Forty-one patients presenting consecutively with acute angle closure glaucoma (AACG) were studied with a median follow-up period of eight months. Four patients presented with bilateral symptoms. Thirty-nine patients underwent Nd-YAG laser iridotomy (42 AACG eyes and 36 fellow eyes). Only 15 patients (36.6%) required simply iridotomy; the remainder required additional long term medical or surgical treatment. Longer duration of symptoms and a history of previous intermittent, spontaneously resolved AACG were more common in those requiring additional treatment. Cataract extraction with intraocular lens implantation was performed for three eyes with AACG, and this mode of treatment is discussed as a possible primary treatment. One eye with AACG suffered a second episode, and two fellow eyes developed AACG despite laser iridotomy. Possible mechanisms are discussed. Provocative testing or frequent careful observation of iridotomy patency is recommended.