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Keywords:

  • congenital III cranial nerve palsy;
  • Knapp procedure;
  • monocular elevation deficiency

Abstract

Purpose:  To document the presentation and management of congenital III nerve palsy and monocular elevation deficiency to single ophthalmologist over a 14-year period. Surgical management was reviewed and visual outcome was analysed.

Methods:  A retrospective study was conducted of all patients presenting during a period between 1992 and 2006 to the private practice of a paediatric ophthalmologist, with either congenital III or monocular elevation deficiency. For patients requiring surgical intervention pre- and post-surgical data were documented and analysed.

Results:  A total of 19 congenital III and 13 monocular elevation deficiency patients were identified. There were eight surgical patients in each congenital III nerve palsy group and in the monocular elevation deficiency group. The congenital III group had a preoperative mean exotropia for near of −36 prism dioptres (PD) compared with postoperative mean exotropia for near −16 PD. Preoperative mean hypotropia for near of −19 PD was improved to postoperative mean hypotropia of −5 PD. The monocular elevation deficiency group had preoperative mean esotropia for near of +6 PD compared with postoperative mean exotropia for near −5 PD. Preoperative mean hypotropia for near of −15 PD was improved to postoperative mean hypotropia of −7 PD. At last follow up both groups had a majority of mild or no amblyopia noted.

Conclusion:  Superficially, congenital III and monocular elevation deficiency may appear similar, both frequently having ptosis and hypotropia as features. Careful clinical assessment of the horizontal alignment and the result of forced duction testing will usually allow them to be distinguished. Congenital III more frequently requires surgery for exotropia as well as surgery for hypotropia and monocular elevation deficiency more often requires surgery just for hypotropia. The ptosis surgery is similar for either diagnosis in this study. Significant cosmetic improvement, as well as excellent visual acuity outcomes can be achieved.