The retrospective study, conducted at Alexandrovska University Hospital in Sofia, evaluated 56 patients representing 67 eyes who underwent uncomplicated phacoemulsification cataract surgery with implantation of the lens into the capsular bag. All operations were performed by a single experienced surgeon, and patients were divided into three groups according to the lens they chose after preoperative counseling. Twenty-five patients received a standard monofocal lens drawn from several commercially available models, 17 patients received the Evolux™ enhanced monofocal lens, and 14 patients received an extended depth of focus, or EDOF, lens. Patients with corneal astigmatism of 0.50 diopters or more and those with toric lenses were excluded, keeping the comparison as clean as the retrospective design allowed.

The Evolux™ lens, developed by AffaMed Therapeutics and SIFI S.p.A., is made from a hydrophobic material and carries a non-diffractive optical profile. Unlike multifocal lenses, which split incoming light between multiple focal points, and unlike diffractive EDOF designs, which redistribute light to stretch the focal range, the enhanced monofocal profile is engineered to sharpen intermediate vision while preserving distance clarity equivalent to a traditional monofocal lens. Its optical technology is reported to show very low dependence on pupil diameter at far and intermediate distances, similar image contrast across different pupil sizes, and good tolerance to residual refractive errors, with a low reported incidence of tilt, decentration, and photic phenomena.

Visual acuity was measured before surgery and again on the seventh and thirtieth postoperative days, using a Snellen chart calibrated at six meters for distance vision and an intermediate chart calibrated at 66 centimeters. Before surgery, the three groups were closely matched: mean best-corrected distance acuity ranged from 0.18 in the monofocal group to 0.21 in the EDOF group, and mean intermediate acuity ranged from 0.25 to 0.30. On the thirtieth postoperative day, distance acuity had converged across all groups, with mean uncorrected values of 0.80 for the monofocal group, 0.83 for the Evolux™ group, and 0.84 for the EDOF group. The researchers emphasize that this convergence is clinically relevant, because any gain in intermediate vision should ideally not come at the expense of distance clarity.

The real separation appeared at 66 centimeters. The monofocal group averaged 0.54 uncorrected intermediate acuity, meaning most patients still needed glasses for computer-distance tasks, and the best individual result in that group was 0.8. The Evolux™ group averaged 0.79, with six eyes reaching 1.0, or 20/20, at the intermediate distance. The EDOF group led with a mean of 0.93, and post hoc analysis confirmed that its intermediate acuity was significantly better than both the Evolux™ lens and the monofocal lenses. Expressed relative to preoperative values, intermediate acuity improved by 116 percent in the monofocal group, 182 percent in the Evolux™ group, and 210 percent in the EDOF group, a hierarchy the authors note is consistent with the intended optical characteristics of each lens category.

Acuity alone, however, does not capture the full quality of vision. Optical strategies that extend the depth of focus necessarily alter how light is distributed across the retina, which can reduce the ability to distinguish objects of similar luminance, particularly under dim or unfavorable conditions. To probe this, the team measured contrast sensitivity on the thirtieth postoperative day using the Pelli-Robson chart at one meter, a logarithmic test on which scores near 2.00 indicate normal contrast sensitivity. The results were striking. In the monofocal group, 79.31 percent of eyes recorded 2.00 log units, and in the Evolux™ group 68.18 percent did so. In the EDOF group, only 25 percent of eyes reached 2.00, while 56.25 percent recorded 1.85 log units. Although the sample size limits definitive conclusions, the distribution suggests that the broader visual range of EDOF optics is accompanied by a measurable reduction in contrast sensitivity, a finding consistent with earlier work by Kohnen and colleagues.

Patient-reported outcomes added a subjective dimension to the objective measurements. On a satisfaction scale from 0 to 10, nearly all patients in every group reported their distance vision as excellent, with only isolated scores of 9 or lower. The differences emerged in the frequency of photic phenomena: one patient in the monofocal group reported halos with nighttime driving difficulties, one reported diplopia, and another reported glare. In the Evolux™ group, only a single patient reported glare, and no one reported halos. In the EDOF group, three patients, or 18.75 percent, reported photic phenomena such as glare or halos around light sources. The authors attribute the low frequency of complaints in the Evolux™ group to its non-diffractive design, which avoids the light splitting that generates halos and glare in diffractive optics.

