Siloton OCT photonic chip takes sub-surface image of human retina

06 Nov 2024

Miniaturized OCT platform should improve diagnosis and treatment of eye disease.

Photonic chip specialist Siloton has announced the first sub-surface image of a human retina taken with its chip-based OCT technology.

This follows on from the announcement in April 2023 that the UK-based developer had obtained the first such image of a retina phantom in a synthetic eye, hailed by the company at the time as a ground-breaking achievement.

The new application of Siloton's first-generation OCT chip, called Akepa, marks a significant step towards its use in clinical eye care, said the company, and makes Siloton the first commercial organisation - as opposed to academic institution - to take such an image of a human subject using this technology.

A photonic chip-based OCT device should be considerably more compact and robust than a traditional platform, making it easier to examine patients for signs of age-related macular degeneration (AMD) and other retinal diseases.

In principle such a device could be suitable for use in domestic settings, easing the pressure on clinics and hospitals.

"Because of the size and cost of existing systems, the technology can only currently be accessed through hospitals and high-end optometrists," commented Siloton. "Akepa compresses a tabletop-worth of heavy, expensive, and fragile optical components onto a single piece of material smaller than a £1 coin."

The potential for photonic chips and silicon photonics to impact clinical OCT implementations has been recognised for some time, as research into suitable low-loss waveguides and integration technology has progressed. Siloton was founded in 2020 to leverage such integrated photonics into the healthcare sector, with ophthalmology its first target.

Tackling a chronic shortage of imaging devices

According to company info Siloton did not spin out of a university, with founders Alasdair Price and Euan Allen developing their OCT technology from scratch. The first proof of concept device was built for under £20,000 in Allen's home, using a repurposed generic chip negotiated for free from a foundry.

That effort attracted £470,000 of funding support in 2022, and Price and Allen were awarded the 2023 Institute of Physics Clifford Paterson Medal for their work and its commercial prospects.

In October 2024 the company announced its most recent fundraising result, a further £860,000 to develop the Akepa OCT chip technology and move towards commercialisation in 2025.

The 2023 medal citation indicated that Siloton had registered three patents outlining its research: one for an on-chip component to compensate for natural variation in the distance of patient retinas from the chip; another relating to the internal structure of the optics used to ensure optimal chip performance; and the third for an optical arrangement for imaging both eyes without doubling the number of components or requiring patient intervention.

"OCT scans are critical to providing the sight-saving eye care that almost everyone will eventually need," commented Alasdair Price.

"However, there is a chronic shortage of imaging devices throughout the world. The Siloton team has shown that we can use affordable and scalable technology to expand the reach of OCT systems, reducing preventable blindness, alleviating pressure on eye clinics, and potentially saving healthcare providers like the UK NHS billions each year."