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ocular prosthesis, artificial eye or glass eye is a type of craniofacial prosthesis that replaces an absent natural eye following an enucleation, evisceration, or orbital exenteration. Someone with an ocular prosthesis is altogether Blindness on the affected side and has monocular (one sided) vision.
The prosthesis fits over an orbital implant and under the . The ocular prosthesis roughly takes the shape of a convex shell and is made of medical grade plastic acrylic. A few ocular prostheses today are made of cryolite glass. A variant of the ocular prosthesis is a very thin hard shell known as a shell which can be worn over a damaged or eviscerated eye. Makers of ocular prosthetics are known as . Ocularists are surprisingly rare: as of 2025, there were fewer than 200 certified practitioners in the United States, and only around three dozen in India.Dan Roche, "The Ancient Art and Intimate Craft of Artificial Eyes", The MIT Press Reader, August 4, 2025. [1]What Is an Ocularist: Definition & Responsibilities, Cleveland Clinic, October 4, 2024. [2]
Visual prosthesis are currently in research which could provide vision to the artificial eye.
It has a hemispherical form and a diameter of just over 2.5 cm (1 inch). It consists of very light material, probably bitumen paste. The surface of the artificial eye is covered with a thin layer of gold, engraved with a central circle (representing the iris) and gold lines patterned like sun rays. On both sides of the eye are drilled tiny holes, through which a golden thread could hold the eyeball in place. Since microscopic research has shown that the eye socket showed clear imprints of the golden thread, the eyeball must have been worn during her lifetime. In addition to this, an early Hebrew text references a woman who wore an artificial eye made of gold.Jerusalem Talmud Nedarim 41c [4] Roman and Egyptian priests are known to have produced artificial eyes as early as the fifth century BC constructed from painted clay attached to cloth and worn outside the socket. Frequently asked questions, American Society of Ocularists
The first in-socket artificial eyes were made of gold with colored enamel, later evolving into the use of glass by the Venetians in the later part of the sixteenth century. These were crude, uncomfortable, and fragile and the production methodology remained known only to Venetians until the end of the 18th century, when Parisians took over as the center for artificial eye-making. But the center shifted again, this time to Germany because of their superior glass blowing techniques. Shortly following the introduction of the art of glass eye-making to the United States, German goods became unavailable because of World War II. As a result, the US instead made artificial eyes from acrylic plastic.
Production of modern ocular prosthetics has expanded from simply using glass into many different types of materials. In the United States, most custom ocular prostheses are fabricated using PMMA (polymethyl methacrylate), or acrylic. In some countries, Germany especially, prostheses are still most commonly made from glass.
PMMA has a good degree of compatibility with human tissue, much more so than glass. Although various materials have been used to make nonintegrated implants in the past, polymethyl methacrylate is one of the implants of choice.
The surgeon can alter the contour of porous implants before insertion, and it is also possible to modify the contour in situ, although this is sometimes difficult.
Since their introduction in 1989 when an implant made from hydroxyapatite received Food and Drug Administration approval, spherical hydroxyapatite implants have gained widespread popularity as an enucleation implant and was at one point the most commonly used orbital implant in the United States. The porous nature of this material allows fibrovascular ingrowth throughout the implant and permits insertion of a coupling device (PEG) with reduced risk of inflammation or infection associated with earlier types of exposed integrated implants.
Hydroxyapatite is limited to preformed (stock) spheres (for enucleation) or granules (for building up defects).
One main disadvantage of HA is that it needs to be covered with exogenous material, such as sclera, polyethylene terephthalate, or vicryl mesh (which has the disadvantage of creating a rough implant tissue interface that can lead to technical difficulties in implantation and subsequent erosion of overlying tissue with the end stage being extrusion), as direct suturing is not possible for muscle attachment. Scleral covering carries with it the risk of transmission of infection, inflammation, and rejection.
A 2008 study showed that HA has a more rapid rate of fibrovascularization than MEDPOR, a high-density porous polyethylene implant manufactured from linear high-density polyethylene.
