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Dawn A. Sim, Catherine A. Egan, Simona D. Esposti, Jack D. Moreland, Anthony G. Robson; Comparison Of The Spatial Distribution And Total Complement Of Macular Pigment In Patients With Macular Telangiectasia (mactel) Type 2 With That In Healthy Subjects. Invest. Ophthalmol. Vis. Sci. 2011;52(14):3636.
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© ARVO (1962-2015); The Authors (2016-present)
To compare the computed total amount of macular pigment (MP) in MacTel type 2 patients with an abnormal paracentral MP distribution with the amount present in healthy subjects
Two-wavelength fundus autofluorescence (2-AF; incident radiation 488nm and 514nm) was used to quantify MP optical density (MPOD) and distribution in 25 healthy subjects and in 28 patients with MacTel type 2 using a scanning laser ophthalmoscope. Values of MPOD obtained in 12 of the healthy subjects were compared with those obtained using minimum motion photometry (stimuli 460nm and 580nm; 13 retinal locations), for the purposes of validation. Two-dimensional 2-AF MP distribution profiles were assessed relative to a reference location at 10 degrees eccentricity and were used to estimate the MPOD and total amount (equivalent "volume") of MP in the MacTel and control groups.
2-AF measurements of MP OD correlated highly with those obtained psychophysically (slope=1, r2=0.89, p<0.005, N=12). In the control group, 2-AF assessment of MP OD was greatest at the fovea and ranged from 0.35 to 0.9. In the MacTel patients, MP was undetectable at the fovea; a broad peak occurred at 3.5 to 7.5 (median 5.3) degrees eccentricity and varied in OD from 0.01 to 0.13 (median 0.05). The mean computed total amount of MP within the central 20 degrees was 80% greater for the controls (mean 5061; SD 2026; range 1229-9435) than for the MacTel patients (mean 2816; SD 1534; range 549-6479) but there was considerable overlap between the two groups.
Patients with MacTel type 2 commonly have an abnormal paracentral distribution of MP. The mean total amount of MP in MacTel type 2 is less than in healthy subjects but there is overlap between the 2 groups. Large amounts of paracentral MP in some MacTel patients are difficult to explain if the paracentral distribution results from retinal loss of central pigment and may be more in keeping with centrifugal displacement or abnormal parafoveal uptake.
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