Breakthrough

Breakthrough

Restoration of vision in the most common form of incurable blindness

5 breakthroughs in medicine this week

Samuel Hume's avatar
Samuel Hume
Oct 27, 2025
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1. Restoration of vision in the most common form of incurable blindness

The most common cause of incurable blindness in adults is dry age-related macular degeneration. The severe form of this, geographic atrophy, leads to loss of cells in the retina — and causes 20% of blindness in the US.

The symptoms are blurring of vision, usually with a central blind spot (where the macula is). There are a couple of therapies approved that slow down the atrophy, and others — even gene therapies — in the pipeline, but we don’t have anything at the moment that can fully restore vision.

The underlying issue is loss of photoreceptors in the retina, which transduce light into electrical signals that can be processed and sent to the brain. This paper reports an implant that’s inserted into the back of the eye, under the retina, to replace the function of the lost photoreceptors.

Composite image of scans of the chip in a patient’s eye.
The implant, a 2mm-square photovoltaic microchip, is implanted into the back of the eye by surgery. Source: NEJM.

Patients need to wear specialised glasses, too, that capture images and send infrared signals to the implant, like this:

The graphic shows how the technology works. There is an illustration of a patient with the implant wearing glasses with a built-in video camera and holding a processor connected by wire to the glasses.
Below, another graphic shows how the camera sends images to the implant at the back of the eye, via infrared beam. A close-up of the eye shows the implant receiving those infrared images and then sending them on to a black hand-held processor. Red arrows highlight that the images are sent to the processor, enhanced and then sent back to the implant and on to the brain.
A third graphic illustrates the way the images are enhanced. On the left is an image from the camera showing part of a word. The letters 'ernoon' are coloured black on a white background and appear slightly blurred. On the right is an enhanced image seen by the patient where the letters (now white) are bold and stand out against a black background.
Source: BBC.

Of 32 patients given the implant, all of whom were legally blind at baseline, 27 regained the ability to read. It takes a few months to figure out how to interpret the images — and requires eye surgery (so it’s not for the faint of heart!).

The implant and glasses are made by Science Corp, and are still being trialled in Europe and the US, with no regulatory approvals (yet).

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2. Semaglutide doesn’t need weight loss to protect the heart

Semaglutide has soared to the second biggest drug in the world (by sales) thanks to its approvals for obesity, type 2 diabetes, chronic kidney disease, and cardiovascular risk reduction. It’s generally thought that the semaglutide achieves this by weight loss — but this study challenges that.

In a re-analysis of a major trial, semaglutide reduced cardiovascular risk, irrespective of how much weight patients lost.

Source: The Lancet.

So there wasn’t a relationship with weight loss, but there was with waist circumference — which explains about 33% of the cardiovascular benefit of semaglutide. Waist circumference gives an idea of the visceral fat (that surrounds organs) rather than the subcutaneous fat (that sits under skin).

What about the remaining 67% of the benefit? This probably comes from the direct anti-inflammatory benefits of semaglutide, or because of its direct effects on vessels.


3. Progress for early cancer detection

Early detection is the future of cancer. To illustrate why it’s so important, here are some numbers. 5-year survival rates for colorectal cancer, pancreatic cancer, and prostate cancer (for example) when diagnosed after distant spread are 13%, 3%, and 37%, respectively. If diagnosed while still local, 5-year survival is dramatically better: 91%, 44%, and >99%, respectively.

Galleri is a multi-cancer early detection blood test that reads methylation patterns on the DNA shed from cancer cells (this is called cell-free DNA, or cfDNA). Through this approach, it aims to detect over 50 cancers in a single test.

In this huge trial (25,000 patients, all aged 50+), Galleri detected a cancer signal in 216 people — 133 of which were subsequently diagnosed via formal testing. 196 received a false negative test — they received no cancer signal, but cancer was later detected.

This means the the positive predictive value for the test was 62%, and the negative predictive value was 99.1%:

Source: GRAIL.

These data are impressive, but there’s still a long way to go: the sensitivity of detection drops for detecting early stage cancers (where we really want it to work); there are potential downstream harms (from false alarms and overdiagnosis); and there’s no data (yet) that kits like this can improve survival.

This space is very very hot, though: other competitors include Cancerguard (Exact Sciences). The Galleri test is already available in the US — but only via prescription — at a cost of $949. The next step is a huge randomised controlled trial run in the UK, with 140,000 patients. Data are expected in 2026…


4. A molecule that reduces inflammation in the brain

This is an extremely interesting new molecule: an oral, brain-penetrant NLRP3 inhibitor. (Usually I don’t spell out molecule names, because they don’t add much. NLRP3, for example, stands for ‘NLR family pyrin domain containing 3’.)

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