Quantitative analysis of macular retinal thickness and volume in patients with different degrees of Parkinson’s disease

Objective To observe the macular retinal thickness and volume in patients with different degrees of Parkinson's disease (PD). Methods Thirty eyes of 30 patients with primary PD and 20 eyes of 20 healthy subjects (control group) in Xuanwu Hospital of Capital Medical University from October 2016 to October 2017 were enrolled in this study. There were 17 males and 13 females, with the mean age of 63.2±6.4 years and disease course of 3.9±2.4 years. The patients were divided into mild to moderate PD group (15 eyes of 15 patients) and severe PD group (15 eyes of 15 patients). The macular area was automatically divided into 3 concentric circles by software, which were foveal area with a diameter of 1 mm (inner ring), middle ring of 1 to 3 mm, and outer ring of 3 to 6 mm. The middle and outer ring were divided into 4 quadrants by 2 radiations, respectively. The changes of retinal thickness and macular volume of the macular center and its surrounding quadrants were analyzed. SPSS 16.0 software was used for statistical analysis. One-way ANOVA were used to analyze all data. Results Compared with the control group, the retinal thickness and volume in macular center and each quadrant of the mild to moderate PD group and severe PD group were reduced. Compared with the mild to moderate PD group, the retinal thickness and volume in macular center and each quadrant of the severe PD group were reduced. The differences of retinal thickness and macular volume among 3 groups were significant(F=5.794, 5.221, 5.586, 5.302, 5.926, 5.319, 5.404, 5.261, 5.603; P=0.001, 0.007, 0.003, 0.005, 0.000, 0.004,0.004, 0.006, 0.002). In inner ring of the mild to moderate PD group and the severe PD group, the retinal thickness and macular volume in the upper and the nasal were the largest, the inferior was followed, and the temporal was the smallest. In outer ring of the mild to moderate PD group and the severe PD group, the retinal thickness and macular volume in the nasal was the largest, the upper was the second, the temporal and the inferior were the smallest. Conclusions The retinal thickness and volume of the macular central fovea and its surrounding areas in PD patients are significantly thinner than that in the healthy subjects. And with the increase of the severity of PD, the macular structure changes obviously, showing macular center and its surrounding macular degeneration thin, macular volume reduced. Key words: Parkinson disease; Macula lutea/pathology; Retina/physiopathology; Tomography, optical coherence/utilization