\u003cp\u003eCNLDO was diagnosed clinically based on the presence of persistent epiphora, mucopurulent discharge, or recurrent ocular infections. Initial treatment included lacrimal sac massage. If symptoms persisted beyond 12 months of age, interventional procedures were considered. Follow-up typically included visits in the postoperative clinic and repeat refraction and visual acuity testing. If the symptoms persisted or reoccurred, further follow-up or additional surgical interventions were performed.\u003c/p\u003e\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\u003ch2\u003eStatistical Analysis\u003c/h2\u003e\u003cp\u003ePaired pre- and postoperative refractions were analyzed in minus-cylinder convention. Spherical equivalent (SE\u0026thinsp;=\u0026thinsp;sphere + \u0026frac12;\u0026middot;cylinder) and cylinder power were compared within patients using paired t-tests, with results reported as means\u0026thinsp;\u0026plusmn;\u0026thinsp;SD, mean change (Δ) with 95% confidence intervals, and p-values (α\u0026thinsp;=\u0026thinsp;0.05). The age at last procedure (\u0026lt;\u0026thinsp;24 vs\u0026thinsp;\u0026ge;\u0026thinsp;24 months) was examined as a stratifying factor, with between-group differences tested using Welch\u0026rsquo;s t-test. Two-cylinder outcomes were prespecified: (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e) the proportion of patients with any measurable cylinder (|cylinder| \u0026gt;0 D), tested with McNemar\u0026rsquo;s test and compared between age groups with a z-test; and (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e) the change in mean cylinder (diopters), with a sensitivity analysis restricted to eyes with non-zero cylinder at either time point. Figures included kernel density plots of cylinder distributions (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e) and line plots of mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD cylinder by age group (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Exploratory analyses evaluated whether refractive change related to baseline features (family history, laterality, symptoms, or surgical details) using McNemar\u0026rsquo;s test, z-tests, or permutation tests as appropriate, with false-discovery rate control. Analyses were performed in Python (v3.13.6).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eOut of the 401 patients for whom data were collected, a total of 25 patients were included in the statistical analysis after applying the exclusion criteria. Among them, 14 undergoing their last procedure before the age of 24 months, and 11 at or after 24 months. Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e summarizes the demographic, perioperative schedule and clinical characteristics of the two groups. Baseline demographics, surgical history, and refraction-related parameters for both groups are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. Notably, children in the late-treatment group were significantly older at the time of their last procedure and at follow-up, and more frequently required repeat probing or silicone intubation.\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, perioperative, and clinical characteristics of children undergoing probing and irrigation (P\u0026amp;I), stratified by age at last procedure.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"3\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eN\u0026thinsp;=\u0026thinsp;25\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eLast procedure before the age of 24 months\u003c/p\u003e\u003cp\u003e(N\u0026thinsp;=\u0026thinsp;14)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eLast procedure after the age of 24 months\u003c/p\u003e\u003cp\u003e(N\u0026thinsp;=\u0026thinsp;11)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMale (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e11 (78.6%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e5 (45.5%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFamily History of Refraction Error (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e3 (21.4%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e2 (18.2%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMore Than One P\u0026amp;I (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0 (0.