Argon laser trabeculoplasty: comparison of bichromatic and monochromatic wavelengths

A randomized prospective study was undertaken to examine the effects of bichromatic argon laser therapy and monochromatic argon laser therapy when used for trabeculoplasty in chronic open angle glaucoma. Fifty patients underwent laser trabeculoplasty with the continuous wave argon laser emitting wavelengths of multiple lines (454.5 nm to 528.7 nm) in the bichromatic spectrum (blue and green). Fifty additional patients underwent laser trabeculoplasty using a continuous-wave argon laser emitting a monochromatic (green) wavelength at 514.5 nm. Patients treated with the bichromatic laser had an average decrease in their intraocular pressure of -7.1 +/- 5.2 mmHg and patients treated with the monochromatic laser had an average decrease of -8.0 +/- 6.2 mmHg. The length of the follow-up was 2 to 13 months with an average of 10 months. For each group, this decrease in intraocular pressure from the pretreatment values was statistically significant (P less than 0.001). However, there was no statistically significant difference in the decrease in the intraocular pressure between the two groups (P = 0.34). No differences were noted in the postoperative course or in the complication rate between the two groups.