The Human Eye

This structure controls the AMOUNT of light entering the eye :

• Retina

• Pupil

• Iris

• Lens

This tough white outer layer protects the eye from dust and irritants and allows muscle attachments :

• Optic Nerve

• Conjunctiva

• Cornea

• Sclera

This structure is found at the center of the eye and helps give it shape :

• Vitreous humor

• Aqueous humor

• Fovea

• Choroid

All are transparent/clear structures of the eye except :

• Cornea

• Blind spot

• Conjunctiva

• Lens

Which structure helps to FOCUS light rays on the retina :

• Cornea

• Iris

• Lens

• Pupil

Which statement is TRUE about photoreceptors in the eye ?

• Only rods are found in the fovea (yellow spot)

• Rods and cones are found in the choroid and helps with color and black and white vision

• Cones allow for color vision and rods allow for black and white or grayscale vision

• The retina only contains cones for color vision

Answer explanation

Rods and cone cells are photoreceptors found in the retina. Rods work best in dim light and cones work best to detect color and detals.

The fovea (yellow spot) is found in the retina but only contains cones. This allows the eye to see things in color and bright light.

The eye creates tears in order to :

• Help keep the cornea moist

• Wash away irritants

• Kills and fights germs that enters the eye

• All of the above

Which common eye disorder is NOT matched correctly with it's definition :

• Glaucoma - build up of pressure causes damage to retina and optic nerve

• Cataract - lens of the eye becomes cloudy causing blurry vision

• Myopia - the eye is too short and light rays focus behind the retina

• Astigmatism - 2 focal points formed on the retina which produces crooked or distorted images

Answer explanation

Myopia (near sightedness) -the eye is usually too long and light rays focus in front of the retina. Persons usually have trouble seeing far distances and typically need concave lenses to correct this disorder.

Hyperopia (far sightedness) the eye is too short and the light rays focus behind the retina. Persons usually have trouble seeing things close up and typically need a convex lens to correct this disorder.

Presbyopia is a type of hyperopia that occurs with aging.

Structure A - contains blood vessels that transport water oxygen and nutrients to the eye. Structure B - carries messages from the brain to the eye :

• Structure A - Olfactory bulbs

  Structure B - Olfactory nerve

• Structure A - Choroid

  Structure B - Optic nerve

• Structure A - Sebaceous glands

  Structure B - Sensory nerve endings

• Structure A : Aqueous Humor

  Structure B : Optical Sensory Nerve

All are ways to care for the eye EXCEPT:

• Eating food rich in Vitamin A

• Sitting atleast 6 ft away from the television screen

• Watching Tik Toks about the human eye for 3 hours

• Keeping dirty hands and sharp objects away from the eye