Argon laser iridotomy in angle-closure glaucoma: a comparison of two methods.

Argon laser iridotomy was performed in a total of 141 eyes with angle-closure glaucoma, using a modified contact lens of Abraham, by means of two methods, both comprising two-step burns of the iris. While the first-step burns were carried out under similar conditions in both methods, the duration of the second-step burn was 0.2 seconds in Method I (long-burn technique) and 0.02 seconds in Method II (short-burn technique). Iris perforation was achieved in one session in 91% of 101 eyes by the former and in 100% of 40 eyes by the latter technique. Both techniques caused a transient elevation of the intraocular pressure (IOP), but it subsided within 24 hours. Retrobulbar injection of lidocaine or instillation of timolol or indomethacin oil drops did not suppress the IOP rise. Also, iritis was seen in all cases, but it disappeared within one week. No anterior chamber hemorrhage nor retinal hazard was encountered. Corneal clouding was mild and rare by the short-burn technique, permitting iridotomy to be carried out in the iris periphery of the upper quadrants. By the long-burn technique, however, the corneal clouding often prevented continued laser irradiation. A comparison with the results of the conventional peripheral iridectomy revealed that the present short-burn technique is a safe and efficient procedure for the treatment of angle-closure glaucoma.