Evaluation Of Dynamic Changes In Pupil And Retinal Blood Flow In Alzheimer’s Disease Patients

Objective:Evaluate pupillary light response,retinal blood flow,retinal oxygen saturation and multispectral fundus reflectance to aid the diagnosis of Alzheimer’s disease.Method:A cross-sectional study.54 Alzheimer’s disease patients and 41 healthy age and sex-matched individuals who were treated in the neurology memory impairment specialist clinic and ophthalmology clinic of Peking University Shenzhen Hospital from June 2020 to November 2021 were selected.Parameters like age,education level,MoCA score,intraocular pressure and blood pressure were collected.Information such as pupillary light response,retinal blood flow,retinal blood oxygen saturation and multispectral fundus reflectance were obtained from custom-built multimodal ophthalmic imaging device.SPSS 26.0 software was used for data analysis.Independent samples t test or Mann-Whitney U test was used to compare the pupillary light response,retinal blood flow,retinal blood oxygen saturation and multispectral fundus reflectance between groups.The Wilcoxon rank-sum test was used to compare the arterioles and venules oxygen saturation between quadrants within the group,and the partial correlation coefficient was used to analyze the correlation between the pupillary light response and the Mo CA score by controlling the age and gender.Results: Compared with the healthy control group,the resting pupil diameter,minimum pupil diameter,pupil constriction amplitude,constriction ratio,constriction phase,average constriction velocity and recovery time to 75% of resting pupil diameter decreased in AD patients(T=2.667,P =0.009;Z=-2.571,P=0.010;Z=-3.635,P<0.001;Z=-2.424,P=0.015;Z=-2.849,P=0.004;T=2.532,P=0.013;Z=-2.835,P=0.005).Pupil constriction amplitude and constriction phase were positively correlated with Mo CA score(r=0.229,P=0.027;r=0.326,P=0.001).Only the oxygen saturation of the superior nasal venules in AD patients was lower than that of the healthy control group(Z=-2.515,P=0.012),neither other quadrants nor the average retina blood oxygen saturation and the difference between arterioles and venules oxygen saturation were significantly different.No difference in the overall retinal blood flow and multispectral fundus reflectance between AD patients and healthy controls groups were observed.Conclusion:The pupillary light response can reflect the deficiency of sympathetic and parasympathetic in AD patients,which may be helpful for non-invasive diagnosis and monitor disease progression of AD.The value of retinal blood flow,retinal oxygen saturation and multispectral fundus reflectance in assisting the diagnosis of AD is limited.