retina

noun

ret·​i·​na ˈre-tə-nə 

ˈret-nə

plural retinas also retinae ˈre-tə-ˌnē 

-ˌnī

: the sensory membrane that lines the eye, is composed of several layers including one containing the rods and cones, and functions as the immediate instrument of vision by receiving the image formed by the lens and converting it into chemical and nervous signals which reach the brain by way of the optic nerve see eye illustration

Examples of retina in a Sentence

Recent Examples on the Web

As light dims, our eyes transition from photopic vision, associated with the retina's cone cells that deliver full colors and fine detail, toward scotopic night vision that relies on rod cells to detect objects in low light. —Bill Chappell, NPR, 6 Apr. 2024

Those changes in turn help to limit mechanical strain on the optic nerve head, the funnel through which more than a million nerve fibers from the retina come together to transmit visual signals to the brain. —IEEE Spectrum, 22 Mar. 2024

The retina, a very sensitive part of our eye, is at risk during these events. —George Dvorsky / Gizmodo, Quartz, 13 Mar. 2024

Read More: 5 of the World’s Most Intelligent Animals In contrast to other night hunters, like owls, who have a handy tapetum layer to reflect extra light through their retina, tarsiers simply evolved very large eyes. —Max Bennett, Discover Magazine, 23 Feb. 2024

In this method, the retina is scanned with a beam of light. —William A. Haseltine, Forbes, 11 Feb. 2024

The retina, located in the back of the eye, contains two types of light-detecting cells called cones and rods. —Matthew Solan, Chicago Tribune, 31 Jan. 2024

The distinctive contours of the solar eclipse the woman stared at days prior were etched onto her retina. —Eduardo Cuevas, USA TODAY, 24 Mar. 2024

The retina plays a critical role in the process of vision, converting light into neural signals that are then sent to the brain through the optic nerve. —George Dvorsky / Gizmodo, Quartz, 13 Mar. 2024

Word History

Etymology

Middle English rethina, from Medieval Latin retina, probably from Latin rete net

First Known Use

14th century, in the meaning defined above

Kids Definition

retina

noun

ret·​i·​na ˈret-ᵊn-ə 

ˈret-nə

plural retinas also retinae -ᵊn-ˌē 

-ˌī

: the light-sensitive inner layer lining the back of the eye that contains the rods and cones and converts the images formed by the lens into signals which reach the brain by way of the optic nerve

retinal

-ᵊn-əl

-nəl

adjective

Medical Definition

retina

1 of 2 noun

ret·​i·​na ˈret-ᵊn-ə, ˈret-nə 

plural retinas also retinae -ᵊn-ˌē 

: the sensory membrane that lines most of the large posterior chamber of the vertebrate eye, is composed of several layers including one containing the rods and cones, and functions as the immediate instrument of vision by receiving the image formed by the lens and converting it into chemical and nervous signals which reach the brain by way of the optic nerve

Retin-A

2 of 2 trademark

Ret·​in-A ˌret-ᵊn-ˈā 

—used for a preparation of tretinoin