“How do I know I have a corneal abrasion?”
A scratch on the eye can cause a painful corneal abrasion. They are one of the most common of minor eye injuries.
Corneal abrasions can be caused by:
- a nick
- a scratch
- a scrape from a sharp object such as paper
- a baby’s fingernail
- a pencil
- a staple
- a nail
- a sewing pin
- a needle
- minor rubbing
- trauma if you have a very dry eye
Corneal abrasions can often occur after LASIK refractive surgery where there is dry eye, and the epithelium is unstable.
How do you know if you have a corneal abrasion?
It will be exquisitely painful and your eye will be very light sensitive. The onset is very rapid and, usually, you can relate it to a minor trauma from one of the objects listed above, or even from contact lens wear and overwear.
What is the cornea?
The cornea is the clear, round, domed covering of the front of the eye, in front of the iris and the pupil. It is transparent, and through it you can see the person’s iris and pupil. It helps to focus light as it enters the eye and directs light through the pupil to the retina, then the brain, so that you can see clearly.
The cornea is very tough and helps to protect the inside of the eye from the outside world. It has various cellular layers starting at the front with a corneal epithelium. This consists of clear epithelial cells without any keratin, and it has a strong, deep layer of the epithelium called the Bowman’s layer.
A corneal abrasion is, in fact, a corneal epithelial abrasion and is usually only affecting the superficial layer of the cornea. The main bulk of the cornea is called the stroma, which is made up of clear collagen fibres. Next to the stroma is another strong membrane called Descemet’s membrane. Just beyond Descemet’s membrane is a single layer of endothelial cells, which have a high metabolism and help to provide nutrients to the deeper part of the cornea.
What are the most common causes of a corneal abrasion?
Small children and paper are probably the most frequent cause of a corneal abrasion.
Small children can accidentally poke your eye with a tiny fingernail, and you can accidentally prod your eye with the sharp edge of a sheet of paper. Though sometimes the immediate cause of your corneal abrasion may not be apparent as the symptoms can appear a few hours after the minor injury to the cornea.
I have already mentioned many sharp objects above, but other things can cause a corneal abrasion, such as something hitting or blowing into your eye, for example:
- plant material
These are either being blown into the eye or getting stuck underneath the eyelid. When you rub the eye, the foreign matter is pushed into the cornea and causes loss of the little epithelial cells and a resultant painful corneal abrasion.
Sports injuries can cause this condition, where somebody else’s fingernail accidentally brushes against your eye, causing a scrape along the corneal epithelium and a painful corneal abrasion.
Contact lenses can cause a corneal abrasion, especially if they are too tight or they are not well maintained, and they have some grit under them.
If you have eye surgery, the eye surface can dry out under the bright lights either from the operating lights or operating microscope and the epithelium, once dry, can slough off causing a corneal abrasion.