Cone Mosaic in Eyes with Varied Axial Length Using Adaptive Optics Scanning Laser Ophthalmoscopy

Abstract

Background Abnormalities in cone photoreceptors are closely associated with the occurrence of many ocular diseases. Adaptive Optics Scanning Laser Ophthalmoscopy (AOSLO) allows visualization of the living human retina with exquisite single-cell resolution. Methods This study aimed to found the potential relationship between cone cells and and axial myopia using a commercial AOSLO system in cone moasic. 74 patients (148 eyes; 30 (40.5%) men) with a mean age of 31.8 ± 10.4 years were icluded in this study. Cone mosic was obtained from the 3° and 5° eccentricities of macular. The relationship between cone cell indexes (linear cone density, cone spacing, cone dispersion and cone regularity) and axial length were analyzed. Results The linear cone density significantly declined with increasing axial length at both 3° and 5° eccentricities (all P<0.001). The cone spacing was significantly increasing with the increasing of axial length and the reduce of cone density. After adjusting for axial length, cone spacing was significantly associated only with linear cone density, both at 3° and 5° eccentricities (all P<0.001). The cone dispersion was significantly increasing with the increasing of axial length and the reduce of cone density. After adjusting for axial length, cone dispersion remained significantly associated with linear cone density only at the inferior 3° (β=-0.43, P = 0.014) and inferior 5° eccentricities (β=-0.4, P = 0.003). Cone regularity significantly increasing with increasing linear cone density and after adjusting for axial length, cone dispersion remained significantly associated with linear cone density only at the nasal 3° (β = 0.71, P < 0.001) and temporal 3° eccentricities (β = 0.25, P < 0.001). Cone regularity significantly decreased with increasing axial length and after adjusting for linear cone density, cone dispersion remained significantly associated with axial length at temporal 5° eccentricity (β=-0.57, P < 0.001). Conclusions Cone cell density was significantly decreased in axial myopia. The uniformity of cone distribution was decreased in axial myopia, which may be the indirected caused by a decrease in cone density due to axial elongation. The cone morphology regularity was significantly decreased in axial myopia, which may result directly from the axial elongation or indirectly from the cone density decrease it causes.