The human eye represents one of the body’s most complex and revealing organs, providing not only the gift of sight but also functioning as an early warning system for numerous health conditions. The ...

Hallucinogen persisting perception disorder (HPPD) is a rare medical condition that can cause visual disturbances (sometimes called flashbacks) if you’ve taken hallucinogenic drugs in the past. With ...

Have you ever noticed a sudden burst of light in your vision or zigzag lines appearing out of nowhere? Such visual changes can happen before an intense headache and may signal migraines. Symptoms vary ...

Robey, William H. — Clinical Professor of Medicine, Emeritus, Harvard University. For record and address of author see "This Week's Issue," page 280. Select the format you want to export the citation ...