Diversity of response of optic nerve head circulation to timolol maleate in gel-forming solution.
OBJECTIVE
This randomized, double-masked, placebo-controlled, two-period crossover study was conducted to investigate the effects of 0.5% timolol maleate in gel-forming solution on intraocular pressure (IOP) and blood circulation in the optic nerve head in patients with untreated ocular hypertension.


METHODS
The effects of 0.5% timolol in gel-forming solution on IOP and optic nerve head capillary blood speed were studied in 12 patients with untreated ocular hypertension. Optic nerve capillary blood speed was measured using the laser Doppler technique before and at the end of each treatment period.


RESULTS
In each patient, IOP decreased after treatment with timolol (mean decrease 16.8% versus placebo). Systemic blood pressure and pulse rate did not differ significantly after treatment with topical timolol from values after placebo. The mean change from baseline in Doppler broadening was 10.6% greater after treatment with timolol than after placebo. There was no significant change in mean Doppler broadening from baseline after treatment with either timolol or placebo. However, optic nerve head capillary blood speed increased in six patients, and was within the range of placebo response in six patients after treatment with timolol. Spearman correlation analysis of the baseline with Doppler broadening measurements after treatment showed a correlation for placebo but not for timolol. The percent change in Doppler broadening after timolol treatment was correlated with iris color.


CONCLUSIONS
These results indicate that administration of timolol for 4 weeks reduces IOP in patients with ocular hypertension and generally does not change the blood circulation in the optic nerve head. Individual patients, however, showed variable changes in optic nerve head circulation after topical administration of timolol. Although the sample size was small, these changes in optic nerve head circulation were correlated with iris color.
Netland
P A
PA
Department of Ophthalmology, University of Tennessee, Memphis 38163, USA.
Schwartz
B
B
Feke
G T
GT
Takamoto
T
T
Konno
S
S
Goger
D G
DG
D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D000328:Adult; D000368:Aged; D001775:Blood Circulation / Q000187:drug effects; D001783:Blood Flow Velocity / Q000187:drug effects; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005127:Eye Color; D005260:Female; D005782:Gels; D006801:Humans; D007429:Intraocular Pressure / Q000187:drug effects*; D017078:Laser-Doppler Flowmetry; D008297:Male; D008875:Middle Aged; D009798:Ocular Hypertension / Q000188:drug therapy / Q000503:physiopathology*; D009883:Ophthalmic Solutions / Q000627:therapeutic use; D009898:Optic Disk / Q000098:blood supply*; D013999:Timolol / Q000627:therapeutic use*
D000319:Adrenergic beta-Antagonists; D005782:Gels; D009883:Ophthalmic Solutions; D013999:Timolol