Comparison between Macular Pigment Optical Density Measurements Using Two-Wavelength Autofluorescence (SLO) and Macular Pigment Reflectometry (MPR)

Abstract

 

Purpose:

 

Two-wavelength autofluoresence and fundus reflectometry are two objective techniques for measuring macular pigment (MP) concentration in the central retinal. The modified scanning laser ophthalmascope (SLO, Heidelberg Retinal Angiographer [HRA1]) uses two-wavelength autofluroesence to measure total optical density (MPOD). The MPR specifically measures the reflectance of two MPs, zeaxanthin (ZOD) and lutein (LOD). We compared MPOD to LOD and ZOD to understand the relationship between results obtained by these two techniques.

 

Methods:

 

Type 2 diabetic patients currently enrolled in an oral carotenoid supplementation trial were imaged with the HRA and MPR at each visit. Results from the initial visit were used for analysis. MPOD at 0.5° and 1° -diameter areas around the fovea were obtained from the HRA. MPR results included ZOD and LOD in a 1°-diameter around the fovea. We compared mean MPOD at 0.5° and 1°-diameters to mean ZOD and LOD using linear regression analysis.

 

Results:

 

A total of 11 eyes from 6 patients were included. The average age was 55±6.3 years. Males and females were not equally represented (80% and 20%, respectively). There was a not a strong correlation between LOD and MPOD at 0.5°or 1° -diameters (r=0.16 and 0.20, p=0.63 and 0.55, respectively). MPOD at 0.5°-diameter and ZOD were strongly correlated (r=-0.51, p=0.11). There is also strong correlation between MPOD at 1° diameter and ZOD (r=-0.48, p=0.13).

 

Conclusions:

 

There is a significant amount of variation in the distribution of macular pigment in the area of the fovea. In the present study, individual LOD and ZOD as measured by reflectometry did not demonstrate a strong positive correlation with two-wave autofluorescence MPOD at 0.5° and 1°-diameters. This may be a result of nonuniform distribution of macular pigment and comparing these techniques at a diameter greater than 1° may demonstrate a stronger correlation.  

 

Keywords: retina