Evaluation on the noninvasive measurement of macular pigment optical density by a novel technique

Abstract

To evaluate the measurement of macular pigment optical density (MPOD) by a novel instrument MPS1000 as compared to that measured by the traditional heterochromatic flicker photometer (HFP). Method-comparative study. MPOD at 0.5° eccentricity was measured simultaneously by the two different instruments in 111 eyes of the 59 healthy subjects. Test-retest variability was evaluated for each instrument over a 1-week period in 8 subjects. The mean MPOD levels measured by the MPS1000 and HFP were 0.40±0.18 and 0.47±0.15, respectively, which were statistically significantly different by the paired t-test (t=3.95, P<0.001). A positive linear correlation was observed for MPOD at 0.5° eccentricity between the two different instruments (r=0.4, P<0.001). The 95% limit of agreement was 0.07±0.35 as shown by Bland-Altman analysis. Intersessional repeatability, expressed as a coefficient of repeatability, was 0.26 for HFP and 0.18 for MPS1000. MPOD levels measured by MPS1000 were significantly higher as compared to that measured by the traditional HFP, suggesting that it is inappropriate to directly compare the MPOD levels measured by these two methodologies.