Retrospective Analysis of Structural Disease Progression in Retinitis Pigmentosa Utilizing Multimodal Imaging

Thiago Cabral,Stephen H Tsang,Jesse D Sengillo,Jimmy K Duong,Sally Justus,Vinit B Mahajan,Rubens Belfort,Janet R Sparrow,Katherine Boudreault,Kaspar Schuerch

doi:10.1038/s41598-017-10473-0

Abstract

In this report, we assess the natural progression rate of retinitis pigmentosa (RP) over an average of three years using spectral-domain optical coherence tomography (SD-OCT) and short wavelength fundus autofluorescence (SW-AF). Measurement of the ellipsoid zone (EZ) line width and hyperautofluorescent ring diameters was performed in 81 patients with RP in a retrospective, longitudinal fashion. Rate of structural disease progression, symmetry between eyes, and test-retest variability were quantified. We observed on average, EZ-line widths decreased by 140 µm (5.2%, p < 0.001) per year, and average horizontal and vertical hyperautofluorescent ring diameters decreased by 149 µm (3.6%, p < 0.001) and 120 µm (3.9%, p < 0.001) per year, respectively. The 95th percentile of this cohort had differences in progression slopes between eyes that were less than 154 µm, 118 µm, and 132 µm for EZ-line width and horizontal and vertical ring diameters, respectively. For all measures except horizontal ring diameter, progression rates were significantly slower at end-stage disease. From our data, we observed a statistically significant progression rate in EZ line width and SW-AF ring diameters over time, verifying the utility of these measurements for disease monitoring purposes. Additionally, calculated differences in progression slopes between eyes may prove useful for investigators evaluating the efficacy of unilateral treatments for RP in clinical trials.

Highlights

Can serve as a metric for future clinical trials and patient counseling, and the present analysis is a follow-up to the previous study over a longer follow-up period
High resolution spectral-domain optical coherence tomography (SD-OCT) visualizes the ellipsoid zone of the retina, an area that approximates the perceptual experience of a patient, as it correlates to visual field boundaries and can be used to monitor progression[22,23,24,25,26,27] (Fig. 1)
It was previously observed that some retinitis pigmentosa (RP) patients possess a progressively constricting hyperautofluorescent ring on Short wavelength fundus autofluorescence (SW-AF), which correlates with worsening of visual function over time as measured by pattern ERG29

Summary

Introduction

Can serve as a metric for future clinical trials and patient counseling, and the present analysis is a follow-up to the previous study over a longer follow-up period. Mid-peripheral scotomas are observed in many patients, likely because this area of the fundus contains the highest rod density[9, 10] These tests correlate to the perceptual experience of the patient, intersessional visual acuity and field measurements are variable. Physicians alter the adaptation state and light stimulus to yield different information from the ERG This modality has been useful in monitoring disease progression and treatment response[16], its intrinsic variability between sessions and large threshold for significant change limit its use over short intervals[17,18,19,20,21]. We provide progression rates for RP over a three-year average follow-up utilizing SD-OCT and SW-AF imaging

Methods

Results

Conclusion