Overview of Corneal Laceration Repair
Eye injuries are quite common, affecting an estimated 24 million individuals in the United States. These injuries can range from a small scratch on the clear front part of the eye (the cornea), known as a corneal abrasion, to a tear or split in the outer part of the globe-like structure of the eye, which is known as a globe rupture. One type of globe rupture is a corneal laceration. In fact, out of 890 eye injuries reviewed over a decade in Iraq and Afghanistan, roughly one-fifth involved a corneal laceration.
Corneal lacerations can come in all shapes and sizes. Some only affect part of the cornea’s thickness while others go all the way through. The lacerations can look like a simple straight line or a more complex, star-like formation. Regardless of what they look like, all lacerations need to be treated urgently to prevent infection, limit tissue death, and relieve discomfort. It’s usually recommended that they get treated within 24 hours.
The usual method for treating a corneal laceration is by stitching up the wound. However, for smaller lacerations (less than 2 mm), a tissue glue or a contact lens can effectively close the wound.
The goal of any treatment is to close the wound securely, restore normal eye structure, and minimize post-surgery scarring and distortion of the cornea, known as astigmatism.
Anatomy and Physiology of Corneal Laceration Repair
The cornea is the clear front part of the eye. It’s job is to lend shape to the eye and to protect it from infections. In most adults, the cornea measures 12 millimeters across and 11 millimeters up and down, with a thickness of half a millimeter.
The cornea is made up of five, or sometimes six layers. These include the epithelium, Bowman membrane, stroma, Descemet membrane, and endothelium. In 2013, scientists discovered a sixth layer called Dua’s layer between the stroma and Descemet membrane. The stroma is the thickest part of the cornea, making up 80 to 85% of its structure. The cornea is kept clear by the endothelium layer which does this by removing water from the cornea.
When the cornea gets injured, different layers respond differently. If the epithelium gets damaged, the cells in that layer get destroyed, creating an empty space. This space then gets filled by migrating epithelial cells. As long as the second layer, the Bowman membrane, isn’t damaged, the cornea can heal without scars.
Damage to the stroma leads to the development of fibrous tissue, or fibrotic deposition, which seals the wound but can disrupt normal function. Excessive such tissue can lead to increased scarring, limiting the clarity of the cornea.
The endothelium layer doesn’t regenerate. So if it gets injured, the cornea can swell and become cloudy because the endothelium layer’s function of removing water from the cornea gets lost.
The cornea is very sensitive and has a lot of nerves. These nerves come from the nasociliary branch of the ophthalmic division of the trigeminal nerve. Because of this, injuries to the cornea can be extremely painful.
Why do People Need Corneal Laceration Repair
If you have a cut or tear on the cornea (clear front surface of the eye), your doctor may diagnose this as a “corneal laceration.” This can happen due a trauma or injury to the eye. Symptoms can include blurry vision, pain in the eye, unusual pupil shape (like a peak or teardrop), something in the eye that shouldn’t be there, or part of the inside of the eye poking out.
A test called a ‘Seidel test’ can be used to confirm this. In this test, a special dye is placed in the eye to see if it leaks out from the cut, which would confirm there’s a tear.
If a corneal laceration is suspected but the doctor is having trouble seeing it clearly (perhaps because the patient can’t keep their eye open long enough or there’s swelling in the eyelid), they might do a more thorough exam under anesthesia in an operating room. This is also referred to as ‘globe exploration’.
In any case, a corneal laceration is a serious condition that needs to be treated as soon as possible to prevent infection, tissue death, damage to the clear, front part of the eye, and to relieve patient discomfort. It’s generally advised that the repair should occur within 24 hours, although no specific timeline is given in the available scientific literature.
When a Person Should Avoid Corneal Laceration Repair
Before a doctor can fix a corneal laceration (a cut on the clear front surface of the eye), the patient must be stable. Being stable means your heart and blood pressure are working well and you’re not in shock. If someone has been severely injured in many places (polytrauma), having general anesthesia (medication that puts you to sleep) can be too dangerous, this makes the repair of the eye cut unsafe.
