Eye Conditions

What is a refractive error?

The cornea and lens of your eye helps you focus. Refractive errors are vision problems that happen when the shape of the eye keeps you from focusing well. The cause could be the length of the eyeball (longer or shorter), changes in the shape of the cornea, or aging of the lens.

Four common refractive errors are:

• Myopia, or nearsightedness – clear vision close up but blurry in the distance

• Hyperopia, or farsightedness – clear vision in the distance but blurry close up

• Presbyopia – inability to focus close up as a result of aging

• Astigmatism – focus problems caused by the cornea

The most common symptom is blurred vision. Other symptoms may include double vision, haziness, glare or halos around bright lights, squinting, headaches, or eye strain.

Glasses or contact lenses can usually correct refractive errors. Laser eye surgery may also be a possibility.

What is presbyopia?

Presbyopia is a progressive vision condition in which the crystalline lens of your eye loses its flexibility, which makes it difficult to focus on close objects. This may seem to occur suddenly, but the actual loss of flexibility takes place over a number of years. Presbyopia is a natural part of the aging process of the eye and usually becomes noticeable in the early to mid-40s.

What is a cataract?

A cataract is a clouding of the lens in your eye. It affects your vision. Cataracts are very common in older people. By age 80, more than half of all Americans either have a cataract or have had cataract surgery.

A cataract can occur in either or both eyes. It cannot spread from one eye to the other. Common symptoms are: blurry vision, colours that seem faded, glare (headlights, lamps or sunlight may seem too bright, halo around lights at night), double vision and/or frequency prescription changes in your eye wear.
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Cataracts usually develop slowly. New glasses, brighter lighting, anti-glare sunglasses or magnifying lenses can help at first. Surgery is also an option. It involves removing the cloudy lens and replacing it with an artificial lens. Wearing sunglasses and a hat with a brim to block ultraviolet sunlight may help to delay cataracts.

What is glaucoma?

Glaucoma is a disease that damages the eye’s optic nerve. The optic nerve is connected to the retina — a layer of light-sensitive tissue lining the back of the eye — and is made up of many nerve fibers, like an electric cable is made up of many wires. It is the optic nerve that sends signals from your retina to your brain, where these signals are interpreted as the images you see.