Purpose:
Macular pigment (MP) protects the retina from damage due to blue light and other oxidative stress. Genetic factors determine the distribution profile of MP, which may also be important in protection from oxidative stress. In addition it has been suggested that the ring pattern (with a "shoulder" in the profile at ~0.5 degrees from the fovea) may be protective of AMD.
Methods:
322 healthy white female twin volunteers, aged 16-50 years (mean age 40+/-8.7 years) had macular pigment optical density (MPOD) measured by 2-wavelength fundus autofluorescence (AF). The sample consisted of 76 monozygotic twin pairs, and 74 dizygotic twin pairs.
Results:
At baseline, mean MPOD by AF was 0.41 density units (SD 0.21; range 0.04 to 1.25) in the central half-degree field, and exhibited a near- normal distribution. The ring like MP distribution profile was observed in 100 subjects (prevalence 0.31, 95% CI 0.26-0.36). Concordance in monozygotic twins was 0.85 (95% CI 0.75-0.95) compared to 0.43 in dizygotic twins (95% CI 0.23-0.63), (p for diff<0.001).
Conclusions:
The finding that the monozygotic twin concordance is approximately double the dizygotic concordance suggests that genetic factors are important in determining the MP distribution in the macula
Keywords: macular pigment • genetics • image processing