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.
