With the large array of scleral lens options, choosing “the right” scleral lens fit set can seem daunting. Common questions that eye care professionals ask prior to ordering a set are: What diameter will I need? Why is one lens set better than another? Do I need to have multiple fitting sets in order to fit specialty lenses?
In general, it is safe to say that amongst all the lenses available, many will provide great options for your patients. There is not one perfect scleral lens fit set for all patients. Oftentimes, you will need a few different fitting sets in your office to manage a wide range of patient conditions.
Although this article is not a comprehensive list of factors to consider when purchasing a scleral lens fitting set, it does provide a starting point to find the best set for your office.
Basic Lens Designs
Start by considering what conditions you are trying to manage and how large the corneas are that you need to vault over. These two factors will help determine what initial diameter you may need.
Depending on whether you are trying to manage a patient with mild keratoconus vs. a Sjögren’s dry eye patient, you may decide to use lenses of different diameters. Often, using larger diameter lenses for dry eye patients is advisable to provide more coverage to protect and heal the ocular surface. This also helps if you are managing a more advanced keratoconus patient who requires greater sagittal depth and distribution of weight across the conjunctival surface.
Some manufacturers offer large and small diameter sclerals, while others have set sizes to choose from. With this in mind, you may need to have a few fitting sets in order to provide adequate options for your patients’ needs.
Consider corneal shape when deciding which lens set may be best for your patients. If your patient requires a flatter central curvature with a steeper mid-periphery, such as a post-corneal transplant or a post-radial keratotomy patient, it may be best to start with an oblate design rather than a prolate design to better contour the corneal shape and provide an equal distribution of clearance. However, not all lens designs may have the capability to customize shape from prolate to oblate or vice versa.
|Adding vaulting to a scleral lens can help with a pinguecula that interferes with proper alignment on the sclera.|
Advanced Design Options
Other key items to consider when selecting a scleral lens are the add-on options that are available. Often, a more advanced adjustment is necessary to provide an adequate fit and all-day comfort. Some examples that could be beneficial include:
• Toric peripheral landing curves: Allow for proper alignment-to-asymmetrical scleral shape by providing bitoric steep and flat meridians of curvature.
• Microvault or edge vault: Allows vaulting over peripheral elevations, such as pinguecula, pterygia or an irregular conjunctiva, that might interfere with proper landing on the sclera. This can be helpful to eliminate unwanted injection and irritation caused by compression of blood vessels.
• Quadrant-specific limbal and peripheral designs: Allow landing zone or limbal zone customization by flattening or steepening in a specified meridian.
• Limbal clearance adjustment: Allows limbal clearance modification without affecting the other lens parameters.
• Front surface toric: Allows for correction of residual astigmatism.
• Multifocal: Allows eye care professionals to fit presbyopic patients who have irregular or regular corneas.
Materials and Coatings
Materials may seem like a minor detail; however, not all companies carry the same materials. This is especially important if you want to order a higher Dk material to address corneal complications or one with Tangible Hydra-PEG (Ocular Dynamics) coating added.
Hydra-PEG is a permanent coating that can be applied to custom contact lenses. The Tangible Hydra-PEG coating is a 90% water, polyethylene glycol–based formulation incorporating two different polymers. The coating is designed to fill the microscopic pits on contact lenses and build up into a smooth, wet layer that is permanently bonded to the surface of the lens.
Hydra-PEG can be used to help extend comfortable wearing time in patients who remove and clean their lenses several times per day due to fogging or poor front surface wetting. This coating can also help prolong wear time in dry eye patients who get lens awareness or a gritty feeling after several hours of wear. Hydra-PEG is beneficial to patients with dry eye symptoms, front-surface depositing, lens fogging and general lens discomfort.1
By taking into account your patient’s eye condition and what lens material they may need, you can help avoid having to refit them into a different lens design.
Costs and Warranties
Although cost can be a big factor when deciding which scleral lens to choose, look at all lens features rather than fixating on pricing alone. Optometrists beginning to incorporate scleral lenses into their practice are advised to think about which features would work best for their patients. You will be able to manage patients with the best possible options in the shortest amount of time, saving money by minimizing follow ups and chair time.
When fitting specialty lenses, cost continues to be one of the greatest concerns for the doctor and the patient. What if the lens does not work out for the patient? What if we end up switching to a different lens design because the patient was unsuccessful with sclerals?
These are all valid concerns, but the great news is most companies offer 100% credit on patient cancellations. This gives eye care professionals peace of mind that if they encounter a roadblock during the fitting process, they will not be stuck with the cost of the scleral lens material. In general, most manufacturers offer a 90-day warranty with unlimited remakes during this period.
Technical consultants are available for most contact lens manufacturers to help assist you in achieving the best fit for your patient. They are a great resource for asking questions and to help you decide which lens changes are essential for your patient. During a practitioner’s first year of fitting scleral lenses, consultants will be the best resource for gaining knowledge and tips when working with their products. Consultants work with hundreds of doctors each year and have the greatest knowledge regarding common trends and troubleshooting.
Some manufacturers provide in-office training when purchasing their fitting set to assist doctors in fitting their first patients, providing them the opportunity to ask questions and learn side-by-side. This one-on-one training can be invaluable.
There are several factors to consider when selecting a scleral lens for a patient. This alone can appear overwhelming when first incorporating scleral lenses into your practice. The great news is regardless of your patient population, there are several scleral lens options from a variety of wonderful manufacturers across the country. Following these guidelines can help you build a steady foundation for sclerals in your practice and pick the best-suited fitting set for your patients.
1. Tangible Science. The science behind Tangible Hydra-PEG. tangiblescience.com/the-science-behind-tangible-hydra-peg/. March 16, 2018. Accessed August 6, 2019.