Abstract
Abstract: :
Purpose: Recent studies indicate that the density of the macular pigment (MP) may play a central role in the development and progression of age-related maculopathy (ARM). We have presented a new instrument for the assessment of macular pigment density (MPD) (Graefe’s 240(8): 666-671). In this study we examine the reproducibility of repeated measurements of MPD obtained from reflectance and autofluorescence images. Methods: A modified confocal scanning laser ophthalmoscope (Heidelberg Engineering, Heidelberg, Germany) was optimized for fundus reflectance and autofluorescence images at 488 and 514 nm. For autofluorescence imaging we used a band pass barrier filter with a short wavelength cut off at 530 nm. MP density maps are computed and MP density is evaluated within 2 degrees around the foveal center. In this study healthy subjects were examined. Each subject underwent repeated measurements with both the reflecance and autofluorescence method within one hour. Reproducibility was assessed by calculating the coefficient of variation for test-retest variation. Results: In this study we included 30 healthy subjects aged form 16 – 75 years (mean: 41 ± 18 years). Using the reflectance method mean MPD of the two measurements was 0.160 ± 0.04 density units (D.U.) and 0.154 ± 0.04 respectively, whereas a MPD of 0.219 ± 0.05 D.U. and 0.219 ± 0.05 D.U. resulted from autofluorescence images with the 530 nm barrier filter. The intraindividual coefficient of variation is 8.4 % for the reflectance and 5.5 % for the autofluorescence method. Conclusions: This study demonstrates good reproducibility of MPD measurements with a modified confocal scanning laser ophthalmoscope. We found higher macular pigment density values calculated from autofluorescence images than from reflectance images. These differences may be caused by artefacts caused by reflecting effects of the inner limiting membrane and the lens. The autofluorescence method provides better reproducable results than the reflectance method. We will therefore use the autofluorescence method for further studies as main source for quantification of MPD.
Keywords: macular pigment • imaging methods (CT, FA, ICG, MRI, OCT, RTA, S • clinical (human) or epidemiologic studies: sys