Optical Coherence Tomography in Patients with Alzheimer’s Disease: What Can It Tell Us?

Song, Ailin; Johnson, Nicholas; Ayala, Alexandria

doi:10.2147/eb.s235238

Cited by 34 publications

(30 citation statements)

References 117 publications

(431 reference statements)

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“…Studies using OCTA techniques have resulted in mixed findings. 25 This may be due to the varied vessel distribution and morphology, including vessel size and number of anastomoses between participants. The lack of uniformity in vessel size may affect vessel density calculations, as the smaller surface area of capillaries may contribute to a more sensitive measure of perfusion compared with larger vessels.…”

Section: Discussionmentioning

confidence: 99%

“…We identified two main retinal scanning methods, OCT and OCTA in this review, with a more sensitive response from OCT. OCTA was primarily used to measure and evaluate retinal vasculature, but measures of retinal thickness via OCT was considerably more effective in detecting cognitive impairment. Studies using OCTA techniques have resulted in mixed findings 25. This may be due to the varied vessel distribution and morphology, including vessel size and number of anastomoses between participants.…”

Section: Discussionmentioning

confidence: 99%

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Association between retinal markers and cognition in older adults: a systematic review

et al. 2022

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ObjectivesTo appraise the existing literature reporting an association between retinal markers and cognitive impairment in adults aged 65 years and over and to provide directions for future use of retinal scanning as a potential tool for dementia diagnosis.DesignSystematic review of peer-reviewed empirical articles investigating the association of retinal markers in assessing cognitive impairment.Data sourcesThree electronic databases, Medline, PsycINFO and EMBASE were searched from inception until March 2022.Eligibility criteriaAll empirical articles in English investigating the association between retinal markers and cognition in humans aged ≥65 years using various retinal scanning methodologies were included. Studies with no explicit evaluation of retinal scanning and cognitive outcomes were excluded. Risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies tool.Data extraction and synthesisData extraction was conducted by two authors (VJ, RS) and reviewed by another author (JS). Results were synthesised and described narratively.ResultsSixty-seven eligible studies examining 6815 older adults were included. Majority of studies were cross-sectional (n=60; 89.6%). Optical coherence tomography (OCT) was the most commonly used retinal scanning methodology to measure the thickness of retinal nerve fibre layer, the ganglion cell complex, choroid and macula. 51.1% of cross-sectional studies using OCT reported an association between the thinning of at least one retinal parameter and poor cognition. Longitudinal studies (n=6) using OCT also mostly identified significant reductions in retinal nerve fibre layer thickness with cognitive decline. Study quality was overall moderate.ConclusionRetinal nerve fibre layer thickness is linked with cognitive performance and therefore may have the potential to detect cognitive impairment in older adults. Further longitudinal studies are required to validate our synthesis and understand underlying mechanisms before recommending implementation of OCT as a dementia screening tool in clinical practice.PROSPERO registration numberCRD42020176757.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Association between retinal markers and cognition in older adults: a systematic review

et al. 2022

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“…It has to be mentioned that although our findings did not support that glaucoma is an independent risk factor for subsequent development of AD, in view of the lack of effective strategies for early screening of AD before the occurrence of memory dysfunction ( 41 ), ophthalmologic examinations remain of potential as early screening tools for AD. With the development of novel techniques such as retinal optical coherence tomography ( 42 , 43 ) and nanomaterial biosensors ( 44 ), it could be expected that eye clinics and ophthalmology facilities may play important roles in the early diagnosis of AD and subsequent reducing the burdens arising from severe dementia ( 45 ).…”

Section: Discussionmentioning

confidence: 99%

Glaucoma Is Not Associated With Alzheimer's Disease or Dementia: A Meta-Analysis of Cohort Studies

Zhao

et al. 2021

Front. Med.

