High Resolution Imaging of Cone–Rod Dystrophy With Adaptive Optics

Abstract

Abstract: : Purpose: Conventional ophthalmoscopes provide limited resolution due to their inability to overcome aberrations in the eye's optics. In contrast, adaptive optics ophthalmoscopes correct these aberrations to provide non–invasive high–resolution views of the living retina. It has been proposed that adaptive optics could be used for early detection and diagnosis of retinal pathology, but to date most reports have involved only normal eyes. Here adaptive optics ophthalmoscopy is used to image cone–rod dystrophy in vivo. Methods: High–resolution retinal images of cone–rod dystrophy were obtained with the University of Rochester’s Adaptive Optics Ophthalmoscope and the University of Houston’s Adaptive Optics Scanning Laser Ophthalmoscope and compared to standard clinical tests including fundus photography, OCT, mfERG, fluorescein angiography, and visual fields. Results: Adaptive optics images were acquired at multiple retinal locations throughout a clinically detected bull’s eye lesion. Within the atrophic regions, we observed large areas devoid of wave–guiding cones. In contrast, images of the clinically less affected regions revealed a completely tiled cone mosaic, though the cones were abnormally large, resulting in an 85% reduction in peak cone density (30,100 cones/mm² compared to the normal average of 199,200 cones/mm²). Consistent with this result, mfERG revealed a 76% functional loss at the central peak (10.8 nV/deg² compared to average normal peak of 45.3 nV/deg²). Conclusions: Here we show that adaptive optics ophthalmoscopy can be used to directly observe retinal pathology, such as photoreceptor loss, that is otherwise invisible using current clinical methods. Additionally, both adaptive optics imaging modalities used here revealed retinal structures never before seen in normal subjects. Future applications of adaptive optics will include detailed longitudinal studies of the mechanism and progression of diseases such as cone–rod dystrophy.

Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • photoreceptors • retinal degenerations: hereditary