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ABSTRACT: Purpose. To evaluate the spatial distribution and total amount of macular pigment (MP) in patients with idiopathic macular telangiectasia type 2 (MacTel) compared to healthy subjects. Methods. Totals of 53 MacTel patients and 38 normal subjects underwent macular pigment optical density (MPOD) measurement using a 2-wavelength autofluorescence (2-AF) technique. The peak MPOD and total MP (sum of pixel OD values) were measured within the central 21 degrees. Data were correlated with motion photometry in a cohort of normal subjects. Results. A Bland-Altman analysis revealed minimal differences between psychophysical and 2-AF measurements of MPOD (bias = 0.025, SD = 0.06, N = 156 values). In the normal comparison group, 2-AF MPOD peak had a median value of 0.57 (range 0.21-0.93), and median eccentricity of the peak was 0.19 degrees (range 0.00-0.41). In the MacTel group, MPOD peak had a median value of 0.08 (range 0.01-0.26), and median eccentricity of the peak was 5.04 degrees (range 0.18-7.27). The median total amount of MP within the central 21 degrees was greater for normal subjects (4802, range 2362-9215) than for the patients (2938, range 142-7198), but there was marked overlap between the groups. Comparison of the total amount within the central 8, 12, or 16 degrees to that within the central 21 degrees revealed underestimation of up to 68% (median 53%), 42% (27%), and 24% (8%), respectively. Conclusions. Most MacTel patients have a normal total complement of MP with an abnormal paracentral distribution. The study highlights the limitations of MP measurement techniques that assume minimal MP at eccentricities less than 10.5 degrees.
Investigative ophthalmology & visual science 08/2012; 53(10):6568-75. · 3.43 Impact Factor
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ABSTRACT: To investigate functional and morphologic alterations over a 1-year review analysis in patients with type 2 idiopathic juxtafoveal retinal telangiectasia (MacTel).
Nine eyes of 9 patients with MacTel underwent repeated scotopic and photopic fine matrix mapping (FMM), 10-2 photopic microperimetry, and imaging studies.
Early Treatment Diabetic Retinopathy Study visual acuity assessment showed a median difference between examinations of 1.0 letter (range, -3 to 4 letters). The difference of sensitivity values of all test points was 4.5 dB (range, 0.4 -5.5 dB) for microperimetry 1, 0.4 dB (range, -0.8 to 1.7 dB) for photopic, and -1.7 dB (range, -6.1 to 1.0 dB) for scotopic fine matrix mapping, respectively. The difference in test points of more than a 10-dB loss compared with age-matched controls was higher for scotopic than for photopic testing (P= 0.03, Wilcoxon signed ranks test). Small progression of scotoma correlated with a slight increase in retinal blood vessel dilatation and hyperfluorescence and subtle enlargement of pigmented plaques.
Changes in central visual acuity and microperimetry testing after 1 year most likely do not extend beyond test-retest variability. The deterioration of scotopic sensitivity confirms our previous results of more severe rod compared with cone dysfunction in MacTel. Changes in fine detail visual function over a 1-year period may be useful parameters for interventional trials.
Retina (Philadelphia, Pa.) 06/2009; 29(9):1314-20. · 2.93 Impact Factor
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Peter J Coffey,
Carlos Gias,
Caroline J McDermott,
Peter Lundh,
Matthew C Pickering,
Charanjit Sethi, Alan Bird,
Fred W Fitzke,
Annelie Maass,
Li Li Chen,
Graham E Holder,
Philip J Luthert,
Thomas E Salt,
Stephen E Moss,
John Greenwood
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ABSTRACT: Age-related macular degeneration is the most common form of legal blindness in westernized societies, and polymorphisms in the gene encoding complement factor H (CFH) are associated with susceptibility to age-related macular degeneration in more than half of affected individuals. To investigate the relationship between complement factor H (CFH) and retinal disease, we performed functional and anatomical analysis in 2-year-old CFH-deficient (cfh(-/-)) mice. cfh(-/-) animals exhibited significantly reduced visual acuity and rod response amplitudes on electroretinography compared with age-matched controls. Retinal imaging by confocal scanning laser ophthalmoscopy revealed an increase in autofluorescent subretinal deposits in the cfh(-/-) mice, whereas the fundus and vasculature appeared normal. Examination of tissue sections showed an accumulation of complement C3 in the neural retina of the cfh(-/-) mice, together with a decrease in electron-dense material, thinning of Bruch's membrane, changes in the cellular distribution of retinal pigment epithelial cell organelles, and disorganization of rod photoreceptor outer segments. Collectively, these data show that, in the absence of any specific exogenous challenge to the innate immune system, CFH is critically required for the long-term functional health of the retina.
Proceedings of the National Academy of Sciences 11/2007; 104(42):16651-6. · 9.68 Impact Factor
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Alan Bird
Proceedings of the National Academy of Sciences 03/2007; 104(7):2033-4. · 9.68 Impact Factor
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ABSTRACT: To review the epidemiology of age-related macular degeneration (AMD).
Evidence from epidemiologic data regarding the natural history of AMD and its risk factors are presented.
Large, soft drusen associated with pigmentary abnormalities increase the risk of progression to advanced AMD. Large soft drusen may fade over time. Advanced AMD is more likely to be present in whites than blacks, despite the similar prevalence of soft drusen in both groups. Neovascular AMD is more frequent than geographic atrophy in most population-based studies in whites in America, Australia, and the Netherlands than in similar population-based studies in Iceland and Norway. After age and family history, there are few consistent relationships of risk factors to AMD. Of these, the relationship of smoking, hypertension, and cataract surgery to advanced AMD have been most consistent.
Long-term epidemiologic studies have provided information on the distribution and the natural history of AMD and its associated risk factors. It is not known what effect reduction of blood pressure and the cessation of smoking might have on the incidence and progression of AMD.
American Journal of Ophthalmology 04/2004; 137(3):486-95. · 4.22 Impact Factor
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Clinical and Experimental Ophthalmology 36(1):92-3. · 1.98 Impact Factor
