Immediate anterior chamber paracentesis (ACP) with a 30-gauge needle as an initial treatment for acute primary angle closure.

Acetamide, given in this study, is a standard treatment for acute angle-closure glaucoma. The participant will receive 1 tablet(250mg) at 1 hours after paracentesis. The following dose will be adjusted according to the level of IOP. The maximal dose is 4 tablets per day. It will be discontinued if the IOP is less than 21 mmHg.

All affected eyes will receive laser peripheral iridotomy with 24 hours after presentation. This a standard treatment for Acute angle-closure glaucoma

At presentation, patients received immediate anterior chamber paracentesis with a 30-gauge needle. The intraocular pressure (IOP) was recorded at immediately, 15 and 30 minutes, and then 1, 24 and 48 hours after paracentesis. The IOP was compared between before paracentesis and each time-point after paracentesis. All affected eyes received antiglaucomatous medications 60 minutes after ACP and underwent peripheral iridotomy within 24 hours.

The intraocular pressure (IOP) was recorded at immediately(within 2 minutes after paracentesis), 15 and 30 minutes, and then 1, 24 and 48 hours after paracentesis. The change of IOP was study between before paracentesis and at each time-point. All affected eyes received antiglaucomatous medications 60 minutes after paracentesis and underwent peripheral iridotomy within 24 hours.

This is to observe the potential complications which may occur during and after paracentesis with a 30-gauge needle. Among the potential complications include lens capsular rupture, hyphema, retinal hemorrhage, hypotony and infection. The study will record each complications as numbers of events at each time-point until 48 hours after paracentesis

The study will record the visual acuity with Snellen's chart at immediately (within 2 minutes after paracentesis), 1 hours, 24 hours and 48 hours after paracentesis.