Analysis of Optic Disc Morphology and the Peripapillary Retinal and Choroidal Thickness by the Swept Source Optical Coherence Tomography in Patients with Moyamoya Disease.

Introduction: Moyamoya Disease (MMD) is a chronic cerebrovascular occlusive disorder. Ocular involvement in patients with MMD has increasingly been recognized and reported in recent years. This study aimed to investigate the changes of optic disc morphology and the peripapillary retinal and choroidal thickness in patients with MMD.

Methods: This cross-sectional study included 56 patients diagnosed with idiopathic MMD and 56 healthy controls matched by age and gender. All participants underwent swept-source optical coherence tomography to capture the optic disc morphology as well as the peripapillary retinal and choroidal thickness. Optic disc parameters, including cup area, rim area, cup volume, rim volume, C/D area ratio (CDR), linear CDR, and vertical CDR were measured and compared between the two groups. Additionally, the thickness of the peripapillary whole retina, retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), and choroid were evaluated and analyzed across 12 clock-hour segments around the peripapillary region.

Results: The rim area in MMD patients was significant less than controls while the CDR in MMD patients was significantly larger than that in the control group. There was no statistically significant difference between the two groups regarding disc area, cup area, cup volume, rim volume, vertical and horizontal diameter of disc. The retinal thickness at the 7 o'clock position was significantly thinner in the MMD group compared to the control group and the temporal RNFL thickness, particularly at the 7 o'clock and 9 o'clock positions, was significantly reduced in the MMD group (p<0.05). The GCL layer at the 7 o'clock position was thinner in the MMD group than in the control group (p<0.05). The MMD group showed a notably reduced average choroidal thickness, particularly in the inferior-temporal region (p<0.05). There was a correlation between peripapillary choroidal and GCL layer thickness in the MMD group, but no significant correlations were found with rim area, CDR, or RNFL.

Conclusions: In patients with MMD, there is an increase in the CDR accompanied by a decrease in the rim area. Additionally, there is thinning of the temporal RNFL, GCL, and choroidal thickness, notably in the inferotemporal quadrant of the optic disc.