Diagnostic and Therapeutic Impact of PCR in Uveitis: Real-World Data from Intraocular Fluid Analysis

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Methods: A retrospective review was conducted on 45 eyes of 45 uveitis patients. PCR testing was performed on AH (n=24) and vitreous samples (n=21) for Herpes simplex virus (HSV), Varicella zoster virus (VZV), Cytomegalovirus (CMV), Toxoplasma gondii , and Mycobacterium tuberculosis based on clinical suspicion. Demographic characteristics, immune status, uveitis type, sampling site, PCR results, and changes between initial and final diagnosis were recorded. The contribution of PCR results to the final diagnosis was classified as “confirmed” or “changed.” Results: The mean patient age was 47.4±17.3 years, with 51.1% females. 28.9% of the patients were immunosupressed. Overall PCR positivity was 42.2 % (19/45), with a higher positivity in immunosuppressed patients (61.5%) than in immunocompetent individuals (34.4%) (p=0.094). AH samples demonstrated 50.0% positivity, whereas vitreous samples yielded 33.3%. PCR results led to a change in clinical diagnosis in 33.3% (15/45) of the patients. Positive PCR findings were significantly associated with a diagnostic certanity (p=0.006). PCR findings influenced clinical management in 80% of the patients. Conclusion: PCR analysis of intraocular fluids provides a diagnostic value in the evaluation of uveitis. Both positive and negative results meaningfully inform clinical decision making by confirming infectious etiologies or supporting non infectious diagnosis. Our findings reinforce PCR as a critical adjunct in the diagnostic work-up of uveitis, particularly in complex cases where clinical features alone are insufficient. uveitis polymerase chain reaction aqueous humor vitreous infectious uveitis Introduction Uveitis comprises a heterogenous group of intraocular inflammatory disorders with infectious and non-infectious etiologies and may also occur in association with systemic disease. Globally, uveitis remains a major cause of visual loss, accounting for up to 20% of cases of legal blindness [1]. Its prevalence and underlying causes vary according to demographic, geographic, environmental, genetic, and socioeconomic factors [2]. Timely and accurate diagnosis is essential, as delays in appropriate treatment may lead to irreversible structural damage and permanent visual impairment. A definite diagnosis can be reached in approximately 70% of patients through detailed history, comprehensive ocular and systemic examinations, and targeted laborator testing. However, the remaining cases often present diagnostic challenges due to several factors: absence of clinically evident systemic disease, overlapping clinical manifestations across different uveitic syndromes, and phenotypic variation within a single disease entity. Additional limitations arise when dense vitreous opacities or haze obscure fundus visualization [3,4]. In such scenarios, polymerase chain reaction (PCR) analysis of intraocular fluids- including aqueous humor (AH) or vitreous samples- can serve as a valuable adjunct. Polymerase chain reaction -based techniques have been studied and applied to intraocular fluids since the end of the 20th century [5,6]. They have been used to discriminete infectious from non infectious causes of uveitis and to identify specific pathogens. Prior studies have reported varying diagnostic yields. According to Rothova et al., in patients with posterior uveitis, AH analysis was useful for etiological diagnosis in approximately 29% of cases [7]. The present study aims to report our indications and results of PCR analysis of AH and vitreous samples in patients with uveitis and to evaluate its diagnostic contribution and analyze findings across clinical subgroups. Materials and Methods A retrospective review was conducted on 45 uveitis patients who were followed up at the Uveitis Department of our clinic and underwent PCR analysis of intraocular fluids between March 2017 and April 2025. Patients under 18 years of age were excluded. Aqueous humor (n=24) and vitreous (n=21) samples obtained from 45 eyes with a preliminary diagnosis of infectious uveitis were analyzed by PCR for Herpes Simplex Virus (HSV), Varicella Zoster Virus (VZV), Cytomegalovirus (CMV), Toxoplasma gondii , and Mycobacterium tuberculosis complex (when indicated). Patients demographic features, immune status, anatomical localization and etiology of uveitis, laterality of the affected eye and analysed eye, sampling site, PCR results, initial and final diagnosis were recorded and analyzed. PCR results were categorized as "confirmed," or "changed" relative to the initial diagnosis. All patients underwent a complete ophthalmologic examination at each visit, including measurement of the best corrected visual acuity (BCVA) assessment with Snellen charts, slit-lamp biomicroscopic examination before and after dilatation with mydriatics, dilated fundus examination and intraocular pressure (IOP) measurement with applanation tonometry and optical coherence tomography (OCT). Fluoresceine angiography (FA), indocyanine green angiography (ICG) and ocular ultrasonography were performed as indicated. Based on the initial clinical diagnosis, laboratory and systemic investigation was carried out for infectious or noninfectious diagnosis. Best corrected visual acuity values were converted to logarithm of the minimal angle of resolution (logMAR) for statistical analysis. Uveitis was classified according to the SUN Working Group criteria [8]. Statistical analyses were performed using SPSS version 27.0 with p<0.05 was considered statistically significant. This study was conducted in accordance with the principles of the Declaration of Helsinki and was approved by the Ethics Committee of our institution on 29.09.2025 with the approval number 2025/010.99/20/24. A written informed consent was obtained from all participants. Intraocular Fluid Sampling and Molecular Analysis Intraocular fluid sampling was performed at operating room under sterile conditions. Aqueous humor sampling was performed via an anterior chamber paracentesis with a 30 G needle. At least 0.1 ml of aqueous was extracted for PCR analysis. Vitreus sampling was performed via vitreous tap using a 25 G needle or during pars plana vitrectomy. DNA extraction was performed using the QIASymphony (Qiagen, Germany) automated platform in accordance with the manufacturer’s instructions. Between March 2017 and March 2024, molecular detection of HSV, VZV, CMV and EBV was carried out using Artus® PCR kits (Qiagen, Germany) on the Rotor-Gene Q real-time PCR system. In March 2024, the workflow was further optimized through the implementation of NeuMoDx® 288 molecular system (Qiagen, Germany), which integrates automated nucleic acid extraction and real-time PCR amplification within a single closed platform. For Toxoplasma gondii, DNA extraction was performed using the Unio B24 automated extraction system (Unio Diagnostics, Turkey), and amplification was conducted with the Bosphore® Toxoplasma Detection Kit (Anatolia Geneworks, Turkey) based on real-time PCR methodology. For Mycobacterium tuberculosis complex, nucleic acid amplification testing was performed using the Cepheid® GeneXpert® MTB/RIF assay (Cepheid, USA), which enables simultaneous detection of M. tuberculosis DNA and rifampicin resistance-associated mutations in the rpoB gene region. Complementary