Ganglion cell analysis at acute episode of nonarteritic anterior ischemic optic neuropathy to predict irreversible damage. A prospective study

Purpose To assess the capability of ganglion cell–inner plexiform layer (GCIPL) thickness analysis by optical coherence tomography (OCT) to detect early neuronal loss in nonarteritic anterior ischemic optic neuropathy (NAION). Methods Sixteen patients with unilateral NAION participated in this prospective study. Complete ophthalmologic evaluation including visual acuity, visual field (VF) test, and spectral domain optical coherence tomography (SD-OCT) of peripapillary retinal nerve fiber layer (pRNFL) and GCIPL thickness were performed in the acute phase (within 1 week: 2.7 ± 2.1 days) and at 2 weeks, 1 month, 3 and 6 months after diagnosis. The mean time elapsed from acute episode to irreversible damage detection by GCIPL and pRNFL analysis was registered. Correlations between the GCIPL thinning and functional parameters such as best-corrected visual acuity (BCVA) and visual field indices [mean deviation (MD) and visual field index (VFI)] in acute and chronic phase were also analyzed. Results NAION eyes showed a significant thinning of the mean GCIPLminimum (min) compared to the unaffected eyes as early as 2.2 days after symptoms onset ( p = 0.017) and at each follow-up visit. ( p ≤ 0.003). The mean GCIPL average (av) was also thinner in NAION eyes compared to uninvolved eyes at 1 ( p = 0.003), 3 ( p = 0.002) and 6 months ( p