Scientists have always shunned assumptions, and for good reason. Assumptions can lead even bright minds astray. That's why it's surprising that for years, scientists studying human brain states have ...

Eye dilation usually lasts four to six hours, but it can last longer depending on various factors. Light-colored eyes may stay dilated longer after an exam. After an eye exam, you may receive special ...

Experts disagree on who needs it and when. Here’s what the evidence suggests. By Michelle Crouch Perhaps the most unpleasant part of an eye exam is when the doctor squeezes in the dreaded drops to ...