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Optical coherence tomography reveals light-dependent retinal responses in Alzheimer's disease
David Bissig, Clarice G Zhou, Vy Le, Jacqueline T Bernard. NeuroImage, 2020-06-05
Topic: Plasma and spinal-fluid biomarkers
Spectral-domain optical coherence tomography (SD-OCT) is an accessible clinical tool for measuring structural changes to the retina, and increasingly as a biomarker for brain-predominant neurodegenerative diseases like Alzheimer's. Information about retinal function can also be extracted from OCT images, but is under-studied, with literature examples often employing challenging protocols or requiring specialized hardware. The first goal of this study was to verify that functional retinal imaging was feasible with a commercially-available SD-OCT device and a clinically practical protocol. Inspired by methods from other functional imaging modalities, we acquired images while repeatedly cycling lights on and off, and spatially normalized retinas to facilitate intra- and inter-individual analyses. In eight healthy young adults, light-dependent increases in reflectivity were easily demonstrated at photoreceptor inner and outer segments, changing by ~7% in bright light and ~3% in dim light. Bright light elicited a subtle (~2%) but consistent light-dependent decrease in reflectivity through much of the rest of the retina, including the avascular outer nuclear layer (ONL). We speculated that some of these changes are influenced by glial function - as through water management - a topic of high interest in neurodegenerative diseases that may involve the glymphatic system. Functional abnormalities in patients with antibodies against aquaporin-4 (n = 3) supported this interpretation. We next compared patients with early-onset Alzheimer's disease (n = 14) to age-matched controls (n = 14), revealing that patients had a relatively exaggerated light-induced change in ONL reflectivity (p < 0.05). Because these measurements can be obtained within 30 min, regular use in research and limited clinical settings is feasible.
Key findings
- In eight healthy young adults, light-dependent increases in reflectivity were easily demonstrated at photoreceptor inner and outer segments, changing by ~7% in bright light and ~3% in dim light.
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Study details
- Evidence strengthLow
How this study scored 39/100
Published in a peer-reviewed journal. Scored zero for study design, sample size, effect reported, studied in people and randomised / blinded because the record does not state it. We have no data on journal's citation record, times cited, citations per year, impact for its field and year, cited by studies here, still being cited, senior author's track record, institution's track record, multi-centre collaboration and free to read, so those were left out: it earned 22 of the 56 points we could judge it on, which is 39 out of 100.
| Component | Points | Why |
|---|---|---|
| Journal tier | 7 / 10 | Tier 3 — peer-reviewed journal (NeuroImage) |
| Journal's citation record | — / 4 | No journal record from OpenAlex — left out of this score |
| Study design | 0 / 12 | No study design recorded — scores zero, not guessed (not stated in the record — scored 0) |
| Strength of evidence | 1 / 5 | Rated “low” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 2 / 5 | 2020 — within 10 year(s) of the newest study here |
| Sample size | 0 / 4 | Participant count not stated — scores zero (not stated in the record — scored 0) |
| Effect reported | 0 / 3 | No effect size reported — scores zero (not stated in the record — scored 0) |
| Studied in people | 0 / 3 | Not stated whether this was studied in people — scores zero (not stated in the record — scored 0) |
| Randomised / blinded | 0 / 2 | No randomisation or blinding stated — scores zero (not stated in the record — scored 0) |
| Times cited | — / 7 | No citation count (not found in OpenAlex) — left out of this score |
| Citations per year | — / 5 | No citation count or no year — left out of this score |
| Impact for its field and year | — / 6 | No field-weighted citation impact (OpenAlex has none yet) — left out of this score |
| Cited by studies here | — / 6 | Not yet checked against this library's citation graph — left out of this score |
| Still being cited | — / 4 | No yearly citation counts — left out of this score |
| Senior author's track record | — / 4 | Senior author's record not available — left out of this score |
| Institution's track record | — / 3 | No institution listed in OpenAlex — left out of this score |
| Multi-centre collaboration | — / 3 | Institutions not listed — left out of this score |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 32512126) |
| Free to read | — / 2 | Access not recorded — left out of this score |
| Points | 22 / 56 | Scored on 10 of 20 parts. We have no data for the rest, so they are left out: 22 of the 56 points we could judge it on is 39 out of 100. |
| Total | 39 / 100 | — |
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Cite this study APA, Vancouver, BibTeX · download .bib or .ris
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APA 7th
Bissig, D., Zhou, C. G., Le, V., & Bernard, J. T. (2020). Optical coherence tomography reveals light-dependent retinal responses in Alzheimer's disease. NeuroImage. https://doi.org/10.1016/j.neuroimage.2020.117022
Vancouver
Bissig D, Zhou CG, Le V, Bernard JT. Optical coherence tomography reveals light-dependent retinal responses in Alzheimer's disease. NeuroImage. 2020. doi:10.1016/j.neuroimage.2020.117022. PMID: 32512126.
BibTeX
@article{bissig2020-32512126,
author = {Bissig, David and Zhou, Clarice G and Le, Vy and Bernard, Jacqueline T},
title = {{Optical coherence tomography reveals light-dependent retinal responses in Alzheimer's disease}},
journal = {NeuroImage},
year = {2020},
doi = {10.1016/j.neuroimage.2020.117022},
pmid = {32512126},
url = {https://doi.org/10.1016/j.neuroimage.2020.117022}
}
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