Visual Acuity

Question 1

What is visual acuity?

Answer 1

• Most common form of clinical measurement for visual function
• Measures ability to receive, transmit and interpret visual images
• Visual status of patient: myopia, hyperopic, astig, amblyopia, cat. surgery, ect.

Question 2

Measuring/Recording VA

Answer 2

1. Monocularly, OD first
2. Record w/ or w/o correction: SC, without; CC, with
3. Start at 20/20, go bigger if nec.

Question 3

Recording VA

Answer 3

Example: If patient can see 3 correct on the 20/30 line but nothing on the 20/25 their VA is 20/30-3

Question 4

Objectives of testing VA

Answer 4

1. Determines best CC VA
2. Determines if decreased vision is due to refractive error or pathology
3. Determines asymmetry (amblyopia)

Question 5

20/400

Answer 5

If the patient cant read 20/400, used printed chart and walk toward them. Record the distance they can see. EX: 20/400 @ 5 feet

Question 6

Beyond 20/400

Answer 6

1. Count finger
2. Hand motion test
3. Pen light
   If they cant see pen light record as NLP, no light perception

Question 7

VA Charts

Answer 7

1. Snellen
2. Charts for children (pics)
3. Tumbling E (nonverbal)
4. Landolt C (nonverbal)

Question 8

Pinhole testing

Answer 8

Differentiates between decreased vision from refractive error and those caused by pathology
Will indicate if further testing is needed

Question 9

Indication of pinhole testing

Answer 9

If VA improves, VA will be corrected by specs
If there is no improvement, VA wont be corrected (Can indicate amblyopia or disease.)