Ultrasound biomicroscopy in chronic ocular hypotony: its impact on diagnosis and management.

PURPOSE: To determine the value of ultrasound biomicroscopy (UBM) in the assessment of ocular hypotony in cases where the underlying pathologic mechanism remains unclear after extensive clinical examination.

METHODS: In a retrospective study, the records of 60 patients who had undergone UBM to elucidate the underlying structural abnormalities of chronic ocular hypotony (intraocular pressure of 0-8 mmHg) were evaluated. Most patients (47 of 60 eyes) had a history of intraocular surgery or of other ocular diseases (e.g., uveitis), and after careful clinical examination, the cause had remained unclear. All patients were observed up for a minimum of 12 months.

RESULTS: The associated pathoanatomy of the hypotony was demonstrated by UBM in 95% of the cases. Ciliary body abnormalities were present in 80% of the eyes. Therapeutic intervention was associated with restoration of normal ocular pressure in 50% of the cases. Often more than one intervention was necessary. A long duration of hypotony did not impede reaching the therapeutic goal of normalizing intraocular pressure and preventing phthisis.

CONCLUSIONS: Ultrasound biomicroscopy is a new tool for detecting the underlying structural abnormalities in ocular hypotony. In cases where clinical examination is not sufficient it can be of great help in deciding on a course of treatment.