Quantitative Analysis of Background Intraocular Pressure Volatility and Retinal Nerve Fiber Layer Loss in Cytomegalovirus Anterior Uveitis

Purpose: To evaluate intraocular pressure (IOP) volatility and long-term glaucomatous progression in cytomegalovirus anterior uveitis (CMV AU). Methods: We analyzed 63 eyes with polymerase chain reaction-confirmed CMV AU (53 patients) with ≥18 months follow-up, ≥10 IOP measurements, and ≥4 optical coherence tomography (OCT) scans. A total of 2304 IOP and 451 OCT measurements were obtained over 5.4 ± 3.1 years. Background IOP volatility was defined as standard deviation (SDb) and coefficient of variation (CVb), excluding IOP >24 mm Hg. Retinal nerve fiber layer (RNFL) thinning was assessed by linear regression. Initial treatment response (ITR) was defined as IOP normalization and inflammation reduction within two weeks. Results: Posner-Schlossman syndrome accounted for 95.2% of cases. Mean IOP was 16.4 ± 7.8 mm Hg in lesion eyes and 14.6 ± 3.0 mm Hg in fellow eyes. Background IOP volatility was 1.7-fold higher in lesion eyes (SDb ratio 1.70 ± 0.74, CVb ratio 1.74 ± 0.69; P < 0.001). Overall, 60.4% showed RNFL thinning. Median RNFL loss rate in lesion eyes was 1.40 µm/year versus 0.81 µm/year in fellow eyes. Univariable predictors included number of attacks (P = 0.012), ITR failure (P = 0.001), and SDb (P = 0.045); ITR failure remained significant in multivariable analysis. Receiver operating characteristic analysis suggested SDb >2.5 mm Hg and CVb >0.17 as possible cutoffs for CMV involvement. Conclusions: CMV AU eyes showed 1.7 × higher background IOP volatility than fellow eyes during normotensive intervals, with RNFL loss in 60% (median 1.40 µm/year). These findings highlight the chronic and aggressive nature of CMV AU. IOP volatility may serve as a supportive biomarker. Translational Relevance: Quantifying background IOP volatility provides a clinically accessible surrogate linking CMV-related trabecular pathology to glaucomatous progression.