(Credit: © Davide Angelini - stock.adobe.com)
In A Nutshell
- Researchers mounted 135 unpackaged intraocular lenses in carriers on the outside of the International Space Station for roughly six months, then analyzed 61 of them against 20 lenses kept on Earth.
- Most held up: 42 of the 61 space-exposed lenses showed no exposure-associated findings.
- Damage clustered by position and material: eight of nine lenses in the most exposed tray cracked or roughened, five lenses yellowed and transmitted less light between 400 and 500 nanometers, and all six light-adjustable lenses came back with an unexplained cobblestone texture.
Cataract surgery is a routine procedure that swaps a clouded natural lens for an artificial one. Performing it millions of miles from the nearest operating room is a different proposition entirely. A Houston eye surgeon believes that day is coming sooner rather than later, and he has been investigating if the tiny lenses used in the procedure can even survive the trip.
Dr. Morgan Micheletti of the Berkeley Eye Center in Houston, Texas, told the 44th Congress of the European Society of Cataract and Refractive Surgeons in London on Sunday that cataract surgery will be needed as humans travel farther and stay in orbit longer. Before anyone attempts that, someone has to answer a much less glamorous question: how do surgical supplies hold up once they leave Earth’s protection?
“I believe someone will need cataract surgery on Mars in my lifetime,” Micheletti said. “A Mars transit can require almost a year, and returning to Earth for a vision-limiting cataract, injury, or other surgical eye problem may not be realistic. Eventually, treatment will need to happen where the patient is.”
Cataract surgery in space starts with 135 lenses mounted outside the ISS
Micheletti’s team sent 135 intraocular lenses, the clear implants that replace a clouded natural lens, to the International Space Station as part of the Joint Assessment Of Material Exposure In Space project, or JAMES. Rather than tucking them safely inside the pressurized crew cabin, researchers stripped off the packaging and mounted them outside the station in carriers called CLAIRE, in three positions: one battered by atomic oxygen, one facing the Sun’s ultraviolet load, and one partly shielded beneath the exposure platform. Another 45 lenses stayed on the ground as controls.
“This was not intended to recreate how a packaged IOL would normally be shipped to Mars. The purpose was to identify potential failure modes under harsh exposure so we can begin designing better packaging, shielding, storage and material selection strategies,” Micheletti said.
Six months in orbit left most lenses untouched
After roughly six months, the flight lenses came home. Dr. Liliana Werner and her team at the Intermountain Ocular Research Center at the University of Utah examined 61 of them alongside 20 Earth-bound controls, checking clarity, material integrity, and surface changes.
Most came through fine: 42 of the 61 showed no exposure-associated findings. Changes turned up in the other 19, in three patterns.
Cracking clustered where atomic oxygen hit hardest. Eight of the nine lenses in that tray showed cracks and localized surface roughening, and all eight were acrylic. Yellowing showed up in five lenses, two acrylic and three silicone, mostly in the sun-facing tray, and laboratory measurements showed those lenses transmitted less light, particularly in the blue end of the visible spectrum.
Strangest was what happened to the light-adjustable lenses, which can be fine-tuned after implantation. All six that flew, spread across all three positions, came back with the same cobblestone texture on both surfaces and along the edge of the optic. Neither matching control on Earth showed anything like it, and nobody yet knows why.
Cataract surgery in space still has hurdles to clear
Micheletti was blunt about the limits. Sample sizes were small and uneven, contamination could not be excluded, and the ground controls never experienced launch or reentry, which weakens any claim that space itself caused the changes. He said the results cannot be used to rank manufacturers and signal nothing about cataract surgery performed on Earth.
Materials are only the first rung. Micheletti next hopes to test how the ultrasound and fluid equipment used to break up and remove a clouded lens behaves during the brief weightlessness of parabolic flights.
“The progression has to be deliberate: first the materials, then the equipment, then the procedure and, ultimately, the surgery. My long-term hope is to help make the first eye surgery beyond Earth possible,” he said.
A yellowed lens or a cracked optic found in a Utah laboratory is a research finding, filed away for the engineers who design the next carrier. Found halfway to Mars, it is a patient with no second option. That is why Micheletti wants those answers long before anyone needs them millions of miles from home.
Study Notes
Limitations
Micheletti described the work as exploratory and descriptive rather than hypothesis-testing, and it was not designed to compare makes or models of lenses. Only a selected subset of the payload, 61 of the 135 flown lenses and 20 of the 45 ground controls, was included in this analysis. Sample sizes were small and uneven, and some carrier positions held only one lens of a given model. Because the lenses traveled without their packaging, handling or environmental contamination could not be fully excluded. Ground controls did not undergo launch, return, or flight handling, which limits how confidently the observed changes can be attributed to external space exposure specifically. Testing beyond transmission spectrophotometry, including image-quality, mechanical, and clinical-performance evaluation, has not yet been completed. Micheletti stated that the findings should not be used to rank manufacturers or lens models and do not indicate a safety concern for routine cataract surgery on Earth.
Funding and Disclosures
J. M. Micheletti reports grant and research support from Bausch & Lomb, Carl Zeiss Meditec, and STAAR Surgical, and consultancy relationships with Alcon, BVI, Bausch & Lomb, Carl Zeiss Meditec, Johnson & Johnson Vision, Lenstec, RxSight, and STAAR Surgical. L. Werner declares none.
Publication Details
Findings were presented by Dr. Morgan Micheletti of the Berkeley Eye Center, Houston, Texas, with laboratory analysis conducted by Dr. Liliana Werner and colleagues at the Intermountain Ocular Research Center, University of Utah, at the 44th Congress of the European Society of Cataract and Refractive Surgeons in London on September 13, 2026. Abstract PP15.04, “The Joint Assessment Of Material Exposure In Space (JAMES): Laboratory analyses of Intraocular Lenses (IOLs) after low-Earth-orbit exposure on the exterior of the International Space Station (ISS),” by Morgan Micheletti et al, was presented in the poster session “Beyond conventional IOLs: emerging technologies and new indications.” Source material: ESCRS news release dated September 13, 2026; media contact Emma Mason, European Society of Cataract and Refractive Surgeons. Conference abstract, not a peer-reviewed journal publication; no DOI assigned.
