Understanding and Treating Corneal Scratches and Abrasions

Corneal Scratches and Abrasions

Call it a scratch, an abrasion or erosion; no matter how you describe it or what the cause, damage to the cornea most always causes pain.

So what exactly is the cornea and why can even a small scratch hurt so much? The cornea is the clear dome at the very the front of the eye. Its primary job is to surface the tears and with them, focus light into the eye. It then passes through the crystalline lens and on to the retina where it is transformed into electrical impulses that are ultimately transformed by the brain into sight.

Because vision is so essential for survival and the cornea so critical to seeing, it is among the most richly innervated and exquisitely sensitive of all tissues. Even the smallest piece of dust that finds its way into the eye and touches the cornea can cause significant discomfort, irritation and copious tearing in an attempt to wash it away. A healthy cornea is transparent and consists of several layers that give the cornea its smooth dome like shape. The outermost layer, the epithelium, is designed to break away to protect the delicate deeper layers if scratched or abraded.
cornea layers - corneal scratches and abrasions

Looking For the Cause

The most common causes of corneal scratches are accidents. Tiny infant fingers and fingernails are a common cause of abrasions in young parents, tree branches are a frequent source of abrasions in hikers and lovers of the outdoors, and makeup brushes are a typical cause in women. Scratches can also be caused by foreign objects that get into the eye and then work their way on to the inside of the upper lid – causing a scratch that occurs with each blink. That’s why its important to carefully investigate the cause of every corneal scratch.

A scratch pr abrasion usually produces near instantaneous pain and tearing as the eye tries to wash away the irritant. Light sensitivity soon follows and can be so intense that the eye can involuntarily shut. This is actually nature’s way of “patching” the eye to facilitate healing.

To confirm you have a scratched cornea, a doctor or other health care professional will often apply a wetted fluorescein strip to the inside lid or white of the eye. Fluorescein is a dye that glows bright green when exposed to black light. The dye is absorbed by damaged areas, clearly showing the area if the scratch or abrasion.

Getting On the Mend

The good news is that most scratches will rapidly heal on their own, especially smaller and more superficial ones. The confocal microscope, a high tech device that provides extreme magnification views of living tissue, has been used to observe corneal healing in real time. The video captures are breathtaking as individual corneal cells can be seen literally stretching over each other to mend and seal the corneal surface.

If an abrasion is larger or deeper it may require patching to help healing. The traditional eye patch applied with tape to keep the eye shut has largely been replaced by the bandage contact lens which is far more comfortable and allows some vision and easier observation during follow up examination. It also allows medication to be applied if needed. Because there is a risk of infection whenever the outer boundaries of the body are breached, topical antibiotics are often used as a precaution in treating scratches of the cornea and ocular surface.

Most commonly the cornea heals quickly and completely, but not always. In rare cases damaged areas of the cornea may not heal fully, leaving the outer layers of the cornea susceptible to coming off again for no apparent reason. This is thought to be more common after scratches caused by organic material such as a tree branch. Called recurrent corneal erosions, they often occur during sleep waking the person with a sudden sharp pain and excessive tearing. There are a variety of treatments for recurrent corneal erosion.

Conclusion

Most people will sooner or later experience a scratched cornea. Most scratches will be minor and will resolve with minimal treatment. However, some can be serious and have significant consequences. The best way to avoid problems is to be aware that they can occur and take measures to protect the eyes in situations where the risk of eye trauma is higher. This includes: wearing safety glasses while working with power tools, or sports where eye contact is possible. This includes cycling and sport shooting.

Be aware of active infants with little fingers that seem to have a magnetic attraction of their parents eyes. If you use eye makeup, leave enough time to properly apply it without rushing and potentially scratching your cornea in the process.

Finally, if you experience a scratched cornea and the pain doesn’t rapidly abate, see an eyecare specialist. Urgent care centers are fine for most things, but when it comes to the eyes finding a knowledgeable eye care professional is wise.