Equipment used for Corneal Laceration Repair
For eye surgery, the medical team uses a variety of special tools. These could include a microscope or surgical glasses that magnify the operation site, a kit for cleaning and preparing the eye for the procedure that includes sponges and a disinfectant solution (5% povidone-iodine), and special coverings for the eye to keep it clean and safe. The medical team also uses a very thin thread (10-0 nylon) to close any cuts in the clear front part of the eye (cornea), or slightly thicker threads (9-0 and 8-0) if the edge of the cornea (limbus) or the white part of the eye (sclera) is involved.
Other tools include a device (eyelid speculum) to hold the eyelids open and prevent pressure on the eyeball, tools to hold the needle and thread (needle holders), and a pair of particularly fine tweezers (0.12 forceps) which may be replaced by a special type of form (Colibri Forceps). The medical team also uses tools for tying the thread (surgical tying forceps), cutting (tenotomy scissors and fine scissors), and a small surgical blade (1.0 to 1.2 mm).
To protect the inner parts of the eye during surgery, the team employs a supportive gel (ophthalmic viscoelastic) and a balanced salt solution that help to maintain the shape and health of the eye. A small syringe (3 mL) with a thin needle (27 or 30 gauge cannula) is used to apply these substances. Other tools used during the procedure include absorbent wads (eye spears) used to keep the area dry, a thin instrument (cyclodialysis spatula) to separate the iris (the colored part of the eye) from any wounds in the cornea, and a specific type of strip (fluorescein strip) to help visualize any wounds or openings in the eye. Lastly, there is a medical adhesive (cyanoacrylate glue) and a special contact lens (bandage contact lens) that protect the eye after surgery.
If some part of the cornea is missing due to injury, the surgeons might use preserved corneal tissue or a tissue from a sac around the heart (pericardium allograft). After the surgery, the eye is covered with rigid eye shield and eye pads to protect it. The patient also gets antibiotics to prevent infection. These antibiotics can be applied directly inside the eye, under the thin membrane covering the white of the eye (subconjunctival), or as eye drops (topical).
The standard thread used for stitching a cut in the cornea is 10-0 nylon. It’s applied with a thin and flat needle (spatulated needle). The needle’s curve (radius of curvature) must be just right – if it is too large, the stitch will be too long, but if it is too small, the stitch will be too short.
Who is needed to perform Corneal Laceration Repair?
An ophthalmologist, who is a special type of doctor that operates on eyes, will be in charge of your surgery. Helping the ophthalmologist, there will be a surgical technician, who efficiently gives the surgeon any necessary tools for the surgery.
An operating room nurse, responsible for looking after your comfort and safety, will also be present. Finally, an anesthesiologist, or a specialized nurse known as a certified registered nurse anesthetist, will be there to ensure you safely sleep through your surgery, so you don’t feel any discomfort or pain.
Preparing for Corneal Laceration Repair
While waiting for their eye to be treated, a person should protect the injured eye with a hard eye cover. If they are feeling pain or nausea, medicines can be used to manage these symptoms. It’s important that the person doesn’t eat or drink anything so they are prepared for surgery. A special type of scan called a Computed Tomography (CT) scan, which takes detailed pictures of the face, may be done before treatment. This scan can help find any foreign objects and is a normal procedure for eye injuries at many hospitals. Tetanus shots and antibiotics should be given early to prevent infection.
A basic eye check-up needs to be done very gently to prevent causing any additional injury or discomfort to the person. While this kind of exam can be difficult, it is crucial to check their vision with an eye chart, examine their pupil with a light, and assess their eye using equipment like a penlight or a slit-lamp. If a cut that goes through the full thickness of the eye is suspected, a test measuring the pressure inside the eye should not be done. If there are doubts about whether the cut is full-thickness, a test called the Seidel test can be performed to confirm this.
