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 2 measurements without mydriasis was statistically significant for all parameters, but not significant between the 2 measurements with mydriasis or between non-mydriatic and mydriatic measures. The ICCs were higher for the 2 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% limits of agreement (LOA) of measurements between the 2 measurements after mydriasis were 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.