Neural and Retinal Characteristics in Relation to Working Memory in Older Adults with Mild Cognitive Impairment

Insight into the Brain: Application of the Retinal Microvasculature as a Biomarker for Cerebrovascular Diseases through Optical Coherence Tomography Angiography

Purpose of review

The present article serves as a comprehensive review of the published research literature surrounding the retinal microvasculature, characterized through the optical coherence tomography angiography (OCTA) and its potential clinical value for understanding and detecting cerebrovascular diseases.

Recent findings

Studies from the past 3 years (2020-2023) have identified a degeneration of the retinal microvasculature, commonly defined through the loss of vascular density, in ischemic stroke, dementia, carotid artery stenosis, cerebral small vessel disease, and a series of rare, potentially inherited cerebrovascular disorders. These retinal microvascular changes often correlate with structure and functional changes in the brain and sometimes occur prior to debilitating neurodegeneration.

Summary

While further investigations with longitudinal data and larger sample sizes are necessary, OCTA shows promising results for characterizing the retinal microvasculature as a potential imaging biomarker in reflecting the changes in the cerebral microvasculature for early detection, prevention, and treatment of cerebrovascular diseases.

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

OBJECTIVES

To 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.

DESIGN

Systematic review of peer-reviewed empirical articles investigating the association of retinal markers in assessing cognitive impairment.

DATA SOURCES

Three electronic databases, Medline, PsycINFO and EMBASE were searched from inception until March 2022.

ELIGIBILITY CRITERIA

All 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 SYNTHESIS

Data extraction was conducted by two authors (VJ, RS) and reviewed by another author (JS). Results were synthesised and described narratively.

RESULTS

Sixty-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.

CONCLUSION

Retinal 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 NUMBER

CRD42020176757.

Development of a Novel Retina-Based Diagnostic Score for Early Detection of Major Depressive Disorder: An Interdisciplinary View

BACKGROUND

Clinically effective markers for the diagnosis of major depressive disorder (MDD) are lacking. Alterations in retinal features are closely related to the pathophysiological progression of MDD. However, the reliable retina-related diagnostic model for MDD remains to be developed. Thus, our study aimed to quantitatively evaluate retinal vascular and structural changes in MDD patients and to develop a reliable diagnostic model of MDD based on retinal parameters.

METHODS

Seventy-eight patients with MDD and 47 healthy controls (HCs) underwent retinal vessel density and structure examination using optical coherence tomography angiography and visual field examination using perimetry. Independent-sample t test was used to assess the differences in retinal parameters between the groups. Meanwhile, we constructed the corresponding retina-based diagnostic model by LASSO logistic regression. Finally, the diagnostic ability of the model was evaluated by area under the curve (AUC) of receiver operating characteristic curves and calibration plot of nomogram.

RESULTS

MDD patients showed lower retinal vessel density (including radial peripapillary capillary vessel density, superficial and deep capillary plexus vessel density), thinner subfoveal choroidal thickness, and poorer visual fields compared to HCs (all p < 0.05). Furthermore, a retina-based diagnostic model was constructed and shows a strong diagnostic capability for MDD (AUC = 0.9015, p < 0.001).

CONCLUSION

Patients with MDD showed distinct retinal features compared to HCs. The retina-based diagnostic model is expected to be a necessary complement to the diagnosis of MDD.