In Vivo Evidence of Inner Retinal Neurodegeneration in Retinitis Pigmentosa Using Spectral-Domain Optical Coherence Tomography

BACKGROUND AND OBJECTIVE: To investigate the topographic changes in macular ganglion cell inner plexiform layer (GCIPL) thickness in eyes with retinitis pigmentosa (RP). PATIENTS AND METHODS: Forty-five eyes of 25 subjects with RP who underwent spectral-domain optical coherence tomography (SD-OCT) using the Cirrus HD-OCT (Carl Zeiss Meditec, Dublin, CA) were analyzed retrospectively. A control group of 67 eyes of 48 age-matched healthy volunteers was also included for comparison. Average, minimum, and sectoral macular GCIPL, as well as retinal nerve fiber layer (RNFL) and outer retinal (OR) thicknesses, were collected and compared between RP and control groups. RESULTS: The average and sectoral macular GCIPL thicknesses were significantly reduced in RP eyes compared with controls (P < .0001). Average macular RNFL thickness was reduced in RP eyes compared with controls (P < .054). CONCLUSIONS: In eyes with RP, display reduced GCIPL, RNFL, and OR thickness. The identification of alteration in RNFL, OR, and GCIPL thickness may be useful for future therapeutic implications.