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. Also be encouraged to check out our overview of all MCAT biology and biochemistry topics.

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

Click here to download more Magoosh MCAT resources

The Human Eye: Structure and Function

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

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!

Get a free MCAT practice test!


  • Kat Thomson

    Kat is the Senior Curriculum Manager at Magoosh with a specialty in the MCAT. She has a BA from the University of California, Santa Barbara, and a Ph.D. in medical sociology from the University of California, San Francisco, where she earned the Distinguished Dissertation Award in the Social and Behavioral Sciences. Kat has been teaching premed and nursing students since 2005 as a Visiting Assistant Professor at the University of San Francisco, Bowdoin, and the University of California, Berkeley, while collaborating on multiple research projects and publications. In addition to the MCAT, Kat has taught courses in Research Methods, Gender, Global and Environmental Health, and others. She is passionate about increasing the number of underrepresented minorities in medicine and helping students get into the medical schools of their dreams. You can join Kat on Instagram and YouTube.

No comments yet.

Magoosh blog comment policy: To create the best experience for our readers, we will only approve comments that are relevant to the article, general enough to be helpful to other students, concise, and well-written! 😄 Due to the high volume of comments across all of our blogs, we cannot promise that all comments will receive responses from our instructors.

We highly encourage students to help each other out and respond to other students' comments if you can!

If you are a Premium Magoosh student and would like more personalized service from our instructors, you can use the Help tab on the Magoosh dashboard. Thanks!

Leave a Reply