Background and objective: To evaluate the progression of retinitis pigmentosa (RP) caused by mutations in either PDE6A or PDE6B by measuring the progressive constriction of the hyperautofluorescent ring and shortening of the ellipsoid zone (EZ)-line width.
Patients and methods: Fundus autofluorescence (FAF) and spectral-domain optical coherence tomography (SD-OCT) images were obtained from seven patients with autosomal recessive RP caused by mutations in either PDE6A or PDE6B. Measurements of the EZ line width on SD-OCT images and horizontal, vertical diameter, and ring area on FAF images were performed by two independent graders. The measurements of these four parameters were correlated with one another.
Results: We observed that the EZ line width decreased by an average of 91 ± 64 µm per year, while the horizontal and vertical diameters decreased by 103 ± 53 µm and 92 ± 49 µm per year, respectively. The ring area decreased by a rate of 0.3 ± 0.18 mm2 per year. Progression rates were similar for the left eye.
Conclusions: We observed a progressive loss of EZ line width and Short-wavelength fundus autofluorescence (SW-AF) ring constriction over time. These results may serve as reference for better prognostic prediction and patients selection for clinical trials promoting cone rescue.
Keywords: Autosomal recessive; PDE6A; PDE6B; disease progression; retinitis pigmentosa.