Retinal nerve fiber layer thickness using spectral-domain optical coherence tomography in patients with no light perception secondary to optic atrophy

Background: Optical coherence tomography (OCT) provides useful structural information that can augment functional data. Newer spectral-domain technology provides faster and higher resolution images than time-domain machines. Although each measures the same structures, the values systematically differ. We evaluated eyes with longstanding no light perception (NLP) visual acuity secondary to optic atrophy using spectral-domain OCT to determine minimum retinal nerve fiber layer (RNFL) thickness. Methods: The authors conducted a retrospective, cross-sectional chart review study to identify patients with NLP acuity for 8 months or more and having a good quality Spectralis OCT (Heidelberg Engineering, Heidelberg, Germany) to measure the RNFL thickness. An unpaired t test compared the eyes with a previously published data set measured with time-domain OCT. Results: Eleven eyes from 10 patients were examined with the Spectralis OCT. The mean duration of documented NLP acuity was 3.72 ± 1.20 years. The mean RNFL thickness was 34.18 ± 2.66 μm (95% confidence interval, 28.26-40.11 μm). Mean RNFL thickness was significantly thinner on this spectral-domain OCT than previously published values on time-domain OCT (34.18 vs 45.42 μm, P = 0.004). Conclusion: Using the Spectralis OCT, mean RNFL thickness for NLP eyes due to optic atrophy is 28-40 μm. This provides clinicians useful information when considering how aggressively to manage patients with optic nerve disease.