The History and Culture of Scleral Lenses

What Are Scleral Lenses?scleral lens vs normal contact lens

Scleral lenses are used to help correct vision problems that are unable to be solved using standard contact lenses. A sclera lens resembles a large contact lens. Instead of resting on the cornea, a sclera lens is large enough to vault over the cornea and sits on the white part of the eye, known as the sclera, instead.

Scleral lenses are made from a permeable polymer material. These lenses are especially useful for patients whose cornea is unable to support the lens itself. The space between the cornea and the lens is filled with artificial tears.

An example of a scleral lens can be seen to the right with a regular contact lens for size comparison.

The First Scleral Lens

The first scleral lenses were made in the early 1880s from blown glass. By the 1920s, manufacturing techniques improved to permit them to be made from ground glass. In the mid-1930s, technology made it possible to take custom imprints and measurements of the eyes. Scleral lenses were made from polymethyl methacrylate during the 1940s and offered an increased level of comfort and precision. Gas-permeable scleral lenses were first manufactured in the 1980s as the first rigid version of the scleral lens and have remained in use to this day.

The Composition of the Human Eye

The human eye is a complex organ with a primary purpose is to process light. The rod and cone cells within the eye permit a person to differentiate between colors and to perceive depth. The human eye is capable of distinguishing approximately 10 million different colors. At birth, the eye is approximately 17 millimeters long when measured vertically. The eye reaches its full size by the age of 13.

The human eye is composed of three layers. The first layer, the fibrous tunic, is made up of the cornea and the sclera. The vascular tunic composes the middle layer and includes the ciliary body, the iris and the choroid. The third layer is the retina. These three layers include a fluid known as aqueous humor, the vitreous body and the flexible lens.

Symptoms Scleral Lenses Can Treatblack scleras in vial

Scleral lenses can be beneficial for individuals who suffer from light sensitivity and pain. Severe dry eye syndrome, Stevens-Johnson syndrome and aniridia are eye problems that are commonly treated with scleral lenses. Because of their larger size, scleral lenses are more difficult to insert and remove than their smaller counterparts. They can also feel more uncomfortable and are generally not worn for more than six hours at a time.

Scleral Lenses vs. “Sclera” Lenses

Scleral lenses should not be confused with “sclera lenses.” Sclera lenses are used as special effects in film-making and are also known as Halloween contacts, gothic lenses, “crazy contacts” and theatrical contact lenses. They can be used to change a person’s eye color to the blacked-out eyes seen in “Underworld” or to the amber and red colors of the “Twilight” movies. An example of sclera lenses can be seen to the right.

These lenses are not necessarily vision-correcting and should only be purchased from an authorized dealer with a valid contact lens prescription to avoid damage to your eyes.

Posted On: 26/02/2015 by Jackson Kernan