Overview of Enucleation
Enucleation is a medical term for a procedure that involves the removal of the entire eye, severing all parts that connect it to the eye socket, including a cord called the optic nerve. This operation, one of the oldest in the field of eye care or ophthalmology, can trace its origins back to 2600BC.
Deciding to proceed with enucleation can be a tough choice and a sensitive topic to discuss with the patient. This procedure is primarily considered in cases involving severe eye trauma, a painful or blind eye that affects appearance, eye cancer, or when the eye is donated. There can be substitutes like evisceration (removing the eye’s contents) or exenteration (removing the eye and some surrounding tissues), depending on the eye’s state and specific diagnosis.
Dealing with the empty eye socket after the operation can be a difficult task, and it’s crucial to decide on the type of implant and the wrapping material before the operation. These materials could be man-made, patient’s own tissue, or sourced from an eye bank. While some patients could benefit from a peg (a small rod) placement for better post-operation eye movement and appearance, this practice is generally avoided nowadays due to potential complications such as infections, exposure, discharge, and peg loss.
The goals of enucleation are to eliminate the diseased tissue, increase patient comfort, fill the eye socket space, and achieve the best possible functionality and appearance for the patient afterwards.
Anatomy and Physiology of Enucleation
Successful treatment after removing an eyeball, technically known as enucleation, relies on a few factors. These include replacing the space left in the eye socket, forming a new lining in the socket with membranes, getting a well-fitted artificial eye, and having good-looking and working eyelids. Sometimes, when the blood flow and metabolism in the eye socket decrease, it can lead to a condition with features known as post-enucleation socket syndrome (PESS). Conditions like orbital fat atrophy (loss of fat in the eye socket) and cicatricial orbitopathy (a scar-like condition of the eye socket) can occur. There may also be damage to the tear producing system, leading to a dry eye socket or issues retaining an artificial eye.
To figure out the right size for the artificial eye, doctors use a method called sizers to guess the size. The size of an adult eyeball can range from 6.9 to 9.0 mL, with lengths averaging between 21 mm to 29 mm. Doctors, considering the size of the removed eye or the size of the healthy eye, provide personalized sizes of artificial eye. Treatment can be even trickier for children, as their eyes haven’t yet reached full size. A child’s eye reaches about 85% of its full size by the age of two and grows about 1% per year until maturity. Therefore, children might need to switch to a larger artificial eye as they grow. However, using larger artificial eyes (16 to 20 mm in size) during the initial treatment may limit the need for future replacements as the child grows.
Why do People Need Enucleation
Before a doctor discusses the possibility of an eye removal surgery, known as enucleation, with a patient, they need to take into consideration the patient’s emotional needs and wishes, how well they might see after the surgery, and any expected complications. The main reasons for performing enucleation are cancer within the eye, a non-functioning eye that causes pain, injuries to the eye, and to prevent a condition known as sympathetic ophthalmia, a severe inflammation in both eyes usually following an injury.
Other reasons could include a smaller than normal eye in a child, or a shrunken, non-functioning eye from a disease, known as phthisis. In extremely rare cases, there can be self-inflicted eye removal, known as autoenucleation, which is often associated with serious mental health conditions like psychosis. Specific conditions requiring enucleation include:
Cancer within the eye
* Choroidal melanoma: A type of cancer that happens in a part of the eye called the choroid, which is a layer of blood vessels and tissue between the white of the eye and the retina (the layer of cells at the back of the eye).
* Retinoblastoma: A cancer that starts in the retina and usually happens in children.
* Other types of eye cancer
Injury to the eye
* Primary enucleation: Immediate eye removal following a severe injury.
* Secondary enucleation for sympathetic ophthalmia: Eye removal due to inflammation in both eyes following initial trauma to one eye; removed to prevent inflammation in the unaffected eye.
* Autoenucleation or Oedipism: A rare self-inflicted eye removal often associated with serious mental health conditions.
Non-functioning eye that causes pain
* Neovascular glaucoma: A type of glaucoma that can cause blindness and is often painful.
* Endophthalmitis and uveitis: Severe inflammation inside the eye, often very painful.
