Abstract
Purpose: :
To characterise and monitor the spatial distribution and the computed total amount of macular pigment (MP) in MacTel type 2 patients over periods of up to 39 months.
Methods: :
76 eyes of 44 patients were graded according to Gass classification of MacTel type 2 (grades 1-5). Two-wavelength fundus autofluorescence (2-AF; incident radiation 488nm and 514nm) was used to quantify MP optical density (MPOD) and MP distribution using a scanning laser ophthalmoscope. Two-dimensional 2-AF MP distribution profiles were assessed relative to a reference location at 10.5 degrees eccentricity and the total amount of MP was measured from the 2-AF image. Measurements were repeated over periods of 12-39 months (mean follow up 21 months).
Results: :
Eight eyes had MP with a peak at the fovea (mean MPOD = 0.37) and 68 had an annular distribution with an eccentric peak (mean MPOD = 0.08; mean eccentricity of peak = 5.04 degrees). Disease severity did not correlate significantly with the MPOD peak or with the lateral extent of MP. The median total MP complement tended to be less in severe disease than moderate disease but there was no significant correlation. The mean change in peak MPOD at follow-up was less than 0.01 and the eccentricity at which lateral MPOD dropped to 0.02 changed by a mean of -0.13 degrees. No patient progressed to a different clinical group and no patient with foveal MP developed a predominantly annular MP distribution over the 12-39 months of the study, although marked reduction in total MP was seen in 14 individuals (mean change -2057, range -1065 to -4752).
Conclusions: :
Patients with MacTel type 2 commonly have an abnormal paracentral distribution of MP. Evaluation of peak MPOD and distribution revealed no significant correlation with severity of disease over the 12-39 months of the study. The total amount of MP did not correlate with disease severity.
Keywords: macular pigment • carotenoids/carotenoid binding proteins • imaging/image analysis: clinical