MedlinePlus

MedlinePlus is a service of the National Library of Medicine (NLM), the world's largest medical library, which is part of the National Institutes of Health (NIH). It was built as an online health information resource for patients and their families and friends.

MedlinePlus presents high-quality, easy to understand, relevant health and wellness information that is trusted.

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MedlinePlus at a Glance

Offers information on health topics, human genetics, medical tests, medications, dietary supplements, and healthy recipes.
Sourced from more than 1,600 selected organizations.
Provides 40,000 links to authoritative health information in English and 18,000 links to information in Spanish.
In 2018, 277 million users viewed MedlinePlus more than 700 million times.

Color Blindness

Most of us see our world in color. We enjoy looking at a lush green lawn or a red rose in full bloom. If you have a color vision defect, you may see these colors differently than most people.

There are three main kinds of color vision defects. Red-green color vision defects are the most common. This type occurs in men more than in women. The other major types are blue-yellow color vision defects and a complete absence of color vision.

Most of the time, color blindness is genetic. There is no treatment, but most people adjust and the condition doesn't limit their activities.