PP has been shown to have a good outcome, and in 2004, it was the most commonly used orbital implant in the United States. Porous polyethylene fulfills several criteria for a successful implant, including little propensity to migrate and restoration of defect in an anatomic fashion; it is readily available, cost-effective, and can be easily modified or custom-fit for each defect. The PP implant does not require to be covered and therefore avoids some of the problems associated with hydroxyapatite implants.
Aluminium oxide has previously been shown to be more biocompatible than HA in cell culture studies and has been suggested as the standard reference material when biocompatibility studies are required to investigate new products. The rate of exposure previously associated with the bioceramic implant (2%) was less than most reports on the HA or porous polyethylene implant (0% to 50%).
As of 2005 the newest model is the multipurpose conical orbital implant (MCOI), which was designed to address the issues of the postoperative anophthalmic orbit being at risk for the development of socket abnormalities including enophthalmos, retraction of the upper eyelid, deepening of the superior sulcus, backward tilt of the prothesis, and stretching of the lower eyelid after evisceration or enucleation. These problems are generally thought to be secondary to orbital volume deficiencies which is also addressed by MCOIs. The conical shape of the MCOI more closely matches the anatomic shape of the orbit than a spherical implant. The wider anterior portion, combined with the narrower and longer posterior portion, allows for a more complete and natural replacement of the lost orbital volume. This shape reduces the risk of superior sulcus deformity and puts more volume within the muscle cone. Muscles can be placed at any location the surgeon desires with these implants. This is advantageous for cases of damaged or lost muscles after trauma, and the remaining muscles are transposed to improve postoperative motility. In anticipation of future peg placement there is a diameter flattened surface, which eliminates the need to shave a flat anterior surface prior to peg placement.
Both implants (COI and MCOI) are composed of interconnecting channels that allow ingrowth of host connective tissue. Complete implant vascularization reduces the risk of infection, extrusion, and other complications associated with nonintegrated implants. Additionally, both implants produce superior motility and postoperative cosmesis.
Polyethylene also becomes vascularized, allowing placement of a titanium motility post that joins the implant to the prosthesis in the same way that the peg is used for hydroxyapatite implants.
Despite the reasoning stating that hydroxyapatite orbital implants without a motility peg would yield a superior artificial eye motility, when similar surgical techniques are used, unpegged porous (hydroxyapatite) enucleation implants and donor sclera-covered nonporous (acrylic) spherical enucleation implants yield comparable artificial eye motility. In two studies, there were no differences in maximum amplitude between hydroxyapatite and acrylic or silicone spherical enucleation implants, thus indicating that the implant material itself may not have a bearing on implant movement as long as the muscles are attached directly or indirectly to the implant and the implant is not pegged. The motility of a nonintegrated artificial eye may be caused by at least two forces:
Imbrication of the rectus muscles over a nonintegrated implant traditionally was thought to impart movement to the implant and prosthesis. Like a ball-and-socket joint, when the implant moves, the prosthesis moves. However, because the so-called ball and socket are separated by layers of Tenon's capsule, imbricated muscles, and conjunctiva, the mechanical efficiency of transmission of movement from the implant to the prosthesis is suboptimal. Moreover, the concern is that imbrication of the recti over nonintegrated implants actually can result in implant migration. The recent myoconjuctival technique of enucleation is an alternative to muscle imbrication.
Although it is generally accepted that integrating the prosthesis to a porous implant with peg insertion enhances prosthetic movement, there is little available evidence in the literature that documents the degree of improvement. In addition to this, although the porous implants have been reported to offer improved implant movement, these are more expensive and intrusive, require wrapping and subsequent imaging to determine vascularization and pegging to provide for better transmission of implant movement to the prosthesis, and are prone to implant exposure.
Age and size of the implant may also affect the motility, since in a study comparing patients with hydroxyapatite implants and patients with nonporous implants, the implant movement appeared to decrease with age in both groups. This study also demonstrated improved movement of larger implants irrespective of material.
Also under anesthesia:
The surgery is done under general anesthesia with the addition of extra subconjunctival and/or retrobulbar anesthetics injected locally in some cases. The following is a description of the surgical procedure performed by Custer et al.:
Living with an ocular prosthesis requires care, but oftentimes patients who have had incurable eye disorders, such as Microphthalmia, Anophthalmia or retinoblastoma, achieve a better quality of life with their prostheses. It is generally recommended to leave the prosthesis in the socket as much as possible, though it may require some cleaning and lubrication, as well as regular polishing and check-ups with ocularists.
