Aug 01, 2023

What might I expect? The art of the artificial eye

A long, loving stare or a quick, angry glance, the eyes expose the unmasked emotional spirit. While able to give steely stares, physical eyes are the opposite, fragile and soft. If an eye is severely damaged, there is a slight possibility that repair is not possible. After determining that the organ must be removed for the patient's health, the physician may prescribe an artificial eye. Today's ocular prostheses so closely resemble natural eyes that it takes more than a glance to grasp the difference.

The use of artificial eyes is an ancient practice. Even thousands of years ago, the loss of an eye could result in "severe physical and emotional problems," Nagaraj Y. Putanikar et al stated in Journal of International Oral Health, April 2015. Although allowing no vision, an artificial eye buffered the stress. "First evidence for the replacement of (a) missing eye was obtained from the Egyptian dynasty, who used precious stones, earthenware, copper and gold."

Archeologists at a dig in Iran found the burial site of a young woman who had died nearly 5,000 years ago. Thought to be royalty or wealthy, the skeleton had "a prosthetic eye made of tar and animal fat in her eye socket," Lisa Katayama said in Wired, Dec. 28, 2006. An optometrist suggested that "the woman wore the fake eyeball for esthetic purposes."

Travel forward from antiquity to the mid-1900s, and prosthetics are less obvious. Peter Falk, the endearing actor portraying television's Lieutenant Columbo, lost his right eye to retinoblastoma, a rare childhood cancer, when he was three years old. Falk was given a glass prosthesis, and he developed his characteristic squint in that eye. Entertainer Sammy Davis Jr. was in a serious car accident in 1954, damaging his left eye. Davis wore an eye patch for several months then received a glass eye, using it for the rest of his life.

Tender and easily injured, eyes may receive destructive trauma in wartime, in accidents during activities or from diseases. Eye care has advanced — fewer eyes need removal now than a few decades ago. However, there are still those who need prosthetics. The artificial eye provides support and structure for bones and tissues around the ocular socket. It also enhances psychological confidence for the patient who has suddenly lost a crucial part of their body. (The surgical removal of the whole eyeball while leaving the eye muscles and eyelid is called enucleation.)

During the world wars, hundreds of Canadian soldiers lost eyes to battle wounds. Wartime injuries spurred innovation, and so did shortages due to conflict. Germany led the field in prosthetic eyes, but inventors in other countries were stymied owing to Second World War shortages. The specifically required sand with low iron oxide content used to make glass eyes could not be shipped to North American customers.

Substitutes were devised that didn't require glass. "The first synthetic eye prosthetics were made in 1943 by a team of three U.S. Army dentists, and ocularists built on their work," according to Stacey Barker et al in Material Traces of War: Stories of Canadian Women and Conflict 1914-1945 (Canadian Museum of History 2021). In Canada, First World War military veteran and ophthalmologist Dr. Clifford Taylor was investigating ocular prosthetics for wounded soldiers at the National Research Council in Ottawa.

The doctor hired Kathleen McGrath in 1941, an experienced nurse and lab technician. "Taylor and McGrath worked with new synthetic compounds to produce safe and accurate replicas of damaged eyeballs for returning veterans," Barker said. The team worked at Sunnybrook Hospital and Christie Street Veterans Hospital and also travelled across the country to fit patients with new artificial eyes. Over a five-year span, "the Canadian government had already provided over 800 ocular prosthetics to blinded servicemen through Taylor's clinic."

Artificial eyes are not round balls that pop in and out, such as the bedraggled sailor had in Pirates of the Caribbean movies. Polymers are formed into a custom-fitted shape — a somewhat flatter, extended oval — and designed to replicate a real eye.

Producing an artificial eye is an art. At about six to eight weeks after enucleation, when the eye socket has healed, the ocularist begins by making a mould of the eye socket. A small impression tray with a tube pointing outward is set into the socket. "Vinyl polysiloxane impression material (the same stuff used to get dental impressions)," is squeezed into the socket with a goop gun. (The materials may vary.) It may feel weird but does not hurt, and "after a few minutes, the impression is removed from the eye socket," described optometrist Dr. Amorette Hannah on Eyecing on the Cake in 2017.

A wax impression is made from the mould and placed in the socket to confirm that it is comfortable, or if it needs adjustments such as smoothing. Rechecking until the wax impression is the right fit to open and close the eye easily, "the ocularist shapes the wax to fill out certain areas around the eye socket so the eye has a natural look," according to "Making an artificial eye" at World Eye Cancer Hope.

The ocularist will next make the acrylic polymer eye from the fitted wax impression. Heated for a half-hour or more, the material is trimmed and carefully smoothed. The new prosthesis is inserted into the socket and the specialist will mark the eye alignment. Drilling a space, a button is put in, a piece that is close to the patient's original eye colour. The artistry begins.

Observing the patient sitting close by, the ocularist paints the iris to achieve depth and symmetry to match the working eye. Veins may be applied, made with red cotton thread. When the eye looks right, a coating of clear plastic is applied and heated again to set. Making small adjustments to ensure a natural gaze, the ocularist polishes the new eye and inserts it into the socket. Instructions on use and care will be given, and the work is done. The patient may still have a long road ahead to adjust to having only one eye, but they can be confident that wounds are not visible.

The field of Canadian ocularists is not crowded. To become an ocularist, 10,000 hours of training is required. This includes class time and working with a journeyman ocularist over five to seven years. Certification is usually required, through the National Examining Board of Ocularists in Iowa.

Technical innovations are changing prosthetic eyes. Among several advancements, scientists are investigating a dynamic iris and pupil with liquid crystal display, so the artificial eye seems to dilate and constrict with light, just like a real eye. Amazing.

Susanna McLeod is a writer living in Kingston.

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