| Background: Parkinson disease is a common neurodegenerative disease in the elderly, which involves not only the dopaminergic neurons in the substantia nigra, but also many other dopaminergic neurons, such as retinal ganglia cells. Optical coherence tomography(OCT) is a non-invasive objective method, which can examine the loss of ganglion cells and rapidly provide highresolution, cross-sectional images of the retina. OCT is capable of assessing the thickness of peripapillary retinal nerve fiber layer(pRNFL) and macular retina. Previous studies suggested that pRNFL and macular retina thinning could be potential prodromal biomarkers in diagnosing the disease. Our aims were not only to compare the thickness of pRNFL and macular retina in patients with PD and in healthy age-matched control subjects, but also to evaluate the correlations between the thickness of pRNFL and macular retina and the severity of PD. We also discussed the feasibility of them being predicting biomarkers in diagnosing the disease and monitoring its progression.Methods: Patients with PD(n = 25) and age-matched healthy controls(n =25) prospectively underwent a neuro-ophthalmologic examination, which included assessment of BCVA, eye movement, pupillary, intraocular Pressure with TOPCON CT-80, and OCT examinations with Cirrus HD-OCT 4000. We evaluated the average and 4-sectoral(inferior, superior, nasal, and temporal) pRNFL thickness by OCT, as well as the macular parameters which include mean retinal thickness of macular volumea, central 1 mm circle representing the fovea, and inner and outer rings measuring 3 mm and 6 mm in diameter, respectively. The inner and outer rings are divided into four quadrants each: superior, inferior, nasal, and temporal. PD severity was assessed using the Unified Parkinson Disease Rating Scale Ⅲ and the Hoehn and Yahr(HY) scale. The eyes ipsilateral and contralateral to the most affected body side in patients with PD were evaluated separately, and compared with the randomly selected eyes of all healthy controls. Statistical analysis was performed using the SPSS17.0. Differences between patients and healthy controls were compared using Student t test, and correlations were examined by Pearson’s test. Values of p<0.05 indicated statistically significant differences.Results: The mean age of patients with PD and agematched healthy controls was 72.2±7.8 years and 70.5±6.3 years, respectively. The mean disease duration was 4.5±2.1 years. The mean PD severity, according to the scores of UPDRSⅢ and HY scale, was 26.8±12.9 and 2.2±1.0, respectively. OCT measurements revealed significant thinner in the average(P<0.001), superior(P<0.001), and inferior(P=0.007) pRNFL of PD patients than healthy controls. Besides, patients with PD showed significantly thinner thickness in foveal retinal(P=0.003), four quadrants of inner rings(superior P<0.001, inferior P=0.009, nasal P=0.002, and temporal P=0.007), four quadrants of outer rings(superior P=0.001 inferior P<0.001, nasal P<0.001, and temporal P=0.041), and mean retinal thickness of macular volumea(P<0.001) compared to controls. In addition, the eyes of PD patients contralateral to the most affected body side are more sensitive than the eyes ipsilateral to the most affected body side. Highly significant inverse correlation between foveal retinal thickness and temporal quadrant of outer rings and total and scores of UPDRSⅢ were observed in patients with PD, respectively(r =–0.430; P = 0.046),(r =-0.456, P =0.033). Whereas, we did not detect any correlation between the thickness of pRNFL and macular retina and HY scale.Conclusions: In PD patients, there is a reduction of p RNFL and macular retina thickness evaluated by OCT, which could be used as sensitive and objective biomarkers for assessment of early neurodegenerative changes of PD. Also, the macular retina thickness is correlated with PD severity that may provide a good biomarker to monitor the disease progression. |
PDF Full Text Request