The pattern that emerges across the three groups is essentially a trade-off between range and quality. Conventional monofocal lenses delivered good distance vision and preserved contrast sensitivity but left patients dependent on spectacles for anything closer than arm’s length. EDOF lenses delivered the highest intermediate acuity and the greatest spectacle independence but showed reduced contrast sensitivity and the most frequent photic symptoms. The Evolux™ enhanced monofocal occupied the middle ground, delivering a substantial gain in intermediate vision over conventional monofocal lenses, comparable distance acuity, preserved contrast sensitivity, and a low incidence of halos and glare. The authors also point to an economic dimension, noting that enhanced monofocal lenses may be an attractive option for patients for whom the premium price of EDOF or multifocal lenses is a limiting factor.

For clinical counseling, the findings suggest that not every patient requires maximal spectacle independence at all distances. Some prioritize excellent distance vision, good intermediate vision for screens, and minimal photic phenomena over the highest possible near acuity, and for these patients an enhanced monofocal lens may represent an appealing alternative. The study’s strengths include its direct three-group comparison in a single clinical setting, the combination of objective acuity and contrast sensitivity with patient-reported satisfaction, and the standardization offered by a single surgeon and uniform postoperative treatment. The authors caution that the retrospective design and modest sample size are real limitations, and they call for larger prospective studies with standardized patient-reported outcome measures and longer follow-up to confirm the position of enhanced monofocal lenses in the cataract surgery landscape.

Subject of Research: Ophthalmology

Article Title: A comparative study of visual outcomes and patient satisfaction with Evolux™, monofocal, and extended depth of focus intraocular lenses

Article References: Zdravkov, Y., Dzhambazov, R., Veleva, N., Haykin, V., & Oscar, A. (2026). A comparative study of visual outcomes and patient satisfaction with Evolux™, monofocal, and extended depth of focus intraocular lenses. Pharmacia, 73, Article e200063. https://doi.org/10.3897/pharmacia.73.e200063

Image Credits: AI Generated

DOI: 10.3897/pharmacia.73.e200063

Keywords: cataract surgery, intraocular lenses, enhanced monofocal IOL, Evolux, EDOF lens, contrast sensitivity, patient satisfaction, intermediate vision, ophthalmology, vision correction, comparative, visual

The reasoning behind the project is straightforward yet profound. A transit to Mars can require almost a year, and returning to Earth for a vision-limiting cataract, an injury, or another surgical eye problem may simply not be realistic. Dr Micheletti told the congress that he believes someone will need cataract surgery on Mars within his lifetime, and that treatment will ultimately need to happen where the patient is. Astronaut candidates, he noted, do not need perfect uncorrected vision, and refractive correction or certain prior refractive surgeries are compatible with selection. More importantly, good vision at launch does not prevent aging, radiation exposure, injury or disease later in the mission. As human spaceflight expands beyond career astronauts, the travelling population will become more diverse, and the medical systems that support it must be designed and validated long before the first patient needs them. In his words, we cannot wait until someone is on Mars to ask whether the lens, equipment and sterile supplies survived the trip.

To begin answering that question, Dr Micheletti launched the Joint Assessment Of Material Exposure In Space, or JAMES, project. The experiment flew 135 unpackaged intraocular lenses to the International Space Station, where they were mounted in special carriers positioned at three different exterior locations. The carriers, named CLAIRE, short for Carrier for Lens Analysis in Interstellar Research Expeditions, held lenses at three distinct test sites: Ram, where the lenses were exposed to high levels of atomic oxygen; Zenith, where they received substantial ultraviolet radiation from the Sun; and Underdeck, where they were partially shielded from direct atomic oxygen and solar ultraviolet by being mounted beneath the exposure platform. This placement strategy allowed the researchers to observe how different combinations of space-environment stressors affect lens materials.

Dr Micheletti was careful to explain that the study was not intended to recreate how a packaged intraocular lens would normally be shipped to Mars. Instead, the purpose was to identify potential failure modes under harsh exposure so that better packaging, shielding, storage and material selection strategies can be designed. Testing the lenses inside the station would not answer the same question, because the interior is controlled and pressurised. The team wanted to minimise packaging and, ideally, determine whether these products can be shipped without climate-controlled crew-cabin storage, because mass and volume carry significant costs in spaceflight. Every kilogram launched toward deep space demands fuel, money and payload capacity, so medical supplies that can survive the journey without elaborate protective enclosures would represent a meaningful engineering advantage.

