Characteristics of the fundus and optical coherence tomography angiography metrics in patients with myelinated retinal nerve fibers

AIMS To investigate the fundus characteristics and macular OCTA metrics in patients with MRNFs and to identify the associations among myopic parameters, fundus metrics, and OCTA metrics METHODS The single-center case-control study included 15 patients with monocular MRNFs and 15 patients without MRNFs, matched for age, affected eyes’ spherical equivalent error (SER), and axial length (AL) between May 2021 and December 2021. Fundus features, including the entire MRNF area (Area1), the denser MRNF area (Area2), and the shortest distance from the fovea to the MRNF border (D _f−m ), along with ocular parameters, including SER, AL, corrected distance visual acuity (CDVA), and OCTA metrics at the fovea, including choroidal (ChT) and retinal (ReT) thicknesses at the fovea, the foveal avascular zone area (FAZ), foveal avascular zone perimeter (FAZP), FAZ-circularity index (FAZ-CI), and foveal vessel density in a 300-µm wide region (FD-300), were assessed. RESULTS The SER, AL, and CDVA were significantly worse and the ChT was thinner in the affected eyes than in the contralateral eyes. Compared with matched eyes, affected eyes had worse CDVA and thinner ReT. In the affected eyes, both Area1 and Area2 were negatively correlated with SER ( r ₁ = -0.84, r ₂ = -0.65), △SER ( r ₁ = -0.86, r ₂ = -0.61), ReT at the vertical superior 3 mm (VS) ( r ₁ = -0.78, r ₂ = -0.67), and ChT_VS ( r ₁ = -0.64, r ₂ = -0.62), and positively correlated with AL ( r ₁  = 0.82, r ₂  = 0.52) and CDVA ( r ₁  = 0.54, r ₂  = 0.59). D _f−m was negatively correlated with CDVA ( r = -0.57). CONCLUSION The presence of MRNFs affects CDVA and ReT at the fovea. The area of the MRNFs, as well as the distance from the MRNFs to the fovea, are closely associated with the affected eyes’ CDVA, SER, AL, and the degree of anisometropia.