For many patients with Keratoconus (a condition of the cornea resulting in corneal thinning and irregular astigmatism) achieving satisfactory vision with glasses is difficult or even impossible. Without functional vision it may be difficult to perform simple daily tasks or do one’s job adequately. For these patients there are alternatives to glasses. Surgical intervention is one option but when not desired contact lenses should be considered.
This form of contact lens fitting is called medical lens fitting or medically necessary contact lenses. This type of fitting may or may not be covered by medical insurance so checking prior to the fitting is important as the fit and lenses are generally more expensive than fitting non-medical contact lenses.
There are different styles of lens fitting for keratoconus: soft lenses, rigid gas permeable lenses (RGP), piggyback (RGP over soft) and hybrid lenses. Soft lenses are generally only effective in very early stages of keratoconus and usually when glasses still provide adequate vision. In most cases some type of rigid material is needed to adequately cover the cornea and conceal the irregularity. RGP lenses may be worn alone or as a piggyback (RGP over soft lens). Hybrid lenses are another option as well. A hybrid lens combines an RGP lens with a soft lens into a one piece system versus the two piece system of a piggyback design. For more severe cases of keratoconus a special RGP lens called a scleral may be necessary. A scleral is a large diameter RGP lens that completely vaults over the cornea and rests onto the sclera (white of the eye).
All these lenses have pros and cons. A medical fitting consult with a specialist is necessary to determine the design that is right for you. The process can be difficult and lengthy but in the end the vision can be greatly enhanced leading to a better quality of life.