analysis of ocular samples was defined according to the clinical suspicion and diagnostic indication. Results Fourty five eyes of 45 patients were included in the study with a mean age of 47.4 ± 17.3 (21-88) years. Among them 51.1% (23) were female and 48.9% (22) were male. Disease was unilateral in 33 (73.3%) and bilateral in 12 (26.7%) of the patients. Based on immune status, 32 (71.1%) of patients were immunocompetent, while 13 (28.9%) were immunosuppressed. Among the immunsupressed patients six (46.2%) were Human Immundeficiency Virus (HIV) positive. Anatomically 25 (55.6%) patients had panuveitis, 12 (26.7%) anterior uveitis, seven (15.6%) posterior uveitis and one (2.2%) intermediate uveitis. Median time from admission to PCR sampling was 5 [(1-370) (IQR= 28)] days. Among 45 patients, PCR sampling was performed from the AH in 24 (53.3%) patients and from the vitreous in 21 (46.7%) of them. Overall PCR positivity rate was 42.2% (n=19/45) and the median viral load was 790.50 copies/mL [(24-1.957.306) (IQR=11492)]. PCR positivity was observed in 34.4% (n=11/32) of immunocompetent patients and in 61.5% (n=8/13) of the immunosuppressed patients (p=0.094). Immunosuppressed patients had a higher viral load compared to immunocompetent cases but the result was not statistically significant (790.50 vs. 620.50 copies/mL; p=0.360). By sample site PCR positivity was 50,0% (n=12/24) in the AH and 33.3% (n=7/21) in the vitreous samples (p=0.259). Among the 12 PCR positive samples in the AH patients, 75% (9/12) were immuncompetent and 25% (3/12) were immunsupressed while the positivity of the PCR in the vitreous was 28.6% (2/7) in immunocompetent and 71.4% (5/7) in immunosuppressed patients. Table 1 presents the distribution of clinical characteristics based on the PCR results. Table 1. The distribution of clinical characteristics based on the PCR results. Variable PCR positive % (number of the patients) PCR negative % (number of the patients) p*value Laterality 0.467 - Unilateral 78.9 (15/19) 69,2 (18/26) - Bilateral 21.1 (4/19) 30,8 (8/26) Sampling site 0.259 -Aqueous humor 63.2 (12/19) 46.2 (12/26) - Vitreous 36.8 (7/19) 53.8 (14/26) Immun status 0.094 - Immunocompetent 57.9 (11/19) 80.8 (21/26) - Immunosuppressed 42.1 (8/19) 19.2 (5/26) Anatomic localization 0.700 - Anterior uveitis 26.3 (5/19) 26.9 (7/26) - Intermediate uveitis 0.0 (0/19) 3.8 (1/26) - Posterior uveitis 21.1 (4/19) 11.5 (3/26) - Panuveitis 52.6 (10/19) 57.7 (15/26) p* value: Fisher exact test, PCR: polimerase chain reaction The initial diagnosis were acute retinal necrosis (ARN) (15, 33.3%), CMV anterior uveitis (8, 17.8%), CMV retinitis (6,13.3%), frosted branch angiitis (4, 8.9%), Toxoplasma uveitis (4, 8.9%), viral anterior uveitis icluding VZV, HSV (3, 6.7%), idiopathic panuveitis (3, 6.7%), Fuchs uveitic syndrome (1, 2.2%) and tuberculosis uveitis (1, 2.2%). The final diagnosis after analysing of the PCR samples were: ARN (9, 20.0%), CMV anterior uveitis (8, 17.8%), CMV retinits (5, 11.1%), frosted branch angiitis (4, 8.9%), Toxoplasma uveitis (3, 6.7%), syphilitic uveitis (3, 6.7%), idiopathic panuveitis (3, 6.7%), primer vitreoretinal lymphoma (PVRL) (2, 4.4%), Fuchs uveitic syndrome (1, 2.2%) , tuberculosis uveitis (1, 2.2%), viral anterior uveitis (1, 2.2%), peripheric exudative hemorrhagic chorioretinitis (PEHC) (1, 2.2%), vasoproliferative tumor (VPT) (1, 2.2%), presumed ocular sarcoidosis (1, 2.2%), orbital apex syndrome (1, 2.2%) and subacute endophthalmitis (1, 2.2%). PCR results changed the clinical diagnosis in 15 (33.3%) of the 45 patients while in 30 (66.7%) patients the initial diagnosis were confirmed. Considering its effect on clinical management PCR results contributed to the clinical management in 80% of the patients. Regarding the sample site, analysis of the intraocular fluid provided valuable diagnostic information. Considering the 24 AH samples, PCR was positive in 12 (50.0%) and negative in 12 (50.0%) of them. Among PCR positive AH samples, the diagnosis was confirmed in 11 (91.7%) samples and changed in one (8.3%) whereas in PCR negative AH samples, the diagnosis was confirmed in six (50%) and changed in six (50%). For 21 vitreous samples PCR was positive in seven (33.3%) and negative in 14 (66.7%). Diagnositic consistency was observed in all of the seven (100%) of the PCR positive VH samples. Among PCR negative vitreous samples the diagnosis was confirmed in six (42.9 %) and changed in eight (57.1%) them. Details of the initial diagnosis, PCR sample site, PCR results and final diagnosis are shown in Table 2. Table 2. Details of the initial diagnosis, PCR sample site, PCR results and final diagnosis. Initial diagnosis Final diagnosis Sample site (PCR result) Patients (number) Aqueous humour (positive) Aqueous humour (negative) Vitreous (positive) Vitreous (negative) ARN ARN 6 2 1 9 PVRL 1 1 Syphilitic uveitis 1 2 3 Idiopathic panuveitis 1 1 2 CMV anterior uveitis CMV anterior uveitis 4 3 7 Fuchs uveitic syndrome 1 1 CMV retinitis CMV retinitis 5 5 PEHCR 1 1 Frosted branch angiitis Frosted branch angiitis 2 2 4 Toxoplasma uveitis Toxoplasma uveitis 1 2 3 VPT 1 1 Herpetic anterior uveitis Herpetic anterior uveitis 1 1 Orbital apex syndrome 1 1 Subacute endophthalmitis 1 1 Idiopatic pauveitis Idiopatic pauveitis 1 1 PVRL 1 1 Presumed ocular sarcoidosis 1 1 Fuchs uveitic syndrome CMV anterior uveitis 1 1 Tuberculosis associated uveitis Tuberculosis associated uveitis 1 1 12 12 7 14 45 PCR:polimerase chain reaction, ARN: acute retinal necrosis, PVRL:primer vitreo retinal lymphoma, PEHCR:progressive exudative hemorrhagic chorioretinopathy, VPT : vasoproliferative tumor These findings indicated that a positive PCR result played a statistically significant role in clinical management (p=0.006). Regarding anatomic localization of the uveitis, changes in the diagnosis was not statistically significant (p= 0.410). Discussion The overall PCR positivity rate in our study was 42.2%, aligning well with previously reported rates ranging between 26.2- 59.0% in the literature [7, 9-11]. However most studies in the literature evaluating PCR results and their diagnostic impact in uveitis have focused exclusively on infectious etiologies [5,9,12,13]. Unlike prior studies focusing solely on suspected infectious uveitis, our cohort included a heterogeneous group of patients including both infectious and non-infectious etiologies. Notably we also included patients in whom an infectious etiology was not initially suspected. In these cases, the purpose of PCR testing was not necessarily to identify a specific pathogen, but rather to confidently exclude infectious causes and thereby support a non-infectious diagnosis. For instance, in our study among four patients with frosted branch angiitis, PCR was performed to rule out cytomegalovirus infection, as well as in three patients with idiopathic panuveitis, the negative PCR results reinforced the non infectious nature of the disease. This approach highlights the dual value of intraocular PCR testing—not only as a diagnostic tool for detecting pathogens but also as a means of confirming their absence—thereby providing critical guidance for appropriate clinical management and therapeutic decision-making. PCR analysis of intraocular fluids especially vitreous may also be performed in severe inflammatory conditions with imminent risk of visual loss, in cases undergoing diagnostic vitrectomy, or when intraocular malignancy