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Baseline Characteristics of Participants in the Natural History Study of Macular Telangiectasia (MacTel) MacTel Project Report No. 2


Journal Article

Clemons, T.E.; Gillies, M.C.; Chew, E.Y.; Bird, A.C.; Peto, T.; Figueroa, M.J.; Harrington, M.W.; Group, T.Macular Te

Ophthalmic Epidemiol




Aged; Female; Fluorescein Angiography; Health Status; Male; Middle Aged; Photography; Retinal Diseases; Retinal Vessels; Telangiectasis; Time Factors; Tomography-Optical Coherence; visual acuity

PURPOSE: To describe the baseline characteristics of a large international cohort of patients with macular telangiectasia type 2 (MacTel Type 2) in anticipation of a longitudinal natural history study to evaluate structural and functional changes, identify potential risk factors and related outcomes. METHODS: Images including fundus photographs, fluorescein angiograms, optical coherence tomography and fundus autofluorescence were collected. A grading system for MacTel type 2 was developed by the central reading center to evaluate lesion characteristics. Relationships between lesion characteristics and visual acuity were evaluated. RESULTS: A total of 310 participants have been enrolled in the study. The mean time since diagnosis was 3 years (range 0 to 25 years). The mean age at the baseline examination was 61 +/- 9 years. The mean visual acuity in the better eye was approximately 20/32 Snellen equivalents and approximately 20/50 in the worse eye. The visual acuity in the better eye of half of the participants was 20/32 or better. We found some relationships between visual acuity and lesions characteristic of MacTel Type 2. CONCLUSIONS: This is the first large-scale study of patients with MacTel Type 2. More than half of the patients had 20/32 or better vision in their better eye, which is a sign that decreased function in these participants may not be reflected in central visual acuity. These findings highlight the limitation of using visual acuity measurements as a measure of function and as an outcome measure in potential clinical trials in patients with MacTel Type 2.

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