Use of ultrasound biomicroscopy to diagnose Ahmed valve obstruction by iris.
BACKGROUND
We report 2 cases in which ultrasound biomicroscopy (UBM) was used to diagnose Ahmed valve obstruction by the iris.


METHODS
Two patients underwent unilateral placement of Ahmed implants, one into the anterior chamber and the other into the ciliary sulcus.


RESULTS
Intraocular pressures increased in the early postoperative period. In each case, a clear view of the aqueous drainage tube was precluded. Occlusion of the end of the tube by iris tissue was demonstrated by UBM. An iridectomy over the tip of the tube instituted filtration in each case.


CONCLUSIONS
UBM was instrumental in diagnosing the presence and cause of occlusion of aqueous drainage tubes.
Carrillo
Monica M
MM
Department of Ophthalmology, Toronto Western Hospital, Ont.
Trope
Graham E
GE
Pavlin
Charles
C
Buys
Yvonne M
YM
D000328:Adult; D000368:Aged; D000867:Anterior Chamber / Q000000981:diagnostic imaging / Q000601:surgery; D000959:Antihypertensive Agents / Q000627:therapeutic use; D002924:Ciliary Body / Q000000981:diagnostic imaging / Q000601:surgery; D005260:Female; D005901:Glaucoma / Q000601:surgery; D020327:Glaucoma Drainage Implants / Q000009:adverse effects*; D006801:Humans; D007429:Intraocular Pressure; D032801:Iridectomy; D007498:Iris / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D008297:Male; D033401:Microscopy, Acoustic; D011183:Postoperative Complications; D011475:Prosthesis Failure
D000959:Antihypertensive Agents