Association between retinal vascular fractal dimension and hearing loss: a cross-sectional study

Hearing loss (HL) is a prevalent health issue, and identifying noninvasive biomarkers for early detection is crucial. This study investigates the association between retinal vascular fractal dimension (FD) and HL in a health checkup population. A retrospective cross-sectional study was conducted with 575 participants who underwent ophthalmological and audiological assessments at Shanghai Health and Medical Center CN between October 2014 and January 2024. Retinal FD was measured using nonmydriatic fundus photography and analyzed using Singapore I Vessel Assessment software. Hearing thresholds were assessed by air-conduction pure-tone audiometry, with the high Fletcher index (hFI) used to evaluate hearing acuity. Results showed that higher retinal FD values were significantly associated with better hearing acuity. Specifically, each 1-SD increase in arteriolar FD (FDa) was correlated with a 2.85 dB decrease in the hearing threshold at 1 kHz (β = -2.85, 95% CI - 4.47 to - 1.23, p < .001), and each 1-SD increase in venular FD (FDv) was correlated with a 2.61 dB decrease at 2 kHz (β = -2.61, 95% CI - 4.42 to - 0.80, p = .005). The study suggests that retinal FD may serve as a noninvasive biomarker for early detection of HL and could assist in the development of preventive strategies.