Interpupillary Distance

Question 1

the definition of pupillary distance is

Answer 1

the distance between the centers of the pupils for a specific viewing distance

Question 2

how is a monocular PD measured and why is it important?

Answer 2

• the distance from the center of the pupil to the middle of the bridge
• important for progressives (PALs) and high Rx

Question 3

some important procedure set ups for PD measurement

Answer 3

• full room illumination
• remove patient spectacles
• keep testing distance equivalent to near working distance (usually 40cm)

Question 4

what is important about the zero mark in PD measurements

Answer 4

must keep zero mark at the same position for distance and near measurement and do not move ruler during measurements

Question 5

for near PD, you close _____ eye and have patient look at open _____ eye

Answer 5

• you close OD

- patient looks at open OS

Question 6

for near PD, where do you position the mm ruler zero mark at?

Answer 6

at the patient’s temporal limbus

Question 7

without moving the ruler, what location on the patient’s eye is used to find near PD?

Answer 7

location of nasal limbus of patient’s OS

Question 8

for distance PD, you close ____ eye and have patient look at open ____

Answer 8

• you close OS

- patient looks at open OD

Question 9

without moving the ruler, what location on the patient’s eye is used to find distance PD?

Answer 9

new location of the nasal limbus of patient’s OS

Question 10

mean PD for adults and range of PDs

Answer 10

mean PD: 63mm

range is from 50-75mm

Question 11

patients with what type of PD will have an increased convergence demand?

Answer 11

patient’s with extremely large distance PDs

Question 12

pupillometer utilizes:

Answer 12

corneal reflex to determine PD

also can be used to determine monocular PDs