On Earth, 45 intraocular lenses were removed from their original packaging and placed in a control carrier called WILLIAM, the Worldly Interface for Lens Logistics and Integrated Astronomical Monitoring. These control lenses remained at room temperature and atmospheric pressure for the duration of the experiment. After approximately six months in orbit, the 135 flight lenses returned to Earth for laboratory analysis. The current analysis included 61 of the space-flown lenses and 20 of the 45 terrestrial controls, a total of 81 lenses. Dr Liliana Werner and her team at the Intermountain Ocular Research Center at the University of Utah examined each lens for overall clarity, how well the lens materials remained intact, and whether any deposits or surface changes had developed during the mission.

The results revealed a spectrum of responses to the space environment. Most of the lenses, 42 of the 61 analysed, showed no notable exposure-associated findings when examined. The remaining 19 lenses displayed three principal patterns of change. In the most directly exposed Ram tray, eight of the nine lenses showed cracks and localised surface roughening consistent with early atomic oxygen erosion. All eight were acrylic lenses, including five hydrophobic and three hydrophilic designs, while the ninth lens, made of silicone, showed yellow discoloration instead. Atomic oxygen, the highly reactive form of oxygen that predominates in low-Earth orbit, is a well-known hazard for spacecraft surfaces, and these findings suggest it can degrade certain ophthalmic materials even over a relatively short orbital stay.

The second pattern involved yellow discoloration in five space-exposed lenses, including two hydrophobic acrylic and three silicone lenses. Four of these were located in the Zenith tray and one in the Ram tray. Spectrophotometry measurements showed lower light transmission in the affected lenses, particularly between 400 and 500 nanometres, the blue region of the visible spectrum that is essential for colour perception and contrast. This finding is especially relevant for a device whose entire purpose is to transmit light clearly to the retina. A yellowed lens inside an eye would act somewhat like a permanent filter, subtly altering the colour and quality of the vision it delivers, which could matter for pilots, scientists or anyone performing precision tasks in space.

The third and perhaps most puzzling pattern emerged among the light-adjustable lenses. All six of these space-exposed lenses, located across all three positions on the station’s exterior, developed a similar cobblestone or bubble-wrap appearance on both surfaces and along the optic edge. Neither of the two corresponding terrestrial controls showed this appearance. The mechanism behind the change remains unknown, and the researchers note that an explanation unrelated to direct space exposure cannot yet be excluded. Light-adjustable lenses are a sophisticated class of intraocular lenses whose optical power can be fine-tuned after implantation using ultraviolet light, making any unexplained surface alteration on their polymers particularly worthy of investigation before such devices are trusted on a mission where no replacement is available.

Dr Micheletti stressed that this was an exploratory, descriptive study, not designed to compare different makes or types of lenses or to test a formal hypothesis. The analysis covered a selected subset of the payload, sample sizes were small and uneven, and in some carrier positions there was only one lens of a given model. The lenses were deliberately unpackaged, so handling or environmental contamination could not be fully excluded, and the control lenses did not undergo launch, return or flight handling, which limits attribution of the observed changes specifically to external exposure. Beyond transmission spectrophotometry, image-quality, mechanical and clinical-performance testing has not yet been completed. The findings, he cautioned, should not be used to rank manufacturers or lens models and do not imply any safety concern for routine cataract surgery on Earth. What they do suggest is that lens material and exposure location may influence the changes observed, and that packaging, shielding and storage are the next protective strategies to test. The engineering challenge, he said, will be providing enough protection without adding unnecessary mass, because every kilogram sent into space carries a cost.

The significance of the work was underlined by Dr Joaquín Fernández, ESCRS Secretary, CEO of Qvision and Medical Director of the Andalusian Ophthalmology Institute at Vithas Hospitals in Almería, Spain, who was not involved in the research. He observed that as more people travel into space and for longer periods, eye surgery will likely be required at some point, making it imperative to understand how lenses and other surgical materials behave beyond Earth’s atmosphere, and he described the research as forward-thinking and certain to play an important role in preparations for deep space exploration. The JAMES study is, to the investigators’ knowledge, the first controlled experiment to expose multiple modern intraocular lens materials directly to the external low-Earth-orbit environment and return them for laboratory analysis. While published clinical reports have described astronauts who flew with implanted lens devices, those devices were protected inside the eye and body, so preimplantation exposure had never been studied. Dr Micheletti now hopes to investigate how a phacoemulsification system, the ultrasound and fluidics platform at the heart of modern cataract surgery, performs during the brief microgravity of parabolic flights, with the longer-term path leading to sustained microgravity testing and eventually an in-orbit surgical experiment. His guiding philosophy is deliberate: first the materials, then the equipment, then the procedure, and ultimately the surgery, in the hope of helping make the first eye operation beyond Earth a reality.

