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May 2017
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Slick Surface Solutions
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Although scleral lenses are miraculous in many ways, they can present with some unique challenges. One of the most frustrating challenges is non-wetting, or poor surface wetting, of the scleral lens anterior surface. This is relatively common during scleral lens wear and can result in suboptimal or “cloudy” vision.1 To distinguish between post lens reservoir fogging and anterior surface fogging, I ask my patients if the appearance is like oil on water (anterior surface) compared to a “milky” appearance (reservoir fogging). Sometimes lens fogginess occurs quickly after scleral lens insertion. Other times, lens fogginess worsens throughout the day. This non-wetting may decrease vision and diminish lens comfort, which increases chair time and costs for both the practitioner and patient.
Patients who are especially at risk for poor surface wettability are those with ocular surface disease including meibomian gland dysfunction, ocular rosacea, graft versus host disease (GvHD), Stevens-Johnson syndrome (SJS), and Sjögren’s syndrome, especially with filamentary keratitis. Exposure from previous eyelid surgery, a stroke or nerve palsy are additional risk factors for poor surface wettability. Makeup and oil based skincare products including lotions and makeup removers can also contribute to surface debris. Hand soaps with moisturizing agents and poor plunger hygiene may also worsen this problem.
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Treating the underlying condition will yield the best outcome for lens surface wettability. First, it is critical to aggressively manage patients with a poor tear film and/or meibomian gland function. Treatments include commercial eyelid cleaners, warm compresses, topical drops, antibiotic ointment, and/or oral antibiotics. Dietary changes such as omega-3 supplementation and reducing fried and fatty food may help. Education on proper lens care and plunger hygiene is crucial to obtain a clean scleral lens surface.
Verify that patients wash hands before handling scleral lenses and use mild hand soaps such as contact lens hand soap or acne treatment hand soaps. Confirm that patients are applying makeup after lens insertion. Avoid oil-based moisturizers to the eyelids and avoid any makeup applied to the inside area of the eyelid margin.
Changing to a hydrogen peroxide based disinfection solution is helpful to eradicate lens surface deposits. According to The Scleral Lenses in Current Ophthalmic Practice (SCOPE) study,2 the most common disinfection system recommended was a hydrogen peroxide based system 61%.2
Previous strategies to improve surface wettability include scleral lens removal, cleaning to eliminate deposits and reapplication. This may be time consuming and inconvenient. On-eye surface cleaning using a saline moistened cotton swab, eye shadow applicator or wet DMV applicator can be used to remove surface debris. Additionally, increased lubrication over the lens with preservative-free artificial tears over the lens throughout the day may be beneficial.
A novel treatment option is FDA approved Tangible Hydra-PEG, a 90% water PEG-based polymer mixture that is permanently bonded to the surface of the contact lens. Tangible Hydra-PEG encapsulates the lens, creating a mucin-like wetting surface which shields the lens from the ocular surface and tear film. Lenses treated with Hydra-PEG result in a surface with optimal wettability, lubricity, tear film stability, and resistance to deposits.3 In my practice, Hydra-PEG has been an amazing problem solver for patients experiencing dryness or discomfort associated with scleral lens wear. Patients are immediately more comfortable and report long lasting end of day comfort, without the need to remove lenses mid-day. Although Hydra-PEG can be used by any patient, good candidates are patients who produce a heavy amount of deposits, patients experiencing dry eye or discomfort with their current lenses, and scleral lens patients who experience lens fogging.
| Figure 1. Scleral lens surface prior to Tangible Hydra-PEG. |
Figure 2. Scleral lens surface after Tangible Hydra-PEG. |
| Images courtesy of Tangible Science. |
Patient education on lens handling, even for existing scleral lens wearers, is imperative since Hydra-PEG results in a more “slippery” scleral lens. It is important to avoid tap water and abrasive or alcohol-based solutions. Lenses are cleaned daily with a multi-purpose or peroxide based solution.
Fortunately, we now have remedies for a slick scleral lens surface. Happy fitting!
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Reference(s):
1. Barnett, M, Toabe, M. Scleral Lens Care and Handling for Scleral Lenses: Understanding Applications and Maximizing Success. Supplement for Contact Lens Spectrum. October 2016.
2. Harthan J, Nau CB, Barr J, Nau A, Shorter E, Chimato NT, Hodge DO, Schornack MM. Scleral Lens Prescription and Management Practices: The SCOPE Study. Eye Contact Lens. 2017 Apr 6. [Epub ahead of print]
3. Walker, M, Redfern, R. Scleral lens surface coating improves vision and comfort. Poster presented at the 8th International Conference of the Tear Film and Ocular Surface Society (TFOS); September 2016. Montpellier, France.
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Dr. Melissa Barnett is a Principal Optometrist at the UC Davis Eye Center in Sacramento, specializing in anterior segment disease and specialty contact lenses. Dr. Barnett is the Immediate Past President of The Scleral Lens Education Society. She lectures and publishes extensively on topics including dry eye, anterior segment disease, contact lenses and creating a healthy balance between work and home life for women in optometry.
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