Scleral lens

A scleral lens, also known as a scleral contact lens, is a large contact lens that rests on the sclera and creates a tear-filled vault over the cornea. Scleral lenses are designed to treat a variety of eye conditions, many of which do not respond to other forms of treatment.

Uses

Medical uses

Scleral lenses may be used to improve vision and reduce pain and light sensitivity for people with a growing number of disorders or injuries to the eye, such as severe dry eye syndrome, microphthalmia, keratoconus, corneal ectasia, Stevens–Johnson syndrome, Sjögren's disease, aniridia, neurotrophic keratitis (anesthetic corneas), complications post-LASIK, higher-order aberrations of the eye, complications post-corneal transplant and pellucid degeneration. Injuries to the eye such as surgical complications, distorted corneal implants, as well as chemical and burn injuries also may be treated by the use of scleral lenses.

Sclerals may also be used in people with eyes that are too sensitive for other smaller corneal-type lenses, but require a more rigid lens for vision correction conditions such as astigmatism.

Special effects

A variant of scleral lenses that do not use reservoirs are commonplace as practical effects in films and television shows, and are used as part of costume design to represent characters with unusually-coloured eyes.

Eye movement measurement

In experiments in ophthalmology or cognitive science, scleral lenses with embedded mirrors or with embedded magnetic field sensors in form of wire coils (called scleral coils) are commonly used for measuring eye movements.

Design

Modern scleral lenses are made of a highly oxygen permeable polymer. They are unique in their design in that they fit onto and are supported by the sclera, the white portion of the eye. The cause of this unique positioning is usually relevant to a specific patient, whose cornea may be too sensitive to support the lens directly.