Subject of Research: Exposure of intraocular lenses to the low-Earth-orbit environment outside the International Space Station to assess their suitability for space-based cataract surgery.

Article Title: ‘Space: The final frontier’ for cataract surgery!

Article References: ‘Space: The final frontier’ for cataract surgery!. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: intraocular lenses, cataract surgery, International Space Station, space medicine, atomic oxygen, ultraviolet radiation, light-adjustable lenses, Mars missions, ophthalmology, JAMES project, low-Earth orbit, ESCRS

Supercritical carbon dioxide, often abbreviated scCO2, is carbon dioxide held above its critical temperature of about 31 degrees Celsius and its critical pressure of roughly 74 bar. In this state, the gas and liquid phases merge into a single fluid with an unusual combination of properties: it diffuses into materials like a gas but dissolves substances like a liquid. Crucially, its solvent power can be tuned simply by adjusting pressure and temperature, and at the end of any process the fluid simply evaporates, leaving behind a dry, residue-free product. Because carbon dioxide is non-toxic, non-flammable, inexpensive, and generally recognized as safe, it has long attracted attention as a green solvent in industries ranging from decaffeination of coffee to dry cleaning of textiles.

The review’s central message is that scCO2 is not just a niche laboratory curiosity but a technology that can be applied at nearly every stage of implant manufacturing. The first stage is cleaning. Polymer devices fabricated by molding, extrusion, or additive manufacturing can carry residues of organic solvents such as chloroform or tetrahydrofuran, which are toxic and strictly regulated by bodies like the European Medicines Agency. Conventional drying and vacuum treatments struggle to remove these residues from deep within polymer matrices, but scCO2, with its high diffusivity and tunable solvency, can extract them efficiently. Studies cited in the review show that carbon dioxide extraction removed residual chloroform from biodegradable polymers and eliminated solvents from PLGA microspheres, producing products that meet stringent regulatory limits on residual solvents.

Cleaning with supercritical fluids also addresses a subtler challenge: the intricate geometry of modern implants. Devices such as angioplasty catheters and microfabricated components contain narrow channels and microholes that liquid cleaning agents cannot reliably penetrate. Pulse cleaning with supercritical carbon dioxide, in which pressure is cycled to drive the fluid in and out of confined spaces, has been demonstrated for deep microholes and is now used industrially. The review notes that companies in the medical device sector have already adopted supercritical cleaning lines, and pharmaceutical contract manufacturers operate GMP-certified supercritical units, evidence that the technology has moved beyond the pilot scale.

The second major application is impregnation, the loading of drugs or bioactive compounds into polymer implants. Traditional methods involve soaking devices in solvent solutions, which can leave toxic residues and offer limited control over how much drug is loaded and where it ends up. Supercritical impregnation works differently: the drug is dissolved in scCO2, which swells and plasticizes the polymer, allowing the active compound to diffuse deep into the matrix. When pressure is released, the carbon dioxide escapes and the drug remains trapped inside. Because scCO2 is a weak solvent for most polar drugs, small amounts of co-solvents such as ethanol can be added to boost loading, and these co-solvents are far less problematic than the chlorinated solvents used in conventional approaches.

The Marseille group and collaborators have applied this technique to a striking range of devices. Foldable intraocular lenses made of hydrophobic acrylic polymers have been loaded with antibiotics and anti-inflammatory drugs such as gatifloxacin, with in situ spectroscopic monitoring of carbon dioxide sorption and polymer swelling used to control and optimize the process. Contact lenses have been impregnated with antifungal and antibacterial agents for the treatment of keratitis. Bioresorbable suture threads have been loaded with drugs in a proof-of-concept study explicitly aimed at industrial scale-up, and biodegradable ureteral stents have been made to elute ketoprofen to reduce patient discomfort. Wound dressings, electrospun polyurethane fibers, and chitosan sponges have all been successfully impregnated with therapeutic agents ranging from natural extracts to hormones.

