Enhanced Depth Imaging Optical Coherence Tomography of Choroid in Highly Myopic Eyes

Abstract

Purpose: : To measure macular choroidal thickness in highly myopic eyes using enhanced depth imaging (EDI) optical coherence tomography (OCT).

Methods: : EDI-OCT images were obtained in highly myopic eyes (≥6 diopters). Images of choroidal thickness were obtained by positioning a spectral domain OCT device close enough to the eye to acquire an inverted image. Choroidal thickness was measured from the outer border of the retinal pigment epithelium to the inner scleral border at 1000 micron intervals of a horizontal section from 3 mm temporal to the fovea to 3 mm nasal to the fovea. Statistical analysis was performed to evaluate choroidal thickness at each location, and to correlate choroidal thickness with age and refractive error.

Results: : The mean age of the 31 patients (55 eyes) was 59.7 years ([±] 17.6 years; range 24 to 90 years), and the mean refractive error was-11.9 diopters (±3.7 diopters). Mean subfoveal choroidal thickness was 93.2 (±62.5) µm, and was negatively correlated with age (P = 0.006), refractive error (P < 0.001), and history of choroidal neovascularization (P = 0.013). Regression analysis suggested that subfoveal choroidal thickness decreased by 12.7 µm for each decade of life, and by 8.7 µm for each diopter of myopia.

Conclusions: : The choroid in highly myopic eyes is very thin, and undergoes further thinning with increasing age and degree of myopia. Age-related loss of choroidal vasculature may play a role in the pathogenesis of myopic degeneration.

Keywords: myopia • choroid • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)