To compare the intraocular pressure (IOP)-lowering effect and safety between superior 180 degree and inferior 180 degree selective laser trabeculoplasty (SLT).

Forty patients with primary open-angle glaucoma and normal tension glaucoma were treated with superior 180-degree SLT, and 28 patients with the same diagnosis were treated with inferior 180-degree SLT. IOP was checked at 1 day, and 1, 2, 3, and 6 months after SLT. Anterior chamber reaction and ocular pain was evaluated at postoperative 1 day. Peripheral anterior synechia was examined at 6 months postoperatively.

At the postoperative 6-month follow-up, the superior treatment group had a mean IOP of 15.53 ± 3.49 mm Hg with a mean reduction of 24.6%, while the inferior treatment group had a mean IOP of 17.18 ± 3.29 mm Hg with a mean reduction of 21.9%. There were no significant differences in IOP reduction between the 2 groups. There was a slightly higher anterior chamber reaction rate in the inferior treatment group.

The site of SLT application is not important for IOP reduction. Both superior 180 degree and inferior 180 degree SLT are safe and effective procedures for glaucoma treatment because of successful IOP reduction and low complication risks.