Distribution of Choroidal Thinning in High Myopia, Diabetes Mellitus, and Aging: A Swept-Source OCT Study

Abstract

Purpose. To compare the macular choroidal thinning between young healthy, aged healthy, young high myopic, and aged type 2 diabetic (T2D) patients using the Early Treatment Diabetic Retinopathy Study (ETDRS) grid and three-dimensional (3D) maps. Methods. A prospective study including 102 eyes of 51 healthy young subjects, 60 eyes of 30 healthy aged subjects, 24 eyes of 12 high myopic patients, and 110 eyes of 55 T2D patients. Choroidal thickness (CT) was examined with swept-source optical coherence tomography Triton DRI (Topcon Corporation, Tokyo, Japan). The choroid was automatically segmented using the software algorithm, and mean CT values of a 6 × 6 mm macular cube were exported. 3D maps were created to represent CT, and its values were compared using the ETDRS grid. Results. Mean age was 27.31 ± 3.95, 66.41 ± 7.54, 27.69 ± 3.89, and 66.48 ± 7.59 years in young healthy, aged healthy, young high myopic, and T2D patients, respectively. CT was not shown to be uniform, as superior and central zones were thicker. All ETDRS sectors were always thicker (p<0.05) in young healthy individuals than in the others. It was found that the choroidal sector which got thinner was inferior in case of age (103.28 μm decrease), inferior-nasal in high myopia (86.19 μm decrease), and temporal in T2D (55.57 μm decrease). In addition, the choroid got thinner in those regions where it was thicker in healthy subjects. Conclusions. 3D maps allow a further comprehension of choroidal changes. The choroidal pattern in young healthy individuals resembles a mountain range; with age, a mountain peak; in high myopia, an inverted gorge; and in aged T2D, gathered hills. Not all choroidal regions are affected in a similar way, as it depends on the pathology. The thicker the zone is in healthy subjects, the thinner it becomes with any pathology.

Predicting Axial Length From Choroidal Thickness on Optical Coherence Tomography Images With Machine Learning Based Algorithms

“…In this study, we proposed that Classifiers 1-6 can predict AXL by means of patients' age, sex, height, weight, and CT measured from OCT images. Studies have reported that CT is negatively correlated with AXL, and people with high myopia tend to have a thinner choroid (7)(8)(9)(10)(11). However, few studies have assessed the prediction of AXL by means of CT.…”

“…Morgan et al (6) suggested that the elongated AXL is the underlying mechanism of myopia development and progression. Choroid, located at the exterior of the retina and which provides blood supply to the outer portion of the retina, has been reported to be thinner in myopic than emmetropic eyes and is related to AXL elongation (7). Choroid thinning not only correlates with myopia progression but is also related to other complications, such as staphyloma and chorioretinal atrophy in high myopia (7)(8)(9)(10)(11)(12)(13)(14).…”

Advances in OCT Imaging in Myopia and Pathologic Myopia

“…Using SS-OCT, researchers found that choroidal thinning actually developed before retinal thinning occurred during myopia progression; myopia shift was found to be independently correlated with central fovea choroidal thinning and axial length [ 70 ], indicating the value of SS-OCT to clarify the critical roles of choroid and retina during myopia progression. In addition, choroidal thinning was also found to be correlated to MMD [ 71 ], and topographic variations were identified in 3D maps of choroidal thickness [ 72 ]. Another important choroidal feature is peripapillary intrachoroidal cavitation, usually located inferior to the optic nerve in highly myopic eyes [ 73 ].…”

Refractive errors, ocular biometry and diabetic retinopathy: a systematic review

“…Based on previous studies discussed in the earlier part of this report, myopic refractive error and long AL may be protective factors against DR. Possible mechanisms might be attributable to the regulating effect of the increase in AL, posterior vitreous detachment, low blood flow perfusion in the retina, choroidal thinning, and the alteration of cytokine profile. 39; 40; 41; 42; 43; 44 While the exact mechanisms of how myopia is protective against DR remain elusive, most of the attention is placed on the pathological changes of the eyeball incurred by the increasing AL during the progression of myopia. 39; 40; 41…”

“…39; 40; 41; 42; 43; 44 While the exact mechanisms of how myopia is protective against DR remain elusive, most of the attention is placed on the pathological changes of the eyeball incurred by the increasing AL during the progression of myopia. 39; 40; 41…”