6: Episode 6: The Window to the Brain: OCT and OCTA (ft. Andrew Rixon, OD, FAAO)
From From Paper to Clinic · 22:16
Show by Optometry Times
In Episode 6 of From Paper to Clinic, “The Window to the Brain: OCT and OCTA,” host Hamza Shah, OD, sits down with Andrew Rixon, OD, FAAO, to unpack a systematic review on retinal biomarkers for early Alzheimer disease detection and what it means for everyday optometric care. Rixon starts by cleaning up our language regarding dementia as a broad clinical syndrome versus Alzheimer disease as a specific pathologic subtype characterized by beta-amyloid deposition and phosphorylated tau. From there, the pair explore why catching patients at the preclinical or very early symptomatic stage matters—when biomarkers may be detectable 10-15 years before overt decline, but current therapies remain only modestly effective. This naturally leads to the “retina as a window to the brain.” Shah and Rixon walk through the shared neuroectodermal origin of the retina and CNS, parallels in vascular and barrier systems, and emerging data showing amyloid and tau in ocular tissues, including retinal ganglion cells and even aqueous humor at levels comparable to CSF.The discussion then shifts from theory to OCT and OCT angiography (OCTA) at the slit lamp. Shah and Rickson review the paper’s heterogeneous OCT/OCTA findings—some studies showing thickening and increased vascular density, others thinning and rarefaction—and explain how early inflammatory or vascular changes could precede later neurodegeneration, making simple “thick vs thin” heuristics unreliable in isolation. Rickson outlines how OCTA actually works in clinic, why it does not replace dye-based angiography, and where it shines today: detecting quiescent, non-exudative macular neovascular membranes in AMD and complementing ultra-widefield imaging rather than supplanting it. They also touch on the still-evolving role of OCTA in glaucoma—particularly in suspected normal-tension glaucoma phenotypes—while underscoring the current lack of robust normative vessel-density databases. Throughout, Shah pushes the conversation toward what clinicians can do now: using OCT/OCTA judiciously rather than reflexively, avoiding overpromising on Alzheimer “screening” from a single scan, and preparing for a future where higher-resolution imaging and AI may finally bring that sci-fi-style, noninvasive neurodegeneration assessment closer to reality.The paper inspiring this discussion is "Retinal biomarkers for early Alzheimer's detection: a systematic review of optical coherence tomography (OCT) findings," by Lepoittevin and colleagues, published in BMJ Open Ophthalmology.
More episodes of From Paper to Clinic
More episodes
- 9: Episode 9: Burnout in Optometry and How to Prevent It
- 8: Episode 8: Dynamic Muscle Stimulation and the Blink Physiology Behind Dry Eye
- Introducing From Paper to Clinic
- 1: The Interventional Glaucoma Paradigm (ft. Austin Lifferth, OD, FAAO)
- 2: Is Geographic Atrophy a Peripheral Retinal Disease? (ft. Raman Bhakhri, OD, FAAO)
- 3: AI in Eye Care: From Diabetic Retinopathy to the Clinic of the Future (ft. Michael Twa, OD, PhD)
- 4: Retire 'Artificial Tears': A Call for Updated Terminology in Eye Care (ft. Kaleb Abbott, OD, MS)
- 5: Reframing Myopia Management: Atropine, Axial Length, and Engaging Young Patients (ft. Brianna Rhue, OD, FAAO)
- 7: Episode 7: GLP-1s and Idiopathic Intracranial Hypertension
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