Deck 5: Keratometry Tonometry and Refractometry

Question 1

What is the radius of the corneal curvature useful for?

A)Determining the power of a spectacle lens
B)Determining the power of an intraocular replacement lens
C)Fitting contact lenses
D)Adjusting the keratometer's mires

Answer 1

Fitting contact lenses

Question 2

If a patient's eyesight is very poor and they cannot focus on the target inside the keratometer, what should be done to assist them?

A)Shine a penlight through the eyepiece
B)Instruct the patient to focus harder
C)Adjust the chinrest
D)Instruct the patient to blink rapidly

Answer 2

Shine a penlight through the eyepiece

Question 3

At the commencement of examination, if the keratometer mires look blurry or doubled to the examiner, what should be done?

A)The focusing knob should be adjusted
B)The eyepiece should be adjusted
C)The joystick should be used to move the barrel
D)A and C

Answer 3

A and C

Question 4

An ophthalmometer is also known as a

A)tonometer.
B)specular microscope.
C)keratometer.
D)ophthalmoscope.

Question 5

If a patient comes in for a keratometry reading, a gonioscopy, and instillation of eye drops, which should be performed first?

A)Keratometry reading
B)Gonioscopy
C)Instillation of eye drops
D)Order does not matter

Question 6

Which of the following keratometry readings is considered shorthand and thus omits the axis of the flatter meridian?

A)OD 42.25 x 175 / 43.50 x 85
B)OD 42.25 / 43.50 x 85
C)OD 42.25 x 175 / 43.50
D)OD 175 / 43.50 x 85

Question 7

Conventionally, the first number in a written keratometry reading is the lowest. What does it correspond to?

A)The axis of the flatter meridian
B)The total refracting power
C)The flattest corneal meridian
D)The steepest corneal meridian

Question 8

If a patient has had refractive surgery, a direct keratometry reading will be

A)accurate.
B)inaccurate.
C)troublesome to attain.
D)very low.

Question 9

To ensure accuracy, the keratometer must be

A)periodically calibrated.
B)properly maintained.
C)protected from dust.
D)all of the above.

Question 10

What part of the cornea does the keratometer measure?

A)Optic cap
B)Corneal endothelium
C)Descemet's membrane
D)Corneal stroma

Question 11

"Against the rule"refers to the corneal astigmatism when

A)the horizontal meridian is flatter than the vertical meridian.
B)the horizontal meridian is steeper than the vertical meridian.
C)the corneal astigmatism from the eye differs from that of the refractive cylinder of the prescription.
D)none of the above.

Question 12

The keratometer measures

A)the refractive error of the eye.
B)depth perception.
C)symmetry of orbits.
D)the curvature of the anterior surface of the cornea.

Question 13

The Goldman Applanation Tonometer measures what?

A)Intraocular pressure
B)Corneal thickness
C)Axial length
D)Visual acuity

Question 14

The normal range of intraocular pressure is between

A)10 and 100 mmHg.
B)10 and 15 mmHg.
C)10 and 22 mmHg.
D)50 and 60 mmHg.

Question 15

The tonometer tip can be disinfected by

A)soaking in 3% hydrogen peroxide for 10 minutes.
B)wiping it off with warm water and soap.
C)wiping it with alcohol for 10 seconds.
D)A and C.

Question 16

Ophthalmic assistants are responsible for calibrating the tonometer. True or False?

Question 17

A patient with conjunctivitis comes in the clinic for contact tonometry. What should you do?

A)Proceed as normal
B)Use another method or reschedule the patient for a future date
C)Let the physician know and then proceed as normal
D)Guess the IOP

Question 18

All of the following are variables that can result in incorrectly high intraocular pressure readings except

A)patient holding breath.
B)patient straining.
C)patient is myopic.
D)patient squeezing eyelids.

Question 19

All of the following are instruments for attaining an intraocular pressure reading except

A)Schiøtz tonometer.
B)Tono-Pen.
C)noncontact tonometer.
D)Campbell tonometer.

Question 20

The fastest method of attaining a tonometry reading is

A)Tono-Pen.
B)Goldman applanation tonometer.
C)noncontact tonometer.
D)Schiøtz tonometer.

Question 21

The least accurate way to attain the intraocular pressure is through

A)Tono-Pen.
B)Goldman applanation tonometer.
C)noncontact tonometer.
D)Schiøtz tonometer.

Question 22

What is determined by the rate aqueous enters and exits the eye?

A)Epithelial cell count
B)Intraocular pressure
C)Presence of a vitreous hemorrhage
D)Corneal curvature

Question 23

How does the flow of aqueous humor begin?

A)By entering the anterior chamber
B)By entering the posterior chamber via the secretion of the ciliary body
C)By flowing through the pupil
D)By leaving the anterior chamber via the trabecular meshwork

Question 24

At what time of the day is the intraocular pressure highest?

