Overview of Corneal Foreign Body Removal
Commonly, people who have scratches (or abrasions) on their corneas or small pieces of foreign material stuck in their eyes go to emergency rooms, urgent care locations, or see their usual healthcare providers or eye doctors. The cornea is the part of your eye that feels the most sensation. People with foreign objects in their corneas often complain about several symptoms: eye pain, sensitivity to light (photophobia), blurry vision, the eye releasing too many tears, an unusual amount of sticky or watery substance in the eye (discharge), an uncontrollable closing of the eye (blepharospasm), and a reddened, blood-filled outer layer of the eye (conjunctival hyperemia). These issues usually come on suddenly and are easy to notice right away.
Interestingly, sometimes people pick up foreign objects unknowingly and only begin to suspect something’s wrong after mild symptoms persist. It’s often reported that the foreign object got stuck in the eye during outdoor activities or while working on home projects. Of significant concern is when injuries occur due to high-speed activities like hammering, grinding, and drilling metals as this can lead to more serious complications.
Our cornea is critical for our vision as it helps focus light onto the retina, contributing to nearly 67% of the eyes’ focusing power. Damage to the cornea not only causes physical discomfort but may also affect your vision. If there’s swelling on the cornea (corneal edema), it may lead to sensitivity to light and difficulty seeing clearly. If objects are deeply embedded, they might also cause irregularities or scars on the cornea, disrupting vision.
The cornea is also essential for protecting the inner parts of the eye from its external environment. The bone structures surrounding our eyes, along with the eye’s blinking and tear formation mechanisms, also aid in this protection and help keep foreign material off the cornea. It’s crucial to remember that if a foreign object penetrates into the inner parts of the eye, it could have serious consequences, such as inflammation within the eye (endophthalmitis) or retinal detachment.
Foreign objects in the cornea can occur due to blunt hits or sharp objects piercing the eye. Such injuries may coincide with other traumatic injuries, including scratches or tears on the eyelid, scleral (white outer layer of the eye) tears, displacement or rupture of the iris, abnormal enlargement of the pupil, defects in pupil reactions, tears in the anterior (front) part of the eye’s outer shell, traumatic or specific types of cataracts, disturbances in the cortex, dialysis (separation) of the zonules (small fibers that hold the eye’s lens in place), and the back part of the eye’s jelly-like substance coming out of place (vitreous prolapse). Injuries to the back part of the eye could result in retinal tears or detachment, choroidal (layer of blood vessels and connective tissue between the sclera and retina) detachment, vitritis (inflammation of the vitreous), and intermediate or extensive uveitis (inflammation of the eye’s middle layer).
Anatomy and Physiology of Corneal Foreign Body Removal
The cornea is the clear front part of the eye that lies just in front of the white part of the eye, called the sclera. Despite having no blood vessels, the cornea stays nourished through the internal eye fluid, known as the aqueous humor, and from oxygen in the tear film outside of the eye.
The cornea consists of five different layers. The outermost, or the epithelium, is often renewed since it constantly sheds old cells and replaces with new ones. This renewal process takes about two weeks, with new cells moving from the outer edge towards the center of the cornea. If a minor injury occurs to this layer, it tends to heal rapidly within one to two days.
Just underneath the epithelium, there is the Bowman layer. Any damage to this layer will likely result in a permanent scar on the cornea since the cells in this layer cannot regenerate.
Followed by the Bowman layer is the stroma. It’s the thickest layer of the cornea, making up almost 90% of its entire thickness. It primarily consists of carefully arranged collagen fibers and water, which help maintain the cornea’s transparency. If there is any disruption in this delicate arrangement, the cornea can become cloudy.
Below the stroma sits another layer called the Descemet membrane. This layer provides a foundation for the cells of the corneal endothelium, which is the innermost layer.
Corneal endothelium is crucial in preserving the moisture balance of the corneal tissues. But, if this layer gets damaged, it can be problematic as these cells cannot grow back. Any damage to this layer might also suggest that a foreign object has entered the eye. Moreover, persistent swelling of the cornea might occur if these cells are lost.
