Cuts of the eye and first aid tips

Corneal lacerations-cuts to the eyeball

Mr L, a trainee carpenter, was trying to remove a nail from a piece of wood. He was thinking of getting off early that day, because of a date that evening to celebrate his girlfriend's birthday. As he levered the nail with the claw of the hammer, he suddenly felt it give and the nail flew off, straight into his eye.

The cornea is the clear window at the front of the eye. It is also the part of the eye closest to the object being looked at. 

Being constantly exposed to the environment, corneal injuries are a fairly common problem. They range from foreign bodies such as metallic particles from drilling or welding work, to abrasions/scratches, lacerations and chemical injuries.

Corneal lacerations occur when a sharp object cuts or pokes the cornea. They may be partial thickness, or they may go through the full thickness of the cornea and affect the inner parts of the eyeball.

Apart from direct damage to the eye, corneal lacerations are serious injuries which may also damage the eye by causing an infection, or impair vision because of corneal scarring after the eye heals.

Causes of lacerations

Common causes include flying objects, which may happen, for example with a nail as above or while cutting grass with an uncovered mower and while drilling and hammering. Broken glass from road traffic accidents are also a notorious cause of lacerations.

At the time of injury, a severe sharp pain will be felt as the cornea is one of the most sensitive parts of the body. There is almost always a clear history of a foreign object cutting or flying into the eye.

After the injury, vison is commonly blurred, especially if the laceration is deep and close to the centre of the cornea. There may be increased sensitivity to light, tearing, and it may be difficult to open the eye.

What the doctor will do to examine the eye

The doctor will usually instil some local anaesthetic eyedrops first to numb the eye and allow comfortable examination. Usually a careful examination on a slit lamp microscope then follows, with the doctor determining whether there are any remaining foreign bodies, and also very importantly, the depth of the laceration. If the cornea suffered a full thickness cut, fluid may leak from inside the eye, or internal parts of the eye such as the iris may protrude outwards.

A full thickness laceration has occurred in the centre of Mr L's eye. The nail penetrated the cornea, and also the lens of the eye, which has become a trauma induced cataract. Fine black nylon stitches were used to close the laceration.

Treatment of corneal lacerations

First aid for suspected corneal lacerations

• ·         Do not attempt to remove any foreign bodies or what appear to be foreign bodies/dirt (protruding parts of the eye may look like foreign bodies or dirt)
• ·         Do not wash or press on the eye
• ·         If possible, obtain an eye shield or fashion one from a plastic cup. This is easily done by cutting the cup around the rim about 1-2cm from the bottom, so that the cup now only has a shallow rim. (see below)
• ·         This can be taped so that the rim rests on the bony edges of the eyebrow and cheek.
• ·         Send the patient straight to a specialist eye clinic or the emergency department.

Cuts of the cornea require different types of treatment, depending on how long or large they are, and even more importantly, whether the eye is penetrated.

If the cut is small and only affects a partial thickness of the cornea, it is treated like a corneal scratch or abrasion. Usually, this type of injury heals well with some antibiotic eyedrops to prevent infection, and the removal of any remaining foreign bodies. A bandage contact lens is sometimes used to protect a long shelving laceration.

For a corneal laceration that cuts through the full thickness of the cornea, the situation is more complicated. Usually, the first step, which is performed by the eye surgeon in an operating theatre, is to clean the wound and to stitch up the cornea so that there is no longer any fluid leakage from the eye. If there is internal tissue protruding from the eye, this is carefully repositioned into the eye when possible. Where there is more extensive damage such as lens damage causing a cataract, this may be dealt with at a second stage when tests are done to allow selection of the most suitable lens implant for the patient.

Mr L had his corneal laceration stitched up, followed by a cataract removal operation and lens implant. He now has good vision in that eye, however, due to the cataract surgery now has 'presbyopia' in that eye because the lens implant cannot autofocus like his original lens could before.

