A vitamin A signal helped pattern the center of the retina in lab-grown human tissue

What the research found

ScienceDaily posted this on 31 October 2026. Robert J. Johnston Jr. and colleagues at Johns Hopkins report in PNAS (Hussey et al., DOI 10.1073/pnas.2510799123) that retinoic acid, a signal made from vitamin A, helps decide which cone cells form in the center of human retinal organoids grown from fetal tissue. The researchers say the foveola accounts for about half of visual perception. In the organoids, some blue cones were present around weeks 10 to 12, and by week 14 those cells appeared to have converted toward red and green cones. Retinoic acid limited blue cones in the center, and thyroid hormone helped leftover blue cones become red or green. That challenges a model, about 30 years old, in which blue cones migrate inward and their identities stay fixed. The work does not fully rule migration out. Hussey is now at CiRC Biosciences. This is lab-grown fetal tissue. It is not a trial of vitamin A pills, and it does not show that an adult vitamin A supplement improves sharp vision. Cell replacement is a long-term research hope, not a treatment from this result. Not medical advice.

Evidence level: Lab study. Results in animals or cells often don't carry over to people.

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