Impact of drug-eluting contact lenses on ocular surface health
Clinical trials evaluate corneal discoloration changes in patients.
Over the past decade, ophthalmic drug research and development has yielded exciting new delivery mechanisms, such as time-release implants and mucus-penetrating nanoparticles, that improve drug performance, minimize the effects side effects and reduce concerns about adherence to eye drop regimens. .
Contact lenses have been identified as a promising mechanism, with investigations of drug-eluting lenses for infection, dry eye disease (DED), glaucoma and allergies ongoing.1
The first drug-eluting contact lens was approved by the FDA earlier this year (Acuvue Theravision with Ketotifen [Johnson & Johnson Vision]), a daily disposable etafilcon that delivers the antihistamine ketotifen commonly used in allergy eye drops.
The effectiveness of the contact lens was comparable to that of eye drops.2 As this is a new drug delivery modality, during clinical studies of this lens, my colleagues and I compiled additional data to assess how the lens affects the integrity of the corneal epithelium during long-term daily wear (12 weeks).
We analyzed 2 clinical trials with identical, randomized, controlled multisite designs and involving more than 500 patients in total. The results, recently published in Clinical and experimental optometry, painted a promising picture for patients, practitioners and the future of this modality.3
Benefits of administering contact lens medication
Chronic use of eye drops is known to cause drug-induced conjunctivitis, which is red, irritated, and burning eyes after continued exposure to the ingredients in the eye drops, including the preservative.4
Discomfort not only affects patients’ daily activities and quality of life, but also discourages continued eye drop compliance because patients do not want to add more drops to already irritated eyes.5
When patients have this condition, corneal staining often reveals compromised corneal epithelial cell integrity, signaling that treatment needs to be adjusted to help the eye heal and prevent further damage.
Avoiding harsh chemicals in eyes susceptible to irritation, such as those compromised by allergies, is especially important for minimizing drug-induced conjunctivitis.
Frequent administration is often necessary because eye drops have poor bioavailability – only 5-10% of the drug is available at the ocular surface6– and are quickly washed away by blinks and tears.
Drug-eluting contact lenses offer multiple benefits that can eliminate some of the challenges associated with eye drops, including:
” Preservative free
Drugs are incorporated into the lenses during the manufacturing process, which also includes a sterilization step in an autoclave. They therefore do not require any preservative, such as BAK, which degrades the junctions between corneal epithelial cells. Each lens provides a sterile dose of medication.
» Longer residence time
A drug-eluting contact lens delivers the drug over several hours, so it has a much longer residence time on the ocular surface compared to eye drops, which wash off quickly. The diffusion-based release profile of a contact lens allows it to provide consistent dosing, rather than the frequent dosing required with some eye drops.
» Easy compliance
When medication is combined with vision correction in a comfortable etafilcon A daily disposable contact lens, patients don’t have to think about their medication schedule. This is an especially promising benefit for patients who struggle to stick to their schedule.
Ocular surface health with a drug-releasing lens
A drug-eluting contact lens can solve some of the problems associated with medication in the form of eye drops, but for eye care professionals the next logical question is: “What is the effect on the ocular surface of daily wear of a medicated lens?
My colleagues and I analyzed data from 2 identical safety clinical trials that lasted 12 weeks and enrolled a total of 560 contact lens wearers. The test lens was worn by 374 patients and a placebo lens by 186 patients.
Corneal staining with fluorescein was performed at baseline, then at 1, 4, 8, and 12 weeks of lens wear. At all visits, there was no statistical difference in staining between the drug-eluting lens group and the placebo group (95.86% and 95.88% grade 0, respectively, at 12 weeks). All stains were light or minute.
After 4 weeks of wearing, patients in both groups showed less corneal staining on average compared to baseline. This noticeable change may be due to patients switching from their usual contact lenses to the new material (etafilcon A, which has a high water contentseven) and/or Wear Program (daily disposable, which eliminates lens cleaning solutions from the equation). Compliance with study lens wear was similar between the two groups (approximately 92%).
In summary, in well-controlled, double-blind clinical trials with a large sample size, we can confidently conclude that this antihistamine-releasing contact lens does not have a significant impact on the integrity of the corneal epithelium. .
Integrate this modality into practice
Eyes wearing these drug-eluting contact lenses should be no different from eyes wearing non-medicated contact lenses – a critical factor in seamlessly integrating this modality into a practice.
Nothing about the lens fitting process or on-eye assessment is different. Patients just need a little more information about lenses, then they can get the vision they expect with extra eye allergy help.
The evidence that the addition of antihistamine did not increase corneal epithelial damage compared to standard contact lenses is encouraging as we consider further applications of the drug-eluting modality.