The structure of the face is designed to protect the eyes from injury. Each eyeball is set into a protective socket of bone (known as an orbit), and the eyelids can close very quickly to form a protective barrier.
However, eye injuries can still occur, usually as a result of a scratch or graze (abrasion) caused by something in the eye such as grit or a contact lens.
These injuries cause damage to the cornea, which is the transparent outer layer of the eye. The cornea covers and protects the coloured part of the eye (iris), and lets light into the hole in the centre (pupil).
Although it appears to be very thin, the cornea is made up of five layers. From the outside of the cornea to the inside, the layers are:
An eye injury is considered to be superficial (affecting only the surface) if it does not penetrate beyond the Bowman's membrane.
A superficial eye injury will usually take 24-72 hours to heal, depending on the size of the abrasion. Eye injuries can be treated with eye drops to prevent infection and oral analgesia (painkillers) to treat pain.
Most eye injuries are caused by scratches, or grazes (abrasions) to the transparent outer layer of your eye (cornea).
In many cases, eye injuries occur as a result of grit coming into contact with your eye, or if you scratch your eye accidentally with a fingernail, plant, or paper.
In some cases, injuries to your eyes can also be caused by small, high-speed objects, such as grit, or small stones being thrown up by lawnmowers, or dust particles created by chiselling, grinding, or hammering.
You should see your GP as soon as possible if your eye injury was caused by an object hitting your eye at high speed.
Wearing contact lenses incorrectly can also injure your eyes. For example, you may injure your eye if your contact lenses do not fit properly, if you have left them in your eyes for too long, or left them in while you are asleep.
It is also possible for a foreign body, such as a tiny particle of dust, or dirt, to become trapped behind your contact lens and cause irritation.
If you think that you have injured your eye, you should see your GP or, if possible, visit the emergency eye clinic at your local hospital.
This is particularly important if your injury was caused by an object hitting your eye at high speed – for example, a stone being thrown up from a lawn mower, or while hammering, or chiselling. Your GP will ask you about your symptoms and how your injury was caused.
In order to assess the extent of your eye injury, your GP will also examine your eye. If your eye is painful, anaesthetic eye drops may be used to numb your eye before examining it.
During the eye examination, your eye will be checked for a scratch or graze (abrasion), and for the presence of a foreign body, such as grit or dust.
If you have an abrasion on the outer layer of your eye (cornea), your GP may put eye drops containing a special dye called fluorescein into your eye. These eye drops stain any damaged areas of your cornea bright green and make them easier to see. A cobalt-blue filter may also be used to further enhance any abrasions.
If your GP thinks that your may have a foreign body stuck in your eye, they may turn your eyelid gently inside out and examine your eye using a magnifying glass.
As part of your eye examination, you may be asked to look around in all directions. This is to check whether or not there is any damage to your extra-ocular muscles, which connect your eyeball to your eye socket (orbit), and control the movement of your eye. You may also be asked to blink several times to test whether your eyelids are working properly.
Your GP may also shine a light into each of your eyes to assess the contraction of your pupils, which should become smaller when the light is shone into them. In some cases, a slit lamp (a lamp that emits a narrow beam of intense light) may be used to check for any damage to your eye which may be difficult to see.
In order to test your sharpness of vision, your GP may ask you to read letters of various sizes from a chart on the wall, as you may have done during an optician's assessment. This is called a Snellen chart.
If your eye is red, other conditions which can cause this will need to be ruled out. Some of the mild conditions which may cause red eye include:
Some of the more severe conditions which can cause red eye include:
If your GP thinks that you may have any of these conditions, they will refer you for specialist treatment from an ophthalmologist (a specialist in eye conditions).
If you have injured the outer layer of your eye (cornea), it is likely that you will have eye discomfort, or the sensation of something being stuck inside it. You may also have a watering eye.
Other symptoms of a superficial eye injury may include:
Superficial eye injuries are minor, but because the area around the eye bruises particularly easily, many look worse than they are.
If you do experience an injury to your eyes this may have implications for driving.
However, you should see your GP if your eye is very painful, if you have a burning sensation or bleeding in your eye, or if your vision becomes more than mildly affected in any way.
The way in which eye injuries are treated depends on the extent of the injury and symptoms, and, in some cases, how the injury was caused. Although infections following eye injuries are rare, they can be severe so it is likely that your GP will prescribe antibiotics to prevent infection.
You may need specialist treatment from an ophthalmologist (a specialist in eye conditions) if:
If there is a foreign body in your eye, such as a piece of grit, your GP may try and remove it. They will put anaesthetic eye drops in your eye first, in order to numb it and prevent any pain.
If the foreign body is easy to get to, it may be possible to remove it by simply rinsing your eye with water, or by wiping it away with a cotton wool bud or triangle of card. However, if this is unsuccessful, your GP may try and remove the foreign body by lifting it out with the tip of a small metal instrument.
The foreign body could be stuck underneath your upper eyelid, especially if you can feel something there, or you have scratches or grazes (abrasions) on the top half of the transparent outer layer of your eye (cornea). If this is the case, it may be necessary to gently turn your eyelid inside out in order to remove the foreign body.
Once the anaesthetic eye drops have worn off, your eye may feel a bit uncomfortable until your abrasion heals.
If your eye is painful, an analgesic (painkiller) may be recommended in order to control your pain. This will usually be paracetamol or ibuprofen, although you should not take ibuprofen if you have asthma.
In order to prevent infection in your eye after an eye injury, you may be prescribed a course of eye drops and ointment containing an antibiotic called chloramphenicol. Most people will need to take the eye drops four times a day, and use the ointment at night before bed, for seven days.
However, you may not be able to take chloramphenicol if:
If you normally wear contact lenses, you should not do so until your eye injury has completely healed. If you are prescribed antibiotic eye drops, you should not start wearing your contact lenses again until 24 hours after finishing your treatment.
In most cases, eye injuries to your cornea heal within 24-72 hours. You will need to return to your GP after 24 hours of your initial treatment, so that your GP can check that your eye injury is healing properly.
Your eye will be re-examined using fluorescein eye drops, which stain any abrasions bright green so that they are easier to see. If your eye injury has begun to heal, you will need to return to your GP daily until it has healed altogether.
However, if your eye injury has not begun to heal after 72 hours, or has worsened, your GP may refer you for specialist care from an ophthalmologist (a specialist in eye conditions).