Treatment strategies for the management of keratoconus are expanding as new technologies are being developed. The choice of what treatment to consider is based on the severity of the disease. As stated previously, early or mild cases of keratoconus can be easily treated with traditional eye glasses. Many of these patients can achieve clear 20/20 vision with spectacles. New spectacle technologies that correct for what are termed “high order aberrations” that are common in keratoconus may play a role for slightly more advanced cases.
Soft contact lenses can be useful in many ways in managing the disease. Again, early and mild cases can achieve clear vision with standard soft contact lenses (including disposable soft lenses), but soft lenses can play more advanced roles in keratoconus management. Custom soft lens designs to treat moderately distorted corneas have been developed. They utilize increased thickness in the central optical portion of the lens to “mask” the irregularity of the cornea. Additionally, high oxygen transmission disposable soft lenses are used to “piggyback” rigid gas permeable lenses over them. This provides somewhat improved comfort in comparison with rigid GP lenses worn directly on the cornea, and also in some cases assists with the fit of the GP lens on these irregular corneas.
Rigid gas permeable contact lenses (RGP’s) provide optimal vision correction and can be designed to fit highly irregular corneas. RGP’s are available in many designs that are specific to fitting the keratoconic cornea. They do suffer from comfort problems and centering problems on some keratoconic eyes. Scleral contact lenses are very large diameter rigid gas permeable lenses. The advantage to these lenses is that they can fit very advanced cases of keratoconus since they “vault” the cornea and “land” or rest on the sclera (the white of the eye). Fitting of these types of lenses is very complex and only performed by limited numbers of contact lens specialists. Cost factors for scleral lenses is also quite high. As such, the fitting of these lenses is relatively limited.
Finally, hybrid contact lenses for keratoconus such as the ClearKone® and SynergEyes® KC designs have had a great impact on the treatment of keratoconus. Hybrid lenses provide improved comfort when compared to rigid gas permeable lenses; however they provide similar quality of vision correction. Developments in design and materials used to produce these lenses has dramatically increased success rates in keratoconus contact lens fitting.
Article Written by: S. Barry Eiden, OD, FAAO
President and Medical Director of North Suburban Vision Consultants, Ltd.
EyeVis Eye and Vision Research Institute
Immediate Past Chair of the Contact Lens and Cornea Section of the American Optometric Association
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