Studies On The Diagnosis Of Alzheimer’s Disease By Observing The Retinal Nerve Fiber Layer Based On OCT

Objectives:Alzheimer’s disease is a group of primary diseases of the central nervous system.Clinical and histopathological studies have shown that neurodegenerative processes affecting the brain may also affect the retina in patients with AD.Optical coherence tomography(Optical Coherence Tomography,OCT)is a non-invasive medical imaging technology.It can obtain an image of the thickness of the retinal nerve fiber layer for evaluation of the fundus.This article aims to observe the retinal morphological changes of AD suffering from AD through OCT.Clarify the importance of OCT in the diagnosis of AD patients.Methods:(1)Twenty-four newly admitted AD patients from NingBo KangNing Hospital from July to November 2018 were selected as the AD case group(12 males and 12 females,with an average age of 76.03±3.69 years old),and 25 normal physical examination patients from Ning Bo First Hospital were selected as the normal control group(12 males and 13 females,with an average age of 74.60±2.51 years old).There was no significant difference in gender and age between AD group and control group.(2)Perform neuroimaging,neuropsychological examination,medical hematology examination,and ophthalmological examination on the case group and normal control group,including visual acuity level,intraocular pressure,etc.(3)Observe the retinal structure of AD case group and normal control group by OCT.Then analyze and extract the quadrant diagram and clock diagram of Retinal Nerve Fiber Layer Thickness(RNFL)with the software tool that comes with the OCT instrument,and observe the disc edge area,vertical cup-to-disk ratio and cup volume.(4)The experimental data were expressed in the form of mean standard deviation,and the experimental data were statistically analyzed through the T test in SPSS19.0 and correlation analysis.Results:(1)Compared with the normal control group,the thickness of RNFL in the left and right eye AD group was thinner in the upper quadrant,and the lower quadrant with statistical significance.There was no significant change in the nasal and temporal quadrants.In addition,in the direction of 12:00,1:00,2:00,5:00,6:00 and 7:00 in the clock chart,the thickness of RNFL in the AD case group was significantly thinner than that in the normal control group with statistical significance.(2)Compared with the normal group,the area of the plate for left and right eye optic disc decreased,while the vertical cup-disc ratio and the volume of the optic disc increased in AD group,all of which showed statistical differences.(3)Through correlation analysis,RNFL thickness of the left and right eyes in the upper quadrant,the lower quadrant,the average thickness and the area of the disc were positively correlated with the score of mini-mental state examination(MMSE).The vertical cup-plate ratio and the apparent cup-volume were negatively correlated with MMSE score.Conclusion: In this study,OCT was used to observe the retinal nerve fiber layer,and it was found that the thickness of the RNFL in the upper and lower quadrants of the left and right eyes of AD patients was significantly thinner than that in the normal group.And as the severity of AD patients increases,the thinner the upper and lower quadrants of the RNFL and the smaller the area of the disk edge,the vertical cup-to-disk ratio and the volume of the visual cup increase.It shows that OCT can be used as a non-invasive auxiliary medical method to help better diagnose Alzheimer’s disease.