Long-term intraocular-pressure outcome following an attack of acute primary angle closure

Abstract

Objective: To study the long-term intraocular-pressure (IOP) outcome after laser peripheral iridotomy (LPI) among patients presenting with acute primary angle closure.

Methods: Records of 64 eyes of 54 consecutive patients diagnosed with acute primary angle closure from March 1996 to November 2003 were reviewed. Follow-up was at least 6 months after LPI to detect any long-term rise in IOP requiring further treatment. Eight predictive factors on the need for long-term treatment were analyzed.

Results: The mean follow-up period was 30.9 ± 23.6 months. The mean presenting IOP was 52.6 ± 14.1 mm Hg. Fifty-two eyes were treated with LPI, of which 48 were patent. Of the 48 eyes, 17 (35.4%) had successful long-term IOP control while 31 (64.6%) required further treatment on follow-up. All developed raised IOP within 6 months of the LPI. Positive predictive factors on the need for long-term treatment include duration of symptoms greater than 6 days (p = 0.01), duration of attack greater than 6 days (p = 0.003), and initial cupdisc ratio >0.4 (p = 0.002). Age and sex of the patient, level of presenting IOP, time it took to perform LPI, and the presence of cardiovascular diseases did not significantly affect the long-term need for treatment. Eleven (35.5%) of the 31 eyes eventually underwent surgery because of uncontrolled IOP. The mean time to trabeculectomy after a patent LPI was 5.6 months.

Conclusions: LPI alone was not sufficient in preventing the long-term IOP rise after an attack of acute primary angle closure in majority of cases. Risk factors for failure of LPI include late presentation, longer duration of attack, and larger cup-disc ratio at presentation. As many eyes developed raised IOP within 6 months of the LPI, close monitoring during this period is essential to detect those requiring further treatment.