There are a significant number of causes of red eye and the most common is having dry eyes. The eye is a delicate organ and is sensitive to both external and internal factors. Red eyes arise due to the blood vessels of the whites of the eye dilating in response to some sort of exacerbation.
Here we will go through just some of the numerous causes of red eye and what can be done about them.
Hay fever and other allergies to pet dander and dust mites are a well-known cause of red eye, typically accompanied by other allergy symptoms such as itching, watery eyes, and sneezing. However, red eyes may also be caused by allergy or hypersensitivity to certain eye medications, such as anti-glaucoma drops or the preservatives contained within any other eye drop.
Antihistamines, either oral tablets or eye drops, can be useful against hay fever or similar allergies, though in very severe allergies such as atopic keratoconjunctivitis, stronger steroids may be required. If the red eyes are a result of sensitivity to topical eye medications it is best to speak to your prescribing eye care practitioner to see what alternatives may be suitable for you.
Irritation from dry eye is probably one of the most common causes of a red eye. Dry eye disease is a complex condition and is now understood to involve a degree of inflammation on the surface of the eye. It may be exacerbated by other factors such as the environment or blepharitis, a condition involving inflammation of the eyelids and accumulation of irritants around the eyelashes. Treating dry eye can be complicated but a good place to start is tear lubricants, which can be purchased off the shelf at pharmacies or supermarkets.
Physical trauma to the eye can easily cause a red eye. This may be blunt trauma, such as a ball to the eye socket, or a sharper injury, such as a fingernail scratch. Chemical burns may come from accidental splashes or spills of acidic or alkaline chemicals, including common household cleaners. Any significant trauma to the eye such as a high-speed blunt injury or chemical burn should be treated immediately as an emergency.
Red eyes from an eye infection can range from a harmless common conjunctivitis to a sight-threatening infection of the cornea, known as keratitis. Infections causing red eyes may come from bacterial causes, viral, fungal, or even parasitic.
Contact lens wearers who experience red eye should immediately remove their lenses and see an eyecare practitioner, as eye infections tend to be more severe in contact lens wearers. Red eyes accompanied by changes to vision and/or discharge from the eye, whether mucous, pus or watery discharge, should see an eye care practitioner for proper diagnosis and treatment.
Inflammation of various structures of the eye can all cause red eyes as a symptom. These include uveitis, episcleritis, and scleritis. Most of these conditions are associated with pain and light sensitivity but may not be in all cases. Examination by an eyecare practitioner will allow proper diagnosis and treatment, often involving anti-inflammatory eye drops or tablets. In some cases, these conditions are associated with an underlying systemic disease and so may require referral to a GP for further testing.
This can involve a sudden, alarming presentation of a very red eye, usually in one section of the whites of one eye. There is usually no pain or any significant discomfort but a patient may mention being able to feel some sort of swelling in the eye. A subconjunctival haemorrhage is a result of a burst blood vessel beneath the clear membrane (conjunctiva) overlying the whites of the eye. Blood becomes trapped in this space and gives the appearance of a bloodshot, red eye.
Such cases often occur with no known preceding trauma, but can sometimes be associated with activities such as strong sneezing, vomiting, or coughing. The blood will clear away itself in a matter of days, depending on the size of the haemorrhage, but applying a warm compress may help it to resolve more quickly.
As you can see, red eyes can come from a myriad of causes, some of which can be ignored and tolerated while others must be attended to urgently. Naturally, the best way of how to get rid of red eyes depends on the underlying cause.
If in doubt of whether it is okay to self-treat a case of the red eye, consider whether there is any accompanying discomfort or effect to the vision and if so, see an eye care practitioner to be safe.