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e4 (36.4%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTube Inserted (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0 (0.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e4 (36.4%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eLast Follow Up Age (Months)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e37.4\u0026thinsp;\u0026plusmn;\u0026thinsp;23.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e72.4\u0026thinsp;\u0026plusmn;\u0026thinsp;52.3\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eLast Procedure Age (Months)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e16.4\u0026thinsp;\u0026plusmn;\u0026thinsp;2.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e54.7\u0026thinsp;\u0026plusmn;\u0026thinsp;29.4\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePre-Operative Cylinder (D)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e-0.39\u0026thinsp;\u0026plusmn;\u0026thinsp;0.81\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e-0.39\u0026thinsp;\u0026plusmn;\u0026thinsp;0.56\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePre-Operative Age in Refraction Measurement (Months)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e13.8\u0026thinsp;\u0026plusmn;\u0026thinsp;3.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e34.5\u0026thinsp;\u0026plusmn;\u0026thinsp;28.8\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePre-Operative Refraction Time Difference from Last Operation (Months)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e1.9\u0026thinsp;\u0026plusmn;\u0026thinsp;2.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e19.7\u0026thinsp;\u0026plusmn;\u0026thinsp;15.1\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePost-Operative Age in Refraction (Months)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e42.2\u0026thinsp;\u0026plusmn;\u0026thinsp;12.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e86.7\u0026thinsp;\u0026plusmn;\u0026thinsp;46.9\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePost-Operative Refraction Time Difference from Last Operation (Months)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e22.6\u0026thinsp;\u0026plusmn;\u0026thinsp;9.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e18.8\u0026thinsp;\u0026plusmn;\u0026thinsp;9.0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"3\"\u003eValues are presented as n (%) or mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation (SD).\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd colspan=\"3\"\u003eD\u0026thinsp;=\u0026thinsp;diopters; P\u0026amp;I\u0026thinsp;=\u0026thinsp;probing and irrigation.\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003eSpherical equivalent\u003c/h2\u003e\u003cp\u003eAcross all patients, the mean SE shifted toward more myopia from 1.72\u0026thinsp;\u0026plusmn;\u0026thinsp;2.11D to 1.29\u0026thinsp;\u0026plusmn;\u0026thinsp;2.56D (Δ = \u0026minus;0.43 D; 95% CI \u0026minus;\u0026thinsp;0.89 to 0.03; p\u0026thinsp;=\u0026thinsp;0.065; d_z\u0026thinsp;=\u0026thinsp;0.39). In children\u0026thinsp;\u0026lt;\u0026thinsp;24 months (n\u0026thinsp;=\u0026thinsp;14), SE changed from 2.55\u0026thinsp;\u0026plusmn;\u0026thinsp;1.63D to 2.21\u0026thinsp;\u0026plusmn;\u0026thinsp;1.23D (Δ = \u0026minus;0.34D; 95% CI \u0026minus;\u0026thinsp;0.79 to 0.11; p\u0026thinsp;=\u0026thinsp;0.124; d_z\u0026thinsp;=\u0026thinsp;0.44). In children\u0026thinsp;\u0026ge;\u0026thinsp;24 months (n\u0026thinsp;=\u0026thinsp;11), SE changed from 0.65\u0026thinsp;\u0026plusmn;\u0026thinsp;2.23D to 0.10\u0026thinsp;\u0026plusmn;\u0026thinsp;3.31D (Δ = \u0026minus;0.55D; 95% CI \u0026minus;\u0026thinsp;1.53 to 0.44; p\u0026thinsp;=\u0026thinsp;0.247; d_z\u0026thinsp;=\u0026thinsp;0.37). Overall, SE tended to become more negative after surgery, but the pre-post change did not reach statistical significance in the whole cohort or within either age stratum.