Macular pigment parameters in patients with macular telangiectasia (MacTel) and normal subjects: implications of a novel analysis.
OBJECTIVE
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.
Moorfields Eye Hospital, London, United Kingdom.
Simona
S
Degli Esposti
Catherine
C
Egan
Catey
C
Bunce
Jack D
JD
Moreland
Alan C
AC
Bird
Anthony G
AG
Robson
D000293:Adolescent; D000328:Adult; D000368:Aged; D006801:Humans; D014975:Lutein / Q000378:metabolism*; D008266:Macula Lutea / Q000378:metabolism*; D018613:Microscopy, Confocal; D008875:Middle Aged; D010783:Photometry / Q000379:methods; D012168:Retinal Pigments / Q000378:metabolism*; D058456:Retinal Telangiectasis / Q000378:metabolism*; D024341:Xanthophylls / Q000378:metabolism*; D055815:Young Adult; D065146:Zeaxanthins
D012168:Retinal Pigments; D024341:Xanthophylls; D065146:Zeaxanthins; D014975:Lutein