* Improve appearance: In cases where the eye is severely diseased or injured and negatively affects a person’s appearance.
When a Person Should Avoid Enucleation
There are certain situations where removing an eye (enucleation) is not the best option. For example, if a patient has a type of eye cancer (intraocular malignancy) that has spread to the area around the eye (orbital spread), they usually need a more extensive surgery, called exenteration.
Also, for patients with a condition called sympathetic ophthalmia, which causes inflammation in both eyes, removing the eye might not be the best move. This is a complex situation where the unaffected eye can eventually have better vision than the initially affected eye. Research has not shown a major advantage of removing the eye over a different procedure (evisceration) in preventing sympathetic ophthalmia.
On a more emotional level, removing an eye may not be recommended for those who might experience increased psychological stress from losing an eye. It’s important that doctors balance the physical and emotional wellbeing of their patients when making treatment decisions.
Equipment used for Enucleation
The tools a surgeon uses can change based on the specific type of surgery technique they choose for an operation called “enucleation” (this is when they need to remove your eye). Here’s the list of the tools they usually include:
An “eye speculum”, which is a device that is used to hold your eye open during surgery.
“Straight dressings forceps”, these are a type of tweezer used for applying and removing dressings.
“Hemostatic forceps”, these are clamps used to control bleeding,
“Straight and curved tenotomy scissors”, these are special scissors used for cutting tissue. “Enucleation scissors” are particular types of these scissors used during the eye removal procedure.
“Enucleation snare”, a tool for removing tissue.
“Retractors”, these are tools used to hold back your tissues or organs to create a clear field for the surgeon to operate.
The “Carter sphere introducer and holder” helps to introduce a certain artificial object called a sphere (like a small ball) into the eye socket and hold it in place.
“Conformer” is a plastic shell that is placed in the eye socket to maintain its shape and to stop it from closing up.
Lastly, there’s a set of tools for sewing the wound closed, we call this the “suturing set for wound closure”.
Who is needed to perform Enucleation?
To carry out a procedure such as enucleation, which involves the removal of an eye, several healthcare professionals are needed. A special eye doctor known as an ophthalmic surgeon performs the surgery with the help of eye-care nurses and theater scrub nurses. Other medical assistants also help with the process.
A psychologist may also be involved before the operation. Their duty is to help the patient understand the surgery and to provide emotional support. This consultation is part of ensuring the patient gives informed agreement to the surgery (the consent process).
For the patient’s care after the surgery, an ocularist, a specialist who designs artificial eyes, will be needed. They create an eye prosthesis as part of helping the patient recover and go back to their normal life.
All children who need to undergo this type of eye surgery should meet with a child psychologist. The psychologist will provide counseling to prepare and help them cope with the operation.
There are also explanatory books available for children and their parents, to help them understand the surgery in a less frightening way and make the whole process less shocking.
Preparing for Enucleation
Before going through with a procedure known as enucleation, which is the removal of the eye while leaving the eye muscles and eyelids intact, the doctor will have a thorough conversation with the patient. During this talk, the doctor will explain why the procedure is necessary, what the risks and benefits are, and what other options are available.
The patient must also be made aware of any potential complications. These will be outlined by the doctor in great detail. This will help the patient fully comprehend what could happen after surgery, allowing them to make an informed decision.
If the patient is currently taking certain medications such as nonsteroidal anti-inflammatory drugs (NSAIDs), aspirin, or blood thinners (anticoagulants), the doctor may advise halting these medications. However, this will only be done if it’s safe for the patient to temporarily stop taking these medications.
Lastly, if a patient is on blood thinners, it’s important to let the doctor who prescribed these medications know about any changes. This is because adjusting these types of medications can affect the body’s ability to form blood clots, which is important during and after surgery.
How is Enucleation performed
Before surgery, it’s crucial that the surgeon and medical team discuss the procedure with the patient and obtain their written consent. The surgeon will also mark the eye to be operated on, ensuring everyone is in agreement about which eye will be removed. It’s then important to triple-check these details before the operation begins, including confirming with the anesthesiologist and the assisting nurses, once the patient is under anesthesia.