\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eProportion with any cylinder\u003c/h3\u003e\n\u003cp\u003eAmong 25 children with paired refractions, the proportion with any cylinder rose from 8/25 (32%) preoperatively to 17/25 (68%) postoperatively (exact McNemar p\u0026thinsp;=\u0026thinsp;0.0117). By age, children\u0026thinsp;\u0026lt;\u0026thinsp;24 months (n\u0026thinsp;=\u0026thinsp;14) increased from 4/14 to 8/14 (Δ_prop\u0026thinsp;=\u0026thinsp;+\u0026thinsp;28.6%; p\u0026thinsp;=\u0026thinsp;0.2188), and those\u0026thinsp;\u0026ge;\u0026thinsp;24 months (n\u0026thinsp;=\u0026thinsp;11) from 4/11 to 9/11 (Δ_prop\u0026thinsp;=\u0026thinsp;+\u0026thinsp;45.5%; p\u0026thinsp;=\u0026thinsp;0.0625). The between-age difference in Δ_prop was not significant (Δ difference\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;0.17; z\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;0.78; p\u0026thinsp;=\u0026thinsp;0.438; 95% CI \u0026minus;\u0026thinsp;0.60 to 0.26).\u003c/p\u003e\n\u003ch3\u003eMean cylinder\u003c/h3\u003e\n\u003cp\u003eFor the whole cohort, the mean cylinder increased from \u0026minus;\u0026thinsp;0.39\u0026thinsp;\u0026plusmn;\u0026thinsp;0.70D to \u0026minus;\u0026thinsp;0.87\u0026thinsp;\u0026plusmn;\u0026thinsp;0.98D (paired t-test p\u0026thinsp;=\u0026thinsp;0.0398; Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Overall, within each age group, the \u0026lt;\u0026thinsp;24-month group (n\u0026thinsp;=\u0026thinsp;14) changed from \u0026minus;\u0026thinsp;0.39\u0026thinsp;\u0026plusmn;\u0026thinsp;0.81D to \u0026minus;\u0026thinsp;0.61\u0026thinsp;\u0026plusmn;\u0026thinsp;0.78D (p\u0026thinsp;=\u0026thinsp;0.38), and the \u0026ge;\u0026thinsp;24-month group (n\u0026thinsp;=\u0026thinsp;11) from \u0026minus;\u0026thinsp;0.39\u0026thinsp;\u0026plusmn;\u0026thinsp;0.56D to \u0026minus;\u0026thinsp;1.20\u0026thinsp;\u0026plusmn;\u0026thinsp;1.14D (p\u0026thinsp;=\u0026thinsp;0.063); the between-group difference-in-differences was not significant (p\u0026thinsp;=\u0026thinsp;0.204). In the analysis restricted to children with non-zero cylinder at either time, the \u0026lt;\u0026thinsp;24-month group (n\u0026thinsp;=\u0026thinsp;9) changed from \u0026minus;\u0026thinsp;0.61\u0026thinsp;\u0026plusmn;\u0026thinsp;0.96D to \u0026minus;\u0026thinsp;0.94\u0026thinsp;\u0026plusmn;\u0026thinsp;0.79D (p\u0026thinsp;=\u0026thinsp;0.391), and the \u0026ge;\u0026thinsp;24-month group (n\u0026thinsp;=\u0026thinsp;9) from \u0026minus;\u0026thinsp;0.47\u0026thinsp;\u0026plusmn;\u0026thinsp;0.59D to \u0026minus;\u0026thinsp;1.47\u0026thinsp;\u0026plusmn;\u0026thinsp;1.09D (p\u0026thinsp;=\u0026thinsp;0.0615); the between-group difference in mean Δ was not significant (p\u0026thinsp;=\u0026thinsp;0.275; Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\u003ch2\u003eExploratory categorical analyses\u003c/h2\u003e\u003cp\u003eAcross the clinical features examined, within-level McNemar tests and between-level comparisons did not show consistent associations with the change in proportion after false-discovery-rate correction. Detailed per-level and across-level tables are provided in the accompanying spreadsheets.\u003c/p\u003e\u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eOur study evaluated the refractive outcomes of children with CNLDO before and after P\u0026amp;I. Using paired cycloplegic refraction measurements, we found that astigmatism tended to increase following surgery both in the early and the late treatment groups, with a significantly greater rise in children whose final procedure occurred after 24 months of age.\u003c/p\u003e\u003cp\u003eSpherical equivalent remained stable, with a trend toward mild myopic shift that did not reach statistical significance. Across all patients, SE decreased from 1.72\u0026thinsp;\u0026plusmn;\u0026thinsp;2.11D to 1.29\u0026thinsp;\u0026plusmn;\u0026thinsp;2.56D (p\u0026thinsp;=\u0026thinsp;0.065). These changes are consistent with physiological emmetropization in early childhood and likely reflect natural refractive development (\u003cspan additionalcitationids=\"CR11 CR12 CR13\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eAccording to the literature, our cohort falls slightly below the typical range of -0.8D to -1.2D at baseline (\u003cspan additionalcitationids=\"CR15\" citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e). Interestingly, cylinder values showed a significant increase postoperatively, rising from \u0026minus;\u0026thinsp;0.39\u0026thinsp;\u0026plusmn;\u0026thinsp;0.70D to -0.87\u0026thinsp;\u0026plusmn;\u0026thinsp;0.98D in the overall cohort (p\u0026thinsp;=\u0026thinsp;0.0398), as seen in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. After stratifying by age at last procedure, children treated before the