Adding Scleral Lenses
A guide to facilitate the process, so you can quickly reap the rewards
Gregory W. DeNaeyer, O.D., F.A.A.O., Columbus, Ohio
A keratoglobus patient, like this one, who experience discomfort and instability with a GP lens, may achieve success with scleral contact lenses.
Does this article's title make you feel apprehensive? If you answered “yes,” I understand. The idea of adding any specialty contact lens to one's practice tends to result in this feeling, as “specialty” often has the connotation of “challenging” and “time-consuming.” But before you move to the next article, I'd like you to consider the following:
(1) Scleral lenses are now available in both comfortable and customizable designs, substantially facilitating their fit.
(2) Successfully fitting just one irregular cornea patient, for instance, results in several word-of-mouth referrals — the best form of marketing — for all types of eye care. These patients realize they're challenging, and thus, are very appreciative when you can meet their needs.
(3) Scleral lens patients are a profitable population. Cornea irregularity patients and those who have ocular surface disease (OSD), for instance, wear scleral lenses because of medical necessity. Therefore, you bill the professional fitting charge and contact lens material fee to their medical insurance. (The CPT-4 code for scleral lens fitting is 92313 - specify right, left, or OU. When fitting for keratoconus, use 92072. For materials, the V code is V2531.) The professional fitting charge and contact lens material fee is usually double that of standard fits/lenses.
(4) Armed with specific tips on how to add these lenses to your practice and market them, all covered in this article, that apprehensive feeling will give way to motivation and excitement.
1. List potential patients
Examine your patient records for the conditions that can benefit from scleral lenses. These conditions: corneal irregularity (e.g. keratoglobus, post-penetrating keratoplasty, etc.), and thus, possible discomfort and instability with corneal GP lenses, and severe dry eye (e.g. OSD, graft vs. host disease and Stevens-Johnson syndrome), as the scleral lens acts as a liquid bandage through its reservoir.1,2
More recently, scleral lenses have become available for high ametropia or presbyopia patients who have been unsuccessful with other lenses. Multifocal scleral lenses function best for patients who wear the lenses to correct ametropia. Patients who have corneal irregularity or ocular surface disease may not function well with multifocal scleral lenses if their vision is less than 20/20 with the best-fit lenses. This is especially true if the patient has corneal scars. The reason: Multifocal optics work best when the patient is 20/20.
|The solutions for the complications that can arise from scleral lens wear:|
► Bubbles. Make sure the lens is filled to the rim with saline. This allows for some spillage during application that won't lead to unwanted bubbles. If, however, the lens' fenestration is the source, reorder the lens without the fenestration.
► Vascular blanching. This indicates the lens is too tight. To improve haptic alignment, have the scleral lens company's lab consultant loosen the peripheral curves of the haptic section. In cases in which this occurs with a with-the-rule fit in a spherical back surface haptic scleral lens, fitting these patients in a back-surface haptic toric lens improves haptic alignment. Contact the scleral lens company's lab consultant to make the correct lens adjustments. Provide photos or ocular coherence images of the diagnostic lens to assist him/her.
► Edge lift. Areas of edge lift indicate the lens may need toric- or quadrant-specific peripheral curve adjustments as well.
► Elevated pingueculas and/or conjunctival blebs. Have the lab consultant bevel a notch into the lens' haptic section, allowing the lens to bypass these elevated areas. Provide photos and measurements of a pre-cut diagnostic lens to help the lab consultant custom adjust the notch and parameters for the lens order.
► Epithelial breakdown from corneal touch. Have the scleral lens company's lab consultant increase the sagittal depth by steeping the base curve, or piggyback the scleral lens onto a silicone hydrogel lens. To simplify lens care, prescribe a daily disposable lens.
► Lens flexure. This can result in astigmatism. If a sphere-cylinder over-refraction yields astigmatism, acquire over-keratometry or over-topography measurements to determine whether the astigmatism is secondary to lens flexure or is lenticular in nature. An astigmatic reading indicates flexure if you are using a spherical front surface scleral lens. In this case, reorder the lens 0.1mm and 0.2mm thicker to prevent flexure. A flexing scleral lens can result from uneven haptic bearing, so refitting the patient with a back-surface toric or quadrant-specific design may lessen flexure.
► Lens seal-off. Have the lab consultant loosen the fit by flattening the back-surface curves just beyond the optic zone. These curves correspond with the paralimbal area proximal to the cornea. Also, have him/her flatten the pe-ripheral curves just beyond the curve of initial flattening to help preserve the original lens profile. Flattening the peripheral curves results in sagittal depth loss, so you may need the lab consultant to steepen the base curve to compensate.
► Limbal bearing. Have the lab consultant steepen the limbal curves or increase the lens diameter to remedy this.
► Residual lenticular astigmatism. Have the lab consultant add front-surface toricity to the scleral lens to correct this. To prevent lens rotation, he/she ballasts the lens.
