Changes In Cone Photoreceptors With An Adaptive Optics Fundus Camera In Cases Of Occult Macular Dystrophy, Light-damaged Maculopathy, And Cone-rod Dystrophy

Abstract

Purpose: : To investigate the structural changes in cone photoreceptors with an adaptive optics (AO) fundus camera in eyes of occult macular dystrophy (OMD), light-damaged maculopathy (LDM) and cone-rod dystrophy (CRD).

Methods: : Macular areas of One OMD, one LDR and one CD patients were examined with an AO fundus camera (rtx1, Imagine Eyes, France) at Toyama University Hospital. Each patient had a complete ophthalmological examination. Electroretinograms (ERG) and spectral domain OCT (optical coherence tomography) were recorded. AO images of cone photoreceptors were obtained more than 6 x 6 degrees in the macula. We counted densities of cone photoreceptors at 250 μm apart from the foveal center in the four directions (up, down, right, and left) and compared them to those of normal eyes.

Results: : Fundus appearances of these patients were normal by conventional ocular examinations. However, the AO images showed patchy dark areas with disruption of the mosaic of bright spots in the macula, which indicated loss of cone photoreceptors. The inner and outer segment (IS/OS) junctions of the photoreceptor in these eyes were disrupted by OCT. From the AO images densities of cone photoreceptors were counted at 250 μm apart from the foveal center and significantly decreased in the eye of OMD (average 15912 cells/mm²), LDM (average 27292 cells/mm²), CD (average 6528cells/mm²), compared to normal eyes (average 41021 cells/mm²).

Conclusions: : AO fundus imaging with rtx1 was useful to detect loss of cone photoreceptors and to observe the area and extent of damaged cone photoreceptors in the macula.

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