"Excuse me, could you please read that for me, my vision isn't as good as it used to be"
The eye, though small (approximately 2.54cm tall, 2.54cm deep and 2.3 cm wide), is a very complex organ that allows us to see our family members, oncoming traffic, and even scenery. Blindness is when your eye does not function properly. To explain this in full, I will first examine to normal workings of an eye.
There are sixteen parts of the eye. They are:
Thi Sclera- The sclera is the toughest part of the eye. It is also on the outermost part of the eye so it only contains cones and is for seeing fine detail. The retina contains a chemical called rhodopsin. This is the chemical that makes light into electrical impulses that the brain makes into vision.
10.Optic nerve- The optic nerve is formed from retinal nerve fibers collecting at the back
of the eye. The optic nerve sends the electrical impulses to the brain.
Now that you fully understand the basic workings of the eye, I will tech you about blindness. blindness is usually defined when your visual sight is less than 20/200 with corrective lenses. Now that you have learned some anatomy of the eye and how it functions, it becomes easier to understand how the following conditions can lead to blindness: 1. Cataracts - This is a cloud in the lens that blocks light from getting to the retina. It is more common as you age, but you can be born with a cataract. As it gets worse, it can need surgery to remove the lens and place an intraocular lens.
1. Glaucoma - If the aqueous humor does not drain out correctly, then pressure builds in the eye. This makes the cells and nerve fibers in the back of the eye die. It can be treated with medications and surgery.
2. Diabetic retinopathy - People with diabetes can get blockage of blood vessels, leakage of blood vessels and scarring that can lead to blindness. You can treat this with laser surgery.
3. Macular degeneration - In some people, the macula (which is responsible for fine detail in the center of vision) can deteriorate with age for unknown reasons. This causes loss of central vision. This can sometimes be helped with laser surgery.
4. Trauma - Trauma or chemical injuries can cause enough damage to the eyes to prevent adequate vision.
5. Retinitis pigmentosa - This is an inherited disease that causes a degeneration of the retina and pigment. It first causes night blindness and then tunnel vision, which often gradually progresses to total blindness. There is no known treatment.
6. Trachoma - This is an infection caused by an organism called Chlamydia trachomatis. It is a common cause of blindness worldwide but is rare in the United States. It can be treated with antibiotics.
Color blindness is also a type of blindness. Color blindness is the inability to tell between different colors. The most common type is red-green color blindness. This is in 8 percent of males and 0.4 percent of females. It happens when the red or green cones are not present or not functioning properly. People with this problem are not completely unable to see red or green, but often confuse the two colors. This is an inherited disease and affects men more often since the color vision is located on the X chromosome. (Women have two X chromosomes, so the probability of inheriting at least one X with normal color vision is high; men have only one X chromosome to work with.). The inability to see any color, or seeing only in different shades of gray, is very rare.