► Reservoir debris. Instruct these patients to remove their lenses and rinse and refill them with saline. Further, educate these patients that they may have to do this several times a day. One study suggests 49% of scleral lens patients must do this one or more times during the day.3 In patients who accumulate excessive debris, prescribe a scleral lens that has less vault, as a smaller reservoir holds less debris. Anecdotally, patients who wear toric back-surface haptic scleral lenses tend to accumulate less debris, probably because a toric design lessens gaps between the lens and sclera.
|Scleral lenses generally range from 15mm to 24mm in diameter and have optic, limbal and haptic zones. The lens must evenly bear on the scleral conjunctiva and fully vault the cornea, including the limbus, so it semi-seals to the eye to hold a fluid reservoir. Also, it shouldn't move upon blinking or saccades.|
To accomplish a successful fit:
► Select a cornea-vaulting diagnostic lens. Determine whether the anterior ocular surface is shallow, medium or steep via your naked eye or slit lamp. If it looks extremely steep, you'd choose a steep diagnostic lens.
► Fill the lenses with saline, and dip a fluorescein strip into the lenses' reservoirs to assess corneal vault. Use an off-label, non-preserved, single-use vial solution to avoid ocular toxicity and contamination, respectively. (Also, prescribe approved hydrogen peroxide products for lens cleaning and disinfection to prevent toxicity or hypersensitivity reactions that can result from residual preserved solutions in the lens' bowl. Prescribe an extra-strength sterile nonpreserved cleaning solution for patients prone to protein/lipid deposits.)
► Gently turn the patient's face parallel with the floor. This prevents the saline from spilling during lens application.
► Evaluate fit with diffuse cobalt light and a wratten filter. If you note central corneal touch, remove the lens, and apply a significantly steeper lens until you observe full vaulting. To estimate vault amount, turn the slit lamp-beam to a 45° angle, and use its white light to compare the fluorescein-highlighted fluid reservoir with the known thickness of the cornea or scleral lens. A scleral lens can settle into the scleral conjunctiva and lose approximately 150 microns of vault through 30-minutes. So, the initial clearance of a well-fit lens must be 250 microns to 500 microns. Next, evaluate the limbal zone with diffuse cobalt light. Lastly, use diffuse white light to observe the lens haptic.
2. Choose a design
Ask a specialty contact lens company with which you have an account whether it offers a scleral lens design and how, specifically, it could help the aforementioned patients. If you don't have such an account or you'd simply like additional “in the trenches” information, ask colleagues which scleral lens designs they prefer and why. You can do this by posting on Internet O.D. message boards.
Also, personally compare and contrast scleral lens designs by visiting the booths of specialty lens manufacturers at eyecare and specialty contact lens meetings and conferences. You can find such meetings and conferences by conducting an Internet search.
3. Acquire a fitting set
A scleral lens fit depends on vaulting the cornea rather than aligning with the anterior surface. Current instrumentation cannot directly translate anterior segment profile measurements into sagittal depth values for an empirical fit. Therefore, you must acquire a diagnostic fitting set (which contains a series of lenses in increasing sagittal depth) from the scleral lens company to successfully fit the lens.
4. Seek fitting workshops
Although the fitting principles across all scleral lens designs are generally the same, you should contact the scleral lens company and your colleagues who use the lens you've chosen to determine where to receive didactic education and hands-on workshops, as each design can have exclusive nuances.
5. Market the service
To garner additional patients who may benefit from scleral lenses:
► Contact corneal specialists in your area. Write letters to these specialists in which you educate them on how, specifically, scleral lenses may benefit their patients. Include with this letter your CV along with any scientific literature that reveals the benefits of scleral lenses.
► Highlight scleral lens fitting on your practice website. Be sure to include “Scleral Lens Fitting” under your “Services Provided” section on your practice website to alert patients that you provide this service. Also, include patient testimonials to emphasize to potential patients that you know what you're doing with regard to lens selection and fit.
► Contact corneal irregularity groups. Communicate with the National Keratoconus Foundation (www.nkcf.org) and the Stevens-Johnson Syndrome Foundation (http://sjsupport. org/) about adding your name to their list of medical professionals who can provide needed services.
On your way
The five steps outlined above, along with the user-friendly sidebars, which you should cut out to have on-hand, will facilitate the addition of scleral lenses to your practice, enabling you to quickly reap the aforementioned rewards of doing so. OM
1. Romero-Rangel T, Stavrou P, Cotter J, et al. Gas-permeable scleral contact lens therapy in ocular surface disease. Am J Ophthalmol. 2000 Jul;130(1):25-32.
2. Schornack MM, Baratz KH, Patel SV, Maguire LJ. Jupiter scleral lenses in the management of chronic graft versus host disease. Eye Contact Lens. 2008 Nov;34(6):302-5.
3. Visser ES, Visser R, van Lier HJ, Otten HM. Modern scleral lenses part II: patient satisfaction. Eye Contact Lens. 2007 Jan;33(1):21-5.
|Dr. DeNaeyer is clinical director for Arena Eye Surgeons in Columbus, Ohio and president of the Scleral Lens Education Society. E-mail him at firstname.lastname@example.org, or send comments to email@example.com.|