CORRELATION OF CLINICAL AND STRUCTURAL PROGRESSION WITH VISUAL ACUITY LOSS IN MACULAR TELANGIECTASIA TYPE MacTel Project Report No. 6-The MacTel Research Group

Purpose: To evaluate progression of macular telangiectasia Type 2 lesions and their correlation with visual acuity. Methods: An international multicenter prospective study with annual examinations including best-corrected visual acuity (BCVA), fundus photography, fluorescein angiography, and optical coherence tomography images graded centrally. Mixed models were used to estimate progression rates, and a generalized linear model to compute the relative risk of BCVA loss, loss of ellipsoid zone (EZ) reflectivity, development of pigment plaques, or neovascularization. Results: One thousand and fourteen eyes of 507 participants were followed for 4.2 +/- 1.6 years. Best-corrected visual acuity decreased 1.07 +/- 0.05 letters (mean +/- SE) per year. Of all eyes, 15% lost >= 15 letters after 5 years. Of the eyes without EZ loss, 76% developed a noncentral loss. Of the eyes with noncentral loss, 45% progressed to central EZ loss. The rate of BCVA loss in eyes with noncentral EZ loss at baseline was similar to eyes without EZ loss. The rate of BCVA loss was significantly higher in eyes with central EZ loss at baseline (-1.40 +/- 0.14 letters, P < 0.001). Conclusion: Ellipsoid zone loss is frequently found in macular telangiectasia Type 2 and is an important structural component reflecting visual function. Its presence in the fovea significantly correlates with worse visual prognosis.