Definition of retina
retinaeplay \-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
Recent Examples of retina from the Web
Dr. Chavis recounts the story of a diabetic patient who developed abnormal blood vessels that were bleeding in the retina, causing a high risk of blindness.
Once the bubble dissolves, Zimmer will find out if the retina can stay in place on its own.
All operate in the 1000-1100-nm wavelength region, which, because the wavelengths are invisible but are transmitted to the retina, leads to a significant operational concern about eye safety in real-world uses.
These example sentences are selected automatically from various online news sources to reflect current usage of the word 'retina'. Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.
Origin and Etymology of retina
Middle English rethina, from Medieval Latin retina, probably from Latin rete net
First Known Use: 14th centurySee Words from the same year
RETINA Defined for English Language Learners
Definition of retina for English Language Learners
: the sensitive tissue at the back of the eye that receives images and sends signals to the brain about what is seen
RETINA Defined for Kids
Definition of retina for Students
: the membrane that lines the back part of the eyeball, contains the rods and cones, and converts the images received by the lens into signals that are transmitted to the brain
Medical Definition of retina
: 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
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