Another classic from a patient earlier today. This time, a teen wondered if she was damaging her eyes by watching movies on her phone.
Damaging the eyes, no. Creating the potential for eyestrain, fatigue, and discomfort, yes.
Objects that we look at short of about 20 feet require extra focusing and eye alignment efforts. The closer the object, the greater the effort required. Trying to sustain this effort for extended periods is similar to trying to hold a dumbbell in mid air. At some point, the muscles fatigue and, in the case of the eye, results in blur.
Television, on the other hand, is usually larger in size and located farther away resulting is less exertion by those same muscles.
One more point about these focusing efforts…our abilities decrease as we age. A child could likely sit and watch movies on a phone for hours without too much trouble. Fast forward 20-30 years and that person’s decreased focusing ability would make a phone-based movie marathon near impossible.