is suspected [14,15]. In this study, our findings demonstrated that PCR analysis also enabled differentiation from masquerade syndromes such as PVRL and non-infectious inflammatory conditions. In our study in two of our patients with panuveitis, vitreous samples were obtained during vitrectomy for diagnostic purposes, where anterior chamber sampling was unlikely to be informative. In these patients with idiopathic panuveitis, vitreous samples obtained during pars plana vitrectomy (PPV) were negative for infectious agents, as anticipated. In one of these cases, atypical B lymphocytes were detected in the vitreous. Although retinal biopsy could not be performed due to the absence of an accessible lesion, the presence of atypical lymphocytes in the vitreous, while not definitive, further supported our presumptive diagnosis of primary vitreoretinal lymphoma (PVRL). In the other case, despite the absence of a definitive diagnosis, the negative vitreous PCR results were consistent with our expectation of a non-infectious etiology. These examples highlight the value of intraocular fluid analysis in guiding differential diagnosis, Considering sample site, studies have shown anterior chamber PCR positivity rates of 19–78.5% and vitreous PCR positivity rates of 19–48% [5,10,16-18]. In our study although PCR analysis was performed on aqueous humor samples in 24 patients and on vitreous samples in 21 patients—indicating that nearly half of the intraocular samples were obtained from each site—aqueous humor sampling demonstrated a slightly higher PCR positivity (50.0%) compared to vitreous sampling (33.3%) which is in line with previous studies suggesting that anterior chamber paracentesis is often sufficient for diagnosis both posterior uveitis and panuveitis [7,15]. In contrast some studies pointed out the value of vitreous sample analysis for diagnostic purpose in case of posterior / panuveitis [5,14,19]. Differences in positivity rates between sampling sites likely reflect the diversity of clinical presentations and sampling indications rather than true differences in diagnostic yield and the positivity rates may vary among studies that include different patient populations and indications for sampling. In our study, vitreous samples for PCR analysis were obtained from one patient (100%) with intermediate uveitis. Among seven patients (100%) with posterior uveitis vitreous sampling was performed in all cases. Of the 25 patients with panuveitis PCR samples were collected from the anterior chamber in 12 (48%) patients and from the vitreous samples in 13 (52%) patients. Among the 24 patients from whom anterior chamber samples were obtained the remaining 12 (50%) as expected had anterior uveitis. This indicates that the decision regarding the sampling site should not depend solely on the anatomical classification of uveitis, but should be guided by a comprehensive evaluation of clinical suspicion and examination findings in conjunction with anatomical localization. Several factors may influence PCR positivity, including disease prevalence in the tested population, pathogen characteristics, sample type and volume, sampling and transport conditions, assay methodology, disease activity, immune status, and prior treatment that may reduce pathogen load [7,9,20]. Given that our study included a mixed cohort and was not designed to evaluate these variables, our focus was primarily on the diagnostic contribution and clinical impact of PCR analysis of intraocular fluids in patients with uveitis. rather than the absolute positivity rate. Our results demonstrated that PCR testing provided valuable diagnostic information, influencing clinical decision-making. PCR results confirmed or changed the initial diagnosis in 30 (66.7%) and 15 (33.3%) of the patients respectively highlighting its important adjunctive role in the diagnostic work up of uveitis. Among the 19 patients with positive PCR results the iniatial and final diagnosis were consistent in 18 cases while a diagnostic change was observed in one case. In contrast among the 26 PCR negative patients the iniatial and final diagnosis were consistent in 12 cases, whereas 14 patients required a revision of the diagnosis. Considering its effect on clinical management PCR results contributed to the clinical management in 80% of the cases. Notably, PCR findings contributed to clinical management in all PCR positive cases Among the PCR negative group, PCR results supported clinical decision making in 17 patients while no contribution to management was observed in 9 patients. This finding confirms that PCR tetsing of intraocular samples remains a reliable diagnostic tool in clinical practice. Althoug PCR positivity was a strong predictor of diagnostic certanity (p=0.006), negative results also provided important information by excluding infectious causes and prompting consideration of alternative etiologes. Therefore, both positive and negative PCR findings should be integrated with clinical, imaging and serologic data to optimize patient management. Although our findings highlight the clinical utility of intraocular PCR testing, there are several limitations which should be acknowledged. The retrospective design and relatively small sample size may limit the generalizability of the results. Comparative studies using standardized intraocular samples across various PCR methodologies with a larger sample size are warranted to better assess the diagnostic performance and ensure the reproducibility of results. Declarations Funding: The authors received no financial support for the research, authorship, and/or publication of this article. Competing Interests: The authors declare no conflict of interest. Ethics approval: This study was conducted in accordance with the Declaration of Helsinki and approved by the Institutional Ethics Committee (Aproval no: 2025/010.99/20/24, Date: 29.09.2025) Consent to Participate: Written informed consent was obtained from all participants included in the study. Consent for Publication: Not applicable. No identifying information of individual participants is included in this manuscript. Data Availability: The data supporting the findings of this study are not publicly available due to patient confidentiality. De-identified data may be made available from the corresponding author upon reasonable request and with the necessary approvals from the patients and the institutional authorities. Authors’ Contributions NZK: drafted the work, wrote the main manuscript text and made substantial contributions to acquisition, analysis, or interpretation of data SDT:made substantial contributions to the conception or design of the work, revised the work critically for important intellectual content MO:made substantial contributions to acquisition, analysis, or interpretation of data İP:made substantial contributions to the acquisition, analysis, or interpretation of data GA:made substantial contributions to the acquisition, analysis, or interpretation of data BT:revised the work critically for important intellectual content All authors read and approved the final manuscript . All authors agree to be accountable for all aspects of the work. Acknowledgments Not applicable References Suttorp-Schulten MS, Rothova A. The possible impact of uveitis in blindness: a literature survey. Br J Ophthalmol. 1996 Sep;80(9):844-8. 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BMC Ophthalmol. 