Detection of progressive retinal nerve fiber layer thickness loss with optical coherence tomography using 4 criteria for functional progression.

PURPOSE

To compare the rates of retinal nerve fiber layer (RNFL) thickness loss using optical coherence tomography (OCT) in progressing versus nonprogressing eyes using 4 methods to define functional progression.

METHODS

Normal and glaucomatous eyes with ≥3 years of follow up were prospectively enrolled. Standard automated perimetry (Swedish Interactive Threshold Algorithm Standard 24-2) and OCT (Stratus OCT, Carl Zeiss Meditec, Dublin, CA) imaging were performed every 6 months in glaucomatous eyes. OCT imaging was performed annually in normal eyes. Functional progression was determined using early manifest glaucoma trial criterion, visual field index (VFI), Progressor software, and the 3-omitting method.

RESULTS

Seventy-six eyes (46 glaucoma and 30 normal) of 38 patients were enrolled with a mean follow-up of 43.9 ± 5.02 months (range: 36 to 48 mo). Eleven eyes progressed using Progressor criterion, 5 eyes using VFI, 2 eyes using the 3-omitting method, and 2 eyes using Early Manifest Glaucoma Trial criterion. The annual rate of average RNFL loss (μm/y) was significantly greater (P<0.05) in progressing versus nonprogressing eyes using Progressor (-1.0 ± 1.3 vs. 0.02 ± 1.6), VFI (-2.1 ± 1.1 vs. -0.002 ± 1.4), and the 3-omitting method (-2.2 ± 0.2 vs. -0.1 ± 1.5). Mean rate (μm/y) of average and superior RNFL thickness change was similar (P>0.05) in nonprogressing glaucomatous eyes compared with normal eyes. Using linear mixed-effect models, mean (P<0.001) and peak (P=0.01) intraocular pressure were significantly associated with rate of average RNFL atrophy in glaucomatous eyes.

CONCLUSIONS

Despite differences in criteria used to judge functional progression, eyes with standard automated perimetry progression have significantly greater rates of RNFL loss measured using OCT compared with nonprogressing eyes.