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ICSC presenters outline tools to make scleral fitting easier, successful
New diagnostic tools and fitting techniques improve outcomes in challenging cases.
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The inaugural International Congress of Scleral Contacts, held in Miami, Fla., featured many of the world’s foremost experts on scleral lens technology and fitting and offered practitioners a rapid fire, interactive educational program. This event was the first international conference to be dedicated solely to the topic of scleral lenses.
Attendees at the International Congress of Scleral Contacts (ICSC) were experienced scleral lens fitters who came to elevate their knowledge and gain greater confidence in scleral lens fitting.
Scleral lens benefits and opportunities, dangers and risks, fitting and troubleshooting, and even physiological implications yet to be understood were all discussed in more than two dozen presentations and wet lab stations. Many clinical pearls covering a vast array of sophisticated scleral lens topics and complex clinical cases were shared.
EyePrintPro
One of the most innovative technologies in scleral lenses presented was EyePrintPro, developed by Christine Sindt, OD, FAAO, FSLS, and Keith Parker, NCLEC, which creates custom prosthetic scleral “shells.” ICSC attendees had the opportunity to see and even experience the impression molding process for creating these lenses. EyePrintPro is designed to precisely match the contours of the eye in patients with anatomical, visual or comfort challenges who cannot be successfully fit in traditional scleral lenses and patients willing to invest in custom lenses for an optimal wearing experience.
Beyond meeting patients’ basic refractive needs, these lenses can also incorporate optical prism or multifocal optics. While the cost of EyePrintPro lenses is significantly greater than that of traditional scleral lenses, Ryan McKinnis, OD, FAAO, pointed out that, relative to the cost of lost productivity for patients with visual impairment, there is tremendous value in this unique option. EyePrintPro-certified practitioners are accepting referrals across the U.S. and Canada.
Other new technology
Nathan Schramm, OD, CNS, FSLS, discussed other new innovations in equipment and lens material technology. New features in anterior segment OCT from Optovue, such as central assessment mapping, augment the scleral lens fitting process and aid in the assessment of lens vaulting and limbal clearance.
Hydra-PEG technology (Tangible Science), which is a lens surface coating that improves wettability, lubricity and deposit resistance, could be a “game changer” for anterior surface lens clouding according to Schramm.
Jan Bergmanson, OD, PhD, DSc, FCOptom, FAAO, FSLS, shared that researchers at the University of Houston have developed and patented a device to aid in the removal of an adhered scleral lens. Bergmanson pointed out that lens adherence and careful removal are especially important concerns in post-surgical patients where the corneal lamellae have been disrupted.
Screening children for keratoconus
Images: Arnold TP
Keratoconus is one of the most common indications for scleral lenses today. Andrew Morgenstern, OD, FAAO, and S. Barry Eiden, OD, FAAO, suggested screening for corneal ectasia in patients as young as 8 years and those with family members with keratoconus. They advised practitioners to keep in mind that the posterior corneal surface is always more involved than the front in keratoconus, so traditional placido disc-based topography may not be sufficiently sensitive.
Morgenstern noted that it is standard practice to screen pediatric patients for glaucoma, despite this condition having an extremely low incidence in children, yet pediatric keratoconus screening is almost unheard of. The incidence of keratoconus, Morgenstern said, may be about one in 750 — much greater than previously thought due to more sensitive diagnostic equipment available today — so more proactively screening young patients is worthwhile.
In addition to contact lens considerations for managing keratoconus, now that corneal collagen crosslinking (CXL) has been FDA approved for progressive keratoconus (and post LASIK ectasia), William Trattler, MD, reinforced the message that earlier screening, diagnosis and treatment with CXL can benefit keratoconus patients.
New approaches
Elevated lesions on the ocular surface, such as pingueculae in the periphery or Salzmann’s nodules in the interior, present obstacles in the path of a successful scleral lens fit. Shelley Cutler, OD, FAAO, challenged ICSC attendees to consider the Zenlens MicroVault design feature offered by Alden Optical. With this option, the fitter can precisely design the size, location and depth of a flute at the lens edge or dome within the lens to vault over these lesions.
