Evaluation of argon green vs krypton red laser for photocoagulation of subfoveal choroidal neovascularization in the macular photocoagulation study. Macular Photocoagulation Study (MPS) Group.

OBJECTIVE

To evaluate the risks and benefits of argon-green compared with krypton red laser photocoagulation in the treatment of subfoveal choroidal neovascularization (CNV).

DESIGN

Prospective randomized clinical trial assessing efficacy of laser treatment vs no treatment in the course of subfoveal CNV. Patients randomly assigned to laser treatment were randomly allocated to either argon green or krypton red laser photocoagulation. Scheduled follow-up for periods up to 5 years was performed.

SETTING

Tertiary retinal referral centers.

PATIENTS

Individuals with age-related macular degeneration and new subfoveal CNV or recurrent subfoveal CNV enrolled in the Foveal Photocoagulation Studies of the Macular Photocoagulation Study.

MAIN OUTCOME MEASURES

Visual acuity, contrast sensitivity, reading spread, persistent and/or recurrent CNV, and treatment complications.

RESULTS

There was no significant difference in average loss of visual acuity or contrast sensitivity from baseline levels in eyes treated with either wavelength. From baseline, eyes treated with argon green laser in the Subfoveal Recurrent CNV Study lost an average of 12 words per minute less than eyes treated with krypton red laser. Comparable rates of persistent and recurrent CNV were observed in the two laser treatment groups. Focal retinal vascular narrowing was more common in eyes treated with argon green laser.

CONCLUSIONS

Small differences in outcomes favored argon-green treatment of subfoveal CNV, but the only statistically significant difference observed between green- and red-laser treatments was a smaller loss of reading speed among argon green-treated eyes in the Recurrent CNV Study. The multiple analyses performed in these two Macular Photocoagulation Study trials failed to identify any consistent clinically and statistically significant differences between green- or red-laser treatment in the management of eyes with subfoveal CNV.