Convergence Insufficiency

• Symptoms of eye strain, double vision with near work, headaches, astenopia worse with prolonged near work
• Abnormally far near point of convergence
• Common accompanying signs:
  • exophoria greater at near than distance
  • decreased or absent fusional convergence
  • normal divergence
  • Low AC/A
  • accommodative insufficiency
• Uncommon accompanying signs:
  • orthophoria
  • esophoria at near

• Point at which a person can no longer hold convergence at near
• Testing procedure
  • Proper correction should be worn
  • Use accommodative target (20/40 image or similar)
  • Patient focuses the target that slowly moves towards the nose
  • Where diplopia occurs is the “break point”
• >6 cm from the nose in non-presbyopes and >10 cm for presbyopes is probably abnormal

• Testing procedure
  • Should be wearing proper correction
  • Measure with base out prism on distance (6 m) then near target (1/3 m)
  • Use accommodative target 20/40 or similar
  • Move the prism bar to the point where patient can no longer maintain single vision on the object, this is the break point.
  • Before reaching the break point, the patient may note a point where the image blurs, the patient can no longer use fusional convergence and resorts to accommodative convergence which may improve convergence but causes a blurred image due to over-convergence
  • Reduce the base out prism until the patient recovers single vision, this is the recovery point.
  • if exotropia present ensure not worse XT in downgaze
  • encouragement often improves convergence

• Low AC/A ratio of <2:1
• Reduced Positive fusional vergence <15PD
• High CI symptom survey score of ≥16

Developed by the Convergence Insufficiency Treatment Trial Investigator Group - Borsting EJ, Rouse MW, Mitchell GL, et al. Validity and reliability of the revised convergence insufficiency symptom survey in children aged 9 to 18 years. Optom Vis Sci. 2003;80(12):832-838. doi:10.1097/00006324-200312000-00014