Evaluation of optical coherence tomography angiographic findings in Alzheimer's type dementia

To identify the retinal vascular pathologies in patients with Alzheimer's type dementia (ATD) through optical coherence tomography angiography (OCTA) imaging.

Our study included 26 patients in the patient group, and age-matched and sex-matched 26 subjects in the control group. A detailed ophthalmological and neurological examination was performed for all subjects included in the study. The retinal, choroidal vascular structures and choroidal thickness (CT) of all subjects were analysed in a detailed way with a commercial spectral domain OCTA. Moreover, all participants underwent detailed neurological examination including Mini Mental State Examination (MMSE) test to evaluate cognitive function.

In the group of patients with ATD, the MMSE score was significantly lower than that of the control group (p<0.001). The retinal vascular density was significantly lower than that of the control group in all zones (p<0.05). Foveal avascular zone (FAZ) was significantly enlarged compared with the control group (p=0.001). CT was significantly lower in the group of patients with ATD (p<0.001). Outer retinal and choroidal flow rates were lower in the group of patients with ATD, while the difference was not significant (p>0.05). Furthermore, significant correlation was found between the MMSE and all vascular density parameters, CT parameter and FAZ tested with OCTA imaging (p<0.05).

In patients with ATD, retinal and choroidal vascular pathologies detected through OCTA imaging can be used as a new biomarker in the early diagnosis of the disease, follow-up of its progression and in investigating the efficacy of the drugs.