MCAT Eye Anatomy: Eye Structure & Function

MCAT Eye Anatomy - image by Magoosh

Want to familiarize yourself with MCAT eye anatomy content? Below, we’ll cover everything you should study: the functions, diagram, and photoreceptor comparison.

Plus, click the link below for a handy PDF version of this overview, and for many other MCAT resources!

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The Human Eye: Structure and Function

StructureFunction
CorneaOutermost lens of the eye responsible for the majority of light refraction
Aqueous humorFluid that adds refractive power
Iris/Pupil Colored tissue that regulates the amount of light entering the eye through the central pupil

*KEY CONCEPT: The pupil dilates in low light conditions and constricts in high light conditions
LensFocuses light, bends to allow accommodation

*KEY CONCEPT: Accommodation: altering the lens so the eye can focus on both near and far objects
Ciliary BodyChanges shape of lens during accommodation
Vitreous HumorJelly-like substance that fills the inner eye
ScleraTough outer coat for protection and muscle attachment
RetinaLight sensitive layer over the back of the eye containing photoreceptors
Macula/FoveaArea of the retina with high visual activity due to high concentration of cones
Optic nerveCarries information from the retina to the occipital lobe of the brain. The blind spot is where the nerve exits the eye.

MCAT Eye Anatomy: Diagram of the Human Eye

Light refracts (bends) as it passes sequentially through the cornea, aqueous humor, lens, and vitreous humor. Errors in refraction cause visual defects which can be corrected by contacts or glasses. Myopia and hyperopia are two types of refractive error.

Here is a basic diagram of the human eye, so you can get a sense of this process:

MCT human eye anatomy diagram with all major structural parts labeled. Image by Magoosh.

Comparison of Photoreceptors

 RodsCones
Used ForNight vision, low resolution Day vision, high resolution
Primary LocationPeriphery of retinaCentral retina: macula and fovea
Relative NumberMoreFewer
Colors PerceivedNoneRed, blue, green

MCAT Eye Anatomy: A Final Word

As always, the goal of studying isn’t just memorization. Rather than trying to cram all of the human eye structures and functions into your mind, focus on how these parts work together to create the phenomenon of vision!

If you’d like more MCAT eye anatomy practice, we highly encourage you to check out Magoosh’s MCAT prep. It includes 380 lessons, 745+ practice questions, personalized email assistance, and more! Happy studying and good luck on the MCAT!

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