Eye Anatomy

Question 1

Where is the palpebral fissure and what is the average size?

Answer 1

• The palpebral fissure is the elliptical-shaped space between the open eyelids. It’s the entryway to the conjunctival sac.
• The average size is 15mm by 30 mm wide

Question 2

Describe the characteristics of the cornea

Answer 2

• It is a transparent tissue with no blood supply of its own
  Provides ⅔ refractive power
• The eye has a total refractive power of approx. 60D
• The average size for the horizontal diameter is 11.7 mm while the vertical diameter is 10.6 mm

Question 3

What does VID stand for?

Answer 3

Visible iris diameter

Question 4

What does HVID stand for?

Answer 4

Horizontal visible iris diameter

Question 5

What is the Crystalline Lens responsible for?

Answer 5

It is responsible for ⅓ of the eye’s refractive power

Question 6

What do you know about the Crystalline Lens

Answer 6

• The average size is 15.00 D to 16.00 D
• Located behind Iris
• Transparent with no blood supply

Question 7

What is connected to the ciliary muscle that helps shape the crystalline lens?

Answer 7

Zonular Fibers

Question 8

What do the zonular fibers and ciliary body do with the crystalline lens to see far and close objects?

Answer 8

• To see objects from far away the ciliary muscle relaxes while the zonular fibers contract making the lends thinner
  -To see objects from close up the ciliary muscle contracts while the zonular fibers relax making the lends thicker

Question 9

What is the loss of accommodation called?

Answer 9

Presbyopia

Question 10

What are cataracts?

Answer 10

• Cataracts are cloudy opacities in the lens
• It is when the vision becomes hazy

Question 11

How do you get cataracts?

Answer 11

• It could be of old age which ranges between 75-85
• Some infants may be born with cataracts which is known as congenital cataracts
• Other ways are injury, trauma, or disease

Question 12

What is Aphakic?

Answer 12

It is when the eye is without a crystalline len

Question 13

What is pseudophakic?

Answer 13

It is when the eye is with an IOL(intraocular implant) which is an artificial lens

Question 14

What does the retina do?

Answer 14

Captures light rays and converts them into electrical impulses

Question 15

How many rods does the retina have and what do they do?

Answer 15

It contains 125 million rods that are responsible for night vision

Question 16

How many cones does the retina contain and what do they do?

Answer 16

• It contains 6-7 million cones responsible for color and light vision.
• Most cones are found in the fovea which is part of the retina and can see the sharpest

Question 17

What is the center of the retina called and what does it do?

Answer 17

Macula: allows us to see fine details

Question 18

What is Macula degeneration?

Answer 18

It is a disease that damages the macula, the part of the eye that controls central vision.

Question 19

What are the symptoms of macula degeneration?

Answer 19

Symptoms Blurred vision, Straight lines appearing wavy or crooked, Loss of clear color vision, A dark or empty area in the center of vision, and Difficulty seeing in low light.

Question 20

What does the optic nerve do?

Answer 20

Carries images from the retina to the brain and creates a blind spot

Question 21

Why do you need a healthy optic nerve?

Answer 21

It is necessary to have optic nerve healthy because it is responsible for healthy vision.

Question 22

Where is the optic nerve located?

Answer 22

Near macula