Traditionally, oblate scleral lens designs were reserved for postsurgical cases or patients with scarring and oblate corneas. Langis Michaud, OD, MSc, FAAO(Dipl), FSLS, discussed the advantages of an “outside the box” fitting approach using oblate lenses on prolate corneas. Michaud pointed out that this can be helpful to lower the required minus power of the lens, improve presbyopic correction and minimize induced spherical aberrations.
Melissa Barnett, OD, FAAO, FSLS, reported that more than a dozen companies now offer multifocal lens options in scleral lens designs, allowing optometrists to better meet our presbyopic patients’ needs. Because scleral lenses tend to decenter temporally due to the architecture and elevation of the nasal sclera, Barnett noted that it is often necessary to decenter the lens optics or the lens itself to achieve visual success.
Lynette Johns, OD, FAAO, BCLA, FSLS, discussed the benefits of incorporating toric peripheral curves into scleral lens designs given that the shape of the sclera is not rotationally symmetric. Johns reported that 95% or more of her scleral lens patients are fit in lenses with toric peripheral curves to improve lens centration, alignment, stability and comfort and reduce excessive debris under the lens, all of which promote long-term success. Johns suggested that using spherical diagnostic lenses and noting the pattern of the fit across the landing zones allows the practitioner to appropriately flatten or steepen the meridians or quadrants necessary to achieve a successful fit. She also noted that if a patient is experiencing sectoral rebound hyperemia after lens wear, incorporating toric peripheral curves into the lens design will often help resolve this issue.
Benefits, risks of tear exchange
Several presenters discussed the potential opportunities and challenges of the scleral lens “bowl” and the limited tear exchange that occurs in scleral lens wear. Laura Periman, MD, noted that the lens bowl creates a microenvironment that we can leverage to our advantage therapeutically and that the minimal amount of tear exchange may be helpful by preventing inflammatory mediators from accessing the cornea. She suggested further consideration and research of the corneal protective effects of certain additives to the lens bowl beyond simply using nonpreserved saline solution.
Conversely, Kenneth Maller, OD, FAAO, FIAO, ABO, FAAOMC, pointed out that the isolation of the cornea and the lack of tear exchange behind scleral lenses also presents physiological concerns. Maller reported that, among other factors, scleral lens wear causes tear film nutrients to be withheld from the cornea, metabolic waste to accumulate on the corneal surface and a reduction in the normal corneal epithelial sloughing.
Maller also highlighted other “unknown” potential risks related to scleral lens wear, such as the compression of Schlemm’s canal, corneal or limbal stem cell stress associated with mechanical factors, reduced oxygen availability, the lack of tear exchange and the implications of conjunctival prolapse that are still not fully understood.
Potential dangers
John Gelles, OD, FIAO, FCLSA, addressed potential dangers of scleral lens wear, specifically in patients with a compromised corneal endothelium. He stressed the need to minimize lens thickness, use a high Dk lens material and minimize lens vaulting when fitting postcorneal transplant patients or any patient with a low endothelial cell count in order to optimize oxygen to the cornea and reduce the risk of corneal edema.
Gelles cited the Cornea Donor Study, which reported that endothelial cell loss occurs after successful corneal transplantation, and, by 5 years post-transplant, patients, on average, have well below 1,000 cells/mm2. He also referred to Eef van der Worp’s guideline that patients with endothelial cell counts below 1,000 cells/mm2 should not be fit in scleral lenses.
As one of the hottest optometric topics in both contact lenses and anterior segment disease management, scleral lenses can offer life-changing benefits to many patients and present unmatched professional rewards to practitioners. However, there is still much to learn about the physiological impact of these lenses, and the complexity of clinical cases continues to present challenges to fitters.
- Reference:
- Cornea Donor Study Investigator Group, et al. Ophthalmology. 2008;doi: 10.1016/j.ophtha.2008.01.004.
- Scleral Lens Education Society. www.sclerallens.org.
- For more information:
- Kerry Giedd, OD, MS, FAAO, practices at Eola Eyes in Orlando, Fla., and is a member of the Primary Care Optometry News Editorial Board. She can be reached at kerrygieddod@aol.com.
Disclosure: Giedd is a consultant to Bausch + Lomb, owner of Alden Optical.