To understand eyestrain, you first need to understand how the eye works. Rod and cone cells on the retina produce light-sensitive chemicals that signal the brain to adjust the eye for available light. In low light, the iris, or the colored part of the eye, relaxes, causing the pupil to become large. This lets the eye collect as much light as possible. In low light, nerve cells in the retina also adapt to focus your vision. When you read, the iris and other muscles contract to hold the focused image on the retina. Reading in low light sends mixed signals to the iris, telling it both to relax to collect light but contract to help the eye focus. Working this hard over a period of time causes the eye muscles to feel as tired as any other muscle. The result may be dry eyes, itchy or sore eyes, blurred vision, neck aches, backaches and headaches.
Sanford I Rakofsky, MD
Location and Office HoursSanford Rakofsky MD
401 Miracle Mile
Miami, FL 33134
What causes eyestrain?
Discovery Health answered
How often do older kids need eye exams and replacement glasses?
Glasses need to be replaced if they are poorly fitting or markedly scratched, not really on the basis of the calendar. Similarly, older children and teenagers who wear glasses do not necessarily need examinations linked to the calendar.
Periodic examinations for a change in the prescription are required whenever there are symptoms of reduced vision or when a patient has had visual acuity measured and determined to be abnormal. For teenagers who wear glasses, the prescription does often change until they are about 20 years of age. Therefore, it is best to have the vision measured at least every 18 months, and if there is a decrease, undergo a complete eye examination.
Can sitting close to the television damage my child’s eyes?
American Academy of Ophthalmology answered
Children can focus at close distance without eyestrain better than adults. They often develop the habit of holding reading materials close to their eyes or sitting right in front of the television.
There is no evidence that this damages their eyes, and the habit usually diminishes as children grow older. However, children with nearsightedness (myopia) sometimes sit very close to the television in order to see the images more clearly, so they should have an eye examination.
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