Past, present and future role of retinal imaging in neurodegenerative disease

Kashani, Amir H; Asanad, Samuel; Chan, Jane W.; Singer, Maxwell; Zhang, Jiong; Sharifi, Mona; Khansari, Maziyar M.; Abdolahi, Farzan; Shi, Yonggang; Biffi, Alessandro; Chui, Helena C.; Ringman, John M.

doi:10.1016/j.preteyeres.2020.100938

Cited by 93 publications

(149 citation statements)

References 439 publications

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“…The retina is an essential part of the CNS. Due to its transparent nature to light, it is possible to use less invasive and high-resolution imaging modalities to visualise the retina [26,27]. It is predominantly known for its involvement in converting light energy into electrical signals [28].…”

Section: Retinal Microgliamentioning

confidence: 99%

“…In addition, their constitutive microglial function starts to decline and show abnormal microglial injury responses. These alterations, combined with molecular and gene expression ageing changes within microglia, resulting in their reduced capability of maintaining homeostasis in the immune environment, and this may contribute to neuronal impairments, cognitive decline and age-related diseases [5,27,[53][54][55].…”

Section: Microglia and Ageingmentioning

confidence: 99%

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Retinal and Brain Microglia in Multiple Sclerosis and Neurodegeneration

Choi¹,

Guo²,

Cordeiro

2021

Cells

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Microglia are the resident immune cells of the central nervous system (CNS), including the retina. Similar to brain microglia, retinal microglia are responsible for retinal surveillance, rapidly responding to changes in the environment by altering morphotype and function. Microglia become activated in inflammatory responses in neurodegenerative diseases, including multiple sclerosis (MS). When activated by stress stimuli, retinal microglia change their morphology and activity, with either beneficial or harmful consequences. In this review, we describe characteristics of CNS microglia, including those in the retina, with a focus on their morphology, activation states and function in health, ageing, MS and other neurodegenerative diseases such as Alzheimer’s disease, Parkinson’s disease, glaucoma and retinitis pigmentosa, to highlight their activity in disease. We also discuss contradictory findings in the literature and the potential ways of reducing inconsistencies in future by using standardised methodology, e.g., automated algorithms, to enable a more comprehensive understanding of this exciting area of research.

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Section: Retinal Microgliamentioning

confidence: 99%

Section: Microglia and Ageingmentioning

confidence: 99%

Retinal and Brain Microglia in Multiple Sclerosis and Neurodegeneration

Choi¹,

Guo²,

Cordeiro

2021

Cells

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“…Additionally, all studies reported up to the present time have used bidimensional representations of retinal characteristics; however, these two-dimensional (2D) representations of three-dimensional (3D) biological structures have their limitations. An analysis of 3D versus 2D algorithms would allow retinal findings to be used in the future to study neurodegenerative diseases from a different clinical perspective [ 37 ]. Finally, it is noteworthy that the reproducibility of OCT measurements depends on the experience and qualifications of users.…”

Section: Optical Coherence Tomography (Oct)mentioning

confidence: 99%

“…In AD patients, it has been suggested that retinal vascular changes share pathogenic mechanisms with those of the cerebral vessels [ 9 , 50 , 51 ]. Several studies have shown that this correlation exists in patients with AD [ 23 , 37 ].…”

Section: Optical Coherence Tomography-angiography (Octa)mentioning

confidence: 99%

“…This light is reflected by the retinal pigment epithelium (RPE), creating the false impression that hematies are moving in the RPE vessels and thereby overestimating the perfusion density. Although these projection artifacts are observed very frequently, there are commercially available algorithms for their removal that greatly diminish the impact of these artifacts on the images [ 37 , 44 , 52 ]. This new modality, due to the need for new equipment and processing techniques, the current limitations of imaging capability, and the rapid advances in both imaging and our understanding of the applicable pathophysiology of the retina and choroid, necessitates a long learning curve.…”

Section: Optical Coherence Tomography-angiography (Octa)mentioning

confidence: 99%

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The Value of OCT and OCTA as Potential Biomarkers for Preclinical Alzheimer’s Disease: A Review Study

López‐Cuenca

Salobrar‐García

Elvira‐Hurtado

et al. 2021

Life

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Preclinical Alzheimer’s disease (AD) includes cognitively healthy subjects with at least one positive biomarker: reduction in cerebrospinal fluid Aβ42 or visualization of cerebral amyloidosis by positron emission tomography imaging. The use of these biomarkers is expensive, invasive, and not always possible. It has been shown that the retinal changes measured by optical coherence tomography (OCT) and OCT-angiography (OCTA) could be biomarkers of AD. Diagnosis in early stages before irreversible AD neurological damage takes place is important for the development of new therapeutic interventions. In this review, we summarize the findings of different published studies using OCT and OCTA in participants with preclinical AD. To date, there have been few studies on this topic and they are methodologically very dissimilar. Moreover, these include only two longitudinal studies. For these reasons, it would be interesting to unify the methodology, make the inclusion criteria more rigorous, and conduct longer longitudinal studies to assess the evolution of these subjects. If the results were consistent across repeated studies with the same methodology, this could provide us with insight into the value of the retinal changes observed by OCT/OCTA as potential reliable, cost-effective, and noninvasive biomarkers of preclinical AD.

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