Optics and Refraction

Question 1

Branch of physics concerned with studying the properties and behavior of light

Answer 1

Optics

Question 2

Also known as wave optics

Answer 2

Physical Optics

Question 3

True about the visible part of the electromagnetic spectrum, except:
a) It is within 390 nm and 760 nm
b) The retina and iris are sensitive to the visible part of the EM spectrum
c) It is paramount in the manufacturing of laser machines and ophthalmic diagnostic equipment.
d) It is studied under physical optics.

Answer 3

B - Iris functions to regulate pupil size and has no refractive capacity. It is the retina that is sensitive to the visible EM spectrum.

Question 4

Describe physiologic optics.

Answer 4

Involves the study of light as it encounters various receptors or the visual processes in the retina

Question 5

It is the study of visual perception and its pathways right after the excitation of the receptors in the retina.

Answer 5

Neuro-ophthalmic Optics

Question 6

Continuation of physiologic optics

Answer 6

Neuro-ophthalmic Optics

Question 7

Emphasizes the connection of the eye and the brain via the optic nerve

Answer 7

Neuro-ophthalmic Optics

Question 8

Refers to ray optics

Answer 8

Geometric Optics

Question 9

Study of the behavior of light as it travels through a medium

Answer 9

Geometric Optics

Question 10

Which of the following is true about Snell’s Law?
a) Light rays travelling from a medium of higher refractive index to a medium of lower RI will be bent toward the normal.
b) Light rays travelling from a medium of lower refractive index to a medium of higher RI will be bent toward the normal.
c) Light rays travelling from a medium of lower refractive index to a medium of higher RI will be parallel the normal.
d) Light rays travelling from a medium of lower refractive index to a medium of higher RI will be bent away the normal.

Answer 10

B
from higher RI to lower RI: bent away from normal

from lower RI to higher RI: toward normal

Question 11

The focal length of the lens is:
a) inversely proportional to the power in diopter
b) directly proportional to the radius of the lens
c) directly proportional to the power in diopter
d) inversely proportional to the radius of the lens

Answer 11

A - Diopter = 1/f
where: f = focal length

Question 12

Most of the refraction occurs at the site of:
a) cornea
b) lens
c) vitreous humor
d) retina

Answer 12

A - cornea contributes 2/3 of the refractive function of the eye, while the lens contributea 1/3

Question 13

What is the average dioptric power of the adult cornea?
a) 32D
b) 42D
c) 62D
d) 52D

Answer 13

B
Textbook - 43D from cornea and 19D from lens

Question 14

Average axial length of the adult eye:
a) 26-28 mm
b) 20-22 mm
c) 16-18 mm
d) 22-24 mm

Answer 14

D
Textbook - 22.5 mm

Question 15

At what age does our power of accommodation usually decline?

Answer 15

40 years old

Question 16

What type of error of refraction is in the following?
OD -2.50 -0.00 180
OS -5.00 -0.00 180

Answer 16

Myopia

Question 17

What type of lens will correct for presbyopia?

Answer 17

plus lens

Question 18

What type of lens will correct for astigmatism?

Answer 18

Cylindrical Lens

Question 19

PRK was performed on patient, wherein the midperipheral stroma was removed. What type of error of refraction waa corrected?

Answer 19

Hyperopia