Cataracts form painlessly. The most common cataract symptom is cloudy or blurry vision. Everything becomes dimmer, as if seen through glasses that need cleaning. Surgery is the only way to cure cataracts, but surgery is not always necessary. Some people can improve their vision with lifestyle changes. In this Health Alert, Johns Hopkins answers the question, "How can you tell it's time to undergo cataract surgery?"

Cataracts cause cloudy, even double vision, and a problem with glare. At first, many people can switch eyeglass prescriptions, use magnification, and add to their home lighting to address any loss of vision. But it's time to consider cataract surgery when changes in vision begin to interfere with day-to-day activities such as driving and reading. In that sense, the decision is personal, and in most cases, you won't harm your vision by taking your time to decide.

However, in young people or in those with diabetes, a cataract can develop rapidly, making the need for a decision more immediate. In other cases, cataracts may interfere with the treatment of another eye problem such as age-related macular degeneration, diabetic retinopathy, or retinal detachment. In those cases, the cataract may need to be removed to allow effective treatment of a retinal disorder, even if the cataract is not con- tributing to the vision deficit.

Before recommending cataract surgery, your eye doctor will ask you about functional difficulties you may be having with reading, driving, or other activities and measure your visual acuity. Your doctor may also test your eyes for loss of contrast sensitivity or the effects of glare. In addition, he or she may ask you to complete a quality-of-vision questionnaire to help assess your ability to do different daily tasks like reading. Your answers and the results from these tests can help determine whether it's time to consider cataract surgery.