MEM Retinoscopy Lecture Notes

Introduction

• MEM Retinoscopy: A technique to determine the accommodative response.
  • Estimates reflex motion without disturbing accommodation.

Key Learning Points

• Aim: To assess the accommodative response.
• Equipment Needed:
  1. Retinoscope: To find lag and lead of accommodation.
  2. Trial Lens Set: Combination of plus and minus lenses.
  3. MEM Card: Monocular Estimated Method card.
  4. Near Vision Chart: Used as an alternative target.

Procedure

1. Room Setup:
   • Proper illumination is required.
2. Target Distance:
   • Hold the near target at 40 cm (walking distance).
3. Patient Interaction:
   • Ask the patient to read words on the MEM card.
4. Retinoscope Technique:
   • Move the retinoscopic beam horizontally across one eye, then the other.
   • Observe reflex motion quickly.
5. Neutralization:
   • Record lens power required to achieve neutrality.
   • Against Movement: Neutralize with minus lens.
   • With Movement: Neutralize with plus lens.

Interpretation of Results

• Normal Values: +0.25 to +0.50 diopters.
• Higher than +0.75 diopter: Indicates lack of accommodation.
  • Possible causes:
    • Near Esophoria
    • Accommodative Dysfunction
    • Uncorrected Hyperopia
    • Over-corrected Myopia
• Below +0.25 diopter: Indicates lead of accommodation.
  • Possible causes:
    • Near Exophoria (Over Acc)
    • Spasm of Accommodation
    • Uncorrected Myopia