Orbital implants and Artificial Eyes
When an eye is removed, an orbital implant is used to replace the area in the orbit (eye socket) that was occupied by the eye. This spherical implant maintains the natural structure of the orbit and provides support for the artificial eye. The implant itself is not visible. An artificial eye (prosthesis) is used to restore the natural appearance of the eye and surrounding tissues (Fig. 1). Artificial eyes are usually made of plastic (acrylic). Custom artificial eyes are hand-crafted by highly skilled ocularists to precisely match the look of the natural eye.
While artificial eyes have been made for thousands of years, the first orbital implants were developed about 100 years ago. These spheres of glass or gold were later replaced by plastic or silicone spheres. Until recently, the basic design of these "first-generation" implants had changed little.
The need for a better implant
The first-generation implants were a major improvement for those having an artificial eye but they were unable to deliver natural movement to the artificial eye. This lack of movement was a major obstacle to restoring a natural appearance. The first-generation implants also tended to drift (migrate) in the orbit and were often rejected (extruded) by the tissues of the body, making further surgeries necessary. These problems inspired researchers to search for a better orbital implant.
Hydroxyapatite: the natural choice
The goal of a more natural appearance was finally achieved with the help of a natural material: ocean coral. A remarkable similarity was noticed between the porous structure of certain coral species and that of human bone. Soon after this discovery, a method was developed to modify the mineral in coral to match that of human bone, known as hydroxyapatite (abbreviated HA). This new, naturally derived material has both the porous structure and the chemical structure of human bone.
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Human Bone (magnified) |
Hydroxyapatite (magnified) |
Thus, the tissues of the body will accept and grow into these hydroxyapatite implants, and essentially become a "living" part of the body.
The first hydroxyapatite orbital implant
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| Bio-eye orbital implant after tissue ingrowth (optional peg shown). |
The first orbital implant made of hydroxyapatite was implanted in 1985, after several years of preliminary research. The eye muscles can be attached directly to this implant, allowing it to move within the orbit just like the natural eye. Some of this movement is automatically transferred to the artificial eye, which fits over the implant. If greater movement is desired a peg (Fig. 4) can be used to connect the artificial eye to the implant. In this way, even the small, darting movements of the natural eye can be delivered directly to the artificial eye. The result is a more natural looking artificial eye that can be difficult to distinguish from a natural eye.
The Bio-eye Hydroxyapatite Orbital Implant
This unique, patented implant was released by the US Food and Drug Administration (FDA) in 1989. Today, over 25,000 people worldwide have benefited from this natural alternative, which is now known as the Bio-eye Hydroxyapatite Orbital Implant, or simply the Bio-eye implant. In addition to natural eye movement, the Bio-eye orbital implant offers many less obvious benefits. It reduces implant migration and extrusion, which were common with the first-generation implants, and it can prevent drooping of the lower lid by lending support to the artificial eye via a peg connection. These are important benefits that can eliminate the need for further corrective surgery and an unsatisfactory appearance. The benefits of natural movement and fewer long-term problems have made the Bio-eye orbital implant the implant of choice among leading oculoplastic surgeons worldwide.