focus and accommodation of eye
This clear, curved structure at the very front of the eye does most of the heavy lifting by bending light as it first enters.
What is the cornea?
This is the tough, white, outer protective layer of the eye that maintains its shape.
What is the sclera?
These photoreceptors help you see in dim light and at night, but they cannot see color.
What are rods?
This is the dark opening in the middle of the iris that lets light into the eye.
What is the pupil?
This innermost layer at the back of the eye contains light-sensitive cells known as rods and cones.
What is the retina?
To focus on something close up, these tiny internal muscles contract, causing the eye's lens to become rounder and thicker.
What are the ciliary muscles?
This is the colored part of the eye that contains muscles to control the amount of light entering.
What is the iris?
These photoreceptors work best in bright light and let you see colors and fine details.
What are cones?
This is the main nerve cable that sends vision signals from the eye to the brain.
What is the optic nerve?
This transparent disc can change its shape to help focus light accurately onto the retina.
What is the lens?
When focusing on a distant object, these slacken or get tight to pull the lens thin and flat.
What are the suspensory ligaments?
This is the transparent, curved layer at the front of the eye that begins the process of refracting light.
What is the cornea?
This spot on the retina is packed with cones and gives you your sharpest, clearest vision.
What is the fovea?
When you walk into a bright room, the pupil does this to protect the back of your eye.
What is constrict? (Accept "gets smaller")
This dark, vascular middle layer prevents light from reflecting inside the eye and provides nourishment to the retina.
What is the choroid?
This is the exact definition of accommodation: the process of changing the shape of this structure to focus on objects at different distances.
What is the lens?
This thin, clear membrane covers the front of the eye and lines the eyelids, protecting against infection.
What is the conjunctiva?
Humans have three types of cone cells that detect these three primary colors of light.
What are red, green, and blue?
In bright light, these ring-shaped muscles in the iris contract to squeeze the pupil smaller.
What are the circular muscles?
This is the jelly-like material behind the lens that maintains the eyeball's firm, spherical shape.
What is vitreous humor?
When the ciliary muscles relax and the suspensory ligaments become tight, the lens becomes this shape to view distant objects.
What is thin and flat? (Accept "less convex")
Externally visible structures like eyebrows and eyelashes function primarily for this biological purpose.
What is protection (from sweat, dust, or debris)?
This spot on the retina has no rods or cones because it is where the nerve connects to go to the brain.
What is the blind spot?
In dim light, these spoke-like muscles in the iris contract to pull the pupil wider.
What are the radial muscles?
This specific pit in the retina has the highest density of cone cells and is responsible for sharp, detailed color vision.
What is the fovea (or fovea centralis)?