Macular Degeneration: Tian Y

Sunness JS, Margalit E, Srikumaran D, Applegate CA, Tian Y, Perry D, Hawkins BS, Bressler NM. · Richard E. Hoover Rehabilitation Services for Low Vision and Blindness, Greater Baltimore Medical Center, Baltimore, Maryland 21204, USA. · Ophthalmology. · Pubmed #17270676 links to  free full text

Abstract: PURPOSE: To report the enlargement rate of geographic atrophy (GA) over time, its relationship to size of atrophy at baseline and to prior enlargement rate, and the implications for designing future treatment trials for GA. DESIGN: Prospective natural history study of GA resulting from age-related macular degeneration. PARTICIPANTS: Two hundred twelve eyes of 131 patients were included in the analysis. METHODS: Annual follow-up included stereo color fundus photographs. The areas of GA were identified and measured, and the rate of enlargement of the atrophy was assessed. Sample sizes for clinical trials using systemic treatment and uniocular treatment were determined. MAIN OUTCOME MEASURE: Rate of enlargement of the atrophy. RESULTS: The median overall enlargement rate was 2.1 mm2/year (mean, 2.6 mm2/year). Eyes with larger areas of atrophy at baseline tended to have larger enlargement rates, but knowledge of prior rates of enlargement was the most significant factor in predicting subsequent enlargement rates. There was high concordance between the enlargement rates in the 2 eyes of patients with bilateral GA (correlation coefficient, 0.76). To detect a 25% reduction in enlargement rate for a systemic treatment (alpha, 0.05; power, 0.80; losses to follow-up, 15%), 153 patients each in a control and treatment group would be required for a trial with a 2-year follow-up period for each patient. For a uniocular treatment, 38 patients with bilateral GA would be required, with the untreated eye serving as a control for the treated eye. CONCLUSIONS: Treatment trials for GA with an outcome variable of change in enlargement rate are feasible.

Sunness JS, Gonzalez-Baron J, Applegate CA, Bressler NM, Tian Y, Hawkins B, Barron Y, Bergman A. · Wilmer Ophthalmological Institute, Lions Vision Research and Rehabilitation Center, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA. · Ophthalmology. · Pubmed #10485549 No free full text.

Abstract: OBJECTIVE: To describe the progression of geographic atrophy (GA) from age-related macular degeneration (AMD) with respect to visual acuity (VA) loss and enlargement of atrophy. DESIGN: A prospectively observed case series. SETTING: Tertiary retinal referral center. PARTICIPANTS: One hundred twenty-three patients with GA due to AMD who completed at least 1 year of follow-up (median follow-up, 3 years) were examined annually. METHODS: At each examination, a protocol best-corrected VA of each eye was measured, a clinical examination was performed, and color fundus photographs were taken. The areas of atrophy were drawn and measured. MAIN OUTCOME MEASURES: Visual acuity loss and enlargement of total and central atrophy. RESULTS: At baseline, median VA was poorer with larger areas of atrophy, but there was wide variation related to sparing of the fovea. Thirty-one percent of all study eyes suffered a three-line VA loss from baseline by 2 years, and 53% had a three-line loss by 4 years. Those eyes with VA better than 20/50 had the highest rate of acuity loss; 27% of these eyes had acuities of 20/200 or worse at 4 years. Visual acuity loss in the GA study eye was similar in patients with bilateral GA and in those with choroidal neovascularization in the fellow eye. Total atrophy enlarged a median of 1.8 Macular Photocoagulation Study disc areas (DA) at 2 years; atrophy within a 4-DA circle centered on the fovea enlarged a median of 0.9 DA. Two (22%) of nine patients with GA in one eye and only drusen without advanced AMD in the fellow eye developed GA in the fellow eye at 2 years. CONCLUSIONS: Geographic atrophy is associated with a significant decline in VA over time in many eyes. Areas of atrophy continue to enlarge over time, even when already large at baseline. The combination of reduced VA with enlargement of atrophy, occurring bilaterally in most patients, can lead to significant impairment of visual function.

Sunness JS, Bressler NM, Tian Y, Alexander J, Applegate CA. · Lions Low Vision Center, The Wilmer Ophthalmological Institute, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA. · Invest Ophthalmol Vis Sci. · Pubmed #10393046 links to  free full text

Abstract: PURPOSE: To present a method developed for measuring areas of geographic atrophy (GA) in advanced age-related macular degeneration, METHODS: A microfilm reader projected the 30 degrees fundus photograph of the macula. Retinal landmarks, atrophic areas, and spared areas within the atrophy were traced, without access to drawings of other years. The total atrophic area was calculated, as was the atrophy within a four-disc-area circle entered on the estimated foveal center. The configuration of the atrophy was documented. RESULTS: Avoidable sources of discrepancy included variability in peripapillary atrophy seen on the photograph, and variability seen in the extent of the field. Reproducibility studies found a median absolute difference of 0.19 Macular Photocoagulation Study disc areas (DA) in total atrophy between repeat drawings, with 75% of repeat drawings having a difference of less than 0.33 DA. For central atrophy measures, there was a median difference of 0.08 DA, with 75% of pairs having a difference of less than 0.18 DA. Features making the definition of borders of GA difficult include the presence of drusen and pigmentary alteration, a fundus in which choroidal vessels are easily visible, and variation in the appearance of GA within a single area of atrophy. CONCLUSIONS: This method provides a reliable means of measuring the size of atrophic areas in GA and will be useful for measuring longitudinal change. It may be difficult to determine whether central spared areas are present, and correlation with visual acuity and macular perimetry may be helpful.