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Understanding Vision Problems -- the Basics

Other Eye Conditions That Lead to Vision Problems

There are other eye conditions that respond in varying degrees to medical and surgical treatment. The most common of these eye problems include:


The lens of the human eye focuses light so that you can see objects clearly at various distances. It contributes about one-third of the eye's focusing power and must remain transparent for clear vision. The clouding of the lens is called cataract. As we age, cataracts block or distort light entering the eye, and we experience a gradual, persistent, painless blurring of vision, as though we are looking through a haze. Cataract vision may be worse in dim light. Glare is a common problem for cataract patients who need to drive at night.

Cataracts are the leading cause of blindness, accounting for more than 20 million cases worldwide. Cataract surgery is the most frequently performed surgery in the U.S. with about 3 million procedures performed every year. The procedure can successfully restore lost eyesight in most cases. Once the cloudy lens is removed, the surgeon implants a transparent artificial lens to take its place.


The conjunctiva -- the moist, transparent membrane that covers the eyeball and your inner eyelid -- can become inflamed for various reasons. Most cases of conjunctivitis (commonly called pink eye) run a predictable course, and the inflammation usually clears up in a few days. Although infectious conjunctivitis can be highly contagious, it is rarely serious and will not usually harm vision permanently if detected and treated promptly.

There are several forms of infectious conjunctivitis:

  • Bacterial conjunctivitis usually infects both eyes and produces a heavy discharge of pus and mucus. It is treated with antibiotic eye drops.
  • Viral conjunctivitis usually starts in one eye, causing lots of tears and a watery discharge. The other eye follows a few days later. Like a common cold, this infection will clear up without treatment.
  • Allergic conjunctivitis produces tears, itching, and redness in the eyes, and sometimes an itchy, runny nose. Allergy drugs in the form of pills or eye drops will relieve these symptoms.
  • Ophthalmia neonatorum is an acute form of conjunctivitis in newborn babies. The infection is acquired from the mother during delivery. It must be treated immediately by a doctor to prevent permanent eye damage or blindness. These infants often have infections elsewhere, such as in the lungs.

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