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L.V. Del Priore, A.R. Shah; Progression of Visual Loss in Untreated AMD Eyes With Subfoveal Exudation Depends on Initial Visual Acuity . Invest. Ophthalmol. Vis. Sci. 2006;47(13):2189.
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© ARVO (1962-2015); The Authors (2016-present)
Previous clinical trials in exudative AMD demonstrate large differences in the behavior of untreated control eyes. For example, there was a large range of initial visual acuity scores in control eyes in the Macular Photocoagulation Study (45 letters), Treatment of Age–Related Macular Degeneration with Photodynamic Therapy Study (TAP, 52.6 letters), Macugen (52.6 letters), Subfoveal Surgery Trial (35 letters) and Anecortave Acetate (47 letters) study; final visual acuity score after two years also varied widely in untreated eyes in these studies. Herein we test the hypothesis that the behavior of the control eyes is essentially the same across all studies, with the apparent differences arising from different entry times for each study.
The visual acuity score of control eyes from the above studies was plotted on a double reciprocal plot [1/LETTERS LOST versus 1/MONTHS AFTER ENROLLMENT]. Individual data sets were translated along the horizontal axis to correct for differences in time of entry into a clinical trial.
After horizontal translations the pooled data from the control eyes in these studies fits a straight line when 1/LETTERS LOST is plotted versus 1/MONTHS (r2 = 0.952). The line intercept predicts that an untreated eye will eventually lose 75 letters (final visual acuity score = 10 letters = 20/640); the slope of the line predicts that without treatment ½ of the visual acuity score is lost within 10.8 months after the onset of exudation.
The rate of visual loss of subfoveal exudative AMD is linear on a double reciprocal plot with a high correlation coefficient (0.952) if adjustments are made for initial visual acuity at the time of entry into study. Our results suggest that the major variables influencing the final visual acuity score are the initial visual acuity score and the timing of treatment.
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