retina
n. countablen. the thin layer at the back of your eye that catches light. It sends signals to your brain so you can see images.
n. the light-sensitive inner surface of the eye, containing the receptor rods and cones plus layers of neurons that begin the processing of visual information.
The doctor looks at your retina during an eye exam.
Light enters the eye and hits the retina, where it is converted into electrical signals for the brain.
Advanced imaging techniques now allow ophthalmologists to examine the delicate layers of the retina in high resolution, facilitating the early detection of degenerative conditions.
From Middle English rethina, borrowing from Medieval Latin rētīna (“retina”, feminine noun), ellipsis of tunica rētīna (“net-like tunic”), used to describe the blood vessel system at the back of the eye. The phrase is attested in the 12th century in Guillelmus the abbot and Gerard of Cremona—the latter may have created this phrase as a translation for Arabic طَبَقَة شَبَكِيَّة (ṭabaqa šabakiyya) "net-like layer", which translates Ancient Greek ἀμφιβληστροειδής χῐτών (amphiblēstroeidḗs khĭtṓn, “retina”), which is attested in the ancient medical writer Galen.
Commonly used in medical or biological contexts; often appears in the singular when referring to one eye.