A)Morning
B)Midday
C)Afternoon
D)Night

Question 25

Which of the following increases intraocular pressure?

A)Thick cornea
B)Glaucoma
C)Steroid use
D)All of the above

Question 26

During diastole, intraocular pressure _______ as blood flows out of the globe.

A)increases
B)decreases
C)maintains the same
D)hits zero

Question 27

Where are the aqueous convection currents the warmest?

A)Posterior chamber
B)Anterior portion of the anterior chamber
C)Peripheral anterior chamber
D)Deep anterior chamber

Question 28

Anticholinergics do what in patients with narrow-angle glaucoma?

A)Increase intraocular pressure
B)Decrease intraocular pressure
C)Dilate pupil
D)Constrict pupil

Question 29

The function of glasses is to

A)improve visual performance.
B)relieve the symptoms of refractive errors.
C)relieve the symptoms of muscular imbalance in the eyes.
D)all of the above.

Question 30

Cycloplegic drops paralyze the eye's

A)accommodative ability.
B)focalizing ability.
C)binocular ability.
D)movement.

Question 31

Another name for near-sightedness is

A)hyperopia.
B)myopia.
C)astigmatism.
D)emmetropia.

Question 32

The inability to focus due to loss of lens elasticity is called

A)astigmatism.
B)aphakia.
C)presbyopia.
D)hyperopia.

Question 33

What is the best method to ascertain the objective refraction of a patient?

A)Manifest refractometry
B)Automated refractometry
C)Cycloplegic refraction
D)Duochrome test

Question 34

The refraction that a patient likes the most is known as the

A)comfortable refraction.
B)subjective refraction.
C)objective refraction.
D)cyclopegic refraction.

Question 35

What type of lenses can be used to correct astigmatism?

A)Prism lenses
B)Cylinder lenses
C)Plus lenses
D)Minus lenses

Question 36

What is the focal length of a 4.00 D lens?

A)0)33 m
B)0)5 m
C)1)0 m
D)0)25 m

Question 37

In the hyperopic eye, distant objects are brought to focus

A)on the retina.
B)behind the retina.
C)before the retina.
D)on the sclera.

Question 38

A toric contact lens is analogous to

A)a prism lens.
B)a cylinder lens.
C)a plus lens.
D)a minus lens.

Question 39

The power of a cylinder lens is found how many degrees away from its axis?

A)30 degrees
B)60 degrees
C)90 degrees
D)120 degrees

Question 40

When examining a patient for objective refraction, it is best for the pupil to be

A)dilated.
B)constricted.
C)myopic.
D)hyperopic.

Question 41

What can be determined from a retinoscopy exam?

A)Subjective refraction
B)Objective refraction
C)Fusional ability
D)Accommodative ability

Question 42

The purpose of refractometry is to

A)diagnose color blindness.
B)measure retinal thickness.
C)measure refractive error.
D)map out the topography of the cornea.

Question 43

If the eyeball is too long for the normal reflective power of the lens and the cornea, what condition does the patient have?

A)Index myopia
B)Axial myopia
C)Curvature myopia
D)Hyperopia

Question 44

Having a new lens, such as the lens placed in the eye after cataract surgery, is known as

A)presbyopia.
B)aphakia.
C)pseudophakia.
D)myopia.

Question 45

The sum of the steps performed in arriving at a decision as to what lens or lenses will most benefit the patient is known as

A)ophthalmology.
B)refraction.
C)refractometry.
D)visual acuity.

Question 46

All of the following are steps performed to ascertain a patient's refraction except

A)measurement of visual acuity.
B)refractometry.
C)measurement of accommodative ability.
D)tonometry.

Question 47

The best correction a patient with astigmatism can obtain without a cylinder is known as

A)irregular astigmatism.
B)cylinder equivalent.
C)spherical equivalent.
D)subjective refraction.

Question 48

The condition in which there is a difference in the refractive error of the two eyes is known as

A)anisometropia.
B)aphakia.
C)presbyopia.
D)pseudophakia.

Question 49

The eye is a compound lens system composed of

A)the lens and the sclera.
B)the cornea and the iris.
C)the lens and the cornea.
D)the cornea and the retina.

Question 50

What kind of astigmatism is commonly the result of trauma, inflammation, scar tissue, or developmental anomalies affecting the cornea?

A)Irregular astigmatism
B)Asymmetrical astigmatism
C)Oblique astigmatism
D)None of the above

Question 51

On an astigmatic clock, the correcting cylinder is placed how many degrees from the blackest line?

A)30 degrees
B)60 degrees
C)90 degrees
D)120 degrees

Question 52

A lens consisting of two cylinders of equal power but of opposite designation, one being plus and the other being minus, and their axes set 90 degrees apart is known as a

A)correcting cylinder.
B)cross cylinder.
C)spherical equivalent.
D)prism.