Hyperfocal Distance Flashcards
what is hyperfocal distance
the location of the point conjugate with the retina , when the distal edge of DOF is at optical infinity
- produces the greatest linear range of clear vision without accommodation
what is max plus to best VA
when the distal edge of DOF is at acuity chart
what is depth of field
the range of object distance (in Diopters) in which the VA is the same level
depth of focus
the distance in (diopters) though which the image recieveing surface (our retina) can be moved without altering quality of image or for fixed image reviewing surface, the greatest focusing consistent with this requirement
if the acuity chart lies within the DOF in both cases what will be different about the VA
best VA will be exactly the same
max plus lens that gives best VA while viewing infinite target will
- give optimal distance VA (distal end of DOF at the chart
- place distal end of DOF coincident with acuity chart
- provide max linear range of clear vision w/o accom.
when performing max plus to BVA, if the chart is at infinity then
the max plus to BVA equals HDR
if you work in a 6m room and your max + to BVA finding is: +5.00 -1.00 x 060, what lenses would you prescribe
6m = optical infinity, Rx doesn’t change
accommodation creates added refractive power, where will the DOF move
towards eye
the first time the target appears clear when the proximal edge of DOF coincides with the target is
the minimum accommodative response necessary to see the target clearly
if the eye continues to increase its accommodative response, what happens to the DOF
moves towards the eye
the maximum the eye can accommodate and still see clearly is when
distal edge of DOF coincides with the target
If the eye accommodates the amount in which the DOF lies in front of the target, what will the pt see
blur
what is emmetropia
point conjugate with the retina at infinity