There is also a recently recognized sixth layer, named the Dua layer, situated between the stroma and the Descemet layer. However, the importance of this layer remains uncertain.
Iron objects are the most common type of foreign bodies that get into the eye. These objects often leave rust particles embedded in the stroma of the cornea, which can trigger inflammation, slow healing, and lead to scarring or unevenness of the cornea.
Why do People Need Corneal Foreign Body Removal
If you feel pain in your eye, a sensation of something in your eye, tearing, sensitivity to light, involuntary eye closure, or blurred vision, you might have a foreign body (like a speck of dust or a small piece of metal) in your eye. It’s really important to remove this foreign object from your eye swiftly because it can lead to infection or lasting damage the longer it stays in there. Plus, you’ll feel much better once it’s gone.
Doctors will generally want to remove a foreign body from the eye if you’re experiencing pain, redness, light sensitivity, involuntary closure of the eye, or blurred vision. It may also be necessary if there’s a ring of rust in the eye, infection, or if pus is accumulating inside your eye. The foreign object might need to be removed if it’s embedded deeply in the layers of your eye, there are cuts on your eye, your eye has been accidentally pierced, there’s an abnormal reaction happening in the chambers of your eye, or if there are multiple foreign bodies in your eye.
When a Person Should Avoid Corneal Foreign Body Removal
If there’s a chance something has gotten into your eye, you should get a check-up from an eye doctor right away. Often, the items that find their way into the eye come from activities like hammering metal, chiseling, or being near an explosion, where fragments can fly at high speed.
When the doctor examines your eye under a bright light microscope, called a slit-lamp, they might look for certain signs. These include a shallow front part of the eye, blood in the eye, an irregular shaped or colored iris (the colored part of your eye), a tear in the inner layer of your cornea, or clouding in the lens of the eye (cataract). If there is a hole in the surface of your eye, a test called a Seidel sign will be done where a dye is put on your eye to see if any eye fluid is leaking out.
Imagining tests can help locate any foreign items that have gone deep into the eye. A CT scan of your eye-sockets can find these items, especially if they are not visible when the doctor looks into your eyes, but are still suspected to be there. An MRI scan is harmful and so is strictly not done if the item in your eye is metal. If a metal or organic item is located very deep in the cornea (the clear front part of your eye), it may have to be taken out by an eye doctor because it may penetrate deeper or leave a scar on your eye.
If you have a foreign body in your cornea, it’s important not to try to take it out during the slit-lamp exam as this can cause eye inflammation or infection. If the area around your eye is very swollen, it doesn’t mean the foreign body has to be taken out right away; the swelling will be treated and the object can be removed at a later date.
Equipment used for Corneal Foreign Body Removal
The following items are necessary when taking out a small object, like a piece of metal or glass, otherwise known as a foreign body (FB), from the surface of the eye (the cornea).
* Sodium fluorescein: This is a special dye that’s used to help visualize the foreign body and any damage to the eye.
* Numbing eye drops: These are used to make the procedure more comfortable for you. Common ones used include a 0.5% solution of proparacaine or tetracaine.
* A Slit-lamp or a Burton lamp: A tool fitted with a cobalt-blue filter that allows the doctor to take a closer look at your eye.
* A Loupe: This is a small magnifying glass used to see small details, especially in pediatric patients (children).
* Sterile saline: This is a safe saltwater solution used to clean the eye.
* Plastic syringe: This is used in combination with the saline to wash the eye efficiently.
* Sterile cotton-tipped applicators: These are used to gently clean the eye.
* Jewelers forceps: These are fine-tipped tools, which can be used to extract the foreign body very carefully.
* Needles and Syringes: Needles ranging in size from 25 to 27-gauge attached to a very small syringe (a tuberculin syringe), possibly with a bent tip, may also be used to remove the foreign body.
* Foreign body spud: This is a tool that can help remove foreign bodies and a magnetic version may be used for metallic ones.
* Rotating burr tool: This tool, such as an Alger brush, can help remove foreign bodies embedded into the cornea.
* Eyelid speculum: This tool may be required to keep the eyelids open during the procedure.
