Visual Assessment 5% Flashcards
The normal human eye can distinguish 2 points separated by an angle of __________
1 arc minute
Each section of the letter E subtends ____________
1 minute of arc
The whole letter E subtends _______________
5 minutes of arc
In recording VA (US measurements) Numerator=
Top number, Distance (in feet) pt is from chart
*In recording VA (US measurements) Demominator=
Bottom number. Distance (in feet) that someone with normal vision could correctly read the letters.
When checking VA, the larger the number___________
the worse the vision.
How to convert feet to meters
3:1 ratio
6m=20ft
1m=3.28
Divide denominator by 3 to get approx meters. (Or drop the 0 and multiply the first number by 3. Ex. 20/40=6/12(2x3 is 6 and 4x3 is 12))
Convert to meters…
20/60
6/18
Convert to meters…
20/400
6/120
Convert to meters….
20/30
6/9
What do you do if pt can’t see 20/400 E?
Have pt move toward the chart until he can read 20/400E
Example charting 4/400 (pt 4’ away from screen, read 400 line)
If pt cannot distinguish the 20/400 E even from close distance what are the next steps?
Hold you one or two fingers up in from a distance of 5’
Move 1’-2’ closer until pt can accurately count your fingers
Record as CF(count fingers) @_______
If pt cannot count fingers…….
Move your hand side to side or up and down in front of eye.
Ask..”am I moving my hand up and down or side to side?”
If s/he can accurately perceive your hand moving record HM(hand motion) @___
If pt can’t accurately detect HM…….
Darken Room
Project transillumintor from 1”(be sure to keep fellow eye covered). Check all 4 quadrants.
If pt can’t see transilluminator, use indirect ophthalmoscope and try again.
Record as LP with proj or Light percetion with projection.
If pt can’t accurately detect the position of the light but CAN perceive the light record as LP or Light perception.
If pt is unable to perceive light…..
Record….Absent Light perception, No light perception, or NLP