To determine the differences in temporal macular thinning among children with Alport syndrome (AS), thin basement membrane nephropathy (TBMN), and age-matched healthy controls and to clarify its diagnostic and differential diagnostic significance.

This was a case-control study. Children with AS and TBMN diagnosed at our hospital between January 2021 and December 2024 were enrolled. All participants underwent comprehensive ophthalmic assessments, including visual acuity, refraction, slit-lamp biomicroscopy with dilated pupils, color fundus photography, biometry, and optical coherence tomography (OCT). Refractive error, lens thickness, axial length, macular retinal thickness in all sectors, and temporal thinning index (TTI) values were compared using one-way analysis of variance (ANOVA) or an independent samples t-test. Receiver operating characteristic (ROC) curve analysis was used to evaluate the diagnostic efficacy of the TTI for AS in males.

The cohort consisted of 40 patients with genetically confirmed AS [33 with X-linked Alport syndrome (XLAS): 16 males, 17 females; 7 with autosomal recessive Alport syndrome (ARAS): 4 males, 3 females], 40 patients with TBMN (male:female=1:1, 40 eyes), and 40 age-matched healthy controls (male:female=1:1, 40 eyes). The standard deviations of the mean TTI values were 12.08±3.18 in the AS group, 6.60±1.88 in the TBMN group, and 6.42±1.14 in the control group. The TTI was significantly greater in the AS group than in both the TBMN and control groups (P<0.001). A statistically significant difference in TTI was observed between sexes in the XLAS subgroup but not in the ARAS subgroup. ROC analysis for males with XLAS revealed an area under the curve of 0.897 (95% confidence interval: 0.844–0.949, P<0.001) for the TTI in the diagnosis of AS. The optimal cutoff value was 9.67, yielding a sensitivity of 0.875 and specificity of 0.826.

Children with AS exhibit greater temporal macular retinal thinning than do those with TBMN and healthy controls. The TTI shows potential as an auxiliary diagnostic marker for AS in male patients.