Comparison of the Anterior Chamber Inflammatory Response to Diode and Argon Laser Trabeculoplasty Using a Laser Flare Meter

Background: Diode laser trabeculoplasty (DLT) has a similar hypotensive action to argon laser trabeculoplasty (ALT). However, anterior chamber inflammatory response and laser-induced discomfort are less pronounced with DLT. The authors compared the breakdown of the blood-aqueous barrier after DLT and ALT over the time course of 1 week and the hypotensive action over 8 weeks. Methods: Twenty-five patients with uncontrolled intraocular pressure (IOP) were randomized to either DLT or ALT. If two eyes required treatment, then the second eye would be treated with the alternative laser to the first. Flare values were measured at 1, 3, 24, 48, 72, 96, and 168 hours using a laser flare and cell meter. Intraocular pressures were measured at similar intervals and at 8 weeks. Results: Of 38 eyes treated, 21 underwent ALT and 17 DLT. Both forms of treatment induced a similar hypotensive effect with a significant reduction in IOP at 8 weeks compared with initial IOP (P Ã 0.01) (paired Student's t test). However, there was a significantly greater disruption of the blood-aqueous barrier with ALT when compared with DLT at 1, 3, and 24 hours (P Ã 0.001) and at 48, 72, and 96 hours (P Ã 0.01) (unpaired Student's t test). By 1 week, however, there was no significant difference in flare values between the two groups. Postlaser pain occurred in seven eyes treated with ALT but in no eyes treated with DLT. In addition, peripheral anterior synechiae occurred in four eyes after ALT by 8 weeks but none occurred in the DLT group. Conclusions: Argon laser trabeculoplasty produces a greater disruption of the bloodaqueous barrier than DLT. This may be associated with the development of complications in the anterior segment.