age of 24 months had a smaller and nonsignificant increase from \u0026minus;\u0026thinsp;0.39\u0026thinsp;\u0026plusmn;\u0026thinsp;0.81D to -0.61\u0026thinsp;\u0026plusmn;\u0026thinsp;0.78D (p\u0026thinsp;=\u0026thinsp;0.38), while those treated later showed a more pronounced increase from \u0026minus;\u0026thinsp;0.39\u0026thinsp;\u0026plusmn;\u0026thinsp;0.56D to -1.20\u0026thinsp;\u0026plusmn;\u0026thinsp;1.14D (p\u0026thinsp;=\u0026thinsp;0.063). Notably, when considering only children with measurable cylinder in the late-treatment group, the mean cylinder after 24 months reached 1.47D, a value at the borderline amblyogenic threshold (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). This trend was also reflected in the proportion of children with any astigmatism, which increased from 32% (8/25) preoperatively to 68% (17/25) postoperatively (p\u0026thinsp;=\u0026thinsp;0.0117). Among children\u0026thinsp;\u0026lt;\u0026thinsp;24 months, the proportion rose from 29% (4/14) to 57% (8/14), and in those\u0026thinsp;\u0026ge;\u0026thinsp;24 months, from 36% (4/11) to 82% (9/11), although the changes within each group were not statistically significant.\u003c/p\u003e\u003cp\u003eThe isolated effect on the cylindrical component may suggest that prolonged obstruction has a localized impact on corneal shaping. Chronic ocular irritation, frequently observed in CNLDO, may lead to subsequent eye rubbing. Eye rubbing is associated with astigmatic shift, as supported by prior studies in pediatric populations (\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e). When treatment is delayed, corneal changes may become less reversible, resulting in sustained alterations in curvature even after successful probing. According to that, habitual eye-rubbing can be a reasonable explanatory mechanism for the predominant effect of CNLDO on the cylindrical component. This finding is in line with earlier studies reporting an association between persistent CNLDO and amblyopia risk factors such as astigmatism and anisometropia (\u003cspan additionalcitationids=\"CR8\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e). Importantly, while previous work often relied on single-timepoint assessments or binary categorizations of amblyogenic risk (\u003cspan additionalcitationids=\"CR7 CR8\" citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e), our study assesses longitudinal data, demonstrating how cylinder values evolve in relation to the timing of intervention.\u003c/p\u003e\u003cp\u003eThe amblyogenic threshold for astigmatism in children decreases with age, ranging from \u0026ge;\u0026thinsp;3.00D in infancy to \u0026ge;\u0026thinsp;1.50D by age 3\u0026ndash;4, with lower thresholds children with for anisometropia (\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eAlthough the mean postoperative cylinder, measured at a mean age of 7 years, was below the amblyogenic threshold (1.50D), 2 out of 14 (14%) in the early intervention group, and 4 out of 11 (36%) of the children in the late intervention group, had amblyogenic cylinder values. Since these refractions were performed after the age of four, when refractive stability is considered to be generally established (\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e), the observed increase in cylinder is unlikely to reflect transient developmental variability. The direction and consistency of change can underscore a potential clinical impact of delayed intervention.\u003c/p\u003e\u003cp\u003eThese findings suggest a clinically meaningful alteration in corneal curvature associated with late resolution of obstruction. While probing effectively resolves symptoms and prevents tear stasis, it may not prevent the refractive consequences of prolonged obstruction, thereby emphasizing the importance of early intervention (\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e The main limitations of our study are its retrospective design and the relatively small cohort, especially after stratification by age. Still, the consistency and novelty of the observed trends supports their clinical relevance.\u003c/p\u003e\u003cp\u003eIn conclusion, our findings suggest that delaying CNLDO intervention is linked with greater astigmatic progression, often toward amblyogenic levels. Early treatment combined with structured postoperative refractive monitoring may help reduce the risk of amblyopia.