Hyperfocal Distance Refraction

Question 1

What is depth of field?

Answer 1

The depth of field is the range of object distances (expressed in diopters) within which visual acuity does not deteriorate

Question 2

What is depth of focus?

Answer 2

For a given object distance, the depth of focus is the distance (expressed in diopters) through which the image- receiving surface can be moved without detriment to the quality of the image, or for a fixed image receiving surface, the greatest focusing error consistent with this requirement

Question 3

What is hyperfocal distance?

Answer 3

Location of point conjugate with the retina (in diopters) when the distal end of the depth of field lies at inifinity

Question 4

What does a HDR (Hyperfocal distance refraction) do?

Answer 4

1. Provides optimal distance VA
2. Places the distal end of the depth of field coincident with the acuity chart
3. Provides the maximum linear range of clear vision without accommodating

Question 5

How do minus spheres move the DOF?

Answer 5

Away from the eye

Question 6

How do plus spheres move the DOF?

Answer 6

Towards the eye

Question 7

How does the MINIMUM accommodative response look like?

Answer 7

Question 8

How does the MAXIMUM accommodative response look like?

Answer 8

Question 9

What does a hyperfocal distance refraction do?

Answer 9

Places the distal edge of the DOF at infinity

Question 10

What does emmetropia do?

Answer 10

Point conjugate with the retina is at infinity

Question 11

What does Maximum plus to best VA do?

Answer 11

The distal end of the DOF is at the acuity chart