How do you assess near vision?

Testing Near Vision

Near vision testing should be performed at 14 to 16 inches (35 to 40 centimeters) using standardized high-contrast charts with black optotypes on a white background. 1

Standard Testing Procedure

Testing Distance and Setup

• Position the near vision chart at 14-16 inches (35-40 cm) from the patient
• Ensure proper illumination with good lighting on the chart
• Test in a quiet, distraction-free environment 1
• Use standardized high-contrast charts with black optotypes on white background

Testing Protocol

1. Test binocularly first, then monocularly (one eye at a time)
2. For monocular testing:
   • Cover the non-tested eye with an adhesive patch or tape
   • Ensure the patient cannot peek around the occluder
   • Test each eye separately 1
3. Record the smallest line the patient can read correctly
4. Document the testing distance and any reading correction used

Chart Options for Near Testing

• Standard near vision cards with Snellen letters or numbers
• LEA SYMBOLS® - particularly useful for young children or non-verbal patients
• HOTV optotypes - good for young children who know these letters
• Sloan letters - preferred for older children and adults 1

Special Considerations

For Children

• Allow practice with matching cards before formal testing
• Consider using a shorter testing distance for younger children
• Use age-appropriate optotypes (LEA SYMBOLS or HOTV for young children) 1, 2
• For children who cannot name letters/symbols, allow them to match optotypes using a hand-held card 1

For Patients with Visual Impairment

• Record the reading add used (if any), letter size, and reading distance
• For patients with very low vision, use larger optotypes or specialized low vision charts 1
• Test at the patient's preferred reading distance in addition to standard distance 1

For Patients with Nystagmus

• Consider using special techniques:
  • Blurring the fellow eye with high plus lenses
  • Using a translucent occluder rather than an opaque one
  • Perform binocular testing to gain additional information 1

Documentation

• Record:
  1. The type of chart used
  2. Testing distance
  3. Any optical correction used
  4. The smallest line read correctly
  5. Any special testing conditions or patient behaviors 1

Common Pitfalls to Avoid

• Inadequate occlusion of the non-tested eye leading to falsely normal results
• Inconsistent testing distance affecting reliability of results
• Improper illumination making optotypes harder to see
• Rushing the patient which may affect performance, especially in children or elderly
• Using single optotypes which can overestimate visual acuity in amblyopia due to lack of crowding phenomenon 1

Near vision testing is an essential component of a comprehensive eye examination and provides critical information about a patient's functional vision for daily tasks like reading, using digital devices, and other close work.