Abstract
Purpose::
To compare between changes in retinal blood oxygen content and visual function in non-neovascular age-related macular degeneration (AMD) patients over a one year period.
Methods::
In a prospective study, 21 subjects with non-neovascular AMD were recruited. All subjects underwent retinal optical density (OD) sampling using a spectral retinal oximeter, as well as visual acuity testing using ETDRS chart and contrast sensitivity exam at 3, 6, 12, 18 cycles/degree. The ratio of OD’s from oxygen sensitive and insensitive images (optical density ratio, ODR), a linear function of oxygen saturation, was calculated for retinal arteries and veins. The difference between arterial and venous ODR (AV ODR difference) in the retina was also calculated. The average coefficient of variation (CV) of the ODRs was calculated for the retinal arteries and veins by analyzing baseline oximetry images three times. Changes in ODRs, visual acuity and contrast sensitivity over a one year period were compared by linear regression analysis.
Results::
Retinal oximetry tests of 18 AMD subjects were of sufficient quality for analysis. No significant difference in arterial ODR, venous ODR, or A-V ODR difference between baseline and 12 months was found. Also, no significant difference was found between ODR parameters and visual acuity. However, the difference between baseline and 12 month in contrast sensitivity at 12 cycles per degree was found to be significantly correlated with the difference in baseline to 12 month venous ODR. (p = 0.0238, r2 = 0.673). No such correlations were found between the ODRs and contrast sensitivity at 3, 6 & 18 cycles/degree.
Conclusions::
Some relationship between retinal oxygenation and contrast sensitivity may exist in non-neovascular AMD. Further research is needed.
Clinical Trial::
IUPUI 0108-34
Keywords: age-related macular degeneration • retina • imaging/image analysis: clinical