Glossary

Photoreceptors: Specialized cells in the retina of the eye, called rods and cones, that are sensitive to light and colors.

Retina: The light-sensitive layer of tissue that is located like a screen at the back of the eyeball. The images that enter the eye are focused on the retina.

Astigmatism: A defect in the eye that results in distorted images when rays of light do not meet at a common focus on the retina. The spherical shape of the lens is disturbed.

Screening test: A laboratory test that helps in identification of a particular disease, disorder or condition.

Quantitative testing: A laboratory test that helps in detecting a disease, disorder or abnormal condition and classifies the condition according to the type and severity.

Most Popular on Medindia