Macular Pigment Optical Density Measured by a Single Wavelength Reflection Photometry with and without Mydriasis.

Purpose: 1. To evaluate the repeatability of macular pigment optical density (MPOD) measurements in non-mydriatic and mydriatic conditions with a single wavelength reflection photometry. 2. To compare the non-mydriatic measurement with the mydriatic measurement of MPOD values. Methods: Fifty-one healthy young subjects were recruited in this prospective study. MPOD parameters including maximum optical intensity (OD), mean OD, volume and area, were measured using a single 460-nm wavelength reflection method (Visucam 200, Carl Zeiss Meditec) twice both before and after pupil dilation. Paired t test, Pearson's correlation, intraclass correlation coefficient (ICC) and Bland-Altman plots were used to evaluate the agreement and correlation of MPOD parameters before and after mydriasis. Results: The differences of maximum OD, mean OD and volume between the two measurements without mydriasis was statistically significant for all parameters, but not significant between the two measurements with mydriasis or between non-mydriatic and mydriatic measures. The ICCs were higher for the two measurements with mydriasis (range: 0.687-0.840) than those without mydriasis (range: 0.448-0.695) or non-mydriatic and mydriatic measures (range: 0.473-0.769). The 95% limit of agreement (LOA) of measurements between the two measurements after mydriasis was the smallest among all the other comparisons. The coefficient of repeatability was lower for the measurements with mydriasis than those without mydriasis. Conclusions: MPOD measurement by Visucam 200 with mydriasis has higher repeatability than the measurement without mydriasis. The non-mydriatic and mydriatic measures had less agreement compared to the two measure after mydriasis. Therefore, mydriasis is recommended.