When first treating keratoconus often the first eye doctor to meet is a contact lens specialist. Other than glasses, contact lenses are perhaps the simplest method of correcting vision and often one of the earliest means of treating keratoconus. Since contact lenses come in many different designs, a contact lens specialist practitioner must be consulted to find the contact lens that offers the best combination of acuity, comfort, and corneal health. For patients with keratoconus, fitting a contact lens can be difficult. A contact lens specialist can therefore be very helpful in selecting the best contact lens to provide the highest level of acuity. In progressed cases of keratoconus, the cornea has become thin to the point where it bulges outward. A contact lens must be fit around this bulge and still maintain proper fit, comfort, centration, and acuity.
Standard rigid gas permeable contact lenses are the simplest fitting choice and are often able to achieve success in mild cases of keratoconus. Because of the spherical shape, rigid gas permeable contact lenses provide clear vision when fitted correctly. Often in these cases, the contact lens specialist will not need to be specifically trained in keratoconic lens fittings.
As more advanced designs are required, often a contact lens specialist will need to be found who specializes in keratoconus treatment. Aspheric shaped lens designs are sometimes necessary in cases of moderate and advancing keratoconus. These designs take into account the cone shape of the cornea caused by keratoconus. This lens will cover the apex of the cone allowing better fit. Because of the nonstandard shape of the lens, the contact lens must center well in order to correct a patient’s vision adequately.
Piggyback contact lenses are occasionally used by contact lens specialists to correct keratoconus. At times, a rigid gas permeable contact lens can be uncomfortable, especially for someone with keratoconus. Sometimes a hard contact lens is also unable to remain centered correctly to provide good vision for someone with keratoconus. In these cases, it is occasionally necessary to use two contact lenses simultaneously. A soft lens, often a silicone hydrogel, is placed directly on the eye. This helps maintain the cornea’s shape. A second lens, a rigid gas permeable contact lens, is then placed on top of the soft lens to help maintain the shape further and improve visual acuity further.
While keratoconus can be treated by a contact lens specialist during the early stages, there are some studies that indicate rigid contact lenses might hasten the onset of keratoconus. It has been suggested that the continual contact and rubbing from a contact lens weakens the collagen linking in the cornea and therefore exacerbates the onset of keratoconus. Despite these studies, contact lenses remain a popular treatment for keratoconus.
Be certain that your contact lens specialist has adequate training with keratoconus treatments and will refer you when your condition requires more advanced levels of treatment.