Amyotrophic lateral sclerosis and retinal changes in optical coherence tomography: A systematic review and meta‐analysis

Abstract

Introduction Increasing evidence suggests Amyotrophic Lateral Sclerosis (ALS) as a widespread pathological process comprising nonmotor features like fatigue, mild sensory symptoms, cognitive decline, and visual impairment. Measurements of retinal nerve fiber layer (RNFL) thickness using Optical Coherence Tomography (OCT) may correlate with the neurodegeneration associated with ALS. In addition to RNFL thickness, other OCT parameters have been explored in the context of diagnosing ALS and predicting disease severity. In this study, we explore the possibility that OCT parameters of patients with ALS may differ significantly from those of healthy controls and thus serve as biomarkers for the disease and its progression. Materials and methods Between 2010 and 2021, the PubMed and EMBASE databases were examined for English language literature. ALS severity was assessed using the revised ALS functional rating scale (ALSFRS‐R). The pooled mean differences in RNFL thickness between ALS patients and controls were calculated using the Standard Mean Difference (Hedges's g) with a 95% confidence interval (CI) in STATA software version 16. Results Eleven studies were reviewed for data collection. RNFL thickness was not statistically significantly different between ALS patients (n = 412) and controls (n = 376) (Hedges's g = –0.22; 95% CI: –0.51 to 0.07, I2 = 73.04%, p = .14). However, the thickness of inner nuclear layer was significantly different between ALS patients and controls (Hedges's g = –0.38; 95% CI: –0.61 to 0.14, I2 = 14.85%, p = .00). Conclusion Our meta‐analysis found that RNFL thickness as a whole or by individual quadrants was not significantly different between ALS patients and controls while the inner nuclear layer (INL) was substantially thinner.

Differential Study of Retinal Thicknesses in the Eyes of Alzheimer’s Patients, Multiple Sclerosis Patients and Healthy Subjects

“…As evidenced, in MS and AD, the thinning of certain layers of the retina presents around the optic disc and in the macula. However, these findings are not specific to these diseases as they also occur in other neurological pathologies [17,18]. It is therefore of value to acquire new insight regarding the possible differences between the two diseases.…”

Longitudinal Changes in the Retinal Nerve Fiber Layer Thickness in Amyotrophic Lateral Sclerosis and Parkinson’s Disease

“… 4 Recent findings suggest that both ALS and PD can affect nonmotor components of the central nervous system, including cognitive impairment and optic nerve involvement. 5 6 7 …”

“… 11 Several studies employing OCT for retinal imaging in ALS patients have produced mostly cross-sectional data and variable conclusions. 6 7 12 …”

Changes in the retina and choroid in patients with internal carotid artery stenosis: a systematic review and meta-analysis

“…OCTA not only allows qualitative analysis of vascular lesions in various tomographies and regions but also provides quantitative analysis of blood flow density ( Xu et al, 2022 ). Numerous studies have indicated that OCTA can be employed for both the diagnosis and assessment of ophthalmological conditions including diabetic retinopathy, glaucoma, retinal vein occlusion, age-related macular degeneration, and ischemic optic neuropathy, as well as for investigating neurological diseases such as Alzheimer’s and demyelinating disorders ( Katsimpris et al, 2022 ; Nepal et al, 2022 ; Mohammadi et al, 2023 ).…”