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. [Ophthalmic Surg Lasers Imaging Retina. 2016;47:828-835.].

Retinal ganglion cells thinning in eyes with nonproliferative idiopathic macular telangiectasia type 2A.

PURPOSE: To analyze the changes in retinal ganglion cells (RGCs) in eyes with nonproliferative macular telangiectasia type 2A (MacTel), by evaluating macular ganglion cell-inner plexiform layer (GCIPL) thickness and macular retinal nerve fiber layer (RNFL) thickness in comparison to age-matched healthy volunteers. METHODS: We performed a retrospective analysis of 99 eyes (53 subjects) with nonproliferative MacTel who underwent fundus fluorescein angiography and spectral domain optical coherence tomography using Cirrus HD-OCT. We also included 44 eyes of 33 age-matched healthy Indian volunteers as control group. Average, minimum, and sectoral GCIPL and RNFL thicknesses were collected. Comparison of GCIPL and RNFL thicknesses between MacTel and control groups was performed using Wilcoxon rank sum test. RESULTS: Eighty-eight eyes of 47 MacTel subjects were included after ensuring good quality of the retinal layers' segmentation. Macular GCIPL thickness was constantly and diffusely reduced in MacTel eyes compared with controls (P < 0.0001 for each GCIPL sector). The mean reduction in "average" GCIPL thickness was 11%, and the mean reduction in "minimum" GCIPL thickness was 23%. Similarly, macular RNFL thickness was diffusely reduced in MacTel eyes compared with controls (P < 0.0001 for each RNFL sector), with 13% of mean reduction. CONCLUSIONS: Our study demonstrated that in eyes with nonproliferative MacTel type 2A there was significant and consistent RGCs degeneration, leading to diffuse thinning of RGCs' dendrites, cell bodies, and axons. These findings are suggestive of neurodegeneration in MacTel type 2A.