Porous polyethylene (PP)
Development in polymer chemistry has allowed introduction of newer biocompatible material such as porous polyethylene (PP) to be introduced into the field of orbital implant surgery. Porous polyethylene enucleation implants have been used since at least 1989. It is available in dozens of prefabricated spherical and non-spherical shapes and in different sizes or plain blocks for individualized intraoperative customizing. The material is firm but malleable and allows direct suturing of muscles to implant without wrapping or extra steps. Additionally, the smooth surface is less abrasive and irritating than other materials used for similar purposes. Polyethylene also becomes vascularized, allowing placement of a titanium motility post that joins the implant to the prosthesis in the same way that the peg is used for hydroxyapatite implants.
Bioceramic
Bioceramic prosthetics are made of aluminium oxide (). Aluminium oxide is a ceramic biomaterial that has been used for more than 35 years in the orthopedic and dental fields for a variety of prosthetic applications because of its low friction, durability, stability, and inertness. Aluminium oxide ocular implants can be obtained in spherical and non-spherical (egg-shaped) shapes and in different sizes for use in the anophthalmic socket. It received US Food and Drug Administration approval in April 2000 and was approved by Health and Welfare, Canada, in February 2001.
Conical orbital implant (COI) and multipurpose conical orbital implant (MCOI)
The safe and effective sphere (still popular and easy to use) was supplemented with the pyramid or COI implant. The COI has unique design elements that have been incorporated into an overall conical shape, including a flat anterior surface, superior projection and preformed channels for the rectus muscles. 5-0 Vicryl suture needles can be passed with slight difficulty straight through the implant to be tied on the anterior surface. In addition, this implant features a slightly recessed slot for the superior rectus and a protrusion to fill the superior fornix.
Pegged (motility post) implants
In hydroxyapatite implants, a secondary procedure can insert an externalized, round-headed peg or screw into the implant. The prosthesis is modified to accommodate the peg, creating a ball-and-socket joint. After fibrovascular ingrowth is completed, a small hole can be drilled into the anterior surface of the implant. After conjunctivalization of this hole, it can be fitted with a peg with a rounded top that fits into a corresponding dimple at the posterior surface of the artificial eye. This peg thus directly transfers implant motility to the artificial eye. However, the motility peg is mounted in a minority of patients. This may partially be due to problems associated with peg placement, whereas hydroxyapatite implants are assumed to yield superior artificial eye motility even without the peg.
Implant movement
Implant and prosthesis movement are important aspects of the overall cosmetic appearance after enucleation, and are essential to the objective of crafting a lifelike eye similar in all aspects to the normal fellow eye. There are several theories of improved eye movement, such as using integrating prosthetic material, pegging the implant, covering the implant (e.g. with scleral tissue), or suturing the eye muscles directly to the prosthetic implant. The efficiency of transmitting movement from the implant to the prosthesis determines the degree of prosthetic motility. Movement is transmitted from traditional nonporous spherical implants through the surface tension at the conjunctival–prosthetic interface and movement of the fornices. Quasi-integrated implants have irregularly shaped surfaces that create an indirect coupling mechanism between the implant and prosthesis that imparts greater movement to the prosthesis. Directly integrating the implant to the prosthesis through an externalized coupling mechanism would be expected to improve motility further.
Surgical procedure
Enucleation and orbital implantation surgery follows these steps:
Aftermath of surgical procedures
Regardless of the procedure, a type of ocular prosthesis is always needed afterwards. The surgeon will insert a temporary prosthesis at the end of the surgery, known as a stock eye, and refer the patient to an ocularist, who is not a medical doctor, but board certified ocularist by the American Society of Ocularists. The process of making an ocular prosthesis, or a custom eye, will begin, usually six weeks after the surgical procedure, and it typically will take up to three visits before the final fitting of the prosthesis. In most cases, the patient will be fitted during the first visit, return for the hand-painting of the prosthesis, and finally come back for the final fitting. The methods used to fit, shape, and paint the prosthesis often vary to suit both ocularist and patient needs.
Notable people with prosthetic eyes
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