Abstract
Purpose: :
To study changes in color fundus image related to the diameter of the confocal aperture in the scanning laser ophthalmoscope (SLO).
Methods: :
Twenty-four eyes with macular disease were included: nine eyes with an epiretinal membrane (ERM), nine eyes with branch retinal vein occlusion (BRVO), and six eyes with drusen or age-related macular degeneration (AMD). The Digital Ophthalmoscope F-10 (Nidek, Gamagori, Japan) was the SLO used in this study. The SLO color fundus images were obtained by combining three color images, i.e., a blue color image converted from a blue (490-nm) laser image, a green color image converted from a green (532-nm) laser image, and a red color image converted from a red (660-nm) laser image. Each image was obtained with a confocal aperture 1.5 to 7 mm in diameter at the detector. The differences in these SLO color images and fundus photographs were studied.
Results: :
Membranes and retinal folds in the ERM were enhanced, and hemorrhages and vessels in BRVO were seen more clearly in the SLO color images compared to the fundus color photography, especially with the small diameter confocal aperture. Pathological lesions (drusen and AMD) were more distinct by adding images of the deeper tissue layers in the SLO color images, especially with a large-diameter confocal aperture. In some cases, these findings, which were barely visible using a fundus camera, were observed even in patients with a cataract.
Conclusions: :
Selecting the appropriate diameter of the confocal aperture depending on the pathology to be viewed can improve the image of the fundus findings. SLO color imaging would be a more useful method to view fundus pathology than fundus color photography.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • image processing • imaging/image analysis: clinical