chapter 17 tonometry Flashcards
The tonometer tip should be cleaned:
a) prior to being sterilized
b) prior to being autoclaved
c) prior to being boiled
d) prior to being disinfected
D- prior to being disinfected
To best disinfect the tonometer tip, one should:
a) wipe it with a moist tissue
b) swipe it with an alcohol wipe
c) put it in a 10-minute soak in 3% hydrogen peroxide
d) place it in the autoclave for 15 minutes
C- put it in a 10-minute soak in 3% hydrogen peroxide
With regular use, soaking the tonometer tip in alcohol:
a) will not affect it
b) will cause the numbers to fade
c) will cause etching on the face
d) will cause the plastic to soften
B- will cause the numbers to fade
If the applanation tonometer falls outside of the calibration allowance:
a) add or subtract from the final reading to offset the problem
b) bend the tonometer arm until calibration is accurate
c) turn the screw in the tonometer arm until calibration is accurate
d) return the tonometer to the manufacturer for calibration
D- return the tonometer to the manufacturer for calibration
The applanation tonometer is preferred in cases of low scleral rigidity because:
a) it does not displace an appreciable amount of aqueous and, therefore, does not cause distention of the ocular structures
b) it does not flatten the cornea and, therefore, does not cause distention of the ocular structures
c) it is performed with the patient in a seated position and, therefore, gravity can equalize distention of the ocular structures
d) topical anesthetic is used and, therefore, does not cause distention of the ocular structures
A- it does not displace an appreciable amount of aqueous and, therefore does not cause distention of the ocular structures
The biprism design of the applanation tonometer:
a) makes it easier to align than an indentation tonometer
b) makes it more accurate than indentation tonometry
c) offsets scleral rigidity factors
d) makes it more comfortable than indentation tonometry
A- makes it easier to align than an indentation tonometer
For proper applanation, the slit-lamp light should be set up as follows:
a) at a 60 degree angle, with the cobalt blue filter, and with the light source completely open
b) at a 45 degree angle, with the red-free filter, and with the light source completely open
c) at a 90 degree angle, with the cobalt blue filter, and a narrow beam
d) at a 60 degree angle, with the cobalt blue filter, and a pinpoint light beam
A- at a 60 degree angle, with the cobalt blue filter, and with the light source completely open
Each mark on the applanation tonometer drum stands for:
a) 10 mm Hg
b) 2 mm Hg
c) 1 mm Hg
d) 2 g/mm2
B- 2mm Hg
When the applanation tonometer mires pulsate, the IOP:
a) is the lowest of the readings
b) is the highest of the readings
c) is the difference between the 2 readings
d) is at the midpoint between the 2 readings
D- is at the midpoint between the 2 readings
In order to compensate for high astigmatism with the applanation tonometer, the biprism should be aligned as follows: a) the steepest axis aligned with the red line on the holder
b) the plus axis aligned with the red line on the holder
c) 45 degrees from the minus cylinder should be placed in the 90-degree position
d) the minus axis aligned with the red line on the holder
D- the minus axis aligned with the red line on the holder
A scarred, irregular cornea is difficult to measure with the applanation tonometer because:
a) there is decreased scleral rigidity
b) one cannot instill topical anesthetic because of tissue melt
c) one cannot use fluorescein because it will infiltrate the tissue
d) the mires are irregular, making it difficult to judge the endpoint
D- the mires are irregular, making it difficult to judge the endpoint
Corneal abrasions from tonometry can best be reduced by:
a) use of anesthetic
b) proper fixation
c) proper lighting
d) holding the lids securely
B- proper fixation
If the patient has known human immunodeficiency virus (HIV), the assistant should:
a) refuse to take a pressure on the patient
b) use only the noncontact tonometer
c) wear gloves during contact tonometry
d) place a tissue on the tonometer prism
C- wear gloves during contact tonometry
Schiøtz tonometry measures IOP by:
a) measuring the force it takes to equalize the eye’s internal pressure
b) measuring the force exerted on the instrument by the eye
c) measuring the force it takes to flatten an area of the cornea
d) measuring the force it takes to indent the cornea
D- measuring the force it takes to indent the cornea
The Schiøtz tonometer readings:
a) are read from the instrument in millimeters of mercury
b) are read from the instrument in gram weights
c) must be converted to millimeters of fluorescein by use of a calculator
d) must be converted to millimeters of mercury by use of a chart
D- must be covered to millimeters of mercury by use of a chart
Patient position for Schiøtz tonometry is:
a) sitting up to the slit lamp
b) sitting up in the exam chair
c) lying back in the exam chair
d) sitting at a 45 degree angle
C- lying back in the exam chair
The aqueous humor is produced by the:
a) ciliary muscle
b) ciliary body
c) trabecular meshwork
d) iris
B- ciliary body
The composition of the aqueous is most like: a) blood plasma
b) tears
c) saliva
d) mucus
A- blood plasma
The flow of aqueous in the eye follows this pattern:
a) angle, posterior chamber, pupil, anterior chamber
b) angle, anterior chamber, pupil, posterior chamber
c) pupil, posterior chamber, anterior chamber, angle
d) posterior chamber, pupil, anterior chamber, angle
D- posterior chamber, pupil, anterior chamber, angle
Regarding the normal diurnal variation of IOP:
a) IOP is higher early in the morning
b) IOP is lower early in the morning
c) IOP reaches a peak around noon
d) IOP is lowest around noon
A- IOP is higher early in the morning
The diurnal curve of IOP in a glaucoma patient:
a) may vary by 4 mm Hg
b) may vary up to 10 mm Hg
c) is less than in an eye without glaucoma
d) shows no variation in morning versus evening
B- may vary up to 10 mm Hg
Elevated IOP as seen in chronic open-angle glaucoma is believed to be the result of:
a) decreased function of cells in the trabecular meshwork
b) obstruction of the trabecular meshwork by particles
c) overproduction of aqueous
d) optic nerve damage
A- decreased function of cells in the trabecular meshwork
If the cornea is extremely thick or scarred:
a) the IOP measurements will always be underestimated
b) the IOP measurements will always be overestimated
c) the IOP measurements can be accepted with reservations
d) no tonometric measurement will be accurate enough to satisfy clinical needs
D- NO TONOMETRIC measurement will be accurate enough to satisfy clinical needs.
