Progression of retinitis pigmentosa
Reviewed by Ivan Yip

This retrospective study evaluates the rate of progression of retinitis pigmentosa (RP) using multimodal imaging, including spectral-domain optical coherence tomography (SD-OCT), fundus autofluorescence (FAF) and microperimtery (MP). Traditional tests used to evaluate RP, for example, Goldmann visual fields and ERG have high retest variability, necessitating multiple assessments over relatively long periods of time to ascertain whether a true change has occurred. This is not feasible for most clinical trials. The study looked at RP in 205 eyes of 106 patients with RP with a one to five year follow-up. Demographics, visual acuity (VA) and SD-OCT were graded for the width of the ellipsoid zone (EZ), FAF was graded for the diameter and area of hyperautofluorescent ring (if present), and MP was graded for mean, central and paracentral sensitivity. Spearman’s correlation was used to measure correlations at baseline. The median VA at baseline was 75 letters and was positively correlated with mean and central sensitivity (r: 0372 and 0394; p=0.01 for both). All except for paracentral sensitivity were strongly correlated with each other (r: 0.673-0.991; p<0.001). The annual rates of change for each parameter were as follows: VA, -2.3 letters; EZ -151μm; ring diameter -132μm; ring area -0.44mm2; mean sensitivity -0.3dB; central sensitivity -0.7dB; paracentral sensitivity -0.4dB (all p<0.001). It was concluded that structural and functional measures were well correlated in RP and can reliably measure disease progression within the course of a year. Limitations include retrospective nature with 8% proportion of missing data. Not all the patients were genotyped.

Progression of retinitis pigmentosa on multimodal imaging: The PREP-1 study.
Ifitkhar M, Usmani B, Sanyal A, et al.
CLINICAL AND EXPERIMENTAL OPHTHALMOLOGY
2019;47:605-13.