This refers to the sharpness or clarity of an object 20 feet away. This means that people can see objects, letters, numbers, or other things with the same clarity as an Frågor och svar adult when standing 20 feet away from the item. It is also the standard that corrective lenses and procedures typically aim to achieve.
A higher second number indicates worsening vision, while a lower number indicates better vision. Ophthalmologists and optometrists diagnose eye conditions. Opticians use refraction to help make the correct glasses. Nurses, primary care doctors, pediatricians, and most school screenings may have an eye chart to help determine acuity, but they are not diagnosing an eye condition.
Vision can change as a person ages. People who reach middle age often notice changes in their near vision. This can make it more difficult to see objects up close or make it more challenging to switch focus from far to near or near to far.
Children should get their eyes examined once they are old enough to cooperate with an eye exam. Certain researchers suggest children can lose their vision as early as 8 or 9. However, children often need glasses before that, so experts recommend having an eye exam before starting school.
The pediatrician often checks for eye alignment before age 5. Learn more about eye health from our dedicated hub. A person may not be able to prevent vision loss, but there are some steps people can take to help reduce their risk.
People who wear corrective lenses should also take steps to properly care for their glasses or contacts and replace them as directed. This can include keeping the contacts clean to help prevent infections. Vision conditions can affect the clarity of vision, such as:.
Some more advanced conditions that can cause people to have poor vision include :. Common correction methods include using glasses or contacts, often known as corrective lenses. A person may need glasses for other eye issues unrelated to visual acuity.
A doctor may prescribe glasses to treat anisometropia a difference in focus between the two eyes or astigmatism an atypical lens curvature. The AAO states that people should have eye examinations at least every decade if they do not have any other eye issues.
Recommended examination frequency varies for children and adults. However, an individual can have a worse vision or better vision. They can recommend treatments, including glasses, contacts, or corrective procedures.
People will need regular eye exams as they age.