Foveal Morphology of Normal Fellow Eyes of Patients with Unilateral Macular Hole

Abstract

To determine the morphology of the fovea in the ophthalmoscopically and tomographically normal fellow eyes of patients with a unilateral idiopathic macular hole (MH) and determine the association between foveal morphological parameters and foveal outer nuclear layer (ONL) thickness. Retrospective observational study. Two hundred three normal fellow eyes of patients with a unilateral MH and 216 normal eyes of 216 healthy subjects. All the eyes were examined using swept-source OCT. A built-in software was used to measure the average retinal and choroidal thickness in the center and in the inner 4 subfields defined in ETDRS. The total retinal thickness, thickness of 3 retinal layers at the fovea and parafovea (0.25 and 0.5 mm nasal and temporal from the fovea), and foveal floor width (FFW) were measured on a scan image of a horizontal line passing through the center of the fovea. We defined the thickness between the internal limiting membrane and outer plexiform layer as inner retinal thickness and the thickness between the external limiting membrane and retinal pigment epithelium as outer retinal thickness. Multiple regression analyses were performed with age, sex, axial length, and the presence of a posterior vitreous detachment as the dependent variables. OCT measurements and correlations between foveal parameters and foveal ONL thickness. The fellow eyes had a thinner central retinal subfield, thinner fovea, thinner ONL at all points except at 0.5 mm nasal, significantly thicker outer retina at all points, and a wider FFW (P= 0.040 to P < 0.0001). The foveal ONL thickness was significantly and positively correlated with the central subfield retinal thickness and foveal thickness and negatively correlated with the FFW (all P < 0.0001). The thinner and deeper fovea and the thinner ONL of the fellow eyes of patients with a unilateral MH make these eyes more susceptible to the formation of an MH.