Vertical disc tilt and features of the optic nerve head anatomy are related to visual field defect in myopic eyes

Abstract

Myopia is significantly growing eye disease which accompanies various ocular pathologies including glaucoma. Understanding visual field (VF) and retinal nerve fiber layer (RNFL) damage observed in myopic eyes is important. Therefore, we evaluated optic disc margin anatomy using spectral-domain (SD) optical coherence tomography (OCT). We enrolled 40 healthy myopic patients and 64 myopic patients with RNFL defects in the superonasal region of the optic disc on red-free photographs and OCT. Optic disc stereophotographs were co-localized to SD-OCT images, and we analyzed the frequency with which the disc margin identified in photographs coincided with Bruch’s membrane (BM) opening, BM/border tissue, or border tissue. For each scan, the presence of border tissue overhang beyond the clinical disc margin and the end of Bruch’s membrane was identified. Among 64 myopic eyes with RNFL defects, 42 had corresponding inferotemporal VF defects. Border tissue overhang was found from 25 to 60% of myopic eyes with RNFL defect at all clock positions. However, border tissue overhang was found from 86 to 97% at 1, 2, 11 and 12 o’clock position in myopic eyes with VF defects. This was significantly different from myopic healthy eyes. We suggest that the OCT structure at the disc margin might contribute to VF damage in myopic patients.