Abstract
Purpose :
Among the 64 genes associated with retinitis pigmentosa (RP), at least 18 encode proteins that localize to the cilia in photoreceptors. There is an unmet need for descriptions of natural disease progression for retinal ciliopathies in order to create metrics for future clinical trials and to help with patient counseling for specific types of RP. In this study, we evaluated and compared the progression of ciliopathy and non-ciliopathy autosomal recessive RP (arRP) patients by measuring the constriction of hyperautofluorescent rings in fundus autofluorescence (FAF) images and the progressive shortening of the ellipsoid zone line width obtained by spectral-domain optical coherence tomography (SD-OCT).
Methods :
FAF and SD-OCT images were obtained from 18 ciliopathy and 15 non-ciliopathy patients with arRP. Measurements were done on the SD-OCT and FAF images documented at each patient visit by using a built-in measurement tool in the Spectralis HRA+OCT software. EZ line length, horizontal diameter, vertical diameter, and area of hyperautofluorescent ring were measured by two ophthalmologists.
Results :
For the ciliopathy group, the estimated mean shortening of the ellipsoid zone line was 259 µm per year and the ring area decreased at a rate of 2.46 mm2 per year. For the non-ciliopathy group, the estimated mean shortening of the ellipsoid zone line was 84 µm per year and the ring area decreased at a rate of 0.7 mm2 per year.
Conclusions :
Our study was able to quantify and compare the loss of EZ line width and short-wavelength autofluorescence (SW-AF) ring constriction progression over time for ciliopathy and non-ciliopathy arRP genes. These results may serve as a basis for modeling RP disease progression, and furthermore, they could potentially be used as endpoints in clinical trials seeking to promote cone and rod survival in RP patients.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.