|part of eye
||Front part of the tough outer coat, the sclera. It
is convex and transparent.
||Protects front of eye and bends light to form an
image on the retina.
||Membrane covering the exposed front part of the eye,
and lining the eyelids. It is kept moist by antiseptic secretions
from the tear glands.
||Protects the cornea
||The opaque 'white of the eye' – also called
the sclerotic. It is a tough and fibrous outer layer covering the
whole of the eye except the cornea.
||Pigmented (determines the color of your eyes) so
light cannot pass through. Its muscles contract and relax to alter
the size of its central hole or pupil.
||Protects the photoreceptors in the retina from being
damaged by too much light
||A black hole in the center of the iris. It is the
dark pigmented layer inside the eye – the choroid – which
makes the pupil appear black.
||Allows light to enter eye
||Transparent, biconvex, flexible disk behind the
iris attached by the suspensory ligaments to the ciliary muscles
||Brings the light entering through the pupil to a
focus on the retina. The ciliary muscles control the lens' thickness
||Ring of muscle fibers around lens
||Controls lens thickness and curvature
||Ligament between lens and ciliary muscle
||Supports lens and connects it to the ciliary muscle
||The lining of the back of eye containing two types
of photoreceptor cells – rods (sensitive to dim light and black
and white) and cones (sensitive to color). A small area called the
fovea in the middle of the retina has many more cones than rods.
||Screen on which images are formed as a result of
light being focused onto it by the cornea and lens. The fovea is the
point of maximum visual sharpness.
||Bundle of sensory neurons at back of eye
||Carries signals from the photoreceptors of the retina
to the brain. At the point where the sensory neurons leave the retina
to form the optic nerve – the so-called blind spot – there
are no rods and cones, and no image can therefore be seen.