2016 Oct 28;16(1):189. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted 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. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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07:24:47","extension":"html","order_by":4,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":83411,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-8320311/v1/baa3e71b2c605c37efc7cb2b.html"},{"id":105033252,"identity":"b23c18ad-5b37-4758-932d-337974c58b8c","added_by":"auto","created_at":"2026-03-20 07:15:53","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":613796,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8320311/v1/435a7dd0-155a-46f3-9798-cb71dd31c9d8.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Diagnostic and Therapeutic Impact of PCR in Uveitis: Real-World Data from Intraocular Fluid Analysis","fulltext":[{"header":"Introduction","content":"\u003cp\u003eUveitis comprises a heterogenous group of intraocular inflammatory disorders with infectious and non-infectious etiologies and may also occur in association with systemic disease. \u0026nbsp;Globally, uveitis remains a major cause of visual loss, accounting for up to 20% of cases of legal blindness [1]. Its prevalence and underlying causes vary according to demographic, geographic, environmental, genetic, and socioeconomic factors [2]. Timely and accurate diagnosis is essential, as delays in appropriate treatment may lead to irreversible structural damage and permanent visual impairment.\u003c/p\u003e\n\u003cp\u003eA definite diagnosis can be reached in approximately 70% of patients through detailed history, comprehensive ocular and systemic examinations, and targeted laborator testing. However, the remaining cases often present diagnostic challenges due to several factors: absence of clinically evident systemic disease, overlapping clinical manifestations across different uveitic syndromes, and phenotypic variation within a single disease entity. Additional limitations arise when dense vitreous opacities or haze obscure fundus visualization [3,4].\u003csup\u003e\u0026nbsp;\u0026nbsp;\u003c/sup\u003eIn such scenarios, polymerase chain reaction (PCR) analysis of intraocular fluids- including aqueous humor (AH) or vitreous samples- can serve as a valuable adjunct.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;Polymerase chain reaction -based techniques have been studied and applied to intraocular fluids since the end of the 20th century [5,6]. They have been used to discriminete infectious from non infectious causes of uveitis and to identify specific pathogens. Prior studies have reported varying diagnostic yields. According to Rothova et al., in patients with posterior uveitis, AH analysis was useful for etiological diagnosis in approximately 29% of cases [7].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe present study aims to report our indications and results of PCR analysis of AH and vitreous samples in patients with uveitis and to evaluate its diagnostic contribution and analyze findings across clinical subgroups.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003eA retrospective review was conducted on 45 uveitis patients who were followed up at the Uveitis Department of our clinic and underwent PCR analysis of intraocular fluids between March 2017 and April 2025. Patients under 18 years of age were excluded.\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e Aqueous humor (n=24) and vitreous (n=21) samples obtained from 45 eyes with a preliminary diagnosis of infectious uveitis were analyzed by PCR for \u003cem\u003eHerpes Simplex Virus\u003c/em\u003e (HSV), \u003cem\u003eVaricella Zoster Virus\u003c/em\u003e (VZV), \u003cem\u003eCytomegalovirus\u003c/em\u003e (CMV), \u003cem\u003eToxoplasma gondii\u003c/em\u003e, and \u003cem\u003eMycobacterium tuberculosis\u003c/em\u003e \u003cem\u003ecomplex\u003c/em\u003e (when indicated).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003ePatients demographic features, immune status, anatomical localization and etiology of uveitis, laterality of the affected eye and analysed eye, sampling site, PCR results, initial and final diagnosis were recorded and analyzed. PCR results were categorized as \u0026quot;confirmed,\u0026quot; or \u0026quot;changed\u0026quot; relative to the initial diagnosis.\u003c/p\u003e\n\u003cp\u003eAll patients underwent a complete ophthalmologic examination at each visit, including measurement of the best corrected visual acuity (BCVA) assessment with Snellen charts, slit-lamp biomicroscopic examination before and after dilatation with mydriatics, dilated fundus examination and intraocular pressure (IOP) measurement with applanation tonometry and optical coherence tomography (OCT). Fluoresceine angiography (FA), indocyanine green angiography (ICG) and ocular ultrasonography were performed as indicated.\u0026nbsp;Based on the initial clinical diagnosis, laboratory and systemic investigation was carried out for infectious or noninfectious diagnosis. Best corrected visual acuity values were converted to logarithm of the minimal angle of resolution (logMAR) for statistical analysis. Uveitis was classified according to the SUN Working Group criteria [8]. Statistical analyses were performed using SPSS version 27.0 with p\u0026lt;0.05 was considered statistically significant.\u003c/p\u003e\n\u003cp\u003eThis study was conducted in accordance with the principles of the Declaration of Helsinki and was approved by the Ethics Committee of our institution on 29.09.2025 with the approval number 2025/010.99/20/24. A written informed consent was obtained from all participants.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eIntraocular Fluid Sampling and Molecular Analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIntraocular fluid sampling was performed at operating room under sterile conditions. Aqueous humor sampling \u0026nbsp;was performed via an anterior chamber paracentesis with a 30 G needle. \u0026nbsp; At least 0.1 ml of aqueous was extracted for PCR analysis. Vitreus sampling was performed via vitreous tap using a 25 G needle or during pars plana vitrectomy.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eDNA extraction was performed using the QIASymphony (Qiagen, Germany) automated platform in accordance with the manufacturer\u0026rsquo;s instructions. Between March 2017 and March 2024, molecular detection of HSV, VZV, CMV and EBV was carried out using Artus\u0026reg; PCR kits (Qiagen, Germany) on the Rotor-Gene Q real-time PCR system. \u0026nbsp;In March 2024, the workflow was further optimized through the implementation of NeuMoDx\u0026reg; 288 molecular system (Qiagen, Germany), which integrates automated nucleic acid extraction and real-time PCR amplification within a single closed platform.\u003c/p\u003e\n\u003cp\u003eFor \u003cem\u003eToxoplasma gondii,\u003c/em\u003e DNA extraction was performed using the Unio B24 automated extraction system (Unio Diagnostics, Turkey), and amplification was conducted with the Bosphore\u0026reg; \u003cem\u003eToxoplasma\u0026nbsp;\u003c/em\u003eDetection Kit (Anatolia Geneworks, Turkey) based on real-time PCR methodology. For \u003cem\u003eMycobacterium tuberculosis\u003c/em\u003e complex, nucleic acid amplification testing was performed using the Cepheid\u0026reg; GeneXpert\u0026reg; MTB/RIF assay (Cepheid, USA), which enables simultaneous detection of \u003cem\u003eM. tuberculosis\u003c/em\u003e DNA and rifampicin resistance-associated mutations in the \u003cem\u003erpoB\u003c/em\u003e gene region. Complementary analysis of ocular samples was defined according to the clinical suspicion and diagnostic indication.