Eye Structures
The transparent part at the front of the eye refracts light.
Cornea
In bright light, which iris muscles contract?
Circular muscles
These cells allow us to see in color
Cones
Color blindness happens because pigments in these cells are missing or faulty.
Cones
The part that changes shape to focus light onto the retina.
Lens
In dim light, which iris muscles contract?
Radial muscles
These cells are more sensitive to light intensity, work in dim light.
Rods
The most common type of color blindness is…
Red–green color blindness
The colored part of the eye controls the size of the pupil
Iris
The iris reflex is voluntary or involuntary?
Involuntary
Where are cones most concentrated in the retina?
Fovea
A very rare form of color blindness where no cones work is called…
Achromatopsia (total color blindness)
This nerve carries signals from the retina to the brain
Optic nerve
Why is the iris reflex important?
Protects retina from damage and optimizes vision in dim light
Why can’t we see colors well in the dark?
Cones don’t work well in dim light
True or False: People with red–green color blindness see the world only in black and white.
False