Abstract
Purpose :
To examine the structure of subretinal drusenoid deposits (SDD) and surrounding photoreceptors during SDD progression and regression over 5.5 years in patients with age-related macular degeneration (AMD), using an adaptive optics scanning laser ophthalmoscope (AOSLO) built for research, in combination with spectral domain coherence tomography (SD-OCT).
Methods :
Four patients with intermediate AMD (grade 5-8 on the AREDS 9-step scale for color fundus photography) were enrolled. Six eyes of all subjects were studied 4 times over 3.5 years. Three eyes of 2 patients were followed over extended periods to 4.5 and 5.5 years, respectively. Participants underwent infrared reflectance (IR), SD-OCT, and AOSLO. SDD presence and progression were assessed by multimodal imaging and a 3-stage SD-OCT-based grading system. To evaluate change over time, shapes and ultrastructure of individual SDD lesions identified at baseline were examined by AOSLO. Photoreceptors surrounding SDD were assessed in AOSLO and SD-OCT.
Results :
By 3.5 years, 1 subject developed outer retinal atrophy (ORA) in 2 eyes, another developed non-central geographic atrophy (GA) in both eyes, and the 2 other patients remained at intermediate stage. Of 822 lesions examined at the baseline, 593 (72%) increased size over the observation time, 143 (17%) decreased size, and 86 (11%) disappeared (fully regressed) with 5 SDD reappearing after complete regression. A return of characteristic photoreceptor reflectivity in AOSLO (punctate) and in SD-OCT (prominent ellipsoid zone) was observed after regression of some SDD in some individuals. Of the 86 regressed lesions, 32 were with full recovery of EZ band in SD-OCT, 11 with partially recovered EZ, and 10 without perceivable EZ recovery. By year 5, the subject with ORA developed GA in both eyes, and the other developed GA.
Conclusions :
Combination of high resolution AOSLO and SD-OCT provided in vivo microscopy of the natural history and impact of SDD on photoreceptor structure in the same eyes over long follow-up periods. The return of photoreceptor reflectivity after SDD regression suggests that photoreceptors resume waveguiding. Understanding the mechanisms by which photoreceptor reflectivity is restored may provide insight into new therapeutic targets.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.