Specialty contact lenses are commonly referred to as custom designed lenses to correct vison problems caused by corneal irregularity. Examples of such condition include Keratoconus, pellucid marginal degeneration, post-laser-surgery ectasia, corneal trauma or some congenital corneal diseases. Because of corneal irregularity, light rays are no longer in point focus which leads to glare, halos, distorted images or impaired vision. These problems cannot be corrected by glasses or normal soft contact lenses.
There are two main types of specialty contact lenses: Corneal RGP Lenses and Scleral Lenses. RGP Corneal lenses sit on the cornea while scleral contacts are large-diameter lenses specially designed to vault over the entire cornea and rest on the white part of the eye (sclera). Both types of lenses artificially create a smooth regular front surface that acts as a new cornea to allow normal vision. The choice of lens type depends on your corneal condition and your personal circumstances. With the right design, both can provide unsurpassed vison in many patients.
Scleral contact lenses can also be used for people suffering from severe dry eye problem caused by conditions such as Sjogren's syndrome, graft-versus-host disease (GVHD) and Stevens-Johnson syndrome.
Hybrid lens is another type of specialty lenses. It combines a RGP centre with a bigger soft skirt resting on conjunctiva like normal soft contact. Although it provides more comfort for the wearer, cleaning process is more complicated due to the combination of two materials and it usually leads to more regular replacement.
Another use of specialty lenses is for patients with high prescription including high myopia, high hyperopia and high astigmatism.
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