Naked Scientists: Retina chips, PrEP injections, pristine star, and crow cognition

The Naked Scientists explore breakthroughs across vision, infectious disease prevention, astronomy, and animal cognition. A wireless, infrared-powered retinal implant in AMD patients demonstrates stable text-reading ability over years, while Cabotegravir PrEP offers two-month HIV protection, potentially broadening access beyond daily pills. Astronomers document an almost metal-free red giant, SDSS JO 7157334, revealing conditions of the universe’s first generations of stars. Finally, Cambridge researchers show rooks can understand and respond to human speech commands, highlighting advanced general cognition in birds. The discussion weaves clinical implications, cosmic origins, and animal intelligence into a coherent view of future science.”

Retinal implants and vision restoration

The episode begins with a report from an early-stage, wireless retinal chip trial designed to help people with age-related macular degeneration. A 2 millimetre by 2 millimetre silicon-gold prosthesis sits beneath the retina, receiving an infrared image from eyeglass-mounted cameras and converting it into electrical stimulation for surviving retinal cells. The external power source is provided optically, via infrared light, which can simplify surgery and improve device longevity. In central retina areas, there are around 200,000 photoreceptors per square millimetre, so the chip’s roughly 378 pixels offer limited detail. Yet the brain can fuse frequent refreshes into usable imagery, potentially enabling reading at shorter distances than full acuity, and the approach may be especially beneficial for younger patients with retinitis pigmentosa. The expert notes that while current resolution is modest, the technology represents a meaningful advance toward practical, long-lasting retinal prostheses. "External power supply via infrared powering marks a real step forward" - Dr. Robert McLaren, professor of ophthalmology, University of Oxford

Long-acting injectable PrEP for HIV prevention

The programme then discusses England and Wales adopting a long-acting injectable HIV preventative regimen using Cabotegravir PrEP, delivering protection for two months. This builds on the existing daily oral PrEP and addresses adherence challenges, potentially expanding access for people who cannot or will not take daily tablets. The NHS is balancing cost with the public-health gains achieved since PrEP’s roll-out, which has led to notable declines in new HIV diagnoses, especially among gay and bisexual men. The injectable option could serve as a discreet, effective alternative for individuals with barriers to daily medication, while NICE provides evidence of cost-effectiveness when compared with other prevention strategies. "Injectable PrEP provides protection for two months, a substantial improvement over daily pills" - Hamish Mohammed, UK Health Security Agency

A pristine star and early universe insights

The discussion then moves to a standout astronomical finding: a red giant star, SDSS JO 7157334, with extremely low metal content, detected through spectroscopy. Located in the Milky Way outskirts with origins traced to the Magellanic Clouds, the star offers a window into the universe’s first generations of stars. The star’s chemical fingerprint—feeled by hydrogen and helium with almost no heavier elements—helps cosmologists refine models of early star formation, cooling, and the role of metals in setting stellar masses. The guest explains that such near-pristine stars are rare but illuminate how the first stars influenced subsequent galaxy evolution. "Pristine metal-poor star lets us study the conditions of the early universe" - Matt Bothwell, space scientist

Crow cognition and language

The final segment highlights Nicky Clayton’s work with rooks at Cambridge, demonstrating that these birds can understand and follow human commands expressed in speech, independent of body language. Training involves building trust and using rewards like waxworms, enabling tasks such as color discrimination and following instruction to wait. The rooks show flexible, general cognitive abilities not tightly bound to wild behaviors, suggesting a broad toolkit for problem-solving that rivals some primates. The researchers emphasize that this cross-species language comprehension underscores advanced cognition in wild-adapted birds and broadens our understanding of animal intelligence. "These rooks understand human commands and can follow words, not just gestures" - Nicky Clayton