Baseline characteristics of participants in the natural history study of macular telangiectasia (MacTel) MacTel Project Report No. 2

Traci E Clemons, Marc C Gillies, Emily Y Chew, Alan C Bird, Tunde Peto, Maria J Figueroa, Molly W Harrington, MacTel Research Group

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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.

Original languageEnglish
Pages (from-to)66-73
Number of pages8
JournalOphthalmic Epidemiology
Issue number1
Publication statusPublished - 27 Jan 2010


  • Aged
  • Female
  • Fluorescein Angiography
  • Health Status
  • Humans
  • Male
  • Middle Aged
  • Photography
  • Retinal Diseases
  • Retinal Vessels
  • Risk Factors
  • Telangiectasis
  • Time Factors
  • Tomography, Optical Coherence
  • Visual Acuity
  • Journal Article
  • Research Support, Non-U.S. Gov't


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