Associations between autofluorescence abnormalities and visual acuity in idiopathic macular telangiectasia type 2: MacTel project report number 5.
PURPOSE: The aim of this study was to determine whether typical abnormalities seen on autofluorescence (AF) imaging in patients with macular telangiectasia (MacTel) type 2 are correlated with visual acuity at presentation and with progression of visual loss over a 2-year follow-up period.
METHODS: A subgroup of 218 patients (413 eyes) enrolled in the MacTel study that underwent AF imaging was included in the present study. Images were graded at the Moorfields Eye Hospital Reading Center. Recorded AF abnormalities at baseline and at 2 years included the presence of increased AF because of loss of masking at the central macula, localized decreased AF at the end of a retinal vessel, and large area of decreased AF. Best-corrected visual acuity was measured using the Early Treatment for Diabetic Retinopathy chart at baseline and after 2 years. Statistical associations were sought by means of a generalized linear model.
RESULTS: Presence of increased macular AF (P = 0.004), a large area of decreased AF (P < 0.001), or decreased AF at the end of a retinal vessel (P < 0.001) at baseline were significantly associated with worse best-corrected visual acuity. Presence of increased macular AF (P < 0.001) or of localized decreased AF at the end of a retinal vessel (P < 0.001) and the absence of a large area of decreased AF (P < 0.001) were predictive of a subtle but significant drop in best-corrected visual acuity at 2 years.
CONCLUSIONS: Increased central AF at baseline heralds worse best-corrected visual acuity and predicts further subtle visual loss in a period of 2 years, which, however, does not stand out from the overall slowly progressive natural history of the disease.