Prevention of corneal lacerations

·      These injuries can be prevented by wearing protective eyewear when engaging in activities such as grass cutting, hammering or drilling.

Corneal lacerations are potentially very serious injuries of the eye. Besides possible internal eye injuries, infections can also occur and lead to impaired vision. Do take care and use safety eyewear when engaging in hazardous activities, as the old adage ‘prevention is better than the cure’ certainly holds true here.

Stories of stubborn grit in the eye

A middle aged man was on his way to Bangkok from Singapore when he felt something blow into his eye at the airport. Trying to clear the irritation, he rubbed his eyes. The irritation persisted and while in Bangkok a doctor could not find anything wrong and patched the eye up. Unfortunately, this did not help much.

He returned to Singapore the next day at the end of the work trip and when I saw him the eye was obviously red and tearing. The picture below shows a green area with surrounding green dots and lines. These represent raw areas on the surface of the eye where the surface cells (epithelium) have been scratched away. 

(Note: I have put some fluorescein drops into the eye-this vegetable based dye tends to stick to raw areas, and gives off a green light when blue light is shone onto it. This makes it very valuable for highlighting abrasions/scratches ont he eye. )

Even before I did anything else, I knew there was something still in the eye. The green lines indicated that very fresh scratches were occurring at the time itself by blinking and eye movements. I automatically 'everted' the eyelid (turned it so that the inner surface faces outwards-some small children like my youngest daughter can do it as a trick to look like a ghoul [below]!)

The picture below shows a tiny yellow spot just to the left of center. The yellowness is actually from the fluorescein dye-if I had not put fluorescein in, it would have been invisible as it was transparent.

Having found the culprit, it was a simple thing to get a pair of jeweller's forceps (mini tweezers) to grab and remove the foreign body. Most of the time when we remove such things, it is impossible to say what it was or where it came from. The picture below shows the offending object at the end of the forceps-a nondescript, fluorescein stained stiff strand-I suspect some little bit of plastic.

When looking for such things, I am fortunate enough to have a slit lamp microscope and of course, the good ol' fluorescein. Very few things escape such scrutiny. Except...

There was a similar case that initially flummoxed me a couple of years ago. A Japanese lady went to the Accident and Emergency Department of a local hospital and I was called to see her. She similarly complained of a stubborn, persisting scratchy sensation in her eye. I did my usual, but try as I might, I could not see a foreign body. She certainly did have scratches on the cornea, but with no sign of a foreign body even with fluorescein eyedrops instilled, I thought the foreign body had been washed out by her tears. I inserted a bandage contact lens and she felt better.

I checked on her a couple of days later and she said she was feeling fine, so I removed the bandage contact lens. Almost immediately, she started tearing and as I looked, scratches were starting to appear on the cornea again! (See pic below) So I everted the eyelid at the slit lamp, but still could not see anything. OK, this calls for plan B...

I brought her to our small treatment room and used an operating microscope this time. With her lying down I could 'double evert' the eyelid-lo and behold-there was a small stitch protruding from the inner surface of the upper eyelid!
NB: In double eversion we evert the eyelid a second time to expose things even higher up in the little pocket called the 'conjunctival fornix'. This stitch was at the upper end of the stiff 'skeleton' of the eyelid, the tarsus.

It turned out that she had double eyelid surgery some years ago, and the person doing it had used a method utilising just stitches. These stitches are often permanent, and do not dissolve on their own. Over time, it had slowly eroded out through the inner surface of the eyelid and the ends of the stitch were now poking the cornea. With that, it was a simple matter to cut the stitch and remove it-problem solved.

Did the double eyelid disappear? No, because after some months collagenous 'scar' tissue forms around the stitch and anchors the skin around the eyelid fold down to the underlying tissues, thus creating a permanent effect that persists even if the stitch is taken out.

I guess the message is, if there is any stubborn grit/irritation in the eye, firstly don't rub the eye, and secondly don't hesitate to visit your friendly eye doctor!