Choroidal Thickness and Visual Acuity in High Myopia Without Myopic Maculopathy: Insights From a Chinese Population Study.

Purpose: To evaluate the association of choroidal thickness (ChT) with best-corrected visual acuity (BCVA) in patients with high myopia (HM) and without myopic maculopathy.

Methods: This study was a retrospective, cross-sectional study of participants aged 7 to 70 years with bilateral HM but without myopic maculopathy. Swept-source optical coherence tomography was used to measure ChT at the fovea. A BCVA of logMAR 0.1 was regarded as the benchmark for normal. The association between ChT and BCVA was evaluated by linear regression models with confounders fully adjusted. Subgroup analyses were performed across sex and age groups.

Results: A total of 412 eligible participants were enrolled in this study. The mean age, spherical equivalence, and subfoveal (SF) ChT of the included participants were 21.17 ± 9.55 years, -9.77 ± 2.40 diopters, and 171.56 ± 61.33 µm, respectively. The SF ChT was thinner in participants with abnormal BCVA (normal. 176.74 ± 60.24 µm; abnormal, 139.30 ± 58.63 µm). A thinner ChT in all subregions of the posterior pole of the Early Treatment Diabetic Retinopathy Study grid was associated significantly with a worse BCVA after adjusting for age, sex, and axial length (SF ChT: coefficient, × 10-4, -2.64; 95% confidence interval, -4.73 to -0.55; P < 0.05 in all subregions). The strongest correlation was observed in the outer inferior region, where a per 21 µm thinning of ChT led to a 0.01 worsening of BCVA. This correlation presented a stronger magnitude in male aged more than 40 years.

Conclusions: In patients with HM without myopic maculopathy, a thinner ChT was associated independently with a worse BCVA.

Translational relevance: The findings of this study suggest that thinning ChT should be considered a vital risk factor for irreparable visual acuity impairment.