Visual Acuity Testing

Objectives Define normal values Describe the rationale for following proper procedures while performing a visual acuity test. Demonstrate accurate performance of a visual acuity test.

Visual Acuity Testing What is your role? Correctly run test Encouragement vs assessment Snellen Chart

Visual Acuity Testing Preparation Question patient about:: –Corrected vision for distance: glasses, contacts laser surgery –Other vision issues that may affect test (eg monovision) Test patient with correction and document Position patient 20 feet from eye chart Rationale: top number of reading refers to distance patient stands from chart

Visual Acuity Testing Preparation Clean the occluder paddle/handle with alcohol and let dry before handing it to the patient. Position self in front of patient, looking in direction of patient Do not point to lines or symbols

Visual Acuity Testing Procedure Have patient completely occlude one eye –start with either right or left; document appropriately Instruct to: –keep eye under occluder open and relaxed –do not apply excessive pressure with occluder Ask patient to read letters beginning at mid chart (line 4 or line 5) –if gets all correct or misses one letter, read next line below –If misses two letters, read next line above

Visual Acuity Testing Procedure Work down the chart to the last line patient reads with 75% accuracy –do not skip lines –no misses on lines with 1-3 letters. –one miss on lines with 4-7 letters. –two misses on lines with 8-11 letters Rationale: test design provides consistency and most accurate reading for patient Repeat for alternate eye, then both eyes Record visual acuity for each eye/both eyes in patient medical record Note anything important

How would you troubleshoot? When asked to move to next line, patient says he cannot do it Encourage patient to try and read as many as possible Patient has memorized the eye chart Ask patient to read row right to left (backwards) Patient is holding occluder so that she can see around it Monitor patient and position of occluder so that you can have patient adjust it Patient is jumping around on a line, not reading letters in order Allow, but ask patient to identify which letter he/she is reading

Other Considerations (Please see Articulate module) PediatricGeriatric

Documentation The procedure isn’t complete until the documentation is done!