Abstract
Purpose: :
To study the clinical applicability of a color perimetry technique for the evaluation of the optical density of macular pigments. To establish normal values taking into account the diet of subjects.
Methods: :
Luminance differential thresholds were measured for blue (450-480 nm) and red (615 nm) stimuli presented at the fovea and at 6 peripheral locations with an eccentricity of 10 degrees. Tests parameters were Goldmann size III over a white background of 10 cd.m-2. Tests were presented on a TFT monitor calibrated according to the DICON standard. A staircase 4-2-2-2 full thresholding strategy was used. Exams were performed on 54 subjects with normal visual acuity, normal eye fundus and no ophthalmic disease.
Results: :
The optical density of macular pigment was estimated as the difference between the thresholds of blue and red stimuli at the fovea. A correction for the blue absorption by the lens was made based on the difference between the thresholds of blue and red stimuli at 10 degrees eccentricity. The median value of the tested population was 0.39 log unitsInfluence of diet:. The tested population was split into 2 groups: one with a "standard French population diet" and one with a diet meeting the recommendations of the Pasteur Institute in Lille. The comparison of the 2 groups showed an estimated optical density of 2.35 for the "standard diet" and 5.06 for the "recommended diet". The difference between the 2 populations was highly significant (p < 0.0001).
Conclusions: :
The color perimetry technique provides estimation of the optical density of the macular pigment quite similar to values found with other techniques . It can be used on standard visual perimetry equipment. It shows a significant effect of the dietary habits
Keywords: age-related macular degeneration