Concave trabeculo-Descemet's membrane as an early sign of viscocanalostomy failure

To correlate trabeculo-Descemet's membrane (TDM) changes with a late rise in intraocular pressure (IOP) in patients with successful viscocanalostomy.

Consultores Oftalmológicos, Hospital Oftalmológico Santa Lucía, and Centro de Estudios Médicos e Investigación, Buenos Aires, Argentina.

Patients who had a viscocanalostomy between July 1998 and September 2001 were retrospectively studied. Gonioscopy was performed in all patients. A subgroup of patients who had a late increase in IOP and were successfully treated with neodymium:YAG (Nd:YAG) laser goniopuncture were studied to correlate gonioscopic findings. Ultrasound biomicroscopy was performed in 10 cases. Intraocular pressure measurements were taken before viscocanalostomy and before and after Nd:YAG treatment.

Sixty-eight eyes of 48 patients had a viscocanalostomy to control IOP. Twenty-six eyes had a late increase in IOP and were successfully treated with Nd:YAG laser goniopuncture. Before goniopuncture, 17 eyes (65.30%) had a concave TDM. The mean IOP in these patients increased from 14.27 mm Hg to 18.73 mm Hg (range 14 to 27 mm Hg). Goniopuncture was performed a mean of 10.7 months (range 1 to 36 months) after surgery. After Nd:YAG treatment, the TDM was flat in all patients who had a concave TDM before treatment. At the last examination, the mean IOP was 13.8 mm Hg, a mean decrease of 52.24% from the baseline preoperative IOP; 61.5% of eyes had a final IOP of 14.0 mm Hg or lower.

A concave TDM was associated with a late IOP rise. The TDM was flat after laser goniopuncture and normalization of IOP.