Optical coherence tomography in neurodegenerative disorders

Abstract

Structural imaging of the brain is the most widely used diagnostic tool for investigating neurodegenerative diseases. More advanced structural imaging techniques have been applied to early or prodromic phases, but they are expensive and not widely available. Therefore, it is highly desirable to search for noninvasive, easily accessible, low-cost clinical biomarkers suitable for large-scale population screening, in order to focus on making diagnoses at the earliest stages of the disease. In this scenario, imaging studies focusing on the structures of the retina have increasingly been used for evaluating neurodegenerative diseases. The retina shares embryological, histological, biochemical, microvascular and neurotransmitter similarities with the cerebral cortex, thus making it a uniquely promising biomarker for neurodegenerative diseases. Optical coherence tomography is a modern noninvasive imaging technique that provides high-resolution two-dimensional cross-sectional images and quantitative reproducible three-dimensional volumetric measurements of the optic nerve head and retina. This technology is widely used in ophthalmology practice for diagnosing and following up several eye diseases, such as glaucoma, diabetic retinopathy and age-related macular degeneration. Its clinical impact on neurodegenerative diseases has raised enormous interest over recent years, as several clinical studies have demonstrated that these diseases give rise to reduced thickness of the inner retinal nerve fiber layer, mainly composed of retinal ganglion cells and their axons. In this review, we aimed to address the clinical utility of optical coherence tomography for diagnosing and evaluating different neurodegenerative diseases, to show the potential of this noninvasive and easily accessible method.

Use of artificial intelligence algorithms to predict systemic diseases from retinal images

“…These diseases may either have an unpredictable course, or it may take years for confirmatory diagnosis (Satue et al, 2016). Due to similarities between the brain's and retina's vascular structures, changes to retinal vascular density might serve as an excellent ocular biomarker for neurodegenerative conditions (Cunha et al, 2022).…”

“…OCT can be used in MS to diagnose ON where there will be an increased RNFL thickness. It can also be used for monitoring response to treatment (Cunha et al, 2022). In the aftermath of ON, OCT can be used for determining RNFL thickness to predict axonal loss (Parisi et al, 1999).…”

“…PD can lead to visual disorders secondary to alpha‐synuclein deposition and dopamine deficiency in the retina, which is similar to the pathological features in the brain (Armstrong, 2008; Weil et al, 2016). OCT could serve as a useful biomarker as imaging the retina could detect early retinal structural changes secondary to dopamine dysfunction (Cunha et al, 2022). Ganglion cells and inner plexiform layers are most affected in PD (Chrysou et al, 2019).…”

The presence of diabetic retinopathy closely associated with the progression of non-alcoholic fatty liver disease: A meta-analysis of observational studies

“…As DR pathogenesis involving metabolic disturbance and features of insulin resistance shows a high degree of overlap with the mechanisms of NAFLD, it is rational that in a population at high risk for DR, such as the diabetic population, the presence of advanced liver fibrosis may further increase this risk. As ocular signs have been more and more referred to in the diagnosis and progression in the nervous system, cardiovascular, and liver diseases ( Gubitosi-Klug et al, 2021 ; Yuan et al, 2021 ; Cunha et al, 2022 ), it is intriguing that a simple non-invasive screening of DR, detected by using a routine ocular check-up, may allow the detection of patients with T2DM at risk of advanced NAFLD. Thus, clarifying the correlation between DR and the onset and progression of NAFLD will be a great help in defining if DR can be a non-invasive indicator in monitoring NAFLD progression.…”

Fisiopatologia Da Doença De Parkinson: Principal Fator Associado Ao Desenvolvimento Da Doença De Parkinson Em Adultos Jovens

“…A doença de Parkinson (DP), descrita pela primeira vez por James Parkinson em 1817, é uma doença neurodegenerativa caracterizada por sintomas motores: rigidez, bradicinesia, tremor de repouso e instabilidade postural, e sintomas não motores: distúrbios neuropsiquiátricos, do sono, autonômicos e sensoriais (TRENTIN et al, 2022). Doenças neurodegenerativas são condições que podem afetar o sistema nervoso central e periférico, levando a comprometimento cognitivo, motor, de fala e até mesmo respiratório (CUNHA et al, 2022). A neurodegeneração é uma característica debilitante e incurável, que tem sido evidenciada na literatura com um aumento exponencial de sua prevalência (RECH et al, 2022).…”