Session: Poster session B

Monocular elevation deficit with ptosis, exotropia and convergence deficit: is stereopsis suitable to plan a muscular bilateral surgery?

Purpose: We describe the correct management of a Monocular Elevation Deficit (MED) misdiagnosed as a Brown Syndrome, and the importance of the stereoacuity, beyond the forced ductions test, to decide the surgical plan.  

Methods: A 7 years old child was checked for a monocular ptosis, hypotropia, exotropia, convergence deficit, anomalous head position (AHP) with chin left rotated. In the past she was misdiagnosed as a Brown Syndrome. The patient underwent a full ophthalmological and orthoptic check that showed a suspected MED type 2. Stereopsis was 480”of arc at TNO test. The forced ductions test done before surgery confirmed the diagnosis. She underwent a modified Knapp procedure on the affected right eye. A recess/resect horizontal surgery on the second eye was done secondary, to improve the stereoacuity, that disappeared after the first operation. Furthermore, after the second surgical intervention, she underwent a series of orthoptic rehabilitation of the convergence deficit.

Results: After the first surgery on the affected eye we obtained a correction of hypotropia and an improvement of the AHP and of the convergence deficit, but stereopsis disappeared due to suppression. After the second surgery we obtained a good resolution of the exotropia and a restoration of the stereoacuity at 120”. The convergence deficit improved after the orthoptic rehabilitation ameliorating the AHP and enhancing stereocuity at 60”.

Conclusions: The good action of the inferior rectus checked by forced ductions test, points-out the central deficit and suggests the correct surgery. Also stereoacuity must be considered a sensitive data to decide for a second surgical approach. Orthoptic rehabilitation must be suggested after surgery to regain a correct fusion mechanism, that may restore the stereoscopic sensory state and guarantee a correct orthotropic position.