Refractive Errors—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
• Colors that seem faded
• Glare – headlights, lamps or sunlight may seem too bright. You may also see a halo around lights.
• Not being able to see well at night
• Double vision
• Frequent prescription changes in your eye wear

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.

NIH: National Eye Institute

• Cataract (Medical Encyclopedia)
• Cataract removal (Medical Encyclopedia)
• Slit-lamp exam (Medical Encyclopedia)
• Standard ophthalmic exam (Medical Encyclopedia)

Also called: Farsightedness, Hyperopia, Myopia, Nearsightedness

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.

NIH: National Eye Institute

• Astigmatism (Medical Encyclopedia)
• Facts about Presbyopia – NIH (National Eye Institute)
• Farsightedness (Medical Encyclopedia)
• Nearsightedness (Medical Encyclopedia)
• Presbyopia (Medical Encyclopedia)
• Refraction test (Medical Encyclopedia)