Before the repair of a cut on the cornea (the outer layer of the eye), a solution containing 5% povidone-iodine is applied on the surface of the eye. This solution is very effective in reducing bacteria. During the preparation for the surgery, care should be taken not to press on the eye, as this could push the contents of the eye out.
How is Corneal Laceration Repair performed
Corneal lacerations, or cuts in the cornea (the clear, front part of the eye) are unique in each patient and repairing them requires specialized skills. Some doctors enjoy the challenge of this, while others find it stressful. No matter how you see it, the aim is to create a tight seal on the cornea, without involving the inner parts of the eye. This restores the eye’s natural shape and prevents further damage from happening.
There are different ways to manage pain during the process. For smaller cuts in the clinic, local anesthesia or a shot around your eye can be enough. However, if the cut is bigger or there’s tissue sticking out, general anesthesia might be needed. This puts you completely to sleep, allowing the doctor to carry out the procedure smoothly and without causing anxiety or pain.
If the doctor cannot confirm the presence of a corneal cut in the clinic or emergency room, you might have to go into the operating room for further examination and possibly surgical repair.
If the cut isn’t too deep, the doctor will clean it out carefully. Then they’ll do a Seidel test to confirm it’s only a partial-thickness cut. If the Seidel test comes back negative, the cut might be sealed with special medical glue or a contact lens to help it heal. If it’s positive, the procedure for a full-thickness cut will be followed.
The doctor will take a sample of the wound for culture. This is done to catch early signs of infection. The care and cleaning of the wound should only be done by the doctor performing the repair. Necrotic (or dead) tissue will be removed, remaining put back into the eye, and any visible foreign bodies or debris will be pulled out.
If the cut goes through the whole thickness of the cornea and is smaller than 2mm, glues, membranes, or lenses might be used. If it’s larger than 2mm, sutures (or stitches) are often needed and the repair is done in the operating room.
Planning and sketching out the repair before starting is crucial. Sutures should be placed at a specific depth in the cornea to prevent injury. The length and location of the sutures can also help reduce scarring and preserve your vision. However, if tissue from inside the eye slips out through the cut, there are several methods to carefully place it back in.
Corneal cuts come in many shapes, but here are some general guidelines:
- Oblique laceration (cut at an angle): The suture will look displaced on one side, but it should not be put under strain.
- Linear laceration (straight cut): Start in the middle and work your way out to both ends.
- Gaping laceration (wide cut): Start at the ends and then ‘zip’ it up, keeping tissue out of the closure.
- Angled laceration: The first suture can be put in at the highest point, and the sides are treated as separate linear lacerations.
- Stellate laceration (star-shaped cut): A special suture is placed, and the remaining parts of the cut are closed with regular sutures.
- Corneoscleral laceration (cut involving cornea and white part of the eye): The first suture is placed at the edge of the cornea. After closing this, the doctor will close the parts on the white of the eye.
In cases where some tissue is missing, a patch graft might be needed. This could involve amniotic membrane, tissue from another person, or specially processed cornea.
Finally, after the repair is complete, the doctor will test for any leaks. If a leak is detected, additional sutures, glues, membranes, or lenses might be applied. All the knots in the sutures are eventually buried, preferably away from your line of sight, so as not to interfere with your vision.
Possible Complications of Corneal Laceration Repair
After an operation, especially ocular surgery, there can be various ways complications may arise. Care before and after the surgery, as well as a skilled surgical technique, can minimize these problems.
One possible issue is what we term as “Posttraumatic Endophthalmitis.” It’s an eye condition that can happen after your eye is injured. Depending on the severity of the injury, this can occur between 3.3% and 17% of the time. Key risk factors include delaying the repair surgery and damage to the lens capsule. Signs of this condition can be difficult to spot because the eye will already be inflamed from the injury. Symptoms may include eye pain, redness, swollen eyelids, discharge, diminished vision, and seeing floaters (small specks or strings ‘floating’ in your field of vision). Several treatments are available, from injections of broad-spectrum antibiotics into the jelly-like substance in your eye to removing the vitreous if vision becomes limited.
