Like a hand searching for a glove, keratoconus eyes search for contact lenses that provide just the right fit.
Those who have lived with keratoconus for decades, or even a few years, have likely experienced different vision correction options including rigid gas permeable lenses, and the increasingly popular large-diameter scleral lenses.
Many KC patients find scleral lenses provide better vision, and are more comfortable since the edges of these lenses rest outside the cornea on the sclera (the white part of the eye). However, the art of finding a proper fit remains a challenge. Contact lens prescribers must take into account irregularities of the cornea surface and the shape, height, and location of the ‘cone’. The use of topography to create a map of a patient’s cornea shape has assisted greatly in identifying areas of concern in fitting KC patients. Knowing the irregularities of an eye, the contact lens fitter must use trial and error to find the best fit from among pre-manufactured lenses.
New technologies are constantly being applied to solving the problem of the “perfect fit”. EyePrintPRO is an impression technology that offers the latest attempt to plot the contours of a keratoconus eye. This very promising method was introduced in 2013.
The EyePrintPRO process consists of first making an impression of the eye using a tray filled media that creates an exact model of the front of the eye. The impression process takes only a few minutes to complete. One benefit is that the procedure can take place almost anywhere and no topographical instruments are needed. The impression is then sent to the laboratory at EyePrint Prosthetics where the model version is processed by a 3D scanner. Working from this 3D model of the eye, EyePrint designs and manufactures lenses that fit a patient’s unique ocular surface. The lenses are then shipped back to the practitioner.
Dr. Paul Blaze, OD of Coast Optometry in Huntington Beach, CA is a referral site. Dr. Blaze says, “I am excited about the new system for my hard-to-fit contact lens patients. I’ve fit these lenses on several patients who were unable to wear other scleral designs; I can obtain the perfect vault over the cornea with a soft landing on the sclera.”
In addition, Dr. Blaze notes that standard topography systems do not capture enough data to get precise information. Corneal topography will look at the central cornea (7 to 9 millimeters (mm) of the diameter). Since most scleral lenses have a diameter of 15-20 mm, the information about the peripheral part of the eye comes from the reflection of the tear layer rather than the actual ocular surface. The EyePrint impression process obtains information of the entire front of the eye (approximately 26 mm).
Since the scleral shell cover is manufactured for the individual, the cost of these lenses is higher than that of prefabricated scleral lenses. For some patients, it may prove to be worth the extra expense. EyePrintPRO is only available at selected locations. Please visit their website at www.eyeprintpro.com to learn more about this new technology and for provider locations.
You can find out more about Dr. Blaze and Coast Optometry at www.drblaze.com.