During the surgery, after sterilizing the operating area, the surgeon uses special tools to gently pull back the patient’s eyelids. After this, the surgeon will give an injection that numbs the area. The surgeon then makes an incision around the eye and carefully removes a layer of tissue called the Tenon fascia. This allows the surgeon to isolate the muscles that control the movement of the eye.
Throughout these steps, the muscles are secured with sutures. The surgeon will then cut the muscles that connect the eye to the socket so that the eye can be safely removed. The optic nerve, which connects the eye to the brain, is also clamped and cut. At this point, the surgeon might use local anesthesia-soaked materials to minimize bleeding, especially in cases where the eye is removed due to a tumor.
After removing the eyeball, it’s sent to another lab for further examination. If an artificial eyeball, or an orbital implant, is to be inserted into the socket, it’s placed into the muscle cone and secured. The muscles and tissues around it are then sewed back together, and a placeholder is put in place to keep the shape of the eye socket. A cream containing antibiotics is applied to aid healing. The surgeon may also choose to temporarily stitch the upper and lower eyelids together to protect the eye socket and prevent the placeholder from falling out.
After the surgery, the patient might get pain medication and antibiotics if needed. A protective patch is usually put over the patient’s eye for about 24 hours to reduce swelling. Patients are advised to regularly clean the area and apply antibiotic and corticosteroid ointments to speed healing.
Many different types of materials can be used for orbital implants. These can be porous like hydroxyapatite, which lets blood vessels grow into them, or non-porous like silicone. Implants help to restore the shape and functionality of the eye socket and can be personalized to the patient’s needs.
Possible Complications of Enucleation
Undergoing a surgery, such as eye removal, can be a worrying prospect and complications can occur. However, most are preventable with proper care before, during, and after the procedure. Here are some possible complications and how doctors work to avoid them:
The wrong eye being removed is a serious and feared complication, but it can be easily avoided. Through good communication, double-checking before surgery, and clearly marking the eye that needs to be removed, your surgical team can ensure they operate on the correct eye. During surgery, there is a small risk of misplacing a ‘rectus’ muscle – a muscle that helps the eye move. If a muscle does retract into the eye socket, your surgeon can carefully navigate through the soft eye tissues to find and secure it. Procedures such as clotting the blood, careful tissue handling, and administering a specific type of anaesthetic can decrease the risk of excessive bleeding during surgery.
If your surgery is due to an eye tumor, like melanoma or retinoblastoma, it may be necessary to cut away a large section of the optic nerve. This can be difficult if the eye is full of tumors. In such cases, the surgeons utilize a special approach to safely locate and cut the optic nerve, minimizing the risk of accidental damage.
After the surgery, there’s a small chance of complications. Serious bleeding is quite rare but can happen. If it does, you might need another surgical procedure. Swelling of the eye socket is common after eye removal but should reduce over time. Infection, while rare, can also occur, potentially leading to wound opening, implant exposure, and even implant removal. Checking your symptoms regularly can help identify this early on so that it can be treated adequately.
Long-term, there can be some effects on the eye socket, such as drooping due to the effects of time, gravity, and stretching from the eye prosthesis (artificial eye). Adjustments can be made over time to ensure the prosthesis fits correctly. In some cases, the socket may appear to sink inwards or lower eyelid may become lax. Techniques have been developed to fill this space and maintain the appearance of the eye.
As a patient undergoing such a surgery, understanding potential complications can ease anxieties and help you take an active role in your recovery. It’s important to remember that your surgical team are experts who strive to ensure a smooth procedure and recovery.
What Else Should I Know About Enucleation?
Enucleation, or the removal of the eye, is a procedure usually performed on patients suffering from severe eye diseases that can’t be fixed and cause significant discomfort. This surgery can be crucial in saving a patient’s life in cases of a dangerous eye tumor and it can also save the patient’s vision in cases of sympathetic ophthalmia, a rare condition where an injury to one eye causes the other eye to develop similar symptoms.
The decision of whether to have this surgery is often a tough one, for both the patient and the healthcare team involved. Various factors need to be considered, like the surgical techniques used and the materials of the implant replacing the eye, as they can impact the likelihood and location of any complications after the surgery.
