Assessment of retinal manifestations of Parkinson's disease using spectral domain optical coherence tomography: A study in Indian eyes

Purpose: To assess the retinal manifestations of Parkinson's disease using optical coherence tomography. Methods: A prospective case-control study comparing 30 eyes from 15 patients with Parkinson's disease and 22 eyes from 11 healthy age-matched controls. Total macular subfield thickness and the thickness of the ganglion cell layer, nerve fiber layer, and peripapillary retinal nerve fiber layer were measured with spectral-domain optical coherence tomography (SD-OCT). Results: The mean age of PD patients was 68.4 years +/- 10.64 (range: 46-82) and in the control group was 66.36 +/- 5.22 (range: 64-68). The average disease duration in patients with PD was 6.7 +/- 2.8 years (range: 2-10 years). The mean best-corrected visual acuity in PD was 20/26 and 20/20 in controls, with P = 0.0059, which was significant. Significant difference was also found in the contrast sensitivity between both groups. Structural differences in the central macular thickness (P = 0.0001), subfield thicknesses in the superior (P = 0.003), inferior (P = 0.001), nasal (P = 0.004), and temporal subfields (P = 0.017) was seen. Severe thinning of the ganglion cell layer was seen in PD patients (P = 0.000) as well as of the nerve fiber layer (P = 0.004). Peripapillary retinal nerve fiber thickness measured showed significant thinning in superotemporal (P = 0.000), superonasal (P = 0.04), inferonasal (P = 0.000), inferotemporal (P = 0.000), nasal (P = 0.000), and temporal quadrants (P = 0.000). Conclusion: Visual dysfunction was observed in patients with PD along with structural alterations on OCT, which included macular volumes, ganglion cell layer, and peripapillary retinal nerve fiber layer.