5-year progression of retinal disease using spectral domain oct in sibling affected by Retinitis Pigmentosa.

Abstract

Purpose : To evaluate the size of the photoreceptor atrophy using spectral domain optical coherence tomography (SD- OCT) and to compare its progression in siblings affected by Retinitis Pigmentosa (RP).

Methods : 53 eyes of 27 patients (12 arRP, 9 adRP, 6 usher II) belonging to 12 family clusters were enrolled. To assess the annual progression rate of photoreceptor atrophy, the length of the ellipsoid zone line (inner/outer segment junction) was measured in a SD-OCT sections through the fovea. Both horizontal and vertical lines were captured. Furthermore, the area of the hyperautofluorescent rings was measured using fundus autofluorescence (AF) and employed as additional index. We used multivariate mixed effects to model the rate of progression and its relation to the initial ellipsoid zone length. While dealing with hierarchically correlated data (family cluster and subjects within the cluster), we used the random effects in the model to calculate Intraclass Correlation Coeffcients (ICCs) as descriptors of correlation within clusters.

Results : During our 4.84 (± 1.44) mean follow up time (range 3-7) 53 eyes were examined (96 horizontal scans, 92 vertical and 197 AF images).
The mean patient age was 37.04 (SD ±14.77, range 15-71) and mean visual acuity was 6.75/10 (SD ±2.35). The length of the ellipsoid zone in our RP patients declined with a yearly average rate of 96.27 µm (0.33°)/year (4.16% / year) (p-value < 0.0001). The diameter of the hyperautofluorescent ring contracted 0.3 mm² per year (6.13%/year), (p-value = 0.016).
Progression rates were poorly correlated within family clusters (p-value = 0.23) and showed statistical difference between affected siblings (p-value = 0.007) (ICC, 0.175).
There was no correlation between progression rate and transmission type (p-value = 0.98) as well as between the age at the start of follow-up and photoreceptor length (p-value = 0.75).
The progression rate was slower as the disease approached the fovea.

Conclusions : in our study we describe for the first time the inter and intra-familiar heterogeneous progression of retinal damage in retinitis pigmentosa using OCT data. The morphological photoreceptor aspects as evaluated by OCT can be useful in association with functional evaluation for future therapeutic trials.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.