* Topical ophthalmic antibiotics like ciprofloxacin, moxifloxacin, or gatifloxacin: These are eye drops that help prevent infection after the foreign body is removed.
* Eye patch or pad and bandage: These are used to cover the affected eye after the procedure to allow it to heal properly.
Who is needed to perform Corneal Foreign Body Removal?
When dealing with treatments such as the removal of something stuck in the cornea (the clear front surface of the eye), it’s important for a team of medical professionals to be involved. This ensures that you are prepped properly, the procedure itself is carried out effectively, and that your aftercare is well-managed. Gathering a detailed account of your health history is a crucial part of this.
If you find it difficult to keep still when examined with the biomicroscope (a device doctors use to closely examine your eyes), a nurse can help you manage your movements during the examination. Besides your doctor, this medical team might include nurses, eye technicians, and helpers in nursing or eye care.
A doctor specialized in eye care, known as an ophthalmologist, will carry out a thorough examination of your eye. Pharmacists will also play a role, making sure that all necessary medications are available for your treatment. Eye care helpers are there to guide you about your medications and your continued care after treatment.
Preparing for Corneal Foreign Body Removal
If you are suspected to have a foreign body (FB) in your cornea (the clear, front surface of your eye), the doctor will take a detailed history of how the injury happened. They will want to know what caused the injury, where it happened, whether you were wearing any eye protection at the time, and what substances may be in your eye. This is because if the eye was injured by a strong force with flying particles, there could potentially be more serious injuries like an infection inside the eye (called endophthalmitis) or retinal detachment, which can cause severe loss of vision.
The doctor will check your vision and examine your eye closely, looking for signs of penetrating injuries such as changes to the depth of the eye’s front chamber, unusual pupil shape, differences in pupil size, cloudiness in the lens, pus in the front of the eye, or increased inflammation in the eye. If there’s a cause for concern about a penetrating injury, you’ll be referred for immediate specialist eye assessment.
Before the doctor examines your eye, they’ll explain the process to you, including any possible risks such as infection, scarring of the cornea, perforation (a hole in the eye), and vision loss. The main tool they’ll use for the examination is a slit-lamp microscope, which enhances the visibility of the superficial structures of the eye. If a slit-lamp microscope is not available, they’ll use other methods to identify the presence of any foreign bodies.
The doctor will determine the location and depth of the foreign body and if there are others obscured by the eyelids. They’ll gently turn your lower eyelid to check the lining for any debris or another foreign body. The same will be done for the upper eyelid. Afterward, they will examine the surface of your eyes with and without sodium fluorescein, a special dye. By using a specific blue light, they will assess if the dye remains in place and look for a sign known as Seidel sign, which indicates a leak of eye fluid due to a hole in the eye.
The doctor will numb the surface of your eye with a couple of eye drops before the examination to avoid discomfort. You will be asked to place your forehead and chin on supports to hold your head steady and reduce the chance of injury during the exam. If you have a strong blink response, they might use a device to keep your eyelids open. Throughout this process, you will need to stay still, and a member of the medical team might help hold your head in place to ensure you stay safe.
How is Corneal Foreign Body Removal performed
If you get something in your eye, like a small piece of metal, glass, or plastic, doctors have different ways to remove it. Some of these foreign objects can be washed away with a sterile solution or lifted out using a soft cotton-tipped tool. If the object is stuck in your cornea (the clear front surface of your eye), your doctor may use a special needle or tool to gently take it out. To avoid making sudden movements, they will stabilize their hand on a steady part of your face while doing this.
Some metal objects can leave a rust ring on your cornea in as short a time as four hours. In these situations, your doctor might use a medical device that works like a gentle rotating brush to remove the rust ring. They need to use this tool very carefully, because applying too much pressure or brushing too much area can cause scarring and slow down your cornea’s healing process.
If the object in your eye is deeply embedded but not harmful (like glass or plastic), your doctor might decide to leave it in place and keep an eye on it.
After removing a foreign object from your eye, your doctor will usually give you antibiotic eye drops to prevent infection. These are normally applied four times a day for a week, but may be used more often and for a longer time if your cornea is particularly damaged. If you wear contact lenses, your doctor will make sure your antibiotic works against a bacteria called Pseudomonas, which can cause severe eye infections.
