Abstract
Purpose :
To evaluate macular pigment optical density (MPOD) measurements obtained using a Macular Pigment Reflectometer (MPR), an objective and commercial prototype instrument, and compare them to the MPOD measurements obtained using QuantifEye MPSII (MPS II, ZeaVision St-Louis MO), a subjective heterochromatic flicker photometer.
Methods :
Thirty eyes of thirty individuals were examined for the purposes of the study. The mean age of the study participants was 30.73 years (SD 6.87 years) and visual acuity of 20/20 or better in the study eye. The participants underwent MPOD measurement using the MPSII device twice. The MPOD measurements were performed using the MPR device (ZeaVision St-Louis MO, USA see figure 1) twice undilated and twice post pupillary dilation. The MPR calculates MPOD using a quartz halogen source and a mask to illuminate 1° at the retina which is also the visual reference to which the participant fixates for 40 seconds. The light reflected from the retina is collected and analyzed by a spectrometer. The instrument software calculates MPOD by averaging the spectrometer signals obtained after eliminating first 10 seconds of the data. The difference in the mean MPR-MPOD and the MPSII-MPOD was examined for statistical significance using paired samples t-test. The correlation between measured MPOD of the two techniques was evaluated and the coefficient of reproducibility was calculated for both MPSII and MPR-MPOD measurements.
Results :
The mean MPSII-MPOD was 0.459 (SD 0.15). The mean MPR-MPOD undilated and dilated condition was 0.704 (SD 0.21) and 0.695 (SD 0.22) respectively. The difference in the mean MPR-MPOD measured using under undilated and dilated condition was not statistically significant (p=0.43). There was excellent correlation between the MPOD measured using the two devices; Pearson correlation coefficient r-statistic 0.92 under both dilated and undilated conditions. The coefficient of repeatability of MPOD measured using the MPS II device was 12.8% whereas the coefficient of repeatability of MPR under undilated and dilated condition was 11.2% and 8.3% respectively.
Conclusions :
The mean MPR-MPOD is significantly correlated with MPSII-MPOD, is not influenced by pupillary dilation and has good repeatability . These results are promising and need to be confirmed in studies with a larger sample size.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.