P Lab: Vision

Question 1

Visual Perimeter

Answer 1

MEasurment of the visual field function

Question 2

Visual Acuity

Answer 2

Clarity of Vision. It is determined as the smalles letters/symbols one can read on a standard chart (Snellen Chart)

Question 3

Optic disc

Answer 3

exit of optic nerve fibers, blind spot, optic nerve head

Question 4

Astigmatism

Answer 4

spherical abberation (irregularly shaped cornea)

Question 5

Glaucoma

Answer 5

increased intraocular pressure due to incomplete evacuation of aqueous humor via Schlemm’s canal

Question 6

Macula degenration

Answer 6

damage to the macula, the area of sharpest vision

Question 7

Myopia

Answer 7

eyes are too long for its optical powers (image is formed in front of the retina)

Question 8

Hyperopia

Answer 8

eyes are too short for its optical power (image is formed behind the retina)

Question 9

Achromatopsia

Answer 9

Loss of color vision due to lesion of cortical area V4

Question 10

Protanopia/protanomaly

Answer 10

missing/malfunctioning L-cone (red); sub-form of red greeen blindness

Question 11

Deuteranopia/deuteranomaly

Answer 11

missing/malfunction M-cone (green)

subform of red-green blindness

Question 12

Tritanopia/tritanomaly

Answer 12

missing/malfunctioning S cone (blue)

Question 13

Snellen Chart

Answer 13

an eye chart used to measure visual acuity

Question 14

Sloan letters

Answer 14

optotypes to test visual acuity; used in Snellens chart

Question 15

What is one letter element on the Snellen Chart?

Answer 15

a horizantal bar in an E subtends 1 minute of arc at the indicated distance (20 feet for the 20/20 line)

Question 16

2 min of arc is a measurement of?

Answer 16

one letter element and one interspace i.e one period of a sinusoidal grid

Question 17

Landolt C

Answer 17

A broken ring

uses a single optotype placed in a different position

Question 18

Lea test

Answer 18

pediatric vision test

pictures of animals and objects

to test visual acuity

Question 19

Amsier grid

Answer 19

test for macula degenration or another vision problem

Do the lines look wavy or areas of visual field missing?

Question 20

Ishihara test

Answer 20

color vision deficiency

Question 21

Astigmatism wheel

Answer 21

radiating spokes placed at angles of 10 degrees

any inequality of the wheel signals astigmatism

Question 22

How do yo correct for myopia?

Answer 22

Use a concave lense which will disperse the image

Question 23

How do you correct for hyperopia

Answer 23

Using a convex lense which will focus the image

Question 24

Which type of color blindess is most common?

Answer 24

Red-green

Question 25

Red green blindness

Answer 25

More common in males

X chromosome linked

Question 26

Which type of color blindness is rare?

Answer 26

Blue

Chromosome 7

Question 27

What is the prevelance of blue blindness between men and women?

Answer 27

Gender equality

Question 28

What conditions can be diagnosed through perimeter testing?

Answer 28

Visual field deficits

Question 29

What is diopter?

Answer 29

A unit of refractive power that is equal to the reciprocal of the docal length (in meters) of a given area