Glaucoma Laser Trial (GLT), Glaucoma Laser Trial Follow up Study (GLTFS)

Glaucoma Laser Trial (GLT), Glaucoma Laser Trial Follow up Study (GLTFS)


To compare efficacy of argon laser trabeculoplasty (ALT) vs. standard medical treatment for primary open-angle glaucoma (POAG)


. GLT was a randomized, controlled clinical trial, done to determine if ALT is

effective in patients with newly diagnosed POAG vs. standard topical


. 271 patients were enrolled, with each eye randomly assigned to ALT or topical


. GLTFS was a follow up study of 203 of initial 271 in GLT over median 7yrs

. Patients were followed every 3 months for a period of at least 2 yrs with VA &

IOP checks

. If IOP elevated, changed medication, added drops to laser eye and eventually

considered surgery or further laser treatment according to standardized  procedure.


– When compared with eyes initially treated with medication, eyes initially treated

with ALT had:

1) 1.2 mmHg greater reduction in intraocular pressure (p<0.001)

2) 0.6 dB greater improvement in the visual field from entry into the GLT

– The overall difference btw eyes with regard to change in cup to disc ratio area from

entry into the GLT was -0.01 (p=0.005) which indicated slightly more deterioration

for eyes initially treated with medication

– Overall, the eyes treated initially with ALT had lower IOP, better visual field and

optic disc status than their fellow eyes treated initially with topical medication

–  Noted a contralateral mean reduction in IOP of 0.5mmHg in the eye that received

ALT (how did they figure that it wasn’t the ALT)


Initial treatment with ALT was at least as efficacious as initial treatment with topical medication

Teaching points:

Consider laser therapy as initial therapy vs. topical medication in POAG