Choroidal thickness and vascularity index in Chinese children with high myopia

Abstract Background To evaluate the choroidal thickness (CT), topographical variation, and vascularity index in Chinese children with high myopia through enhanced depth imaging optical coherence tomography (EDI-OCT). Methods A total of 93 eyes of children were enrolled:35 in the high myopia group and 58 in the normal group. The choroidal architectural parameters were determined using OCT. The 7 measurements of the macular CT were obtained at different spots, including right beneath the fovea or the subfoveal area (SFCT) spot, and temporal and nasal spots at a radius of 0.5-mm, 1.5-mm, and 3-mm. The total choroidal area (TCA), stromal area (SA), and luminal area (LA) was measured. The choroidal vascularity index (CVI) was defined as the ratio of LA to TCA. The correlation between choroidal vascular parameters and other factors were analyzed. Results CTs were thinner in high myopic groups than the normal control group at all the locations (P for trend <0.01 for all locations). TCA, LA, and SA of the high myopia eyes were significantly smaller than that of the normal controls. TCA, LA, and SA of the high myopia eyes were significantly smaller than that of the normal controls. AL was negative correlated with SFCT, LA, SA, and TCA (P < 0.05, respectively), SE was positive correlated with SFCT, LA, SA, and TCA (P < 0.05, respectively). Conclusion The topographical variations of choroidal thickness with high myopia are the thickest temporal to the fovea. The myopic eyes had thinner CTs, TCA, LA and SA compared to normal controls, indicating its potential role to serve as the sensitive indicator for predicting myopic severity. The CVI does not change significantly in children high myopia, which may suggest choroid microstructure impairment is in the early stage, thus warranted further investigations in a follow-up study.