Log 4 - Distance and Near PD

Question 1

What are the 4 Reference points to measure the distance or anatomical PD?

Answer 1

1. Pupil centers
2. Inner and Outer pupil edges
3. Inner and Outer limbus
4. Inner and Outer Canthi

Question 2

If a patient has dissimilar pupil sizes which type of pupil measurement would you take?

Answer 2

Inner and Outer pupil edges can be used to measure as reference points.

1. Distance from outer edge of OD pupil to inner edge of OS pupil (measurement A)
2. Distance from inner edge of OD pupil to outer edge of OS pupil (measurement B)
3. Add A and B then divide by 2 = distance PD

Question 3

If the patient is an uncooperative child, how may PD’s have to be measured?

Answer 3

Dispenser may have to measure canthus-to-canthus

Question 4

When using light relex PD’s the optician holds a pen light directly below their _________ eye and shines the light in the patients eye

Answer 4

OPEN

Question 5

The most accurate PD readings today are made from a corneal reflex ___________

Answer 5

Pupillometer

Question 6

What are 6 reasons for taking or when to take a monocular PD measurement

Answer 6

1. When the OD and OS monocular PDs are not equal
2. When their prescription is greater than +/- 4.00D
3. Px with an anisometropia
4. When px is ordering lenses of higher index
5. When px is ordering aspheric lenses
6. When px is ordering any type of multifocal

Question 7

A px has dissimilar sized pupils. The distance from the outer edge of the px’s OD pupil to the inner edge of the OS equals 54 mm. The distance from the inner edge of the OD pupil to the outer edge of the OS equals 58mm. What is the px’s distance PD?

Answer 7

58+54
_____
2
=56