Unit 2

Question 0

The keratometer is designed to measure the cornea at the….

Answer 0

Visual center

Question 1

What instrument provides a computer generated map of corneal curvature?

Answer 1

Topographer

Question 2

A _____ lens can be used to extend the range of the keratometer from 52.00-61.00D.

Answer 2

+1.25

Question 3

What type of astigmatism?

43.00@145/41.00@55

Answer 3

Oblique

Question 4

Subtract K’s for measurable corneal astigmatism:

46.00@180/43.75@090

Answer 4

2.25

Question 5

The area of the cornea with the STEEPEST curvature is?

Answer 5

Apex

Question 6

Calculate the residual astigmatism.

Rx:-2.00-1.50@180
K’s:41.50/43.25@090

Same type, subtract astigmatism
Different type, add astigmatism

Answer 6

Same type:

0.25

Question 7

What type of astigmatism ?

45.00@020/46.00@110

Answer 7

With the rule

Question 8

Before using any keratometer what must you do first?

Answer 8

Focus the eye piece

Question 9

With the rule astigmatism:

Answer 9

Flattest K @180 (-/+ 30)

ex. 41.00@180/43.00@090

Question 10

Against the rule astigmatism:

Answer 10

Flattest K @090 (-/+ 30)

ex. 45.00@180/42.00@090

Question 11

Oblique astigmatism:

Answer 11

Flattest K between 30/60 or 120/150

ex. 42.50@035/44.75@125

Question 12

Irregular astigmatism:

Answer 12

Flattest & steepest meridians are notably more or less than 90 apart.

ex. 41.00@180/42.00@060