You might find an intraocular foreign body remaining in the eye after trauma, occurring between 18% and 41% of the time. These are essentially foreign objects lodged inside your eye. We can try to identify these foreign bodies before repairing the eye through imaging. Occasionally, certain foreign bodies can’t be removed during surgery, especially if they are lodged in the vitreous, and further operations might be necessary. Metallic foreign bodies are usually toxic to the eye, so their removal is recommended.
Another complication could be wound leaks. A day after your primary surgery, doctors would inspect for wound leaks using a dye test. If your doctor finds a leak, they may try to seal it with a bandage contact lens or medical-grade glue. Fenestrating the eye and applying additional stitches may be crucial if the leak is substantial. This is important as wound leaks can significantly increase the risk of infection.
Sometimes, suturing issues may cause discomfort and serve as a potential entry route for microorganisms. Therefore, it is very important to make sure all suture knots are concealed during surgery. If any come to light after the operation, they can be rotated at the slit lamp.
Damage to the iris is another risk, as it could tear or become dislodged during the injury or the repair procedure. An unusual iris might cause light sensitivity, visual disturbances, and an unpleasant aesthetic appearance. If the patient is troubled by the symptoms, surgical techniques, corneal tattooing, contact lens, and artificial iris implants are available options.
Cataracts are another common issue post-injury or post-operation if the flexible covering of the lens is damaged. Cataracts are cloudy patches in the lens of the eye that can make your vision blurry. However, these can usually be safely removed and substituted with an artificial lens to improve vision.
Infectious Keratitis refers to a type of eye infection that can follow injury. Bacteria can build up on the sutures or form abscesses (pockets of pus). Antibiotics are the usual initial treatment, although potent antibiotics may be needed for serious infections or drug-resistant bacteria.
If the retina, the thin layer of tissue at the back of the eye, detaches, it can lead to vision loss. Risk of this is increased post-trauma or post-operation, so early intervention is key to help preserve vision.
Sometimes, a condition called secondary glaucoma can occur after penetrating trauma due to various reasons. It’s important to monitor the intraocular pressure during the postoperative period and inform the patient about the long-term risk.
A rather rare condition known as Sympathetic Ophthalmia can occur, usually in the non-injured eye post-trauma. This is due to an immune reaction after injuries or surgeries that involve the uveal tissue (the middle layer of the eye). It is important to inform the doctor if inflammation occurs in the non-injured eye.
Finally, vision loss can result from any of these complications. Damage due to trauma on the optic nerve or other parts of the eye can also lead to vision loss. Scarring of the cornea, new blood vessels formation, and irregular corneal shape are common reasons for decreased vision after an injury. Hard contact lenses could help in understanding if the visual complaint is because of the cornea versus other parts of the eye. Specialists can significantly improve vision with a well-fitted contact lens. If the vision loss is related to a corneal condition and not improved with a contact lens, a cornea transplant could be beneficial once the eye has fully healed post-injury.
What Else Should I Know About Corneal Laceration Repair?
Loss of visual acuity, or clearness of vision, can have a negative impact on a person’s lifestyle. In fact, according to the United States Eye Registry, about a quarter of patients experiencing an eye injury may have permanent changes to their vision. There could still be some vision loss even after a successful repair of a cornea laceration, due to scar tissue on the cornea, irregularities in the shape of the cornea (astigmatism), or harm to other areas of the eye.
Preventive measures like using protective eyewear can give the best results for maintaining good eyesight and avoiding injuries. In fact, the decision to make wearing eye protection compulsory in the U.S military resulted in less severe eye injuries and fewer injuries overall. For a person experiencing vision loss, it is highly advised to wear eye protection to safeguard the eye that has better vision. So, education about the importance of protective eyewear should be a vital part of post-injury care and advice for patients who’ve experienced eye trauma.
