Red Eye

What causes red eyes?

There are a number of causes of red eyes. The first was to determine the cause is to consider whether the red eye is painful or not.

If it is painful, the differential diagnosis includes conjunctivitis, corneal abrasion, corneal ulceration, uveitis, acute glaucoma. In general, it is worth getting seen by an optician or ophthalmologist for most of these as they can be permanently sight threatening.

In cases where the eye is red but not painful, the differential diagnosis includes conjunctivitis, episcleritis, dry eye and blepharitis. These conditions are relatively more benign and can often be treated with less urgency.

Considerations include whether one or both eyes are affected as conditions such as blepharitis, dry eye and conjunctivitis usually affect both either immediately or sequentially. Episcleritis is a benign, usually self-limiting condition and usually affects only one eye at a time.

Vision is an important factor and if the vision is impeded, it is worth instigating an appointment with an optician or ophthalmologist more promptly. To test the vision, it is necessary to test one eye at a time as they work together. This can be done by covering each eye sequentially with the palm of a hand and looking through the other eye as a fixed object in the distance and comparing the two eyes.

What should I do if I have a red eye?

If in doubt, it is worth seeing advice and the first port of call can often be your own optician. This may be quicker than seeing your GP and more convenient than getting to the hospital. They will have all the equipment to distinguish the more serious causes such as corneal ulceration, iritis and acute glaucoma and can usually refer you to the hospital eye casualty clinic promptly without having to go through the accident and emergency department. In fact, opticians do a four-year training programme looking at eyes and relevant problems whereas the general doctor in accident and emergency has only had a two-to-four-week placement in medical school to learn about eye problems. Many optometrists can prescribe drops to treat a number of eye conditions independently. An ophthalmologist is a doctor that specialises in eyes and you may be referred to the hospital eye clinic if further treatment or surgery is needed for an eye condition.