The results of a landmark study comparing hydrophilic and hydrophobic intraocular lenses (IOLs), presented at the 2025 ESCRS Congress, has confirmed both IOL materials can be clinically and statistically equivalent in preventing posterior capsular opacification (PCO), says a media release from Rayner.
Rayner, a UK-based producer of IOLs, said the safety of hydrophilic IOLs compared with hydrophobic IOLs had been a subject of debate for decades.
Detractors of hydrophilic IOLs point to a predisposition to PCO formation and IOL calcification. Conversely, international experts have highlighted the many benefits of hydrophilic lenses, including their foldability and ease of implantation in micro incisional surgery, uveal biocompatibility, and reduced risk of IOL glistenings.1
Furthermore, calcifications with advanced hydrophilic materials like Rayner’s proprietary Rayacryl are rare – with zero cases of primary calcification and a secondary calcification rate of 0.0007%.2
The release said that, to settle the debate on IOL material, researchers at the prestigious St Thomas’ Hospital in London, UK – where the world’s first IOL implantation was performed in 1949 – conducted a prospective single-centre randomised controlled trial (RCT) comparing both materials.
Led by Professor David O’Brart, the study compared PCO rates and visual outcomes between two aspheric acrylic monofocal IOLs – Rayner’s hydrophilic RayOne (RAO600C) and the hydrophobic counterpart (RAO800C).
The 24-month results were presented at the ESCRS 2025 congress in Copenhagen by Dr Khayam Naderi.
Both groups experienced statistically significant improvements in uncorrected distance visual acuity (UDVA), best-corrected distance visual acuity (BDVA), and CATPROM-5 scores compared to baseline (p<0.0001), with comparable visual outcomes between groups.
Importantly, the release said, visually significant PCO formation (defined as PCO requiring Nd:YAG laser capsulotomy) showed no significant difference between the IOL groups (p=0.14).
Rayner said this was the first known RCT to directly compare long-term PCO outcomes between hydrophobic and hydrophilic IOLs from the same manufacturer, implanted by the same surgeon. Both IOLs are structurally similar, and feature Rayner’s Amon-Apple 360° enhanced square edge design that minimises the migration of lens epithelial cells (LECs) to the posterior capsule. Thus, all possible variables, namely, surgeon, clinic, manufacturer, and IOL optic, were controlled to facilitate a scientifically robust comparison.
In summary, a hydrophilic IOL with optimised anti-PCO design was comparable to its hydrophobic equivalent, leading the authors to conclude that the surgical technique and IOL edge design could have a greater influence on PCO formation than the lens material.
Mr Tim Clover, CEO of Rayner, said: “With millions of Rayner hydrophilic and hydrophobic lenses sold, we are uniquely able to study material difference by removing critical variables like edge design, manufacturing quality and haptic shape.
“This result proves equivalence and is important in establishing patient safety profiles. It allows surgeons to choose their lens material based on handling characteristics alone and supports Rayner’s strategy to offer the best patient outcomes in the material that you prefer.”
The full St Thomas’ study results are expected to be published in the coming months.
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References
1.Eurotimes, May 2023.
2. Rayner vigilance data on file, July 2025.
3. Ashmal J, Khayam N, Chun Fung JL, et al Twenty-Four month results of a prospective randomized control trial to measure posterior capsular opacification rates and visual outcomes following insertion of two monofocal, aspheric, acrylic intraocular lenses: the hydrophobic RayOne 800C and the hydrophilic RayOne 600C, presented at ESCRS 2025.