2/10/15

AArthur B. Epstein, OD, FAAO
co-founder of Phoenix Eye Care
and the Dry Eye Center of Arizona
Fellow of the American Academy of Optometry
American Board of Certification in Medical Optometry
Chief Medical Editor of Optometric Physician™

Dry Eye and Tear Dysfunction

4/24/14

With an aging population and increasing awareness of the condition, dry eye has become one of the hottest topics in eye care today. There have been numerous advances in our understanding of the condition as well as several breakthroughs in treatment.
eye drops in eye
Lets start with the most fundamental question. Why do we have tears? Tears serve many functions, but perhaps the most important is that they create a perfectly smooth optical surface at the front of the eye to allow sharp focusing. The sharper your vision the more quickly you can spot and run from a predator or find a supply of food. Hence, a stable tear film is critical for survival. As a result, the body has evolved many ways to help keep the tears healthy and intact.

When I describe the tears to a patient I describe it as a structure. Tears have a foundation that anchors them to the eye’s surface, an elastic protective support section not that different than the walls in a building and even a roof, just like a house has. Like a house, problems with any structural part can adversely impact the entire building.

Over the past few years the most important breakthroughs in understanding dry eye have focused on the outer portion of the tear structure – what you might think of as the roof. When a roof develops holes and it rains, water gets in which can destroy the entire structure of the house. With the tears, holes in the “roof” can let moisture evaporate causing the structure to collapse and become unstable.

The outer layer of the tears consist of lipid or oil produced by the meibomian glands – glands that run radially through the lids and express small amounts of complex oil with each blink. When these glands work properly, the oils they produce coat the tears, preventing evaporation and stabilizing and lubricating. When the glands become blocked – which can occur for a number of reasons including decreased blinking due to excessive computer use, the lack of oil can lead to a down spiral of damage to the eye’s surface with symptoms that can range from annoying to life altering.

Lets talk for a moment about symptoms. We know that dry eye is progressive and, if left untreated will worsen over time, so the sooner we know about it, the sooner treatment can begin. I am often surprised that even with increased awareness, most patients don’t recognize that they suffer from dry eye until the condition is fairly advanced. One reason is that many people think that the symptoms of dry eye are a normal and expected part of aging. For the most part they are not. If you experience, burning, irritation, unstable vision, grittiness or any change in your vision or eye comfort, you should bring this to the attention of your eye care practitioner.

One of the most common signs of dry eye is excessive tearing. Patients often complain that their eyes are too wet and I have to explain that the excessive tearing is the eye’s way of trying to correct for dryness and prevent further damage. Unfortunately excessive tearing further destabilizes the tears and makes matters worse.

Lipiview System
Lipiview System

Perhaps the greatest advance today is the recognition that meibomian gland dysfunction causes or contributes to nearly 90% of all dry eye. Many eye care providers are adding high tech tools like meibography which can show the actual state of the meibomian glands like an X-Ray and LipiView which measure the actual thickness of the lipid layer of the tears. As a result diagnostic ability has improved.

Lipiflow Device
Lipiflow Device

Recently introduced eyedrops like Alcon’s Systane Balance and Allergan’s Refresh Optive Advanced Formula drops can help restore absent or deficient oils in the tears. And new treatments including moist heat goggles like Tranquileyes by EyeEco can help improve comfort. LipiFlow, a technology pioneered by TearScience, offers a breakthrough treatment that can clear blocked and reset meibomian glands. It can produce amazing improvement.

There have also been significant advances for contact lens wearers suffering from dry eye. Scleral lenses are especially helpful for patients with advanced dry eye who also must wear contact lenses to see, such as those who have keratoconus. The large scleral lens serves as a barrier that protects the eye and provides sharp stable vision. In fact, scleral lens designs are used as a treatment for severe dry eye and ocular surface disease.

Finally, if you have been diagnosed with dry eye previously and are still suffering despite treatment, this may be a good time to return to your eye care provider to discuss your condition and explore the possibility of new treatment options.

AArthur B. Epstein, OD, FAAO
co-founder of Phoenix Eye Care
and the Dry Eye Center of Arizona
Fellow of the American Academy of Optometry
American Board of Certification in Medical Optometry
Chief Medical Editor of Optometric Physician™