Longitudinal spatial correlation of retinal sensitivity and structural changes in macular telangiectasia type 2

Purpose This study aimed to investigate the spatial correlation between retinal structure and function in macular telangiectasia type 2 (MacTel) using Compass fundus-tracked microperimetry. Methods Medical records of 54 eyes from 28 patients were retrospectively reviewed. The relationship between retinal sensitivity and structural parameters including retinal thickness, ellipsoid zone (EZ) integrity, and visual acuity was analyzed. Retinal sensitivity was calculated for nine macular sectors defined by the Early Treatment Diabetic Retinopathy Study (ETDRS) grid, and changes over a 2-year follow-up were evaluated. Results The mean central retinal thickness was 254.3 ± 103.7 μm, and the mean central retinal sensitivity (mRS) was 28.9 ± 5.4 dB. Microscotomas (< 10 dB) were detected in 18.5% of eyes, predominantly in the temporal macula. Although visual acuity and retinal thickness remained stable during follow-up, the central mRS showed a significant decline (29.51 ± 2.02 dB vs. 28.84 ± 1.38 dB, p = 0.038). The spatial distribution of microscotomas corresponded closely to areas of EZ loss, although pointwise mismatch occasionally occurred. Conclusion These findings demonstrate that Compass microperimetry can detect subtle longitudinal functional decline despite a lack of significant change in visual acuity and retinal thickness. These results suggest that microperimetry may serve as a complementary functional biomarker for early disease monitoring in MacTel.