PRIMA retinal implant with camera glasses helps AMD patients read
MIT Technology Review explains the PRIMA system, built by the California-based Science Corporation to improve sight in people with advanced age-related macular degeneration (AMD). In advanced AMD, a blind spot develops in the middle of the visual field. The article says more than 5 million people worldwide with AMD experience atrophy in their retinas, and that until now no treatment could restore their vision. PRIMA combines a retinal implant with camera-equipped eyeglasses. It was approved in Europe in July and is awaiting FDA clearance in the US. After training sessions, more than 80% of recipients were able to read, do crosswords and use their phones.
The approach rests on the fact that AMD does not damage all retinal circuitry. Only the photoreceptors, the cells that convert light into an electrical signal, die off. The implant mimics those cells and passes visual information directly to healthy eye circuitry and on to the brain. Frank Brodie, an ophthalmologist at the University of California, San Francisco, and Science Corp.'s chief medical officer for ophthalmology, says: "We’re leveraging all of the body’s own natural functions to process and transmit the information."
The article walks through the system in four steps. Capture: glasses with a miniature front-facing camera record what the wearer is seeing in real time. The video feed is roughly five megapixels at 30 frames per second, which the article compares to TV. Raw video travels to a connected processor over a fiber-optic cable. Convert: a small handheld processor, which can sit on a table or in a pocket, turns the video into infrared light signals that route back to the glasses. It has physical buttons to adjust contrast, brightness and zoom. Display: a laser projector on the glasses faces the wearer and shines pulses of near-infrared light, at 880 nanometers, an invisible wavelength, directly at the eye. The signal passes through the pupil to the implant at the back of the eye. See: the implant has 378 pixels, each with an electrode and two photovoltaic cells that do double duty. They convert the light into a current that healthy bipolar and ganglion cells pass on to the brain, and they also act as solar cells that power the chip, so no battery is needed.
The piece carries an editorial update saying it was revised to clarify the specific cases of AMD that the PRIMA system treats. It is written by Linda Marsa, a former Los Angeles Times reporter and author who covers medicine, health, science and the environment.
Key facts
- PRIMA, from California-based Science Corporation, combines a retinal implant with camera-equipped glasses for patients with a central blind spot from advanced AMD.
- It was approved in Europe in July and is awaiting FDA clearance in the US.
- After training sessions, more than 80% of recipients could read, do crosswords and use their phones.
- The glasses send near-infrared light at 880 nanometers to a 378-pixel implant whose photovoltaic cells also power the chip, so it needs no battery.
- A handheld processor converts the roughly five-megapixel, 30 frames per second video and has buttons for contrast, brightness and zoom.
Why it matters
The article says more than 5 million people worldwide with AMD experience retinal atrophy and that until now no treatment could restore their vision. PRIMA is presented as the first to change that, with more than 80% of recipients able to read, do crosswords and use their phones after training. The design works with the eye's own pathways: the implant replaces the dead photoreceptors and hands signals to healthy bipolar and ganglion cells.
Who it affects
Patients with advanced AMD who have a blind spot in the middle of their vision, the group the system is meant to help. The article also notes an update clarifying the specific cases of AMD that PRIMA treats. Ophthalmologists such as Frank Brodie, who is both a UCSF clinician and Science Corp.'s chief medical officer for ophthalmology, are directly involved in the work.
How to use it
The wearer uses glasses with a front-facing camera and a laser projector, plus a small handheld processor that can sit on a table or go in a pocket. Physical buttons on the processor adjust contrast, brightness and zoom. Recipients learn to use the system in training sessions. The article gives no price, and no availability or eligibility details beyond advanced AMD. It was approved in Europe in July; FDA clearance is pending.
How solid is it
The main evidence in the article is the statement that more than 80% of recipients could read, do crosswords and use their phones after training. The source does not name the clinical trial, its size, or how "more than 80%" was measured. The technical description is specific: 378 pixels, 880 nanometer light, a roughly five-megapixel feed at 30 frames per second. The article is an explainer in MIT Technology Review, and the key quote comes from a Science Corp. executive.
Risks and caveats
FDA clearance is still pending, and no timescale is given for it. The source gives no safety data, side effects or visual acuity figures, and does not say how many patients have received the implant. The year of the European approval is not stated in the text. The 80% figure comes from the article's summary rather than from published trial detail.
“We’re leveraging all of the body’s own natural functions to process and transmit the information”
— Frank Brodie, ophthalmologist at the University of California, San Francisco, and Science Corp.'s chief medical officer for ophthalmology