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Background: Previous studies evaluating the relationships of glaucoma with Alzheimer's disease (AD) and dementia showed inconsistent results. We performed a meta-analysis of cohort studies to evaluate the association between glaucoma with incidence of AD, all-cause dementia, and non-AD dementia.Methods: Cohort studies which evaluated the association between glaucoma with incidence of AD, all-cause dementia, and non-AD dementia in adult population with multivariate analyses were identified by systematic search of PubMed, Embase, and Cochrane's Library databases. A random-effects model incorporating the potential intra-study heterogeneity was used for the meta-analysis.Results: Eleven cohort studies including 4,645,925 participants were included. Results showed that compared to those without glaucoma at baseline, adult patients with glaucoma was not independently associated with increased incidence of AD [adjusted risk ratio (RR): 1.03, 95% confidence interval (CI): 0.93–1.05, P = 0.55; I2 = 83%], all-cause dementia (adjusted RR: 1.08, 95% CI: 0.97–1.19, P = 0.15; I2 = 79%), or non-AD dementia (adjusted RR: 1.05 95% CI: 0.91–1.21, P = 0.49; I2 = 82%). Sensitivity analyses by excluding one study at a time did not significantly affect the results of the meta-analyses. Moreover, subgroup analyses showed consistent results in meta-analysis of prospective or retrospective cohort studies, and in meta-analysis of patients with primary open-angle glaucoma or primary angle-closure glaucoma (P-values for subgroup difference all > 0.05).Conclusions: Current evidence from cohort studies did not support that glaucoma is an independent risk factor of AD, all-cause dementia, or non-AD dementia in adult population.

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“…Once AD is diagnosed, patient will have an irreversible process, leading to dementia starts. On average patient can live for 4.6 years longer once diagnosed [ 3 ]. MCI possibly is a suggestion of preclinical stage of AD.…”

Section: Introductionmentioning

confidence: 99%

Detection of retinal changes with optical coherence tomography angiography in mild cognitive impairment and Alzheimer’s disease patients: A meta-analysis

Hui

Zhao

et al. 2021

PLoS ONE

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Objective To assess retinal microvascular network impairments in the eyes of mild cognitive impairment (MCI) and Alzheimer’s disease (AD) patients with optical coherence tomography angiography (OCTA). Design Systematic review and meta-analysis. Methods A literature search was conducted in the PubMed and EMBASE databases to identify relevant studies detecting retinal microvascular attenuation among AD, MCI patients and cognitively healthy controls (HCs) by OCTA. Data were extracted by Review Manager V.5.4 and Stata V.14.0. Results Eight investigations were included in this meta-analysis, with 150 AD patients, 195 MCI patients and 226 HCs were eligible for meta-analysis. Evidence based on these studies demonstrated that there was a significantly decreased vessel density (VD) of the Optovue group in superficial capillary plexus (SCP): WMD = -2.26, 95% CI: -3.98 to -0.55, p = 0.01; in deep capillary plexus (DCP): WMD = -3.40, 95% CI: -5.99 to -0.81, p = 0.01, VD of the Zeiss group in SCP:WMD = -0.91, 95% CI: -1.79 to -0.02, p = 0.05 and an enlarged fovea avascular zone (FAZ):WMD = 0.06, 95% CI: 0.01 to 0.11, P = 0.02 in OCTA measurements of MCI patients. Additionally, in OCTA measurements of AD patients, there was a significantly decreased VD in the SCP: WMD = -1.88, 95% CI: -2.7 to -1.07, p<0.00001. In contrast, there was no significant decrease in DCP nor enlargement of FAZ in AD patients. Conclusion Retinal microvascular alternations could be optimally screened in MCI patients detected by OCTA, which could be a warning sign of relative changes in the MCI before progressing to AD. Retinal microvasculature changes worth further investigation in larger scale clinical trials.

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Optical Coherence Tomography in Patients with Alzheimer’s Disease: What Can It Tell Us?

Cited by 34 publications

References 117 publications

Association between retinal markers and cognition in older adults: a systematic review

Association between retinal markers and cognition in older adults: a systematic review

Glaucoma Is Not Associated With Alzheimer's Disease or Dementia: A Meta-Analysis of Cohort Studies

Detection of retinal changes with optical coherence tomography angiography in mild cognitive impairment and Alzheimer’s disease patients: A meta-analysis

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