Physiological Optics

Question 1

What is the Refractive Index of the Cornea?

Answer 1

1.37

Question 2

What is the Refractive Index of the Aqueous?

Answer 2

1.33

Question 3

What is the Refractive Index of Lens?

Answer 3

1.43

Question 4

What is the Refractive Index of Vitreous?

Answer 4

1.33

Question 5

What is the Total Refractive Power of the Eye?

Answer 5

60 D

Question 6

What is the Corneal Power?

Answer 6

43 D

Question 7

What is the Lens Power?

Answer 7

+15 D to +20 D

Question 8

What occurs as the light travel through the eye? and what is the image?

Answer 8

Refraction

Inverted

Question 9

What is Emmetropia?

Answer 9

The focal point parallel light rays coming into the eye is on the retina
“perfect vision”

Question 10

What is Ametropia?

Answer 10

Refractive error is present

Question 11

What is Myopia?

Answer 11

Nearsightedness

Question 12

What is the shape of a myopic eye?

Answer 12

Eyeball is too long

Question 13

Where does the focal point land for myopic eye?

Answer 13

Within the vitreous

In front of the retina

Question 14

What lens can correct myopia?

Answer 14

Diverging or Minus lens

Concave

Question 15

What is Hyperopia?

Answer 15

Farsightedness

Question 16

What is the shape of a hyperopic eye?

Answer 16

Eyeball is too short

Question 17

Where does the focal point land for hyperopic eye?

Answer 17

Behind the retina

Question 18

What lens can correct hyperopia?

Answer 18

Converging or Plus Lens

Convex

Question 19

What is Astigmatism?

Answer 19

Refractive Error is not equal in all meridians

One meridian is curvier than the other

Question 20

What is the shape of the cornea for an Astigmatism eye

Answer 20

Football

Question 21

Where does the focal point land for astigmatism?

Answer 21

There is 2 focuses in the eye

No focal point

Question 22

What lens can correct astigmatism?

Answer 22

Sphero-cylindrical Lenses

Question 23

What are examples of Amplitude of Accomodation?

Answer 23

Gradually decreases with age

Lens becomes less flexible

Question 24

What is the Conoid of Sturm?

Answer 24

How rays are refracted through two different power meridians
Optical Condition refractive power of cornea and lens is not the same in all meridians

Question 25

What is the Unequal image sizes called?

Answer 25

Aniseikonia

Question 26

What is the Unequal Refractive Errors called?

Answer 26

Anisometropia

Question 27

What is the Amplitude of Accomodation?

Answer 27

Measured in Dioptres Gradually Decreases in age Lens becomes less flexible

Question 28

What are Accommodative Conditions?

Answer 28

Presbyopia | Latent Hyperopia

Question 29

What is the Accommodative Condition for loss of accommodation associated with aging?

Answer 29

Presbyopia

Question 30

What is the Accommodative Condition for amount of hyperopia that can be overcome with accomodation?

Answer 30

Latent Hyperopia

Question 31

What is the Refractive of the Eye?

Answer 31

63 D

Question 32

What is the Reduced or Simplified Eye?

Answer 32

Gullstrand is 58.60 D Eye is 22.6m in length Anterior focal point is 17mm in front of the cornea Nodal point is 5.6mm behind the cornea