Assessment Of Visual Acuity Flashcards
1
Q
Define VA
A
The appreciation of differences in the external world
-colour, position etc. Resulting from the simulation of the retina by light
2
Q
Define aided VA
A
- resolving power of The Eye
- indicates capacity for seeing DISTINCTLY details of an object
3
Q
Define near VA
A
-capacity for seeing DISTINCTLY the details of an object at near (25-50cm)
4
Q
Types of acuity
A
Grating, vernier, contour, letter
5
Q
Explain grating acuity
A
- determine a group of points of lines are separable and distinct
- 52 to 64s for detection
- expressed as angular subtense (seconds of arc)
6
Q
Explain vernier acuity
A
- to distinguish between 2 lines place end-to-end with one of them laterally displaced
- 2 to 12s
7
Q
explain Contour acuity
A
Simple form (C or E) used with a task (orientation) -minimum cognizable/legible
8
Q
Letter acuity
A
- most common
- complex patterns used: numbers and letters
-minimum cognizable/legible
9
Q
Types of letter chart for distance
A
- logmar
- snellen (letter, number, tumbling e, pictogram)
10
Q
Types of letter chart for near
A
The point system, jaeger system, reduced snellen, m system, logmar
