What causes bad eye sight (Color blindness (caused by problems in the…
What causes bad eye sight
How the Human eye takes in light
The iris (the colored portion of the eye that surrounds the pupil) opens and closes
This regulates the amount of light passing through
light rays pass through the lens, so it can change shape so it can further bend the rays and focus them on the retina
Far sighted eye
nearby objects appear fuzzy or unfocused
Cones and rods
Rods are located outside the macula and extend all the way to the outer edge of the retina.
Cones are active at higher light levels.
Cones are concentrated in the center of the retina.
Rods are responsible for vision at low light levels.
Thin layer of tissue that contains millions of tiny light sensing nerve cells.
The nerve cells are the Cones and Rods.
The retina sits at the back of the eye.
Near sighted eye
light enters the cornea and is refracted, or “sent” to a spot in the eye before reaching the retina
when the cornea and lens receive light waves, they send it to the wrong place in the eye, usually because of the shape of the eyeball
The brain and the eye
The optic nerve carries these signals to the brain so it can interpret them as visual images
The retina sends nerve signals are sent through the back of the eye to the optic nerve
The part of the brain that processes visual input and interprets the messages that the eye sends is called the visual cortex
Birth defects or damage to any portion of the eye, the optic nerve, or the area of the brain responsible for vision can lead to blindness
visual impairment cannot be corrected with surgery or corrective lenses, and the condition can make it difficult to perform everyday activities
can be temporary or permanent and it has many causes
problems with the macula, and eye changes because of aging account for most blindness in adults in the United States
caused by problems in the pigments of the cones in the retina
Most people who are color-blind can see some colors
most cases, someone who is color-blind confuses some colors with others, usually red and green
can be born color-blind or they may develop the condition over time
most common form of color blindness is an inherited condition that affects boys much more often than girls
cataracts are much more prevalent in the elderly
cloudiness of the eye's lenses that prevent images from being seen clearly or at all
In infants and young children, cataracts must be treated early to prevent permanent problems with development of vision