\u0026nbsp;\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eFourty five eyes of 45 patients were included in the study with a mean age of 47.4 \u0026plusmn; 17.3 (21-88) years. \u0026nbsp;Among them 51.1% (23) were female and 48.9% (22) were male. Disease was unilateral in 33 (73.3%) and bilateral in 12 (26.7%) of the patients. Based on immune status, 32 (71.1%) of patients were immunocompetent, while 13 (28.9%) were immunosuppressed. Among the immunsupressed patients six (46.2%) were \u003cem\u003eHuman Immundeficiency Virus\u003c/em\u003e (HIV) positive. Anatomically 25 (55.6%) patients had panuveitis, 12 (26.7%) anterior uveitis, seven (15.6%) posterior uveitis and one (2.2%) intermediate uveitis.\u003c/p\u003e\n\u003cp\u003eMedian time from admission to PCR sampling was 5 [(1-370) (IQR= 28)] days. \u0026nbsp; Among 45 patients, PCR sampling was performed from the AH in 24 (53.3%) patients and from the vitreous in 21 (46.7%) of them. Overall PCR positivity rate was 42.2% (n=19/45) and the median viral load was 790.50 copies/mL [(24-1.957.306) (IQR=11492)]. PCR positivity was observed in 34.4% (n=11/32) of immunocompetent patients and in 61.5% (n=8/13) of the immunosuppressed patients (p=0.094). Immunosuppressed patients had a higher viral load compared to immunocompetent cases but the result was not statistically significant (790.50 vs. 620.50 copies/mL; p=0.360). \u0026nbsp;By sample site PCR positivity was 50,0% (n=12/24) in the AH and 33.3% (n=7/21) in the vitreous samples (p=0.259). Among the 12 PCR positive samples in the AH patients, 75% (9/12) were immuncompetent and 25% (3/12) were immunsupressed while the positivity of the PCR in the vitreous was 28.6% (2/7) in immunocompetent and 71.4% (5/7) in immunosuppressed patients. Table 1 presents the distribution of clinical characteristics based on the PCR results.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTable 1. The distribution of clinical characteristics based on the PCR results.\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eVariable\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003ePCR positive\u003c/p\u003e\n \u003cp\u003e% (number of the patients)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003ePCR negative\u003c/p\u003e\n \u003cp\u003e% (number of the patients)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003ep*value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eLaterality\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.467\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;- Unilateral\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e78.9 (15/19)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e69,2 (18/26)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;- Bilateral\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e21.1 (4/19)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e30,8 \u0026nbsp;(8/26)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eSampling site\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.259\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;-Aqueous humor\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e63.2 (12/19)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e46.2 (12/26)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;- Vitreous\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e36.8 \u0026nbsp;(7/19)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e53.8 (14/26)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eImmun status\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.094\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;- Immunocompetent\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e57.9 (11/19)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e80.8 (21/26)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;- Immunosuppressed\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e42.1 (8/19)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e19.2 \u0026nbsp;(5/26)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eAnatomic localization\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.700\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;- Anterior uveitis\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e26.3 \u0026nbsp;(5/19)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e26.9 \u0026nbsp; (7/26)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;- Intermediate uveitis\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp; 0.0 \u0026nbsp; \u0026nbsp; (0/19)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;3.8 \u0026nbsp; \u0026nbsp; (1/26)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;- Posterior uveitis\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e21.1 \u0026nbsp;(4/19)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;11.5 \u0026nbsp; \u0026nbsp; (3/26)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;- Panuveitis\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e52.6 \u0026nbsp;(10/19)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e57.7 \u0026nbsp; (15/26)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;p* value: Fisher exact test, PCR: polimerase chain reaction\u003c/p\u003e\n\u003cp\u003eThe initial diagnosis were acute retinal necrosis (ARN) (15, 33.3%), CMV anterior uveitis (8, 17.8%), CMV retinitis (6,13.3%), frosted branch angiitis (4, 8.9%), Toxoplasma uveitis (4, 8.9%), viral anterior uveitis icluding VZV, HSV (3, 6.7%), idiopathic panuveitis (3, 6.7%), Fuchs uveitic syndrome (1, 2.2%) and tuberculosis uveitis (1, 2.2%).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe final diagnosis \u0026nbsp;after analysing of the PCR samples were: \u0026nbsp;ARN (9, 20.0%), CMV anterior uveitis (8, 17.8%), CMV retinits (5, 11.1%), frosted branch angiitis (4, 8.9%), Toxoplasma uveitis (3, 6.7%), syphilitic uveitis (3, 6.7%), idiopathic panuveitis (3, \u0026nbsp;6.7%), primer vitreoretinal lymphoma (PVRL) (2, 4.4%), Fuchs uveitic syndrome (1, 2.2%) , tuberculosis uveitis (1, 2.2%), \u0026nbsp;viral anterior uveitis (1, 2.2%), peripheric exudative hemorrhagic chorioretinitis (PEHC) (1, 2.2%), vasoproliferative tumor (VPT) (1, 2.2%), presumed ocular sarcoidosis (1, 2.2%), orbital apex syndrome (1, 2.2%) and \u0026nbsp; subacute endophthalmitis (1, 2.2%). \u0026nbsp;\u003c/p\u003e\n\u003cp\u003ePCR results changed the \u0026nbsp;clinical diagnosis in 15 (33.3%) of the 45 patients while in 30 (66.7%) patients the initial diagnosis were confirmed. Considering its effect on clinical management PCR results contributed to the clinical management in 80% of the patients.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;Regarding the sample site, analysis of the intraocular fluid provided valuable diagnostic information. Considering the 24 AH samples, PCR was positive in 12 (50.0%) and negative in 12 (50.0%) of them. Among PCR positive AH samples, the diagnosis was confirmed in 11 (91.7%) samples and changed in one (8.3%) whereas in PCR negative AH samples, the diagnosis was confirmed in six (50%) and changed in six (50%). For 21 vitreous samples PCR was positive in seven (33.3%) and negative in 14 (66.7%). Diagnositic consistency was observed in all of the seven (100%) of the PCR positive VH samples. Among PCR negative vitreous samples the diagnosis was confirmed in six (42.9 %) and changed in eight (57.1%) them. \u0026nbsp; Details of the initial diagnosis, PCR sample site, PCR results and final diagnosis are shown in Table 2.