A randomized trial of brimonidine versus timolol in preserving visual function: results from the Low-Pressure Glaucoma Treatment Study.
OBJECTIVE
To compare the alpha2-adrenergic agonist brimonidine tartrate 0.2% to the beta-adrenergic antagonist timolol maleate 0.5% in preserving visual function in low-pressure glaucoma.


METHODS
Randomized, double-masked, multicenter clinical trial.


METHODS
Exclusion criteria included untreated intraocular pressure (IOP) >21 mm Hg, visual field mean deviation worse than -16 decibels, or contraindications to study medications. Both eyes received twice-daily monotherapy randomized in blocks of 7 (4 brimonidine to 3 timolol). Standard automated perimetry and tonometry were performed at 4-month intervals. Main outcome measure was field progression in either eye, defined as the same 3 or more points with a negative slope ≥-1 dB/year at P<5%, on 3 consecutive tests, assessed by pointwise linear regression. Secondary outcome measures were progression based on glaucoma change probability maps (GCPM) of pattern deviation and the 3-omitting method for pointwise linear regression.


RESULTS
Ninety-nine patients were randomized to brimonidine and 79 to timolol. Mean (± SE) months of follow-up for all patients was 30.0 ± 2. Statistically fewer brimonidine-treated patients (9, 9.1%) had visual field progression by pointwise linear regression than timolol-treated patients (31, 39.2%, log-rank 12.4, P=.001). Mean treated IOP was similar for brimonidine- and timolol-treated patients at all time points. More brimonidine-treated (28, 28.3%) than timolol-treated (9, 11.4%) patients discontinued study participation because of drug-related adverse events (P=.008). Similar differences in progression were observed when analyzed by GCPM and the 3-omitting method.


CONCLUSIONS
Low-pressure glaucoma patients treated with brimonidine 0.2% who do not develop ocular allergy are less likely to have field progression than patients treated with timolol 0.5%.
Department of Ophthalmology, Feinberg School of Medicine, Northwestern University and the Chicago Center for Vision Research, Chicago, Illinois 60611, USA. krupin@northwestern.edu
Theodore
T
Krupin
Jeffrey M
JM
Liebmann
David S
DS
Greenfield
Robert
R
Ritch
Stuart
S
Gardiner
D000287:Administration, Topical; D058647:Adrenergic alpha-2 Receptor Agonists / Q000009:adverse effects / Q000627:therapeutic use*; D000319:Adrenergic beta-Antagonists / Q000009:adverse effects / Q000627:therapeutic use*; D000368:Aged; D000068438:Brimonidine Tartrate; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D006068:Gonioscopy; D006801:Humans; D007429:Intraocular Pressure / Q000187:drug effects; D057066:Low Tension Glaucoma / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009883:Ophthalmic Solutions / Q000627:therapeutic use; D011810:Quinoxalines / Q000009:adverse effects / Q000627:therapeutic use*; D013999:Timolol / Q000009:adverse effects / Q000627:therapeutic use*; D014065:Tonometry, Ocular; D016896:Treatment Outcome; D014786:Vision Disorders / Q000503:physiopathology*; D014792:Visual Acuity / Q000502:physiology; D014794:Visual Fields / Q000502:physiology*
D058647:Adrenergic alpha-2 Receptor Agonists; D000319:Adrenergic beta-Antagonists; D009883:Ophthalmic Solutions; D011810:Quinoxalines; D000068438:Brimonidine Tartrate; D013999:Timolol