The long-term effect of Nd:YAG laser iridotomy on intraocular pressure in Taiwanese eyes with primary angle-closure glaucoma

Background: To investigate the long-term effect of Nd:YAG laser iridotomy on intraocular pressure (IOP) in Taiwanese eyes with primary angle-closure glaucoma (PACG). Methods: The medical records of 81 patients (130 eyes) who were diagnosed with PACG and who had undergone Nd:YAG laser iridotomy between 1998 and 2002 were reviewed. According to the presence of symptomatic glaucoma attack, eyes were divided into an acute angle-closure glaucoma (AACG) group and chronic angle-closure glaucoma (CACG) group. In the AACG group, the acute episode was treated and resolved after Nd:YAG laser iridotomy. These eyes were diagnosed to have or developed glaucoma during the follow-up period. All patients were followed-up for at least 24 months. The presenting features, treatment and IOP during the follow-up period were analyzed. Results: The mean follow-up period was 44.1±17.8 months (median, 36 months). There were 27 eyes (from 25 patients) in the AACG group. Only 2 eyes (7.4%) did not require any treatment after Nd:YAG laser iridotomy. Eleven eyes (40.7%) eventually underwent filtering surgery at a mean of 3.2 months (median, 3 months) after Nd:YAG laser iridotomy. There were 103 eyes (from 56 patients) in the CACG group. Eighty-five eyes (82.5%) required further medical treatment, of which 21 eyes (20.4%) eventually received filtering surgery at a mean of 9.8 months (median, 5 months) after Nd:YAG laser iridotomy. Conclusion: For most Taiwanese eyes with PACG after Nd:YAG laser iridotomy, additional medicine and surgery are required in the long term. Eyes in the AACG group needed more surgical intervention than those in the CACG group.