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTable 2. Details of the initial diagnosis, PCR sample site, PCR results and final diagnosis.\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"602\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eInitial diagnosis\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eFinal diagnosis\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eSample site\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;(PCR result)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ePatients\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(number)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eAqueous humour\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(positive)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eAqueous humour\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(negative)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eVitreous\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(positive)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eVitreous\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(negative)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eARN\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eARN\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003ePVRL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eSyphilitic\u003c/p\u003e\n \u003cp\u003euveitis\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eIdiopathic panuveitis\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eCMV anterior uveitis\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eCMV anterior uveitis\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eFuchs uveitic syndrome\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eCMV retinitis\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eCMV retinitis\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003ePEHCR\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eFrosted branch angiitis\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eFrosted branch angiitis\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e4\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eToxoplasma uveitis\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eToxoplasma uveitis\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eVPT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eHerpetic anterior uveitis\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eHerpetic anterior uveitis\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eOrbital apex syndrome\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eSubacute endophthalmitis\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eIdiopatic pauveitis\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eIdiopatic pauveitis\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003ePVRL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003ePresumed ocular sarcoidosis\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eFuchs uveitic syndrome\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eCMV anterior uveitis\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e1\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e1\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eTuberculosis associated uveitis\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eTuberculosis associated uveitis\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e12\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e12\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e7\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e14\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e45\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003ePCR:polimerase chain reaction, ARN: acute retinal necrosis, PVRL:primer vitreo retinal lymphoma, PEHCR:progressive exudative hemorrhagic chorioretinopathy, VPT : vasoproliferative tumor\u003c/p\u003e\n\u003cp\u003eThese findings indicated that a positive PCR result played a statistically significant role in clinical management (p=0.006).\u003c/p\u003e\n\u003cp\u003eRegarding anatomic localization of the uveitis, changes in the diagnosis was not statistically significant (p= 0.410).\u0026nbsp;\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe overall PCR positivity rate in our study was 42.2%, aligning well with previously reported rates ranging between 26.2- 59.0% in the literature [7, 9-11]. However most studies in the literature evaluating PCR results and their diagnostic impact in uveitis have focused exclusively on infectious etiologies [5,9,12,13]. Unlike prior studies focusing solely on suspected infectious uveitis, our cohort included a heterogeneous group of patients including both infectious and non-infectious etiologies. \u0026nbsp;Notably we also included patients in whom an infectious etiology was not initially suspected. In these cases, the purpose of PCR testing was not necessarily to identify a specific pathogen, but rather to confidently exclude infectious causes and thereby support a non-infectious diagnosis. For instance, in our study among four patients with frosted branch angiitis, PCR was performed to rule out cytomegalovirus infection, as well as in three patients with idiopathic panuveitis, the negative PCR results reinforced the non infectious nature of the disease. This approach highlights the dual value of intraocular PCR testing\u0026mdash;not only as a diagnostic tool for detecting pathogens but also as a means of confirming their absence\u0026mdash;thereby providing critical guidance for appropriate clinical management and therapeutic decision-making.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003ePCR analysis of intraocular fluids especially vitreous may also be performed in severe inflammatory conditions with imminent risk of visual loss, in cases undergoing diagnostic vitrectomy, or when intraocular malignancy is suspected [14,15]. In this study, our findings demonstrated that PCR analysis also enabled differentiation from masquerade syndromes such as PVRL and non-infectious inflammatory conditions. In our study in two of our patients with panuveitis, vitreous samples were obtained during vitrectomy for diagnostic purposes, where anterior chamber sampling was unlikely to be informative. In these patients with idiopathic panuveitis, vitreous samples obtained during pars plana vitrectomy (PPV) were negative for infectious agents, as anticipated. In one of these cases, atypical B lymphocytes were detected in the vitreous. Although retinal biopsy could not be performed due to the absence of an accessible lesion, the presence of atypical lymphocytes in the vitreous, while not definitive, further supported our presumptive diagnosis of primary vitreoretinal lymphoma (PVRL). In the other case, despite the absence of a definitive diagnosis, the negative vitreous PCR results were consistent with our expectation of a non-infectious etiology. These examples highlight the value of intraocular fluid analysis in guiding differential diagnosis,\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eConsidering sample site, studies have shown anterior chamber PCR positivity rates of 19\u0026ndash;78.5% and vitreous PCR positivity rates of 19\u0026ndash;48% [5,10,16-18]. In our study although PCR analysis was performed on aqueous humor samples in 24 patients and on vitreous samples in 21 patients\u0026mdash;indicating that nearly half of the intraocular samples were obtained from each site\u0026mdash;aqueous humor sampling demonstrated a slightly higher PCR positivity (50.0%) compared to vitreous sampling (33.3%) which is in line with previous studies \u0026nbsp; suggesting \u0026nbsp;that anterior chamber paracentesis is often sufficient for diagnosis both posterior uveitis and panuveitis [7,15]. In contrast some studies pointed out the value of vitreous sample analysis for diagnostic purpose in case of posterior / panuveitis [5,14,19]. \u0026nbsp;Differences in positivity rates between sampling sites likely reflect the diversity of clinical presentations and sampling indications rather than true differences in diagnostic yield and the positivity rates may vary among studies that include different patient populations and indications for sampling.