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis research did not receive any grant from funding agencies in the public, commercial, or other sectors. The authors declare that they have no conflicts of interest. This article have not been presented in a conference before.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of Interest Statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no conflict of interest.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding Statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contribution Statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIS was responsible for data curation, study planning, literature search, and manuscript drafting. HLB contributed to data curation. OLA participated in data curation and study planning. OR performed the statistical analysis and contributed to manuscript editing and writing refinements. OZ conceptualized and planned the study, supervised all stages of the work, and contributed to editing and writing refinements. All authors reviewed and approved the final version of the manuscript\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eBagheri A, Safapoor S, Yazdani S, Yaseri M. Refractive state in children with unilateral congenital nasolacrimal duct obstruction. J Ophthalmic Vis Res. 2012;7(1):29-33.\u003c/li\u003e\n \u003cli\u003eSathiamoorthi S, Frank RD, Mohney BG. Spontaneous resolution and timing of intervention in congenital nasolacrimal duct obstruction. JAMA Ophthalmol. 2018;136(12):1281-6.\u003c/li\u003e\n \u003cli\u003eMorrison DG, Wallace DK, Freedman SF, et al. Office- or facility-based probing for congenital nasolacrimal duct obstruction. Ophthalmology. 2021;128(7):920-7.\u003c/li\u003e\n \u003cli\u003eHarvey EM, Dobson V, Clifford-Donaldson CE, Miller JM. Optical treatment of amblyopia in astigmatic children: the sensitive period for successful treatment. Ophthalmology. 2007;114(12):2293-301.\u003c/li\u003e\n \u003cli\u003eSims DT, Silbert DI, Matta NS, et al. Anisometropia and amblyopia outcomes in early versus late resolution of congenital nasolacrimal duct obstruction. Ophthalmic Plast Reconstr Surg. 2024;40(1):39-42.\u003c/li\u003e\n \u003cli\u003eBadakere A, Veeravalli TN, Iram S, Naik MN, Ali MJ. Unilateral congenital nasolacrimal duct obstruction and amblyopia risk factors. Clin Ophthalmol. 2018;12:1255-7.\u003c/li\u003e\n \u003cli\u003eKilic D, Aydin I, Sirem MR, Birgin H, Guven S. Congenital nasolacrimal duct obstruction and refractive amblyopia risk factors: effect of age at the time of probing. Beyoglu Eye J. 2022;7(1):30-4.\u003c/li\u003e\n \u003cli\u003eOzgur OR, Sayman IB, Oral Y, Akmaz B. Prevalence of amblyopia in children undergoing nasolacrimal duct irrigation and probing. Indian J Ophthalmol. 2013;61(12):698-700.\u003c/li\u003e\n \u003cli\u003eMatta NS, Singman EL, Silbert DI. Prevalence of amblyopia risk factors in congenital nasolacrimal duct obstruction. J AAPOS. 2010;14(5):386-8.\u003c/li\u003e\n \u003cli\u003eWen G, Tarczy-Hornoch K, McKean-Cowdin R, et al. Prevalence of myopia, hyperopia, and astigmatism in non-Hispanic white and Asian children: the multi-ethnic pediatric eye disease study. Ophthalmology. 2013;120(10):2109-16. doi:10.1016/j.ophtha.2013.06.039.\u003c/li\u003e\n \u003cli\u003eMargines JB, Huang C, Young A, Yu F, Coleman AL. Epidemiological characteristics associated with astigmatism in a population of 3- to 5-year-old children in Los Angeles, CA. Ophthalmic Epidemiol. 2025;32(4):437-42. doi:10.1080/09286586.2024.2410302.\u003c/li\u003e\n \u003cli\u003eHuynh SC, Kifley A, Ip J, Mitchell P. Distribution and heritability of cylinder power in 6-year-old children: the Sydney childhood eye study. Invest Ophthalmol Vis Sci. 2007;48(2):556-63.\u003c/li\u003e\n \u003cli\u003eChou YS, Tai MC, Chen PL, Lu DW, Chien KH. Impact of cylinder axis on the treatment for astigmatic amblyopia. Am J Ophthalmol. 2014;157(1):174-80.\u003c/li\u003e\n \u003cli\u003eHutchinson AK, Morse CL, Hercinovic A, et al. Pediatric eye evaluations preferred practice pattern. Ophthalmology. 2023;130(3):P222-70. doi:10.1016/j.ophtha.2022.10.030.\u003c/li\u003e\n \u003cli\u003eCowen L, Bobier WR. The pattern of astigmatism in a Canadian preschool population. Invest Ophthalmol Vis Sci. 2003;44(10):4593-600. doi:10.1167/iovs.02-0730.