Analysis of imaging biomarkers and retinal nerve fiber layer thickness in RPGR-associated retinitis pigmentosa.

Purpose: To investigate multimodal retinal imaging characteristics including the retinal nerve fiber layer (RNFL) thickness in patients with RPGR-associated retinitis pigmentosa (RP).

Methods: This cross-sectional case-control study included 17 consecutive patients (median age, 21 years) with RPGR-associated RP who underwent retinal imaging including optical coherence tomography (OCT), short-wavelength fundus autofluorescence (AF) imaging, and RNFL scans centered on the optic disc. RNFL thickness was manually segmented and compared to clinical and imaging parameters including the transfoveal ellipsoid zone (EZ) width, the horizontal diameter of the macular hyperautofluorescent ring. RNFL thickness was compared to 17 age- and sex-matched controls.

Results: In patients with RPGR-associated RP, the EZ width (R = 0.65), the central hyperautofluorescent ring on AF images (R = 0.72), and visual acuity (R = 0.68) were negatively correlated with age. In comparison to controls, a significantly (p < 0.0001) increased global RNFL thickness was identified in RPGR-associated RP, which was, however, less pronounced in progressed disease as indicated by the EZ width or the diameter of the central hyperautofluorescent ring.

Conclusions: This study describes retinal characteristics in patients with RPGR-associated RP including a pronounced peripapillary RNFL thickness compared to healthy controls. These results contribute to the knowledge about imaging biomarkers in RP, which might be of interest for therapeutic approaches such as gene replacement therapies.