Acquired Pseudo-Brown's syndrome immediately following Ahmed valve glaucoma implant.

A 76-year-old woman noted vertical and horizontal diplopia one day following placement of an Ahmed valve in the superonasal quadrant of her left eye. She was unable to elevate her left eye, especially in adduction. She refused implant removal and strabismus surgery alone failed to satisfactorily resolve her problem. On forced duction testing, the implant became wedged between the globe and orbit superonasally. Subsequent repositioning of the valve resulted in resolution of her motility problem. Implant-orbital disproportion can produce a pseudo-Brown's syndrome. Surgeons are encouraged to perform forced duction testing at the time of glaucoma implant placement to detect and prevent this complication.