In cases where the object in your eye was a plant or vegetable matter, your doctor might also give you antifungal drops to prevent fungal infections. In very rare cases, you might need to take oral antifungal medication.
To help your eye heal, your doctor might suggest using lubricating eye drops. These can help protect the surface of your eye, flush out debris, and relieve discomfort. However, you should avoid using cortisone eye drops as these can make any infection worse.
Your eye may hurt for a while after the procedure, but the pain will lessen as your eye heals. Applying local anesthetic eyedrops for the first 24 to 48 hours after the object’s removal can ease the pain. If you are still in pain, over-the-counter oral painkillers can help.
Once your cornea is fully healed, using cortisone eye drops can help reduce any inflammation. In cases where the foreign object was large and caused a lot of swelling, your doctor might give you cortisone drops to prevent scarring.
Finally, your doctor may recommend wearing a special contact lens to protect your eye and correct your vision while your cornea heals. This is particularly helpful if blinking causes you discomfort. If the injury affected more than half of your cornea’s surface, your doctor might also consider using an eye patch. However, in most cases, not using a patch can lead to faster healing and less discomfort.
Generally, doctors will want to see you within 24 hours after removing the foreign object from your eye to make sure your eye is healing well.
Possible Complications of Corneal Foreign Body Removal
If a patient doesn’t report that they’re feeling stable or getting better, doctors need to look out for potential problems. For example, 24 hours after a tiny object, like a piece of dust or dirt (foreign body or FB), is removed from the surface of the eye (the cornea), the doctor should check the eye again. They are looking for any other foreign bodies, areas that aren’t healing properly, or ulcers. They’ll also do a Seidel test, which can detect leaks from the eye, and examine the front part of the eye (the anterior chamber) again to check for changes or signs of inflammation.
A foreign body in the eye can cause various complications, including:
* Continued red, irritated eyes (persistent conjunctivitis)
* Areas on the eye’s surface that don’t heal (nonhealing epithelial defect)
* Changes to the cornea, such as patches of infection or inflammation (infiltrates), scarring, thinning, or even a hole (perforation)
* Formation of a rust-colored ring around the foreign body (rust ring formation)
* A type of eye pressure problem (secondary glaucoma)
* Inflammation in the front part of the eye (anterior uveitis)
* Tearing of the muscle that changes the shape of the eye’s lens (iridodialysis)
* Pupil becoming permanently large (traumatic mydriasis)
* Damage to the part of the eye where fluid drains out (angle recession), which can lead to glaucoma
* Connections (synechiae) forming between different parts of the eye
* Tears or ruptures in the protective layer of the lens (the lens capsule)
* Clouding of the lens leading to blurred vision (traumatic cataract)
* Damage to the fibers holding the lens in place (zonular dialysis)
* The jelly-like substance within the eyes pushing forward (vitreous prolapse)
* Tears in the retina or a foreign body becoming trapped in the retina
* The retina or layer under the retina pulling away from the back of the eye.
What Else Should I Know About Corneal Foreign Body Removal?
If something foreign like dust or metal has gotten stuck in your eye (this is known as a “corneal foreign body” or FB), you might experience symptoms like redness, eye pain, blurry vision, excessive blinking, and light sensitivity. It’s very important to get it removed as soon as possible to prevent eye damage.
The way your eye heals depends on what the foreign body was and how it got there. If it was small and shallow and is removed quickly, your eye can often heal without any long-term effects. However, if the foreign body was large or deep, or got stuck in the middle of your eye, you might have lasting scars that could affect your vision. In some cases, the foreign body might even be carrying harmful germs that can cause an infection.
If the object pierces through your eye, it could lead to blindness. Certain signs, like an obvious eye wound, irregularities in the iris or pupil, blood in the eye, or damage to the lens, could indicate a severe eye injury. If these symptoms are present and you can’t find a foreign body, it might have gotten inside your eye. If you suspect this might have happened, you need to contact an eye doctor immediately.
