Abstract
Abstract: :
Purpose: To look for trends in macular pigment density (MPD) among Normal, Primary relatives of AMD (PRAMD) and AMD eyes, as well as to determine if MPD at one location can accurately predict MPD levels throughout the rest of the macula. Methods: MPD was determined at 10min, 30min, 1 degree, and 2 degrees eccentric to the foveal center using heterochromatic flicker photometry. MPD calculation was based on a reference value found at 7 degrees. At each locus, 4 or 5 measurements were taken. The results were graphed for each group to find a best fitting exponential trend line using Microsoft Excel, and to see if there was a trend in MPD between different individuals in the same group. To determine if the exponential trend line had any predictive value, MPD at one location was taken, and the coefficient of the exponential trend line was changed to match the MPD at that location. For the remaining three locations, MPD values predicted by this new exponential line were compared to the actual measured values. This method was employed using the 10minute, 30minute, and 1 degree MPD as base measurements. Results: Ninety-three Normal, 66 PRAMD, and 36 AMD eyes were included in the study. The Normal and PRAMD groups showed very similar exponential MPD patterns at different parts of the macula based on the 30min measurement, but not the AMD group. Even though MPD values of the AMD group looked similar to the other groups from 30min and further out, MPD at 10min were significantly lower. A best fitting exponential trend line was also done for this group without considering the 10min measurement. The exponential value taken from the trend line predicted MPD values at other parts of the retina fairly accurately, with average percent errors comparable to those found in the Normal and PRAMD groups. However, MPD values predicted for 10min showed high percent errors as expected, due to the sudden decline of macular pigment levels at this locus. Conclusion: Overall, definite MPD trends were seen in the Normal, PRAMD and AMD groups. Measuring MPD at 30min can predict MPD levels throughout the rest of the macula.
Keywords: 462 macular pigment • 308 age-related macular degeneration