Progression detection capability of macular thickness in advanced glaucomatous eyes

Purpose: To evaluate the progression rate of macular and circumpapillary retinal nerve fiber layer (RNFL) thickness in advanced glaucomatous eyes using spectral domain optical coherence tomography (Cirrus HD-OCT, Carl Zeiss Meditec, Dublin, CA).

Design: Longitudinal, observational study.

Participants: A total of 98 eyes of 98 patients with advanced glaucoma (visual field [VF] mean deviation [MD] <-10 dB) with a mean follow-up time of 2.2 years.

Methods: Three glaucoma experts independently reviewed optic disc and RNFL photographs and classified patients into 3 groups: progressed, stable, and undetermined (criterion 1). Patients in the undetermined group could not be evaluated because of advanced optic disc cupping. The eyes were also classified into 2 groups, progressed and stable, by serial VF data (criterion 2).

Main outcome measures: Progression rates as determined by linear regression analysis against patient age using serial macular and RNFL thickness parameters were compared among different groups.

Results: By criterion 1, 25 eyes (25.5%) were classified as stable, 13 eyes (13.3%) were classified as progressed, and 60 eyes (61.2%) were classified as undetermined. By criterion 2, 86 eyes (87.8%) were classified as stable, and 12 eyes (12.2%) were classified as progressed. By criterion 1, the mean progression rate of average macular thickness was significantly higher in the progressed group than in the stable and undetermined groups (-4.74±4.40, -0.53±1.44, and -2.72±4.75 μm/year, respectively; P = 0.01). The undetermined group showed a higher progression rate than the stable group (P = 0.045). However, the progression rate of average RNFL thickness did not differ significantly among the 3 groups (-1.19±2.62, -0.33±1.29, and -1.21±2.75 μm/year, respectively; P = 0.34). By criterion 2, the mean progression rate of average RNFL thickness did not differ significantly between the stable and progressed groups (-0.90±2.42 and -2.08±2.85 μm/year; P = 0.459). However, the progression rate as revealed by average macular thickness was significantly different between the 2 groups (-2.22±4.33 and -5.12±2.40 μm/year, respectively; P = 0.039).

Conclusions: Exploration of changes over time in macular thickness may improve detection of progression in patients with advanced glaucoma.