The third application is foaming, which is central to tissue engineering. Porous scaffolds provide a three-dimensional template for cells to colonize and regenerate tissue, but conventional methods for creating porosity, such as solvent casting with particulate leaching or freeze-drying, often leave toxic residues or produce poorly connected pore networks. In supercritical foaming, carbon dioxide is dissolved into the polymer under pressure and then rapidly depressurized, causing the gas to nucleate into countless bubbles that expand into pores. The process is solvent-free, operates at relatively low temperatures compatible with biodegradable polyesters, and yields scaffolds with interconnected porosity. Researchers have produced foams of polylactic acid, polycaprolactone, and their composites with hydroxyapatite for bone regeneration, and combined foaming and impregnation in a single step to create drug-loaded porous patches and scaffolds in one continuous operation.

Underpinning all of these applications is a body of physical chemistry that the review examines in detail. Carbon dioxide sorption into polymers lowers the glass transition temperature and, in semicrystalline polymers, can depress the melting point, effects that are exploited in foaming but must be controlled to avoid unwanted deformation during cleaning or impregnation. Techniques such as in situ ATR-FTIR spectroscopy, high-pressure differential scanning calorimetry, and quartz crystal microbalance measurements allow researchers to follow swelling, sorption, and thermal transitions in real time. Solubility data for drugs in scCO2, modeled with density-based correlations and increasingly with machine learning approaches, guide the selection of process conditions. This chemical engineering perspective, the authors emphasize, is what turns promising laboratory results into robust, reproducible industrial processes.

The final and perhaps most consequential application is sterilization. Conventional methods each carry drawbacks for polymer implants: gamma and electron-beam irradiation can degrade polymer chains and alter mechanical properties, ethylene oxide leaves toxic residues and raises environmental and worker-safety concerns, and steam autoclaving requires temperatures that destroy many biodegradable materials. Supercritical carbon dioxide sterilization works at near-ambient temperatures. The mechanism is multifactorial: the pressurized fluid penetrates cells and spores, rapid depressurization can rupture membranes, and carbon dioxide acidifies intracellular environments. Additives such as hydrogen peroxide, water, or ethanol dramatically enhance spore kill rates, allowing the process to achieve the sterility assurance levels required by international standards such as ISO 14937.

Evidence for clinical relevance is accumulating. Decellularized heart valves sterilized with supercritical carbon dioxide retained their biomechanical properties, and a study of anterior cruciate ligament reconstruction using scCO2-sterilized allografts reported favorable clinical outcomes. Sensitive biomaterials including collagen-based products, polysaccharide membranes, and hydrogels have been sterilized at low temperature without loss of structure or bioactivity. The technology has even been applied to inactivate SARS-CoV-2 on personal protective equipment. Regulatory momentum is building: the U.S. Food and Drug Administration has run innovation challenges to identify new sterilization methods, partly driven by concerns over ethylene oxide emissions, and a commercial supercritical sterilization system has received NIH funding for further development. The review concludes that while challenges remain, particularly in validating processes across diverse device geometries and scaling high-pressure equipment, supercritical carbon dioxide stands out as a sustainable, gentle, and remarkably flexible platform that could one day serve as a standard across the whole life cycle of polymer implants, from the first wash to the final sterile pouch.

Subject of Research: Use of supercritical carbon dioxide in the cleaning, impregnation, foaming, and sterilization of implantable polymer-based medical devices

Article Title: Implantable Polymer-Based Medical Devices Go Supercritical: From Cleaning to Sterilization

Article References: Laggoune, Z., Masmoudi, Y., Pepe, V., & Badens, E. (2026). Implantable Polymer-Based Medical Devices Go Supercritical: From Cleaning to Sterilization. Annals of Biomedical Engineering. https://doi.org/10.1007/s10439-026-04392-3

Image Credits: AI Generated

DOI: 10.1007/s10439-026-04392-3

Keywords: supercritical carbon dioxide, implantable medical devices, biomedical polymers, sterilization, drug impregnation, foaming, tissue engineering scaffolds, green solvents, residual solvent removal, intraocular lenses, biodegradable polymers, chemical engineering