Vision Diagnostic Procedures Summary

Vision Diagnostic Procedures

• Snellen Test

  • Standard test for visual acuity
  • Measures ability to distinguish shapes/details at a distance
  • Electronic versions available for one-line viewing
  • Normal vision: 20/20 (can read letters from 20 feet away)

• Vision Measurements

  • Nearsighted (myopic) individuals read larger letters at 20 feet
  • Vision notation (e.g., 20/40, 20/60) represents ability compared to normal vision
  • Example: 20/60 means reading at 20 feet what normal vision reads at 60 feet

• Ishihara Test

  • Detects color blindness
  • Uses colored plates with numbers
  • Non-color blind individuals distinguish numbers, color-blind do not

• Ophthalmoscopy

  • Visual examination of the inside of the eye
  • Uses an ophthalmoscope
  • Techniques include fundoscopy to examine retina, optic disc, etc.
  • Slit lamp ophthalmoscopy utilizes a narrow beam of light to inspect cornea, iris, and lens.