Prosthetic Eye - Indications, Types, and Complications

Introduction

A prosthetic eye, also known as the ocular prosthesis, is a custom-made or artificial eye used as a replacement for the natural eye after its loss. It primarily helps restore the esthetics and performs arbitrary functions of the eye.

What Are the Causes of the Loss of the Natural Eye?

The leading cause behind the loss of the natural eye include:

• Infections.

• Malignancies.

• Trauma.

• End-stage glaucoma.

• Fragmented eye.

How Is the Damaged Eye Removed?

The removal of the eye depends upon the severity of the situation. There are three surgical ways through which the natural eye is removed.

• Evisceration is a process in which all intraocular parts are removed by keeping the sclera, extraocular muscles, optic nerve, and cornea intact.

• Enucleation involves the removal of the globe and a part of the optic nerve. It is mainly performed in primary malignancies.

• Orbital exenteration is characterized by en bloc removal of the orbit and partial or complete removal of the eyelids. It is done in malignancies of the orbit.

What Are the Clinical Procedures Performed Before the Fabrication of the Prostheses?

The prosthesis fabrication is preceded by asking the patient about the time duration elapsed after eye removal and the cause of its removal.

• The socket is examined for proper healing.

• Patients are advised to wear a conformer before the arrival of the final prosthesis to help stabilize the implant.

• Temporary or stock trays are fitted till the fabrication of the permanent prosthesis.

What Is the Composition of Eye Prostheses?

The materials used for the fabrication of ocular prostheses are:

• Glass.

• Acrylic.

• Hydroxyapatite.

• Aluminum oxide.

• Polyethylene.

• Bioceramic.

What Are the Different Types of Ocular Implants?

The types of implants are categorized based on several criteria.

• Based on the Shape of the Implant, It Is of Two Types:

  • Oval.

  • Spherical.

• Based on the Type of Fabrication, It Is of Two Types:

  • Stock implants. Stock implants are ready-made implants given when there is a lack of time. It is cost-effective.

  • Custom implants. Custom-made implants are fabricated after making an impression.

• Based on Porosity, It Is of Two Types:

  • Porous or Integrated implants. Porous implants can allow the ingrowth of fibrovascular tissues inside the implant. It improves motility and comprises hydroxyapatite crystals, aluminum oxide, and polyethylene.

  • Non-porous or non-integrated implants. Non-integrated implants do not have special apparatus for attaching to the muscles, and they do not allow for the ingrowth of tissues. It includes acrylic, glass, and silicone implants.

How Does the Eye Prosthesis Work?

Eye prosthesis mainly provides esthetics and limited movement of eye movements. It also helps prevent the ingrowth of the ocular tissues into the empty socket.

How Are Artificial Eyes Placed Inside the Socket?

The surgery to place the implant is planned under general anesthesia.

• The structure surrounding the loose tissue covering the eye (conjunctiva) is opened, and the Tenon’s fascia is separated from the opaque white part of the eye (sclera).

• The rectus muscle is disinserted from the globe, followed by removal of the globe.

• The blood vessels and the nerve supply of the globe are cut.

• Bleeding is stopped by digital pressure, and the orbital implant is inserted.

• Antibiotics are administered before placing the porous implant. Porous implants are covered with a wrapping material (autogenous tissue, polyglactin tissue) to help reinsert muscles.

• Reattach the muscles over the implant and close the Tenon’s fascia.

• The conjunctiva is resutured.

• Import ocular conformer until the prosthesis is received (four to eight weeks).

How Are the Ocular Prosthesis Fabricated?

The fabrication of custom-made prostheses takes approximately six to eight weeks. The fabrication of the prostheses involve the following steps:

• Iris disc painting and packing.

• Wax scleral form is fitted.

• Wax model investment into dental stone.

• Investment of sclera into acrylic.

• Modification with artificial blood vessels.

• Prostheses finishing and polishing.

• Delivery of the prostheses.

What Happens Immediately After the Surgery?

Patient experiences pain, swelling, and nausea within seventy-two hours of surgery. Painkillers and anti-sickness medicines are prescribed for the same. The eyelids are sutured for two weeks over the implant.

Can Prosthetic Eye Placement Surgery Cause Any Side Effects?

Surgery of the prosthetic eye sometimes causes inflammation of the uvea or middle layer of the healthy eye. Although completely treatable, it can cause vision loss. Other common side effects include:

• Infections.

• Tightness of the eyes.

How Are Ocular Prosthesis To Be Handled?

The following are instructions given to patients with the prosthetic eye:

• Patients are instructed about the insertion and removal of the prostheses with digits or suction cups.

• The prostheses should be worn by the patient every day and night.

• Wash the prosthesis with tepid or soap water once a day.

• Mucus secretion may cause a feeling of foreign sensation. Hence the prostheses should be polished immediately.

• Annual polishing of the prosthesis is necessary.

• Remove any debris from the prostheses.

Are the Prosthetic Eye Permanent?

An adult needs to get his ocular prosthesis replaced once every five years. The conformer is changed every four to six weeks for neonates, depending on their growth.

What Are the Complications Associated With Prosthetic Eyes?

The most frequent complications linked to the placement of ocular prosthetics are:

• Mucous secretion.

• Posteriorly displaced eye.

• Rotating prosthesis.

• Displacement of the prosthesis.

• Protruding eyes.

What Practices Are to Be Avoided by Patients Wearing Eye Prostheses?

Patients wearing eye prosthesis should be cautious about the cleanliness and avoid the following practices:

• Leaving the prostheses anywhere.

• Lack of protective eyewear while diving or swimming.

• Exposure to alcoholic solvents.

• Unnecessary removal of the prostheses.

What Is the Prognosis of the Prosthetic Eye?

Replacing the eye with a prosthesis is a safe procedure with fewer complications.

Conclusion

A prosthetic eye is an artificial eye used to replace the natural eye lost for various reasons. Ocular implant placement is an uncomplicated process providing an excellent outlook at the end. Although a prosthetic eye improves the functional and cosmetic aspects of the eye, it also enhances the psychological well-being of a person.