title: Natural history of predominantly classic, minimally classic, and occult subgroups in exudative age-related macular degeneration.
abstract: OBJECTIVE
  We previously showed that the pattern of vision loss in eyes with subfoveal neovascularization in age-related macular degeneration (AMD) is uniform across a wide range of clinical trials, with apparent differences arising from differences in the time of entry of patients into clinical trials. In the current study, we used a similar analysis to compare the visual loss of untreated control eyes classified as predominantly classic (PC), minimally classic (MC), and occult with no classic (occult) based on fluorescein angiography.
  
  
  METHODS
  Meta-analysis of prior clinical trials.
  
  
  METHODS
  Data from patients enrolled in the Macular Photocoagulation Study (MPS), Treatment of Age-related Macular Degeneration with Photodynamic Therapy (TAP) Study, Verteporfin in Photodynamic Therapy (VIP) Study, Anecortave Acetate (AA) Trial, VEGF Inhibition Study in Ocular Neovascularization (VISION), and Minimally Classic/Occult Trial of the Anti-VEGF Antibody Ranibizumab in the Treatment of Neovascular Age-Related Macular Degeneration (MARINA) Trials.
  
  
  METHODS
  Visual acuity (VA) data of untreated control eyes for each study from appropriate subgroups were plotted on a double reciprocal (Lineweaver-Burke) plot of 1/[letters lost] versus 1/[months]. To correct for differences in time of entry into clinical trials, we introduced a horizontal translation factor to shift each data subset.
  
  
  METHODS
  We determined the coefficient of determination before and after adjustments for visual acuity at the time of enrollment.
  
  
  RESULTS
  On a Lineweaver-Burke plot, the cumulative subgroups had an overall coefficient of determination of only r(2)<0.01 for the raw data but improved to a remarkably high r(2) = 0.90 when data were corrected for time of entry into clinical trials. For each subgroup there was excellent correlation between 1/[letters lost] versus 1/[months of exudative disease] for PC (r(2) = 0.91), MC (r(2) = 0.95), and occult (r(2) = 0.98) choroidal neovascularization.
  
  
  CONCLUSIONS
  We were able to demonstrate a strong correlation for visual acuity as a function of time that is independent of the fluorescein angiography classification of a lesion, suggesting that initial protocol visual acuity, rather than angiographic classification, is the major determinant of the behavior of visual acuity as a function of time in exudative AMD.
authors: The Department of Ophthalmology, Columbia University, New York, NY, USA.
authors: Ankoor R
authors: AR
authors: Shah
authors: Lucian V
authors: LV
authors: Del Priore
mesh_terms: D020256:Choroidal Neovascularization / Q000175:diagnosis / Q000503:physiopathology*; D018450:Disease Progression; D005122:Exudates and Transudates; D005451:Fluorescein Angiography; D006801:Humans; D008268:Macular Degeneration / Q000175:diagnosis / Q000503:physiopathology*; D013997:Time Factors; D014786:Vision Disorders / Q000503:physiopathology*; D014792:Visual Acuity / Q000502:physiology*