Domain III 2: Instrumentation for Measurement and Observation

Question 1

i) 1-2 mm slit
ii) medium to high magnifications

Answer 1

Indirect set up

Question 2

i) opaque structures
ii) lids, sclera, conjunctiva pathology
iii) enables observation of fine vesiculation of the corneal epithelium

Answer 2

indirect uses

Question 3

Opaque structures lids, sclera, conjunctiva. Vascularization, pingueculae,
pigmentation

Answer 3

Indirect area adjacent to the slit

Question 4

i) 1-2mm slit
ii) medium to high magnification, light is reflected off an opaque structure behind the
area being viewed, corneal neo-vascularization

Answer 4

Retro illumination

Question 5

i) 1-2mm
ii) medium to high magnification

Answer 5

Retro set up

Question 6

i) corneal neovascularization
ii) microcystic edema

Answer 6

uses retro illumination

Question 7

2-4 mm slit, microscope in front of eye, with low mag
angle between micro and illum 45 degrees or greater

Answer 7

Sclerotic scatter set up

Question 8

i) halo around the eye
ii) patch edema, corneal scars, incisions
iii) the only one not looking in the eye

Answer 8

Sclerotic scatter uses

Question 9

2-4mm slit, aimed at limbus from a wide angle, look for circumcorneal halo, View
straight ahead w/ no magnification

Classic use is to view patch edema

Corneal Scars

Incisions

SCL edge lift

Answer 9

Sclerotic scatter

Question 10

Refraction device combining a large variety of spherical and cylindrical
lenses, prisms, occluders and pinholes; used in determining an eye’s optical correction

Answer 10

Photopter

Question 11

A large variety of spherical and cylindrical lenses, prisms, occluders and
pinholes; used in determining an eye’s optical correction

Answer 11

Trial set

Question 12

Hand-held device for measuring the eye’s refractive error, with no verbal
response required from the patient. Light movement is neutralized by lenses from either
the phoropter or trial lenses

Answer 12

Retinoscope

Question 13

Device used for examining the interior of the eye, especially the
fundus and retinae.

Answer 13

Ophthalmoscope

Question 14

Electro-mechanical or computerized device used for determining an eye’s
refractive error

Answer 14

Autorefractor

Question 15

Corneal edema is observed inferiorly under a prism ballast toric soft lens. What is the probable cause?

Answer 15

Prism thickness is too great

Question 16

Corneal microcysts are most apparent via biomicroscopy with which method of illumination?

Answer 16

retro

Question 17

Punctal occlusion may be most beneficial for which of the following conditions?

Answer 17

tear deficient dry eye

Question 18

When there is slight pooling of fluorescein in the peripheral curve portion of a rigid lens, it indicates:

Answer 18

slight edge lift

Question 19

Which of the following will cause flair?
 A. wrong power
 B. allergies
 C. small optical zone
 D. spoiled solution

Answer 19

C. small optical zone

Question 20

The angle that a bead of water makes with the surface of a given material, the smaller the
wetting angle the greater the wetting ability

Answer 20

wetting angle

Question 21

contains two curves, a primary base curve and a flatter peripheral curve.

Answer 21

bicurve lens

Question 22

contains two peripheral curves the intermediate curve may be very narrow

Answer 22

Tricurve lens

Question 23

A contact lens has a base curve of 7.50mm. Its posterior peripheral curve would most likely be:
 A. 42.50D
 B. 30.00D
 C. 7.45mm
 D. 7.35mm

Answer 23

A. 42.50D

Question 24

The secondary curve of a rigid contact lens is generally:

Answer 24

2 to 4 diopters flatter than the Central posterior curve

Question 25

The fitting characteristics of a gas-permeable rigid contact lens may be altered by:

Answer 25

changing the radius of curvature of the CPC
increasing the diameter
widening the PPC

Question 26

A soft contact lens demonstrates excessive movement. This may be remedied by:
 A. disinfecting the lens
 B. a smaller diameter lens
 C. a larger diameter lens
 D. a flatter lens

Answer 26

C. a larger diameter lens

Question 27

In making the concentric style bifocals, the different power zones (distance and near may be ground on:

Answer 27

either surface

The distance power may be in the center zone, with the near zone encircling it, or vice-versa.

Question 28

The addition of fluorine to the rigid lens ingredients increases:

Answer 28

wettability

Question 29

Which of the following instruments would be used to verify the lens diameter in the office?

Answer 29

Diameter gauge
Projection Magnifier
Measuring Magnifier

Not Radiuscope

Question 30

The radiuscope can be used for all of the following

Answer 30

peripheral curves
Warped base curve
toric base curve

no lens power

Question 31

How is the power measured on a Rigid Contact Lens?

Answer 31

Lensometer - with the concave surface facing the lens stop

Question 32

When rigid lenses are manufactured, which parameter is cut first?

Answer 32

central posterior curve

Question 33

Lens blends and “ski edge” can be verified using a

Answer 33

long fluorescent light bulb

Question 34

The practitioner should suspect ________ astigmatism if there is a difference between the amount of
cylinder found by keratometry readings and the amount of cylinder found by refractometry.

Answer 34

internal

Question 35

For patients with a moderate amount of corneal astigmatism (between one and two diopters), which
lens type will provide the crispest, most stable vision?

Answer 35

rigid spherical

Question 36

How much corneal astigmatism is present on a cornea with K-readings:
44.00/42.00 @ 90 ?

Answer 36

2.00 D
difference between the two