Association between metamorphopsia and neuroglial cellular changes in eyes with epiretinal membrane: an adaptive optics optical coherence tomography study

Abstract

Purpose : Epiretinal membrane (ERM), a common vitreoretinal disease, can result in concomitant symptoms such as decreased visual acuity (VA) and metamorphopsia. Due to the limited resolution of spectral domain optical coherence tomography (OCT), used in diagnosis and evaluation of ERM, retinal morphologic changes at the cellular level remain unclear. In this cross-sectional study, we aimed to examine the cellular morphological changes in the foveal neuroglia and their associations with visual function in eyes with ERM using adaptive optics (AO)-OCT.

Methods : We included 54 patients with idiopathic ERM (age: 68 ± 9 years) and 37 participants with healthy eyes (age: 68 ± 10 years) as controls. In eyes with ERM, VA and low-contrast VA were measured. The degree of metamorphopsia was evaluated using M-CHARTS, and the scores in the horizontal and vertical directions were measured, respectively; the average score was calculated for each eye.
In both the healthy and diseased eyes, we obtained vertical AO-OCT images of 400 µm width centered on the foveola. From the obtained images, we observed each cone nucleus and measured the number and density of cone nuclei, and we observed Müller cell running between the internal limiting membrane and external limiting membrane in the control and diseased eyes

Results : In eyes with ERM, the VA (logMAR) was 0.1 ± 0.2, low-contrast VA was 9 ± 14 letters, and M-CHARTS score was 0.54 ± 0.44.
The running course of Müller cells had changed—obliquely to more vertically—by the afferent contraction of the ERM, compared to that in healthy eyes. The cone cells deviated afferently in the retinal plane in accordance with the afferent deviation of the Müller cells. The cone nuclear density was 6,096 ± 879 /mm² in control eyes and 7,329 ± 1,125 /mm² in diseased eyes, which was a significant increase (p<0.001). The cone nuclear density of eyes with ERM showed a significant and positive association with the M-CHARTS score (R=0.39, p=0.004).

Conclusions : In eyes with ERM, the afferent contraction in the vitreoretinal interface, parallel to the retinal plane, changed the running course of the Müller cells, which concomitantly increased the cone nuclear density at the fovea. The cellular morphological changes in the retinal neuroglia may be associated with the severity of metamorphopsia.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.