Measuring and Documenting Distance Visual Acuity

Introduction

• Presenter: Sergeant Patel, Ophthalmology Registrar
• Purpose: Tutorial on measuring and documenting distance visual acuity (VA)
• Importance: VA is essential for assessing patients with eye complaints, measuring the eye's ability to distinguish details at a distance.

Tools

• Stellen Chart: Commonly used in emergency departments and general practice
  • Standard chart read at 6 meters (20 feet)
  • Alternative setups: mirror at 3 meters or reduced Stellen chart at 3 meters

Documenting Visual Acuity

• Expressed as a ratio (X/Y)
  • X: Testing distance
  • Y: Smallest letter patient can identify
• Normal VA: 6/6

Procedure

1. Preparation
   • Wash hands
   • Wear appropriate PPE
   • Explain procedure to the patient
   • Ensure good lighting
2. Testing
   • Assess one eye at a time using an occluder
   • Ask patient to read down the chart starting from the top
   • Document results:
     • Example: 6/7.5 +2 (two extra letters read on 6/6 line)
     • Use minus (-) if letters are missed (e.g., 6/6 -1)
3. Using a Pinhole Occluder
   • Helps to correct refractive error
   • Provides VA with corrected glasses prescription
4. Repeating for the Other Eye
5. Documenting Results
   • Unaided VA
   • VA with distance glasses/contact lenses
   • VA with pinhole

Alternative Measures

• If low VA (cannot see 6/60 line):
  • Move closer to the chart and document (e.g., 3/60)
  • Ask to count fingers
  • Detect hand movements
  • Perception of light

Conclusion

• Visual acuity testing is crucial for assessing visual function
• Accurate testing helps in appropriate triage and management of patients

Note: Ensure accurate documentation for effective patient management.