By Clark Chang, OD, MSA, MSc, FAAO
June 17, 2015
Offer services that your competition does not offer, by prescribing hybrid contact lenses that provide keratoconus patients with comfort and long-term visual acuity.
KERATOCONUS OCCURS MORE FREQUENTLY THAN EXPECTED. Keratoconus may affect as many as 2.5 percent of patients; be prepared to serve the needs of those affected.
MAKE PROGRESS ON PROGRESSION. Several corneal cross-linking techniques currently under study have been shown to slow the progression of keratoconus and delay the need for corneal transplants; patients undergoing corneal cross-linking will still need vision-care solutions, however.
MANAGE HYBRID HOPES. Hybrid contact lenses offer keratoconus patients the optics of GP lenses but with enhanced comfort. This means shorter adaptation, and patients report better vision and quality of life.
Keratoconus is a degenerative, bilateral, asymmetric, and noninflammatory corneal disorder with a previously established prevalence of approximately 1/2000 or 0.05 percent among the general population. However, recent epidemiology studies have reported prevalence rates as high as 2.5 percent in different regions of the world. Progression of the disease leads to mishapening and gradual thinning of the cornea, causing irregular astigmatism and corneal scarring, which may ultimately necessitate corneal transplantation in as many as 20 percent of these patients.
In 2015, SynergEyes expanded its hybrid contact lens products to include a new lens for post-refractive patients, UltraHealth FC (flat curve).
This new lens offers similar GP vision and patient satisfaction benefits of UltraHealth while maintaining a straightforward and dependable fitting approach. UltraHealth FC is ideal for post-RK, post-LASIK and other cornea conditions where a vaulted lens design with more peripheral clearance and an oblate base curve is preferred. With UltraHealth FC, practioners can now reach beyond the keratoconus patient and offer a hybrid lens option to a broader patient base.
SynergEyes is a world leader in the specialty contact lens market offering a hybrid contact that promotes eye health while providing GP vision and soft-lens comfort.
More information is available at synergeyes.com/professional.
Historically, the primary goal of eyecare professionals treating keratoconus has been to preserve the visual function of those afflicted for as long as possible—with penetrating keratoplasty considered inevitable as the condition progresses. The current management paradigm, however, emphasizes early disease detection and keratoconus stabilization. Not only does this new clinical approach defer or potentially reduce the need for penetrating keratoplasty, but it also allows patients to maintain their best visual potential with spectacles and/or contact lenses. These management goals have been realized in many cases due to the advent of corneal cross-linking and the breakthroughs in specialty contact lens platforms such as the UltraHealth hybrid lenses from SynergEyes.
Corneal cross-linking is a new medical treatment that is still being evaluated here in the US for approval by the Food and Drug Administration as an indicated intervention for keratoconus and post-LASIK ectasia. I practice in a referral-based irregular cornea clinic and nearly 90 percent of my patients have keratoconus. As a result, our practice continues to serve as one of the largest clinical trial sites for ongoing corneal cross-linking investigations.
There are many corneal cross-linking techniques currently being studied; as yet, we don’t know which of these approaches achieves the most optimal results. In general, the procedure combines ultraviolet-A (UVA) light and riboflavin (photosensitizer, vitamin B2) to foster enhanced biomechanical properties within the corneal stroma. Although chemical bonds between collagen fibrils within corneal stroma have been proposed as a possible source of improved corneal rigidity, the exact location(s) of these induced “cross-links” still remain unclear.
Since 2008, our center has worked extensively with the corneal cross-linking technique known as the Dresden Protocol, which involves the removal of epithelium in the central 9mm area and allows riboflavin to better penetrate the stromal tissue. After riboflavin saturates the stromal tissue, focalized corneal exposure to UVA light (365nm) is used for a total duration of 30 minutes. Thus far, this approach has proved safe and effective at arresting or slowing keratoconus progression in 97 percent of the patients at our study site. In recent years, we have also studied the transepithelial cross-linking approach and found comparable clinical success in our patients.
We have opted to fit many of these patients in hybrid lenses such as UltraHealth, both before and after corneal cross-linking. This is made possible because of the combination of superior gas permeable (GP) lens optics and improved comfort afforded by the new hybrid technologies. In the past, of course, our specialty contact lens of choice for keratoconus patients were GP lens designs, which offered excellent optics. However, many patients fitted with GP lenses experienced higher levels of associated discomfort during the adaptation period, as the lens material exerts pressure on the corneal tissue, which is highly sensitive due to its exquisite innervation. In some cases, many of these patients would opt to have corneal transplant surgery earlier because of their frustration with GP lens adaptation.
The hybrid lens’ GP center maintains the advantage of excellent GP optics while the reverse geometry designs incorporated in its GP center and soft skirt allow for enhanced corneal vaulting capacity—these complementary features yield a lens platform with improved patient comfort and better lens alignment with one’s visual axis. As a result, not only can patients achieve excellent visual outcome, but also the adaptation period is often smoother and shorter.
Studies comparing visual performance of GP lenses to hybrid lenses in keratoconus patients have shown that these patients often report higher overall visual quality and satisfaction with hybrid lenses, which likely attests to the improved comfort achieved. This has significant impact to the quality of life in these keratoconus patients. In addition to demonstrating the importance of good visual acuity in keratoconus patients, the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study has also shown that subjective mental health scores in these patients to be between those of Stage III and Stage IV macular degeneration patients. Thus, through earlier diagnosis and treatment with corneal cross-linking and hybrid contact lenses, we have been able to intercept the downward spiral of this disease and keep our keratoconus patients both healthy and happy.
In addition, because Intacs are designed to manage irregular corneal optics, we have also found success in utilizing these devices as part of our treatment plan. Intacs can be implanted before or after cross-linking and the two procedures effectively complement each other to improve post-operative prognosis in keratoconus patients. Similarly, scleral GP lenses can provide higher corneal vaulting capacity, which also make them an effective treatment option, especially when more corneal clearance is desired from the best-fitting UltraHealth lens. In addition, patients with concurrent ocular surface disorders may also benefit from the fluid reservoir afforded by these scleral GPs.
Cross-linking is awaiting FDA approval in the US, and not all patients feel comfortable with this approach as such. In general, if a qualified candidate elects to defer cross-linking treatment, we focus our management efforts on disease progression monitoring, as well as visual rehabilitation with the goal of maximizing quality of life. In most cases, specialty contact lenses such as UltraHealth are the best treatment options for these patients, provided that proper lens fitting and satisfactory patient comfort can be obtained.
Any way you look at it, specialty contacts are a vital component of disease management in patients with keratoconus. As such, if you are treating these patients, you need to make these technological advancements part of your practice. Their use has been associated with improved outcomes, and increased patient satisfaction and quality of life, which can only help to grow your practice in the long run.
Clark Chang, OD, MSA, MSc, FAAO, is Director, Specialty Contact Lens Service at Cornea and Laser Eye Institute-Hersh Vision Group in Teaneck, New Jersey. In addition to being President of New Jersey Academy of Optometry, he is also an advisory board member at International Keratoconus Academy for Eye Care Professionals (IKA), Optometric Council on Refractive Technology (OCRT), and Gas Permeable lens Institute (GPLI). He is a subinvestigator in many ongoing clinical trials and has published multiple articles on keratoconus and specialty contact lenses. To contact him: email@example.com.