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIn our study, vitreous samples for PCR analysis were obtained from one patient (100%) with intermediate uveitis. Among seven patients (100%) with posterior uveitis vitreous sampling was performed in all cases. Of the 25 patients with panuveitis PCR samples were collected from the anterior chamber in 12 (48%) patients and from the vitreous samples in 13 (52%) patients. Among the 24 patients from whom anterior chamber samples were obtained the remaining 12 (50%) as expected had anterior uveitis. This indicates that the decision regarding the sampling site should not depend solely on the anatomical classification of uveitis, but should be guided by a comprehensive evaluation of clinical suspicion and examination findings in conjunction with anatomical localization.\u003c/p\u003e\n\u003cp\u003eSeveral factors may influence PCR positivity, including disease prevalence in the tested population, pathogen characteristics, sample type and volume, sampling and transport conditions, assay methodology, disease activity, immune status, and prior treatment that may reduce pathogen load\u003csup\u003e\u0026nbsp;\u003c/sup\u003e[7,9,20]. Given that our study included a mixed cohort and was not designed to evaluate these variables, our focus was primarily on the diagnostic contribution and clinical impact of PCR analysis of intraocular fluids in patients with uveitis. rather than the absolute positivity rate. Our results demonstrated that PCR testing provided valuable diagnostic information, influencing clinical decision-making. PCR results confirmed or changed the initial diagnosis in 30 (66.7%) and 15 (33.3%) of the patients respectively highlighting its important adjunctive role in the diagnostic work up of uveitis. \u0026nbsp;Among the 19 patients with positive PCR results the iniatial and final diagnosis \u0026nbsp;were consistent in 18 cases while a diagnostic change was observed in one case. In contrast among the 26 PCR negative patients \u0026nbsp; the iniatial and final diagnosis \u0026nbsp; were consistent in 12 cases, whereas 14 patients required a revision of the diagnosis. Considering its effect on clinical management PCR results contributed to the clinical management in 80% of the cases. Notably, PCR findings contributed to clinical management in all PCR positive cases Among the PCR negative group, PCR results supported clinical \u0026nbsp; decision making in 17 patients while no contribution to management was observed in 9 patients. \u0026nbsp;This finding confirms that PCR tetsing of intraocular samples remains a reliable diagnostic tool in clinical practice.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAlthoug PCR positivity was a strong predictor of diagnostic certanity (p=0.006), negative results also provided important information by excluding infectious causes and prompting consideration of alternative etiologes. Therefore, both positive and \u0026nbsp;negative \u0026nbsp;PCR findings should be integrated with clinical, imaging and serologic data to optimize patient management.\u003c/p\u003e\n\u003cp\u003eAlthough our findings highlight the clinical utility of intraocular PCR testing, there are several limitations which should be acknowledged. The retrospective design and relatively small sample size may limit the generalizability of the results. \u0026nbsp;Comparative studies using standardized \u0026nbsp;intraocular samples across various PCR methodologies with a larger sample size are warranted to better assess the diagnostic performance and ensure the reproducibility of results.\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eFunding:\u003c/strong\u003eThe authors received no financial support for the research, authorship, and/or publication of this article.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting Interests:\u003c/strong\u003e The authors declare no conflict of interest.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval:\u003c/strong\u003eThis study was conducted in accordance with the Declaration of Helsinki and approved by the Institutional Ethics Committee (Aproval no: 2025/010.99/20/24, Date: 29.09.2025)\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to Participate:\u003c/strong\u003eWritten informed consent was obtained from all participants included in the study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for Publication:\u003c/strong\u003eNot applicable. No identifying information of individual participants is included in this manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData Availability:\u003c/strong\u003eThe data supporting the findings of this study are not publicly available due to patient confidentiality. De-identified data may be made available from the corresponding author upon reasonable request and with the necessary approvals from the patients and the institutional authorities.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; Contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNZK: drafted the work, wrote the main manuscript text \u0026nbsp;and made substantial contributions to acquisition, analysis, or interpretation of data\u003c/p\u003e\n\u003cp\u003eSDT:made substantial contributions to the conception or design of the work, revised the work critically for important intellectual content\u003c/p\u003e\n\u003cp\u003eMO:made substantial contributions to acquisition, analysis, or interpretation of data\u003c/p\u003e\n\u003cp\u003eİP:made substantial contributions to the acquisition, analysis, or interpretation of data\u003c/p\u003e\n\u003cp\u003eGA:made substantial contributions to the acquisition, analysis, or interpretation of data\u003c/p\u003e\n\u003cp\u003eBT:revised the work critically for important intellectual content\u003c/p\u003e\n\u003cp\u003eAll authors read and approved the final manuscript\u003cstrong\u003e.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors agree to be accountable for all aspects of the work.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eSuttorp-Schulten MS, Rothova A. The possible impact of uveitis in blindness: a literature survey. Br J Ophthalmol. 1996 Sep;80(9):844-8.\u003c/li\u003e\n\u003cli\u003eTsirouki T, Dastiridou A, Symeonidis C, Tounakaki O, Brazitikou I, Kalogeropoulos C, et al. A Focus on the Epidemiology of Uveitis. Ocul Immunol Inflamm. 