Choroid vascular index (CVI) may be a viable biomarker for best-corrected visual acuity (BCVA) in patients with high myopia, as it is not affected by age, axial length, or spherical equivalent, according to research published in Eye.
Researchers included individuals aged between 4 and 40 years with high myopia (≤6 diopters [D]) from a single center in the observational, cross-sectional study (median age, 22.4 years; median spherical equivalent [SE], -10.1 D; 195 women and girls). The study participants underwent enhanced depth imaging-optical coherence tomography (EDI-OCT) and choroidal thickness, horizontal and vertical total choroidal area, luminal area, and stromal area measurements within a 3 mm area centered over the fovea. The research team evaluated correlations between age, sex, axial length, central corneal thickness, anterior chamber depth, lens thickness and choroidal parameters.
Overall, 2.8% of eyes had category 0 myopic degeneration, 67.5% had category 1, 28.2% had category 2, and 1.5% had category 3. Participants’ BCVA correlated with axial length (β, 0.450; P =0.000) and fundus grade (β, 0.184; P =.001).
Stratified by SE, BCVA correlated with inferior choroidal thickness (r, -0.393; P =.008), vertical luminal area (r, -0.365; P =.014), superior choroidal thickness (r, -0.359; P =.015), vertical total choroid area (r, -0.355; P =.013), horizontal luminal area (r, -0.345; P =.020), vertical stromal area (r, -0.336; P =.024), and subfoveal choroidal thickness (r, -0.300; P =.045) in individuals with a SE greater than -10 D. No correlations between these choroidal parameters were observed in patients with SE less than -10 D.
According to the report, every 1% increase in horizontal and vertical CVI was associated with a 0.0053 and 0.0051 logarithm of the minimum angle of resolution (logMAR) BCVA improvement, respectively.
“The choroidal circulation has been shown to be altered during the development of [high myopia],” according to the researchers. “Thus, an objective assessment of structural changes in the choroidal vasculature will provide insights into the characteristics of [high myopia] and progression, which may be useful in predicting the occurrence, monitoring the progression, and managing the treatment of complications associated with [high myopia].”
Study limitations include the use of noncycloplegic examination for participants older than 13 years and failure to perform optical coherence tomography-angiography (OCT-A).
Han R, Chang W, Ding X, et al. The choroid vascular index and its association with visual acuity in children and young adults with high myopia. Eye (Lond). Published online December 20, 2022. doi:10.1038/s41433-022-02369-9