The aim of this study is to compare optical coherence tomography (OCT) findings of retinal thickness (RT) and retinal nerve fiber layer thickness (RNFLT) of idiopathic Parkinson's disease (IPD) patients to those of healthy subjects, and to investigate whether there is any relationship between the severity of the disease and the RNFLT values. This prospective study was included 25 IPD patients and 29 healthy controls. In the IPD group, the Hoehn and Yahr (H&Y), Unified Parkinson's Disease Rating Scale (UPDRS), and Mini-Mental State Exam (MMSE) were performed. Intraocular pressure (IOP), visual acuity (VA), spherical equivalent, axial length (AL), and central corneal thickness (CCT) were measured using OCT in both groups. The RT was measured in the central retinal (RTc), nasal (RTn), and temporal (RTt) segments. Nasal (RNFLTn), nasal superior (RNFLTns), nasal inferior (RNFLTni), temporal (RNFLTt), temporal superior (RNFLTts), and temporal inferior (RNFLTti) measurements were made and mean RTFLT was calculated (RNFLTg) for each individual. In the patient group, IOP and VA values were statistically significantly lower The RTn and RNFLTg were significantly thinner in the patient group. There was no statistically significant relationship between the severity of IPD and these findings. In our study, RNFLTg and RTn were found to be thinner in the IPD group, which may have caused lower VA scores. The effects of retinal dopamine depletion on RT and RNFLT, and lower IOP values in the non-glaucomatous IPD patients should be further investigated.