Abstract
Abstract: :
Purpose: Longitudinal monitoring of early features of age–related maculopathy/ degeneration (AMD) may be useful as endpoints in clinical trials evaluating preventative therapies. We performed this study to determine if longitudinal changes in drusen features could be detected with infrared (IR) reflectance imaging of the macula. Methods: Resorption of drusen following laser photocoagulation for choroidal neovascularization (CNV) is a well known phenomenon. We identified 6 patients treated with focal laser for CNV secondary to AMD meeting predefined study criteria. Longitudinal changes in drusen features on color fundus photographs and IR reflectance images at baseline and 11 to 34 months following laser photocoagulation were studied Results: As expected, drusen faded in intensity or disappeared on color fundus photographs in most patients. Two predominant IR reflectance patterns from drusen were observed. We refer to these patterns as bright white spots or dark spots with halos. Intensity of reflectance from drusen decreased after laser photocoagulation. Mean drusen diameter decreased from 130 µm to 104 µm (P = .007). Three–dimensional intensity profiles of scaled images enabled visualization of quantitative changes in individual drusen features including reflectance intensity, drusen size, and pattern of reflectance. Changes in global properties of the reflectance pattern across the macula were observed including modulation in spatial frequency and amplitude. Conclusion: Longitudinal changes in drusen features were detectable and quantifiable with infrared reflectance imaging. Drusen no longer visible on color photography remained detectable on IR reflectance images. Both drusen specific and global properties of macular reflectance warrant further study as endpoints for study of early AMD.
Keywords: age–related macular degeneration • imaging/image analysis: clinical • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)