Detecting Glaucoma Progression Using Guided Progression Analysis with OCT and Visual Field Assessment in Eyes Classified by International Classification of Disease Severity Codes.

Purpose: To compare the detection and rates of progressive retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer (GCIPL) loss with spectral-domain (SD) OCT and visual field (VF) loss using Guided Progression Analysis (GPA; Carl Zeiss Meditec, Dublin, CA) in glaucomatous eyes classified using International Classification of Diseases (ICD) diagnosis codes.

Design: Retrospective cohort study.

Participants: Glaucoma patients with at least 3 years of follow-up and a minimum of 4 SD OCT and 5 reliable VF examinations.

Methods: Glaucoma severity was classified using ICD, 10th Edition, Clinical Modification, diagnosis codes. Rates of RNFL, macular GCIPL, and VF loss were calculated, and progression estimates were compared using generalized estimating equations and McNemar's tests.

Main Outcome Measures: Progressive RNFL, GCIPL, and VF loss assessed by GPA criteria.

Results: A total of 147 eyes of 116 patients (mean age, 69.9±8.5 years) were included with mean follow-up of 69.67±18.64 months. Overall, 38 of 147 eyes (25.9%) showed RNFL progression, 35 eyes (23.8%) showed GCIPL progression, and 20 eyes (13.6%) showed VF progression. Progression by all 3 methods was noted in 10 eyes (7.0%). Eyes with mild (n = 62) and severe (n = 46) glaucoma showed significantly more progression on SD OCT compared with VF (P < 0.001 and P = 0.004). Retinal nerve fiber layer, GCIPL, and VF progressors showed faster rates of loss in average RNFL, GCIPL, and VF mean deviation compared with nonprogressors (mean ± standard error: -1.47±0.30 μm/year vs. -0.03±0.12 μm/year [P = 0.0001], -1.68±0.34 μm/year vs. -0.29±0.07 μm/year [P = 0.0001], and -1.07±0.20 dB/year vs. -0.19±0.04 dB/year [P = 0.0001], respectively).

Conclusions: Spectral-domain OCT progression was significantly more common than VF progression in glaucomatous eyes classified with mild and severe disease. Structure and function should be monitored closely across the entire spectrum of glaucoma severity.