cornea

Everyday

The clear, curved, dome-shaped layer at the front of the eye that covers the iris and pupil and helps focus light. tree →

In the lessons

In science lessons on the eye and seeing, pupils label the parts: cornea, iris, pupil, lens, retina, optic nerve. The cornea bends light first, then the lens finishes focusing it on the retina. In health and safety, goggles protect the cornea from chemicals and flying bits; a scratch on the cornea hurts a lot. Some people receive a donated cornea in a transplant. Phrases: «a scratched cornea», «corneal transplant».

Examples

• Light passes through the cornea before it reaches the lens. tree →
• We labelled the cornea on our diagram of the eye. tree →
• Wear goggles to protect your cornea in the lab. tree →
• The doctor said I had a tiny scratch on my cornea. tree →
• The cornea has no blood vessels, so it is clear. tree →
• A cornea transplant can help some people see again. tree →

Note

Said «KOR-nee-uh». Plural: corneas. The adjective is «corneal». Do not confuse the cornea (clear front window) with the iris (the coloured part) or the retina (at the back, where light is sensed).