Instructions: Given a passage and a query based on the passage, generate an unambiguous, concise and simple answer to the query from information in the passage. Note that the answer may not be present in exact form.
Input: But replacing the cloudy cataract with a conventional artificial lens will at least improve their vision to some degree. Q: Can cataracts be prevented? A: Good question. There are many places in the world where cataract surgery isn't available. As a result, an estimated 20 million people worldwide are totally blind from cataracts. So if you could delay the onset of this aging change, you might prevent severe vision loss in a significant number of people. The First Few Weeks After Surgery. 1 You can bath or shower, but avoid getting water in or near your eye. 2 Typically, you will have a follow-up visit with your cataract surgeon the day after surgery. 3 Have someone drive you to your follow-up visit. 4 Wear dark, ultraviolet (UV) protective sunglasses when outdoors. Occasionally, cataract surgery fails to improve vision because of underlying eye damage from other conditions, such as glaucoma or macular degeneration. If possible, it may be beneficial to evaluate and treat other eye problems before making the decision to have cataract surgery. Seek medical advice as soon as possible if you experience: 1 a throbbing or severe pain in or around your eye. 2 a severe frontal headache with or without nausea and vomiting. 3 a sudden deterioration or loss of vision. 4 increasing redness in your eye. A review of a number of studies found 95% of people with a monofocal lens and about 70% of people with a multifocal lens needed glasses after having cataract surgery. Another type of artificial lens called an accommodating lens is designed to act in a similar way to a natural lens. If you have cataracts in both eyes, your doctor usually schedules the second surgery after the first eye has healed. Results. Cataract surgery successfully restores vision in the majority of people who have the procedure. People who've had cataract surgery may develop a secondary cataract. You may have a pad and plastic shield over your eye when you leave hospital, which can usually be removed the day after surgery. Feeling should start to return to your eye within a few hours of surgery, but it may take a few days for your vision to fully return. It's normal to have: grittiness ; watering; blurred vision; double vision; red or bloodshot eye; These side effects usually improve within a few days but it can take 4 to 6 weeks to recover fully. If you need new glasses, you won't be able to order them until your eye has completely healed usually after 6 weeks. Cataract surgery has a high success rate in improving your eyesight and should allow you to return to your normal activities, like driving. When to seek help. Contact your eye surgery department as soon as possible if you experience: increased pain and/or redness; increased stickiness; decreased vision; Dos and don'ts. For the first few weeks after surgery: Do: use your eye drops as instructed ; take it easy for the first 2 to 3 days; use your eye shield at night for at least a week ; take painkillers if you need to A , Ophthalmology, answered. Vision usually improves rapidly (within a few days) following cataract surgery. For some, vision may be excellent within hours. For others, it may take several days or even a few weeks to return to normal. This longer interval does not necessarily indicate any complication or failure of the surgery. Immediately After Cataract Surgery. 1 At the conclusion of your cataract surgery, a lightweight protective shield will be placed over your eye, held in place with surgical tape. This shield will decrease the risk of injury from inadvertently rubbing or accidentally bumping your eye. Activity Suggestions. Returning to the activities that you engage in every day will help your eyes and brain adjust to life after cataract surgery. But you will likely find your vision so improved that you are motivated to resume activities or hobbies that you haven't been able to do for a long time. And you may even find that you'd like to take up a few new ones. Depending on how long it has been since your surgery, and whether you need or have had surgery in one or both eyes, you may still be adjusting to the change. Query: how long does it take for vision to improve after cataract surgery
Output:
Vision usually improves within a few days following cataract surgery.