Enucleation is a surgical procedure involving the complete removal of the eyeball, or globe, from the eye socket, while leaving the surrounding tissues and eye muscles intact. This operation is a measure of last resort, typically reserved for cases where the eye is severely diseased, damaged beyond repair, or poses a significant risk to the patient’s overall health. The procedure’s goal is to remove the diseased tissue, provide pain relief, and prepare the socket for the eventual fitting of an ocular prosthesis, which is a custom-made artificial eye.
Medical Indications for Enucleation
The decision to perform enucleation is often driven by malignancy, irreparable damage, and intractable pain. Intraocular tumors, such as uveal melanoma or retinoblastoma, are a common indication, requiring removal of the entire eye to prevent the spread of cancer cells. In these cases, a section of the optic nerve is removed along with the globe to ensure all cancerous tissue is excised.
Severe ocular trauma, where the eye has sustained unrepairable structural damage and lost all visual potential, is another frequent reason for surgery. Enucleation is also indicated for eyes that are blind and persistently painful due to end-stage conditions like advanced glaucoma or chronic infection (phthisis bulbi).
A third consideration is the prevention of sympathetic ophthalmia, a rare inflammatory condition where the immune system attacks the remaining healthy eye following a severe injury to the other eye. Promptly removing the severely injured eye eliminates the source of inflammation, protecting the vision in the uninjured eye.
The Enucleation Procedure and Orbital Implant
The enucleation procedure is typically performed under general anesthesia and usually takes about an hour. The surgeon makes an incision in the conjunctiva, the clear membrane covering the white of the eye, and separates the four rectus and two oblique muscles from the globe. After the optic nerve is severed and the globe is removed, these eye muscles are preserved within the socket.
A spherical orbital implant is then placed deep within the socket to replace the volume lost. These implants are often made from porous materials like hydroxyapatite or porous polyethylene, allowing blood vessels and tissue to grow into them. The surgeon attaches the preserved eye muscles directly to the implant.
Attaching the muscles is essential because it anchors the implant and allows for the transfer of movement to the future ocular prosthesis, ensuring the implant functions as a mobile base. Once the implant is secured, the conjunctiva and Tenon’s capsule (a layer of connective tissue) are closed over the implant in distinct layers to provide proper coverage.
Immediate Post-Operative Care and Recovery
A pressure dressing is often applied for the first 24 hours following surgery to minimize initial swelling and bruising. Discomfort is managed with prescribed oral pain medication and antibiotics to prevent infection. Swelling and bruising are common and gradually subside over the next few weeks.
Before the patient leaves, a small, clear plastic shell called a conformer is placed behind the eyelids over the surgical site. The conformer maintains the shape of the conjunctival socket and prevents tissue contraction during healing. Patients receive specific instructions for wound care, including keeping the area clean and applying prescribed antibiotic drops or ointments.
Activity restrictions, such as avoiding heavy lifting and strenuous activity, are necessary for several weeks. Regular follow-up appointments monitor the healing process, check for complications like implant exposure, and determine when the socket is ready for the permanent prosthesis. The conformer typically remains in place until the first visit with the ocularist, usually six to eight weeks after the procedure.
Prosthetic Eye Fitting and Maintenance
Fitting the final, custom-made ocular prosthesis begins once the surgical site has fully healed, typically six to ten weeks post-surgery. This task is performed by an ocularist, a specialist who creates and fits artificial eyes. The ocularist takes a detailed impression of the eye socket to ensure the prosthesis fits comfortably and precisely.
The prosthesis is a thin, curved shell, not a full sphere, usually made of medical-grade acrylic despite the common term “glass eye.” To achieve a natural appearance and optimal cosmetic symmetry, the ocularist meticulously hand-paints the iris and sclera to match the color, size, and pattern of the patient’s remaining eye.
Although the muscles attached to the orbital implant allow the prosthesis to move in tandem with the natural eye, the extent of movement is usually limited. The pupil on the prosthesis is fixed and cannot dilate or constrict. For long-term care, the prosthesis generally remains in the socket and only needs to be removed infrequently, such as every few weeks, for cleaning.
Patients must visit the ocularist annually for professional cleaning and polishing to remove protein deposits. Because the eye socket can change shape over time, the prosthesis typically requires replacement every five to seven years to maintain a good fit. Regular check-ups with the ocularist and ophthalmologist ensure the continued health of the eye socket.