One of the things we love about AskTrip is seeing the connections that emerge between different clinical questions.
Recently, four questions came in — seemingly from two different users — that all seemed to circle around a shared theme: the retina, Alzheimer’s disease, and early biomarkers.

That got us curious. Were these topics just coincidentally linked, or was there a meaningful thread here? We pulled the latest evidence from AskTrip to find out.

1. How reliable are retinal OCT measurements?

Two of the questions focused on the reliability of optical coherence tomography (OCT) — both angiography and retinal thickness measurements.
The evidence shows that OCT performs well:

  • Angiography: Intraclass correlation coefficients (ICCs) indicate good repeatability, especially for small scan sizes, though variability can increase with larger scans or different measurement setups.
  • Retinal thickness: High repeatability and strong ICC values across devices, suggesting this is a robust measurement tool for research and clinical monitoring.

Why it matters: For any biomarker to be clinically useful, we need to trust the measurement. These results suggest OCT has the reliability needed for potential inclusion in early-detection pathways.

2. Shared vascular mechanisms in the retina and brain

Another question asked about parallels between vascular leakage in the retina and brain, linked to pericyte dysfunction in Alzheimer’s disease.
The literature points to common processes: pericyte loss or dysfunction undermines vascular integrity, disrupting both the blood–brain and blood–retina barriers.
In Alzheimer’s, this could contribute to early pathology in both systems — supporting the idea that retinal imaging might give a non-invasive “window” into brain health.

3. Plasma biomarkers — how do they compare?

The final question looked at plasma levels of Aβ42/Aβ40 for distinguishing mild cognitive impairment or preclinical Alzheimer’s from normal controls.
Reported area under the curve (AUC) values range from 0.68 to 0.80 — suggesting moderate discriminative ability. This is promising, though still far from a stand-alone diagnostic tool.

Why we’re watching this space

When several AskTrip questions start circling the same idea, we take notice. Here, the connection is clear:

  • Retinal OCT is reliable enough to measure subtle changes.
  • Pathophysiological parallels between retina and brain make those measurements relevant to Alzheimer’s research.
  • Blood biomarkers like Aβ42/Aβ40 add another dimension to early detection efforts.

This combination of imaging and blood-based biomarkers could, in the future, help detect Alzheimer’s before symptoms appear. The evidence isn’t there yet for widespread screening — but the building blocks are taking shape.

Explore the full Q&As: