Common eye disorders
Learn about common types of eye problems below. Visit the supplied links for additional information.
You should treat any sudden changes to your vision as a medical emergency. See an optometrist or ophthalmologist immediately.
A refractive error is the most common eye problem. When the shape of the eye is abnormal, the eye doesn't bend (or refract) light properly, and so vision is blurred.
The most common types of refractive errors are:
- Long-sightedness (hypermetropia) - causing blurred close and distance vision.
- Short-sightedness (myopia) - causing blurred long-distance vision.
- Astigmatism - causes an uneven focus of light and blurred vision.
- Presbyopia - the eye lens loses flexibility, making close work difficult. This is most common with people over 40 years of age.
These errors can be corrected with glasses or contact lenses.
A cataract is a clouding of the lens of the eye. The lens is normally clear. Cataracts can occur in one or both eyes. Cataracts develop mostly in older people, but younger people can also get cataracts, and, in rare cases, babies are born with a cataract (congenital cataract).
Early cataract may be found during an optometrist or ophthalmologist’s examination, and good vision can be achieved with an adjustment in the prescription of previous distance glasses.
Early cataract can also coincide with the need to wear distance glasses for the first time for up to 30% of people older than 60 years, and cataract surgery may be unnecessary for these people for many years, where new glasses provide satisfactory visual acuity.
Cataract surgery is only necessary when, despite wearing appropriate glasses, the cataracts interfere with everyday visual tasks, e.g., reading, driving, hobbies and safe mobility.
Occasionally, there are other eye health reasons for cataract surgery such as narrow angles in the eye and differences in glasses prescription between the two eyes, but these are uncommon.
Diabetic eye disease
Diabetes can affect your eyes in several ways. That’s why it’s important to have a comprehensive eye exam as soon as you’re diagnosed with diabetes, then continue to have regular eye exams.
You should keep these regular appointments even if you don’t notice any symptoms. Early detection and treatment are the best way to prevent vision loss.
The retina is a layer of light-sensitive tissue on the inside back of the eye. In people with diabetes, the retina can slowly become damaged and cause vision problems. This condition is called diabetic retinopathy and it can cause permanent visual loss without timely detection treatment.
The longer you have diabetes, the more likely it is that you’ll get diabetic retinopathy.
Age-related macular degeneration (AMD) is a chronic and painless disease of the macula. The macula is an area at the very centre of the retina, at the back of your eye.
AMD causes progressive loss of central vision. It does, however, leave the peripheral vision intact. This loss of central vision affects the ability to read, watch TV, and recognise faces. By itself, AMD doesn’t lead to total vision loss (black blindness).
For some people, AMD advances very slowly and may not impact vision. For others, AMD may progress faster and lead to vision loss in one or both eyes.
If you have AMD, you should treat any sudden changes to your vision as a medical emergency. See an optometrist or ophthalmologist immediately.
Glaucoma is the name given to a group of eye diseases where vision is lost due to damage to the optic nerve. It causes irreversible vision loss due to damage to the optic nerve. The loss of sight is usually gradual and a considerable amount of side vision may be lost before there is an awareness of any problem.
Unfortunately, there is no cure for glaucoma, and vision loss can’t be reversed once it happens. If left untreated, glaucoma slowly causes irreversible vision loss and blindness.
The only way to manage glaucoma is to maintain the treatment prescribed by an eye care professional. Treatments can prevent further vision loss.Currently the only established treatment for glaucoma is to lower your eye pressure to an acceptable level.
Ongoing follow-up appointments are vital in maintaining effective glaucoma management.
Retinal detachment happens when the layer of tissue on the inside of the back of the eye (the retina) separates from the eyeball. It is more common in people who are short-sighted.
This is a medical emergency. The retina controls how you see. If it is damaged, you can lose your vision. Symptoms of detached retina are:
- light flashes and/or moving specks or cobwebs (floaters) from one eye
- Sudden loss of or change in vision - like a curtain pulled over their eye, or a shadow
- blurred vision or seeing an empty circle in front of you
- changes to peripheral vision
If you think you have retinal detachment, go to an emergency department immediately.
A corneal ulcer is an open sore on the cornea, which is the clear dome that covers the coloured iris in the eye.
Corneal ulcers are often caused by infection, such as infection after a physical injury to the cornea.
Symptoms include a red and irritated painful eye, foreign body sensation, blurred vision, and discharge.
Immediate medical treatment for a corneal ulcer lessens the chance of long-term damage to your vision.
Discharge from the eyes may mean you have an eye infection. Infections can be caused by a number of different things.
Common eye infections include:
- scratches or irritations caused by allergies to pollen, dust or smoke can also cause a discharge from your eyes
Blepharitis is inflammation of the margins of the eyelids. Both eyes are usually affected. The condition appears in two forms - anterior (or front) and posterior (or back) of the eyelid margins.
The most common cause is bacterial infection in the glands of the eyelids and eyelash follicles. Blepharitis can occur in children and adults of any age. Signs and symptoms include:
- a feeling of “something in the eye”
- excessive or frothy tears
- excessive blinking
- photophobia (sensitivity to light)
- crusty or sticky eyelashes, particularly in the morning
Conjunctivitis (pink eye)
Conjunctivitis, or ‘pink eye’, is a condition where the white part of the eye becomes pink or red. This is due to inflammation of the eye’s clear outer layer (known as the conjunctiva) and the inside of the eyelid.
Conjunctivitis can be highly contagious, and it is important that a doctor, optometrist, or pharmacist diagnoses the exact cause to ensure the right treatment can be given.
If it is bacterial conjunctivitis, there will often be yellow or green discharge from the eyes, which can make the eyelids stick together. One or both eyes might be affected.
If it is viral or allergic conjunctivitis, the discharge is likely to be clear. You might also have hay fever symptoms like an itchy nose and sneezing.
A stye is a small, painful cyst on your eyelid. It is usually caused from infection by bacteria at the base of an eyelash follicle.
The stye may feel sore and tender and may block part of your vision until it goes away. Styes usually clear up by themselves in 1 to 3 weeks, without treatment.
Uveitis is inflammation inside the eyeball. It involves the uvea – a layer of blood vessels that sits within the eyeball, under the white of the eye.
Uveitis can cause redness, pain, floaters, sensitivity to light and blurred vision. In serious cases, it can damage the eye tissue and lead to blindness.
Squint (strabismus or turned eye)
A squint or strabismus refers to a misalignment of the eyes. There are many different types of squint, but broadly speaking they can be divided into the following groups:
- esotropias, where one eye turns in towards the nose
- exotropias, where the one eye turns outwards
- hypertropias and hypotropias, where one eye is higher (hypertropia) or lower (hypotropia) than the fellow eye.
Blocked tear ducts
Tears form to keep the eye moist. They usually drain away through a small opening, near the nose, on each of the upper and lower eyelids. Then they travel through a narrow tube called a tear duct before draining into the nose. This is why your nose runs when you cry.
About 1 in 20 babies are born with a blocked tear duct. The duct might not be fully developed, or it might be too narrow. This then causes a blockage.
Adults get blocked tear ducts too, often from an infection. They can be caused by injuries, and occasionally by medicines.
Keratoconus is an eye condition affecting the cornea, which is the transparent surface of the eye.
Keratoconus occurs when the cornea slowly changes shape. While the cornea is normally shaped like a dome, with keratoconus it thins and becomes shaped like a cone. This affects the way the eyes focus light and can distort vision.
Keratoconus usually develops in younger people between about 16 and 30 and progresses until about the age of 40. It usually affects both eyes, though one eye may be worse than the other. If you notice any eye symptoms or changes to your eyesight, you should see your optometrist or doctor.
A 'twitching eye' or an 'eye twitch' are terms that describe muscle spasms in the eyelid. Most of the time these are mild and go away on their own. A twitching eye happens when the muscles in the eyelid contract (spasm) without someone's control.
Numerous factors can cause eye twitches, including:
- bright lights
- irritation of the eye or inner eyelids
- excess caffeine or alcohol.
Eye twitches can remain for longer than a week or become more serious, such as when the eyelid closes for a few seconds. See your doctor if they last more than 1 week or if they become serious and have other symptoms associated with them.
If you are colour blind, you will see colours differently to how most people see them.
Colour blindness is a common condition that is easily diagnosed and might not make too much difference to your life.