Purpose: To evaluate the performance of Cirrus spectral domain optical coherence tomography (SD-OCT)-guided progression analysis (GPA) software to detect progression of retinal nerve fiber layer (RNFL) thinning in glaucoma patients.
Materials and methods: This retrospective cohort study included 272 eyes of 154 glaucoma patients. Median follow-up time was 2.2 years, during which time data from at least four good-quality OCT examinations were collected. Glaucomatous eyes were classified as either early or advanced group according to visual field (VF) severity. Reference standard of glaucoma progression was defined by expert assessment of optic disc/RNFL photographs or VF GPA data, or visual field index (VFI) linear regression analysis. Sensitivity and specificity of OCT GPA, and agreement between OCT GPA findings and each reference standard strategy were estimated.
Results: Fifty-three eyes (19.5%) showed progression by at least one of the reference standard strategies, while OCT GPA detected progression in 36 eyes (13.2%). When expert assessment of optic disc/RNFL photographs and/or VF analysis was used as the reference standard, the sensitivity and specificity of OCT GPA employed to detect glaucoma progression were 20.8% and 88.6%. Agreement between OCT GPA and either optic disc/RNFL photographic evaluation or VF analysis was poor (κ = 0.12 and 0.03, respectively). RNFL photographic assessment in early stage glaucoma showed best agreement with OCT GPA in terms of progression detection.
Discussion: The Cirrus OCT GPA detected a considerable number of eyes exhibiting glaucoma progression. OCT GPA may be useful for progression detection in earlier stage of glaucoma to complement other reference standard strategies.