The term “eye removal surgery” encompasses several distinct surgical procedures, chosen based on the patient’s specific medical condition. The primary goal of these surgeries is to relieve pain, treat disease, or prevent a condition from spreading. The distinction between procedures lies in how much of the eye and surrounding tissues are removed, which directly influences the post-operative outcome and the fitting of an artificial eye.
Defining the Types of Eye Removal Surgery
The three main terms used by surgeons to describe the removal of the eye or orbital contents are evisceration, enucleation, and exenteration. Evisceration is the least invasive procedure, involving the removal of the internal contents of the eyeball, such as the iris, lens, and retina. The outer white shell of the eye, known as the sclera, and the eye muscles that control movement are intentionally left intact.
Enucleation is the surgical removal of the entire eyeball (globe), including the sclera and the optic nerve, which is severed behind the eye. The surrounding tissues within the eye socket, such as the eyelids and the extraocular muscles, are preserved. This technique provides the entire eye specimen, which is often necessary for pathological examination.
Exenteration is the most extensive and least common of the three procedures, reserved for severe cases. This surgery involves removing the entire eyeball along with the eyelids and most or all of the orbital contents, which includes the fat, muscles, and nerves within the eye socket. Exenteration is typically performed when a tumor has spread aggressively beyond the globe into the surrounding orbital tissues.
Evisceration Versus Enucleation
The choice between evisceration and enucleation depends heavily on the underlying medical reason for the surgery. For instance, enucleation is the procedure of choice when an intraocular tumor, such as an ocular melanoma, is present. Removing the entire globe ensures the complete resection of the tumor, and the intact specimen allows pathologists to confirm the diagnosis and check for any spread along the optic nerve.
During an enucleation, the six extraocular muscles that control eye movement are detached from the globe. These muscles are then reattached to a spherical orbital implant placed deep within the eye socket to restore volume. This reattachment transmits movement to the implant and, eventually, to the artificial eye.
Conversely, evisceration is preferred when the eye is removed due to chronic pain or severe infection, and cancer has been ruled out. Since the scleral shell and the attached eye muscles remain in their natural position, the procedure is less disruptive to the surrounding anatomy. This preservation allows the orbital implant to be placed inside the remaining scleral shell, which maintains the connection between the muscles and the implant.
The intact connection in evisceration often results in a better range of motion for the subsequent ocular prosthesis compared to enucleation. The evisceration procedure is also quicker and less invasive, which contributes to a faster initial recovery time for the patient.
Primary Reasons for Surgical Eye Removal
Surgical removal of the eye is undertaken when other treatment options have failed or are deemed unsafe. A primary indication is the presence of an intraocular tumor, such as ocular melanoma or retinoblastoma, where removal is a life-saving measure to prevent the cancer from metastasizing. Severe, irreparable trauma to the eye, such as a penetrating injury, is another frequent reason, especially when the damage results in complete loss of vision and structural integrity.
A common scenario involves a blind eye causing intractable pain that cannot be managed with medication. Conditions like end-stage glaucoma or a non-resolving infection, known as endophthalmitis, can lead to a chronically painful eye, making removal the best option for patient comfort.
Furthermore, enucleation is sometimes recommended following a severe eye injury to prevent sympathetic ophthalmia. This rare autoimmune condition involves the immune system mistakenly attacking the healthy, uninjured eye, potentially causing vision loss in the remaining eye.
Managing the Ocular Socket and Prosthetics
The process of restoring the appearance of the eye socket involves a two-part system: the orbital implant and the ocular prosthesis. The orbital implant is a spherical device, often made of materials like silicone or porous polyethylene, which is surgically placed deep into the socket immediately following the eye removal. Its purpose is to replace the volume lost by the removed eye, preventing a sunken appearance of the eyelid and face.
After the surgery, a clear plastic shell called a conformer is placed in the socket under the eyelids. This maintains the shape and size of the space during the initial healing phase. The conformer also helps prevent the tissues from shrinking, which is important for the later fitting of the artificial eye.
The ocular prosthesis, or artificial eye, is a custom-made, hand-painted shell that fits over the orbital implant. An ocularist, a specialist in creating and fitting these devices, meticulously paints the iris and pupil to match the patient’s natural eye color and size. Fitting for the final prosthesis typically begins about six to eight weeks after surgery, once the swelling has subsided and the socket has fully healed. The ocular prosthesis rests in the socket and moves in concert with the underlying implant, aiming to achieve a natural, symmetrical appearance with the healthy eye.