Contact Lens Care & Compliance
Contact Lens Care & Compliance
Scleral GP Lens Preparation: The Latest Standard of Care
BY SUSAN J. GROMACKI, OD, MS, FAAO
Scleral GP contact lenses represent one of the fastest-growing contact lens designs and are especially beneficial for patients who have diseased or surgically repaired corneas. While these patients require the optics of a rigid lens, the inevitable corneal bearing of a small-diameter GP lens can have devastating consequences, both short- and longterm (Korb, 1982).
Scleral lenses protect the cornea by completely vaulting over it, landing on the bulbar conjunctiva/sclera. As a result, they need to be filled with ophthalmic solution before application to prevent air bubbles between the cornea and the lens.
Filling Scleral Lenses
A comprehensive survey from three years ago (van der Worp, 2010) illustrated that practitioners were recommending various solutions for this purpose. However, as scleral lens fitting has become more prevalent, we have learned more about how to optimize their performance and preserve corneal health. The preparation and care of these lenses contribute greatly to their on-eye success. For filling the lens before application, a standard of care is quickly emerging: nonpreserved, unit-dose 0.9% sodium chloride inhalation/irrigation solution.
The most important characteristic of this solution is that it has no preservatives or active ingredients. Because scleral lenses provide minimal tear exchange, any substance behind the lens has a longer contact time with the cornea as compared to corneal contact lens wear. Thus, it is wisest to refrain from exposing the cornea to preservatives or buffers that may induce allergic or hypersensitivity reactions.
Larger (e.g., four-ounce) bottles of nonpreserved saline typically contain buffers, which can contribute to debris or mucin beneath the lens (Baylus, 2013). In addition, touching the tip of the container to any surface can cause contamination of the bottle’s contents; and the larger the bottle size, the less likely that patients will comply with discarding it.
More on Unit-Dose Saline
Unit-dose saline solution is available in 3ml or 5ml vials from a pharmacy or online at www.amazon.com/Addipak-Vials-sterile-solution-inhalation/dp/B000K6WHEG. It is by definition a non-prescription item (Gromacki, 2013), but some pharmacies require one anyway. Also, writing a prescription not only can ensure insurance coverage, it also can educate pharmacists on scleral lenses. It must be noted that the use of this solution, in addition to anything else used to fill a scleral lens, is considered off-label in the United States. Patients should be advised not to soak their lenses overnight in nonpreserved saline, as it provides no disinfection capability (van der Worp, 2010).
Other nonpreserved fluids can be used to fill scleral lenses, particularly for troubleshooting purposes. For example, an artificial tear may benefit dry eye patients or provide extra lubrication and corneal protection for patients whose lenses may exhibit areas of touch or minimal clearance (Byrnes, 2013). In addition, Refresh Celluvisc (Allergan) can be used to partially or completely fill a lens in an attempt to prevent solution loss upon application. Its increased viscosity helps prevent spillage (DeNaeyer, 2011).
Although research will one day likely produce a solution that is more biocompatible and more similar to the tear film, unit-dose, nonpreserved saline is the best option we have at this time, and it works well for most patients. CLS
For references, please visit www.clspectrum.com/references.asp and click on document #216.
Dr. Gromacki is a diplomate in the American Academy of Optometry’s Section on Cornea, Contact Lenses and Refractive Technologies and practices in Chevy Chase, Md.
Contact Lens Spectrum, Volume: 28 , Issue: November 2013, page(s): 25