A pinhole projector is a device for safely viewing a partial solar eclipse or total solar eclipse. These can be made easily by hand using tape and a shoe box,

Partial solar eclipses occur when the moon passes in front of the sun, but only blocks part of the sun. Viewing a partial solar eclipse can expose your eye to

Presbyopia (prez-bee-OH-pea-uh) is the slow loss of your eyes’ ability to focus objects up close. It’s a common condition that occurs with age, and usually becomes noticeable in the early

The opening in the center of the iris that appears as a black dot and through which light enters the eye.

Total number of cases of a problem or disease in the population at a given time.

The ability to perceive the presence or motion of objects outside the direct line of vision.