\u003c/li\u003e\n \u003cli\u003eYahya AN, Sharanjeet-Kaur S, Akhir SM. Distribution of refractive errors among healthy infants and young children between the age of 6 to 36 months in Kuala Lumpur, Malaysia: a pilot study. Int J Environ Res Public Health. 2019;16(21):4234.\u003c/li\u003e\n \u003cli\u003eSatilmaz MF, Aslan MG, Besenek M. Evaluation of ocular parameters in newly diagnosed obsessive-compulsive disorder children with eye-rubbing compulsion. Clin Pediatr (Phila). 2025;64(6):877-86. doi:10.1177/00099228241304469.\u003c/li\u003e\n \u003cli\u003eScotto R, Vagge A, Traverso CE. Eye rubbing and transient corneal ectasia detected by topography in a pediatric patient. Cornea. 2021;40(2):251-3. doi:10.1097/ICO.0000000000002497.\u003c/li\u003e\n \u003cli\u003ePiotrowski TJ, Diehl NN, Mohney BG. Neonatal dacryostenosis as a risk factor for anisometropia. Arch Ophthalmol. 2010;128(9):1166-9.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Nasolacrimal Duct Obstruction, Cylinder, Amblyopia, Probing and Irrigation","lastPublishedDoi":"10.21203/rs.3.rs-7854321/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7854321/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e\u003cp\u003eCongenital nasolacrimal duct obstruction (CNLDO) is a frequent condition during infancy. While it is often self-limited, persistent cases may require probing and irrigation (P\u0026amp;I). Because this disorder affects the critical period of visual development, concerns have been raised about its potential role in amblyopia through induced refractive changes, particularly astigmatism.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e\u003cp\u003eA Retrospective, single-center cohort study. Medical records of children with CNLDO treated at Sheba Medical Center (2009\u0026ndash;2024) were reviewed. Inclusion required P\u0026amp;I and paired cycloplegic refractions before surgery and 6\u0026ndash;36 months postoperatively. Pre- and postoperative spherical equivalent (SE) and cylinder were compared using paired t-tests, stratified by age at last procedure (\u0026lt;\u0026thinsp;24 vs\u0026thinsp;\u0026ge;\u0026thinsp;24 months). Proportions with any measurable cylinder were tested with McNemar\u0026rsquo;s test.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e\u003cp\u003eOf the 401 children screened, 25 met the inclusion criteria. Fourteen were treated before 24 months of age, and 11 at or after 24 months. SE showed a nonsignificant myopic shift (Δ = -0.43D, p\u0026thinsp;=\u0026thinsp;0.065). In contrast, cylinder values increased from \u0026minus;\u0026thinsp;0.39\u0026thinsp;\u0026plusmn;\u0026thinsp;0.70D to -0.87\u0026thinsp;\u0026plusmn;\u0026thinsp;0.98D (p\u0026thinsp;=\u0026thinsp;0.040). The proportion of measurable cylinder rose from 32% to 68% (p\u0026thinsp;=\u0026thinsp;0.012). Later treated children had a greater mean increase (to -1.20\u0026thinsp;\u0026plusmn;\u0026thinsp;1.14D), and among those with baseline cylinder, the mean reached \u0026minus;\u0026thinsp;1.47D, which is a borderline amblyogenic value.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e\u003cp\u003eCNLDO is associated with increased cylinder and astigmatism, with children treated later in life showing an even higher risk of progression toward amblyogenic levels. These findings support structured postoperative refractive follow-up and early surgical intervention whenever possible.\u003c/p\u003e","manuscriptTitle":"Changes in Astigmatism in Children With Congenital Nasolacrimal Duct Obstruction Undergoing Probing and Irrigation","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-11-10 05:37:46","doi":"10.21203/rs.3.rs-7854321/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"ba6a19c9-b2dd-47e1-ae0a-348b32c64afd","owner":[],"postedDate":"November 10th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":57019363,"name":"Health sciences/Diseases/Eye diseases/Refractive errors"},{"id":57019364,"name":"Health sciences/Diseases/Eye diseases/Lacrimal apparatus diseases"}],"tags":[],"updatedAt":"2026-01-29T15:36:54+00:00","versionOfRecord":[],"versionCreatedAt":"2025-11-10 05:37:46","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7854321","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7854321","identity":"rs-7854321","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}