Therapeutic limitations of argon laser trabeculoplasty

Sixty-one patients (82 eyes) were studied after argon laser trabeculoplasty (ALT) to determine the lasting efficacy of such treatment. This investigation, now in its fourth year, was prospective, and the information derived was analysed with the aid of a computer. Success was defined as intraocular pressure (IOP) below baseline (22 mmHg). The mean follow-up time was 24.5 months, when the success rate was 74% compared with 75% at three months. Success declined to 45% at 42 months. No significant difference was noted when (a) first lasered eyes of all patients and those fellow eyes treated were analysed separately, (b) when right and left eyes were analysed separately, nor (c) when patients were divided into two treatment groups, (I) 100 burns at 1 W, and (II) 65 burns at 850 mW. Eight of 11 eyes showed progressive postlaser field loss despite below-baseline intraocular pressures. ALT is an alternative to carbonic anhydrase inhibitor therapy, with a success rate of 66.7% at two years. However, repeat ALT was successful in only 25% of patients seven months after treatment.