The characteristics of multifocal microperimetry and its relationship with visual acuity and multifocal ganglion cell complex in nonarteritic anterior ischemic optic neuropathy

Abstract

Objective To observe the characteristics of multifocal microperimetry and its relationship with visual acuity and multifocal ganglion cell complex (GCC) in nonarteritic anterior ischemic optic neuropathy (NAION). Methods A retrospective case study. A total of 38 patients (54 eyes) with NAION were enrolled in this study. 25 NAION eyes (25 patients) and 29 contralateral health eyes (29 patients) were randomly selected into case group and control group respectively. All eyes underwent best corrected visual acuity (BCVA), slit lamp microscope, indirect ophthalmoscope, color fundus photography, optical coherence tomography (OCT), visual field and multifocal microperimetry. Logarithm of the minimum angle of resolution (logMAR) was used to calculate BCVA. There were no significantly differences on age (t=−0.647), gender, dominant eyes ( χ2=0.128, 0.099), intraocular pressure (t=0.376) between two groups (P>0.05). Macular GCC thickness, superior and inferior GCC thickness were measured by OCT, focal loss volume (FLV) and global loss volume (GLV) were obtained at the same time. Microperimetry were measured by macular integrity assessment instrument (MAIA microperimetry), and mean retinal sensitivities (MS) in macular area 10° and fixation rate in the macular central 2° and 4° were determined. The relationship between MS, macular GCC and BCVA were analyzed by Spearman correlation analysis. Results The mean logMAR BCVA of case group and control group were 0.68±0.79 and 0.07±0.06, respectively. There was significantly statistical difference in MS between two groups (t=−2.507, P=0.037). There were no significantly statistical difference in mean GCC (t=−1.245, P=0.259), superior and inferior GCC (t=−1.336, −1.024; P=0.230, 0.346), FLV (t=1.058, P=0.331) and GLV (P=0.182) between two groups. The correlation between BCVA and MS (r=−0.809, P=−0.005) was observed. However, there were no correlation between BCVA and GCC, superior and inferior GCC, FLV, GLV (r=−0.98, −0.466, −0.061, 0.442, 0.442; P=0.817, −0.244, 0.885, 0.273, 0.273). And also, there were no correlation between MS and GCC, superior and inferior GCC, FLV, GLV (r=0.238, 0.524, 0.286, 0.643, −0.619; P=0.570, 0.183, 0.493, 0.086, 0.102). Conclusions MS reduced in early stage NAION eyes, which did not correlate with macular GCC. Key words: Optic neuropathy, ischemic; Visual fields; Tomography, optical coherence