Domain III: Instrumentation for Measurement and Observation

Question 1

Rigid contact lenses are verified before/after dispensing to the patient

Answer 1

before

Question 2

Verify CPC/base curve, power, diameter, optic zone, center thickness, peripheral curves, tint

Answer 2

For rigid lens contacts

Question 3

Base curve ansi

Answer 3

0.1mm

Question 4

diameter

Answer 4

0.1mm

Question 5

POZ

Answer 5

0.1mm

Question 6

pc’s

Answer 6

0.1mm

Question 7

thickness

Answer 7

0.1mm

Question 8

power

Answer 8

0.12D

Question 9

also know as the base curve, falls on the back of the lens/tear film of the eye
base curve=size of contact

Answer 9

central posterior curve

Question 10

radius of curvature measures the …, not the linear measurment

Answer 10

curve

Question 11

measures to 0.01 mm, drop of saline in the lens holder, lens floats concave side up
read clockwise

Answer 11

radiuscope

Question 12

a) Determines size of both diameter and optical zone.
b) Used to examine surface of contact lens and edge of contact lens.

Answer 12

Shadowgraph

Question 13

a) Used to determine diameter of lens and optical zone
b) Used to examine front surface of contact lens
c) Check Edge Contour

Answer 13

Hand held magnifier

Question 14

Measured with handheld magnifier or shadowgraph

Answer 14

Optical zone

Question 15

Curves flatten towards the periphery as the cornea flattens.
Specified to nearest 0.1 mm

Answer 15

peripheral curve

Question 16

posterior optical zone is always … than the diameter

Answer 16

smaller

Question 17

What checks blends

Answer 17

Profile analyzer

Question 18

RGP tint

Answer 18

usually Blue, Gray or Green

Question 19

on keratometer steeper curve = more

Answer 19

minification

Question 20

In keratometer steeper curve =

Answer 20

Higher diopter
lower base curve

Question 21

In keratometer flatter curve =

Answer 21

lower diopter
higher base curve

Question 22

in keratometer record … first

Answer 22

horizontal reading

Question 23

symmetrical astigmatism has … or … k readings

Answer 23

180 90

Question 24

between 30 and 60 or 120 & 150

Answer 24

oblique astigmatism

Question 25

Can observe the entire extent of a corneal scar or
infiltration

Answer 25

Diffuse illumination

Question 26

The presence of folds in Descemet’s membrane
become visible

Answer 26

Diffuse illumination

Question 27

The presence of any invading blood vessels in the
cornea is disclosed.

Answer 27

Diffuse illumination

Question 28

set-up
(1) wide-open slit (flood light)
(2) low magnification

Answer 28

Diffuse illumination

Question 29

Overall view of anterior segment. Lens position and movement of contact lenses. Surface quality of lens.

Answer 29

Diffuse illumination

Question 30

1-2mm slit, medium to high magnification, Cross-sectional view of cornea, Corneal clarity, Lens deposits

Answer 30

Parallelpiped

Question 31

Useful in observing scars, infiltrates, staining, and the corneal-lens relationship

Answer 31

parallelpiped

Question 32

1-2mm slit, Medium to high mag., Fine lens deposits, Subtle corneal imperfections, corneal endothelium

Answer 32

Specular reflection

Question 33

direct illuminations ( microscope trained directly into the slit)

Answer 33

Parallelpiped
Optic section
specular reflection

Question 34

Lets one identify the tear layer, epithelium, bowman’s layer, stroma, endothelial zone

Answer 34

Optic section

Question 35

helps to discover thickening, thinning, and distortions in the corneal contour.

Answer 35

Optic section

Question 36

Determines the depth of foreign bodies or opacities in the cornea and capable of perceiving flare in the aqueous

Answer 36

Optic section

Question 37

microscope trained adjacent to the slit

Answer 37

indirect, Retro illumination and sclerotic scatter