|NovaKone by Alden fits patients with irregular astigmatism.|
|The Duette by SynergEyes combines the comfort of a soft contact lens with the crisp vision of a GP lens.|
Scleral lenses may be the darling of the industry, but they’re not the only option.
In recent years, there’s been a boom in the specialty contact lens industry, largely attributed to an increase in scleral lens fittings. However, the innovation and growth within the market is not limited to sclerals. While this part of the market continues to grow, product cost, convenience of insertion and removal, along with fitting complexity, may form a ceiling limiting this intriguing design.
Fortunately, innovation in specialty soft and hybrid contact lenses has produced products that can rival the comfort and vision of scleral lenses. In other words, there have been advances within the contact lens arena that allow you to manage more difficult-to-fit patients. While scleral lenses have, of late, produced the most buzz, they’re not the only choice for GP-averse (gas permeable) or intolerant patients. Here’s a rundown of options””and opportunities.
Corneal ectasias such as keratoconus are conditions that optometrists are uniquely qualified to manage. Eyecare professionals (ECPs) have the knowledge to educate the patient regarding the course of the disease, co-manage surgeries such as corneal crosslinking, and fit contact lenses that keep patients from requiring more invasive procedures such as corneal transplants.
The Pentacam‘ from Oculus, Inc. and the GALILEIâ„¢ from Ziemer Ophthalmology use Scheimpflug technology to offer descriptions of the anterior segment that are not possible with placido-based topography. In addition to describing the shape of the anterior corneal surface, these products provide posterior corneal surface shape equations to detect ectasias, anterior chamber imaging, and a limbus-to-limbus display of corneal thickness.
This technology allows the optometrist to fit contact lenses, determine candidacy for refractive surgery, and thoroughly evaluate corneal disease using the most detailed information available.
CATERING TO ASTIGMATS
Patients with high levels of astigmatism (>2.75D) were formerly restricted to GP lenses to achieve spectacle-free vision. While these lenses provided great vision, corneal GP lenses took up to a month to adapt to and were very sensitive to environmental stimuli such as wind or dust.
Although the introduction of soft lenses improved comfort, the quality of vision for astigmats was limited by the powers and parameters available as well as rotational stability. Early custom soft lenses removed the limitation of parameter availability, but the custom soft lens materials that were available had minimal oxygen permeability and could lead to hypoxic complications with long-term wear. Breakthroughs in custom contact lens materials and hybrid lens technology offer new solutions for high astigmats and astigmatic presbyopes.
|This illustration from SpecialEyes portrays a toric base curve with machined edge and diagnostic mark.|
Custom soft lens manufacturers such as SpecialEyes offer custom soft contact lenses that can correct eyes with up to 25.00D spherical refractive error, 8.00D astigmatism, and can include multifocal designs. In fact, many laboratories that have traditionally offered exclusively GP lenses have begun offering custom soft lenses in a variety of materials. The definitive silicone hydrogel material from Contomac U.S., Inc. allows for custom lens production in a more oxygen permeable material.
Custom lenses can solve problems related to comfort, fit, or vision in eyes with unusual prescriptions, shapes, or sizes. Fitting these lenses offers a custom contact lens solution that won’t drain your chair time. The only measurements needed to order are the horizontal visible iris diameter (HVID), keratometry values, and manifest refraction.
The Duetteâ„¢ by SynergEyes‘ is a hybrid contact lens that combines the comfort of a soft contact lens with the crisp vision of a GP lens. Unlike older hybrid lenses, the Duette seamlessly combines highly oxygen permeable soft and GP materials into a more durable, comfortable contact lens. In addition to correcting astigmatism, the Duette Multifocal offers correction for patients suffering from astigmatism and presbyopia.
These lenses can be inserted and removed similar to a soft contact lens (in most cases) and can be cleaned using readily available and convenient contact lens solutions such as CLEAR CARE‘ by Alcon, and Biotrue‘ by Bausch + Lomb. To make things easier for you and your practice, SynergEyes allows for empirical ordering and no longer requires the return of lenses to receive credit for warranty replacement or discontinued fits.
Keratometry values and manifest refraction are the only measurements needed to get started. Keep in mind that the patient’s corneal astigmatism must be roughly equal to her refractive astigmatism to minimize residual astigmatism and provide crisp vision.
KERATOCONUS AND POST-SURGICAL CORNEAS
Corneal GP lenses are the most inexpensive and widely used form of correction for irregular corneas. Unfortunately, while your patients may love their vision with their GP lenses, discomfort and/or dryness can limit them from wearing the lenses as much as they’d like. Scleral lenses are not the only option for GP-intolerant patients. Specialty soft and hybrid lens designs can provide quality vision while maintaining comfort and convenience similar to traditional soft lenses.
NovaKone (Alden Optical) and Bausch + Lomb’s KeraSoft IC are soft lens designs available to fit patients with irregular astigmatism. While these lenses are handled and cared for like other soft lenses, the fitting process differs. Before you begin fitting these items, review the fitting process of the lens you have selected and discuss any questions with a laboratory consultant. This will save you time and help your practice’s bottom line.
For those patients with irregular corneas, the UltraHealth from SynergEyes is a hybrid lens design that works wonders. Like the Duette, the UltraHealth was designed with a silicone hydrogel skirt and a highly permeable GP center. To achieve success, the soft lens skirt comfortably centers the GP optic and the variable lift curves help the UltraHealth vault the cornea to minimize the progression of scarring. This lens must be filled with non-preserved saline prior to insertion, similarly to a scleral lens design. Although the Duettes can be ordered empirically, the UltraHealth hybrid lens must be fit using a diagnostic fitting set.
The specialty market, with its numerous changes, offers a host of options for those in your practice dealing with contact lens challenges. Custom soft and hybrid contact lenses can provide comfortable wear and crisp vision for normal and irregular corneas alike. Look into them. You””and your patients””will appreciate these new possibilities.
Alex Nixon practices at The Ohio State University College of Optometry in Columbus, OH, and at SouthWest Eyecare in Grove City, OH.
|WHERE TO FIND IT:|
|Alcon Laboratories, Inc.
|Alden Optical, Inc.
|Bausch + Lomb
|Contamac US, Inc.