Early hypotony after trabeculectomy.

The occurrence of early hypotony after trabeculectomy was analysed retrospectively in 60 glaucoma patients. Fifty-two per cent of the eyes had an intraocular pressure < or = 10 mmHg on the first postoperative day. In about one-third of the eyes, the intraocular pressure was < or = 5 mmHg at the first postoperative visit and in more than 70% of these eyes the hypotony was almost unchanged one week after operation. The hypotony one week after operation was not correlated to the age of the patients and the intraocular pressure at operation, nor to the glaucoma type, and showed no significant statistical dependence on the depth of anterior chamber and hyphema. The final untreated intraocular pressure and progression of the postoperative cataract were studied in four groups of patients, formed on the basis of the intraocular pressure level one week after operation: patients with marked hypotony, slight hypotony, normal pressure or with hypertension. The final untreated intraocular pressure in the eyes with early marked hypotony was not significantly different from the final untreated intraocular pressures in the slightly hypotonic and normotonic eyes. However, the untreated intraocular pressures in these three eye groups were significantly different from the untreated intraocular pressure in the eye group with hypertension. Fifty-two per cent of the eyes suffered from cataract progression during a mean follow-up period of 24 months. Postoperative cataract progression in the markedly hypotonic eyes was not significantly different from the cataract progression in the other groups of eyes.