Evaluation of Structural Retinal Layer Alterations in Retinitis Pigmentosa

Objective: This study aimed to analyze retinal layers in the macular region using spectral-domain optical coherence tomography (SD-OCT). Additionally, we examined the retinal vascular plexus densities of the eyes using optical coherence tomography angiography (OCT-A), specifically in patients with retinitis pigmentosa (RP). Methods: In the study, 36 eyes from patients with retinitis pigmentosa (RP) and 36 eyes from healthy controls were included. Measurements involved assessing the thicknesses of each retinal layer at the central fovea, parafoveal, and perifovea using spectral domain optical coherence tomography (SD-OCT). Moreover, the study involved the evaluation of retinal capillary plexus densities (RCPD), encompassing deep capillary plexus density values, superficial capillary plexus, and radial peripapillary capillary plexus. This assessment was performed using optical coherence tomography angiography (OCT-A). Results: No statistically significant difference in retinal thickness was found in the central fovea between the two groups. The thicknesses of the INL, OPL, and PRL in the parafoveal regions as well as the RPE in the perifoveal regions increased in the RP group. Nonetheless, the ONL, IPL, GCL, and RNFL demonstrated reduced thickness in both the perifoveal and parafoveal areas. The OCT-A findings indicated that patients with RP exhibited lower values for all RCPD. Conclusion: The retinal layers and RCPD were significantly impacted at varying rates of RP. It is essential to acknowledge that this alteration may be significant in the context of the retinal findings in patients with RP. Abbreviations: SD-OCT = Spectral-domain optical coherence tomography, OCT-A = Optical coherence tomography angiography, RP = Retinitis pigmentosa, ETDRS = Early Treatment Diabetic Retinopathy Study, SD = standard deviation, TRT = Total Retinal Thickness, IRT = Inner Retinal Thickness, ORT = Outer Retinal Thickness, RNFL = Retinal Nerve Fiber Layer, GCL = Ganglion Cell Layer, IPL = Inner Plexiform Layer, INL = inner nuclear layer, OPL = Outer Plexiform Layer, ONL = Outer Nuclear Layer, PRL = Photoreceptor layer, RPE = Retinal Pigment Epithelium, µm = micrometer, PaFoSu = parafovea superior, PeFoSu = perifovea superior, PaFoNa = parafovea nasal, PeFoNa = perifovea nasal, PaFoTe = parafovea temporal, PeFoTe = perifovea temporal, PaFoIn = parafovea inferior, PeFoIn = perifovea inferior.