2018;26(1):2-16. \u003c/li\u003e\n\u003cli\u003eRathinam SR, Tugal-Tutkun I, Agarwal M, Rajesh V, Egriparmak M, Patnaik G. Immunological tests and their interpretation in uveitis. Indian J Ophthalmol. 2020 Sep;68(9):1737-48. \u003c/li\u003e\n\u003cli\u003eSato T, Kinoshita R, Taguchi M, Sugita S, Kaburaki T, Sakurai Y, et al. Assessment of diagnostic and therapeutic vitrectomy for vitreous opacity associated with uveitis with various etiologies. Medicine (Baltimore). 2018 Jan;97(2):e9491.\u003c/li\u003e\n\u003cli\u003eSantos FF, Commodaro AG, Souza AV, Pinho JR, Sitnik R, Garcia C, et al. Real-time PCR in infectious uveitis as an alternative diagnosis. Arq Bras Oftalmol. 2011 Jul-Aug;74(4):258-61.\u003c/li\u003e\n\u003cli\u003eMochizuki M, Sugita S, Kamoi K, Takase H. A new era of uveitis: impact of polymerase chain reaction in intraocular inflammatory diseases. Jpn J Ophthalmol. 2017 Jan;61(1):1-20.\u003c/li\u003e\n\u003cli\u003eRothova A, de Boer JH, Ten Dam-van Loon NH, Postma G, de Visser L, Zuurveen SJ, et al. Usefulness of aqueous humor analysis for the diagnosis of posterior uveitis. Ophthalmology. 2008 Feb;115(2):306-11. \u003c/li\u003e\n\u003cli\u003eJabs DA, Nussenblatt RB, Rosenbaum JT; Standardization of Uveitis Nomenclature (SUN) Working Group. Standardization of uveitis nomenclature for reporting clinical data. Results of the First International Workshop. Am J Ophthalmol. 2005 Sep;140(3):509-16. \u003c/li\u003e\n\u003cli\u003eKumar A, Singh MP, Bansal R, Gupta A, Ram J, Ratho RK. Development and evaluation of multiplex real-time PCR for diagnosis of HSV-1, VZV, CMV, and Toxoplasma gondii in patients with infectious uveitis. Diagn Microbiol Infect Dis. 2017 Nov;89(3):191-96.\u003c/li\u003e\n\u003cli\u003eKongyai N, Pathanapitoon K, Sirirungsi W, Kunavisarut P, de Groot-Mijnes JD, Rothova A. Infectious causes of posterior uveitis and panuveitis in Thailand. Jpn J Ophthalmol. 2012 Jul;56(4):390-95.\u003c/li\u003e\n\u003cli\u003eScheepers MA, Lecuona KA, Rogers G, Bunce C, Corcoran C, Michaelides M. The value of routine polymerase chain reaction analysis of intraocular fluid specimens in the diagnosis of infectious posterior uveitis. ScientificWorldJournal. 2013 Oct 22;2013:545149.\u003c/li\u003e\n\u003cli\u003eKharel Sitaula R, Janani MK, Madhavan HN, Biswas J. Outcome of polymerase chain reaction (PCR) analysis in 100 suspected cases of infectious uveitis. J Ophthalmic Inflamm Infect. 2018 Jan 10;8(1):2. \u003c/li\u003e\n\u003cli\u003eTombolini B, Menean M, Cicinelli MV, Marchese A, Cavalleri M, Brambati M, et al. Diagnostic and therapeutic results of aqueous real-time polymerase chain reaction in infectious uveitis. Can J Ophthalmol. 2024 Aug;59(4):e365-e370.\u003c/li\u003e\n\u003cli\u003eOahalou A, Schellekens PA, de Groot-Mijnes JD, Rothova A. Diagnostic pars plana vitrectomy and aqueous analyses in patients with uveitis of unknown cause. Retina. 2014 Jan;34(1):108-14. \u003c/li\u003e\n\u003cli\u003eSantos HNVD, Ferracioli-Oda E, Barbosa TS, Otani CSV, Tanaka T, Silva LCSD, et al.H. Usefulness of aqueous and vitreous humor analysis in infectious uveitis. Clinics (Sao Paulo). 2020 Jan 24;75:e1498.\u003c/li\u003e\n\u003cli\u003eNakano S, Tomaru Y, Kubota T, Takase H, Mochizuki M, Shimizu N, et al.; Strip PCR Project Group. Evaluation of a Multiplex Strip PCR Test for Infectious Uveitis: A Prospective Multicenter Study. Am J Ophthalmol. 2020 May;213:252-59.\u003c/li\u003e\n\u003cli\u003eFallon J, Narayan S, Lin J, Sassoon J, Llop S. The impact of polymerase chain reaction (PCR) on diagnosis and management of infectious uveitis at a tertiary care facility. J Ophthalmic Inflamm Infect. 2022 Jan 6;12(1):1.\u003c/li\u003e\n\u003cli\u003eCalvo CM, Khan MA, Mehta S, Garg SJ, Dunn JP. Correlation of Clinical Outcomes with Quantitative Polymerase Chain Reaction DNA Copy Number in Patients with Acute Retinal Necrosis. Ocul Immunol Inflamm. 2017 Apr;25(2):246-52.\u003c/li\u003e\n\u003cli\u003eJeroudi A, Yeh S. Diagnostic vitrectomy for infectious uveitis. Int Ophthalmol Clin. 2014 Spring;54(2):173-97.\u003c/li\u003e\n\u003cli\u003eChronopoulos A, Roquelaure D, Souteyrand G, Seebach JD, Schutz JS, Thumann G. Aqueous humor polymerase chain reaction in uveitis - utility and safety. BMC Ophthalmol. 2016 Oct 28;16(1):189. \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":"uveitis, polymerase chain reaction, aqueous humor, vitreous, infectious uveitis","lastPublishedDoi":"10.21203/rs.3.rs-8320311/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8320311/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003ePurpose:\u003c/strong\u003e\u003cbr\u003e\nTo evaluate the diagnostic utility and clinical impact of polymerase chain reaction (PCR) analysis of aqueous humor (AH) and vitreous samples in patients with uveitis of diverse etiologies.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods:\u003c/strong\u003e\u003cbr\u003e\nA retrospective review was conducted on 45 eyes of 45 uveitis patients. PCR testing was performed on AH (n=24) and vitreous samples (n=21) for \u003cem\u003eHerpes simplex virus\u003c/em\u003e (HSV), \u003cem\u003eVaricella zoster virus\u003c/em\u003e (VZV), \u003cem\u003eCytomegalovirus\u003c/em\u003e(CMV), \u003cem\u003eToxoplasma gondii\u003c/em\u003e, and \u003cem\u003eMycobacterium tuberculosis \u003c/em\u003ebased on clinical suspicion. Demographic characteristics, immune status, uveitis type, sampling site, PCR results, and changes between initial and final diagnosis were recorded. The contribution of PCR results to the final diagnosis was classified as “confirmed” or “changed.”\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults:\u003c/strong\u003e\u003cbr\u003e\nThe mean patient age was 47.4±17.3 years, with 51.1% females. 28.9% of the patients were immunosupressed. Overall PCR positivity was 42.2 % (19/45), with a higher positivity in immunosuppressed patients (61.5%) than in immunocompetent individuals (34.4%) (p=0.094). AH samples demonstrated 50.0% positivity, whereas vitreous samples yielded 33.3%. PCR results led to a change in clinical diagnosis in 33.3% (15/45) of the patients. Positive PCR findings were significantly associated with a diagnostic certanity (p=0.006). PCR findings influenced clinical management in 80% of the patients.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion:\u003c/strong\u003e\u003cbr\u003e\nPCR analysis of intraocular fluids provides a diagnostic value in the evaluation of uveitis. Both positive and negative results meaningfully inform clinical decision making by confirming infectious etiologies or supporting non infectious diagnosis. Our findings reinforce PCR as a critical adjunct in the diagnostic work-up of uveitis, particularly in complex cases where clinical features alone are insufficient.\u003c/p\u003e","manuscriptTitle":"Diagnostic and Therapeutic Impact of PCR in Uveitis: Real-World Data from Intraocular Fluid Analysis","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-12-25 07:23:44","doi":"10.21203/rs.3.rs-8320311/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":"93cc9196-968b-4eaf-96ef-44f4219121a1","owner":[],"postedDate":"December 25th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-03-02T12:56:55+00:00","versionOfRecord":[],"versionCreatedAt":"2025-12-25 07:23:44","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8320311","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8320311","identity":"rs-8320311","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}