CLINICAL SCIENCE

Ultrasound biomicroscopy and its value in predicting the long term outcome of viscocanalostomy

S Roters, C Lüke, C P Jonescu-Cuypers, B F Engels, P C Jacobi, W Konen and G K Krieglstein

University of Cologne, Centre of Ophthalmology, D-50924 Cologne, Germany

Correspondence to:
Correspondence to:
Sigrid Roters, MD, University of Cologne, Centre of Ophthalmology, Joseph-Stelzmann-Strasse 9, D-50931 Cologne, Germany;
Sigrid.Roters{at}medizin.uni-koeln.de

Aims: To examine whether the early postoperative morphology at the site of sclerectomy, as visualised by ultrasound biomicroscopy (UBM), is an indicator of the mechanisms that lower intraocular pressure (IOP) and/or predictors of the long term outcome of viscocanalostomy.

Methods: 15 eyes of 14 patients with medically uncontrolled open angle glaucoma and no history of surgery underwent viscocanalostomy according to Stegmann’s technique. Ultrasound biomicroscopy was performed during the first month after surgery. The following parameters were assessed: dimensions of the intrascleral "lake," presence of a filtering bleb, presence of a subconjunctival cavity or a suprachoroidal hypoechoic area, and the thickness of the residual trabeculocorneal membrane. A complete ophthalmological examination was performed the day before and the day after surgery. Follow up visits were scheduled 1 week, 4 weeks, 6 months, and 12 months after surgery.

Results: At 1 year successful control of IOP (<20 mm Hg) was achieved without further manipulation or medication in six of 15 eyes. The size of the intrascleral "lake" (average 0.62 mm³) did not correlate with later IOP; however, a visible route under the scleral flap and accidental perforation of the trabeculocorneal membrane were associated with long term lowering of IOP. Normal thickness of the trabeculocorneal membrane (0.10–0.15 mm) was indicative of IOP control with and without medication. When UBM showed an early collapse of the intrascleral cavity, control of IOP was not achieved. Other UBM findings did not predict long term function.

Conclusion: In accordance with previous studies, the authors found that UBM examination is a useful method to evaluate outflow mechanisms after glaucoma surgery. This study shows that UBM imaging of external filtration during the early postoperative period can be used to predict the success of viscocanalostomy. However, to establish conclusively what parameters of UBM predict successful viscocanalostomy a larger number of patients must be studied.

Keywords: high frequency ultrasound; ultrasound biomicroscopy; viscocanalostomy; non-penetrating glaucoma surgery

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

• Anand, N, Arora, S, Clowes, M (2006). Mitomycin C augmented glaucoma surgery: evolution of filtering bleb avascularity, transconjunctival oozing, and leaks. Br. J. Ophthalmol. 90: 175-180 [Abstract] [Full Text]