By: Alexis O’Neil
EN
What is an Ocular Prosthetic?
While many may picture a 'fake eye' as a marble-like structure that replaces the natural eye, ocular prosthetics actually resemble a thick, opaque contact lens or shell that covers the remaining structures in the eye socket. These prosthetics are crafted from a durable acrylic material, designed to be removable and adjusted within the eye socket. The prosthetic is traditionally hand painted to match the fellow eye, but new techniques using digital photography are currently being developed.
It's important to distinguish between a "prosthetic" and an "ocular implant". When patients undergoocular amputation, a round ocular implant is permanently placed deep into the eye socket by the surgeon2. This implant is often enveloped with living tissue or a synthetic cushioning material before insertion to prevent migration or eventual exposure over time. The goal of the ocular implant is to replace the volume lost by amputation and provide support and motility for the prosthetic. Once the eye socket has healed, the prosthetic
is custom fitted over the embedded implant.
Who requires an ocular prosthesis?
Ocular prosthetics are prescribed for patients who have undergone surgical removal of their eye with the intention to enhance comfort and improve ocular appearance. Ocular amputation is considered in cases of severe trauma, chronic pain from a non-functional eye, advanced glaucoma, and eyes with significant cosmetic issues. Removal may also be required in cases of treatment-resistant endophthalmitis as well as malignant cancers such as retinoblastomas and ocular melanomas.
There are two techniques for eye removal: enucleation and evisceration. Evisceration involves removing the inner structures of the eye, but leaves the sclera, extraocular muscles, and surrounding tissues intact. Meanwhile, enucleation entails removing the entire eyeball, leaving only the surrounding orbital structures. Evisceration is typically preferred in cases of severe trauma, while enucleation is commonly used for advanced cases of intraocular malignancy.
Prior to surgery, doctors explore all available treatment options and only use amputation as a last resortdue to potential complications and the emotional impact on the patient. Doctors must also carefully weigh the visual potential of the eye - if there is no possibility of restoring vision with treatment, removal might be the best course of action.
Who makes ocular prosthetics?
Surgical patients are typically referred to an ocularist 6-8 weeks after ocular amputation to allow for sufficient healing and stability in the eye socket. An ocularist is a skilled technician who specializes in the art and science of fitting prosthetic eyes. Their expertise lies in assessing the condition of the orbit, crafting and fitting a customized ocular prosthesis, and providing ongoing care.
During the initial visit, an ocularist takes precise measurements of the patient's eye socket and evaluates the orbital shape. The ocularist observes the eyelids, noting any anomalies that are present, and creates a mold of the eye socket. A uniquely shaped prosthetic is created to optimize eyelid positioning, enable transfer of movement, ensure a comfortable fit, and allow for symmetrical eyelid alignment. The prosthetic is meticulously matched to the coloration of the patient's iris and sclera of the fellow eye. Once the prosthesis is ready, the ocularist inserts it into the orbit, making any necessary adjustments to achieve a natural appearance. An ideal prosthetic will not exert pressure on the surrounding tissue and should move freely in all gazes – thus being very comfortable for the patient. Lastly, the ocularist educates patients on the proper handling, insertion, and removal, as well as the essential care routines for the prosthesis.
The job of an ocularist does not end at fitting the prosthetic – patients typically undergo long term follow up. Prosthetics require polishing 1-2 times a year due to stubborn deposits and fine scratches on the plastic surface. Additionally, the fit of a prosthetic will deteriorate over time with a lifespan of around 5 years. As orbital tissue atrophies, the eyelids narrow, and the prosthetic begins to migrate within the socket. This causes discomfort and diminishes cosmetic appearance; thus replacement becomes imperative over time.
Becoming an ocularist in Canada is not easy! One must complete an apprenticeship with an approved ocularist. The American Society of Ocularists (ASO) requires candidates to undergo five years or 10,000 hours of practical training on top of completing 750 course credits. When all requirements are fulfilled, candidates are awarded the distinguished title of "Diplomate of the American Society of Ocularists.” Despite the hard work required, working with ocular amputation patients is a rewarding and necessary profession!
BIBLIOGRAPHY
1. Raizada K. Ocular prosthesis. Contact Lens and Anterior Eye. 2007;30:152-162.
2. Rasmussen MLR. The Eye Amputated - Consequences of Eye Amputation with Emphasis on Clinical Aspects, Phantom Eye Syndrome and Quality of Life. Acta Ophthalmol. 2010;88:1-26. doi:10.1111/j.1755-
3768.2010.02039.x
3. Yousuf SJ, Jones LS, Kidwell ED. Enucleation and Evisceration: 20 Years of Experience. Orbit. 2012;31:211-215. doi:10.3109/01676830.2011.639477
4. Koylu M, Gokce G, Uysal Y, Ceylan O, Akıncıoglu D, Gunal A. Indications for eye removal surgeries. A 15-year experience at a tertiary military hospital. Saudi Med J. 2015;36:1205-1209. doi:10.15537/smj.2015.10.12031
5. Kondo T, Tillman WT, Schwartz TL, Linberg J V, Odom JV. Health-Related Quality of Life After Surgical Removal of an Eye. Ophthalmic Plast Reconstr Surg. 2013;29:51-56. doi:10.1097/iop.0b013e318275b754
6. American Society of Ocularists . https://www.ocularist.org/
7. Piercy R. Prosthetic Eye Fitting Methods. Published online November 2018. https://ocularpro.com/best-prosthetic-eye-fitting-methods/
