Long-term intraocular pressure-lowering efficacy and safety of timolol maleate gel-forming solution 0.5% compared with Timoptic XE 0.5% in a 12-month study.

PURPOSE: To evaluate the long-term intraocular pressure-lowering efficacy and safety of timolol maleate gel-forming solution 0.5% (Timolol GFS 0.5%, Alcon Research Ltd, Fort Worth, Texas) compared with Timoptic XE 0.5% (Merck, Inc, West Point, Pennsylvania) in patients with open-angle glaucoma or ocular hypertension. METHODS: Two hundred forty-one patients with open-angle glaucoma or ocular hypertension, who had intraocular pressure between 22 and 36 mm Hg in at least one eye, were randomly assigned in a 2:1 ratio to receive either Timolol GFS 0.5% once daily or Timoptic XE 0.5% once daily, in a 12-month randomized, multicenter, double-masked, prospective study. The primary efficacy variable was mean trough intraocular pressure measured at 8:00 AM, approximately 24 hours after dosing. RESULTS: The Timolol GFS 0.5% group produced significant trough intraocular pressure reductions from a baseline of 4.5 to 5.2 mm Hg (P =.0001), compared with reductions of 4.1 to 5. 3 mm Hg (P =.0001) in the Timoptic XE 0.5% group. The difference in mean intraocular pressure between the two treatments was 0.9 mm Hg or less, and the upper 95% confidence limit between groups was 0.92 mm Hg or less at all time points, demonstrating both clinical and statistical equivalence. A similar percentage of patients in the Timolol GFS 0.5% group (71%) and Timoptic XE group (72%) had clinically relevant reductions in intraocular pressure. There was no significant difference in the safety profiles of the two treatments. CONCLUSION: Both treatments were clinically effective in lowering intraocular pressure and maintaining the reductions over long-term use. Timolol GFS 0.5% is a safe and effective therapy for open-angle glaucoma or ocular hypertension and is both clinically and statistically equivalent to Timoptic XE 0.5% in reducing intraocular pressure.

Fluorophotometric study of epinephrine and timolol in human subjects.

The action and interaction of topical 2% epinephrine hydrochloride and 0.5% timolol maleate therapy were studied in 12 normal and 16 ocular hypertensive subjects. Measurements of intraocular pressure, outflow facility, and aqueous secretion by fluorophotometry were made. Uveoscleral outflow values were calculated. Epinephrine, applied topically twice daily for one week, resulted in a decrease in IOP of 3.3 +/- 0.9 mm Hg and an increase in outflow facility of 0.05 +/- 0.01 microL/min/mm Hg, as well as an increase in the rate of aqueous production of 0.32 +/- 0.09 microL/min. Uveoscleral outflow showed an increase of 0.83 +/- 0.23 microL/min. Timolol, applied topically twice daily for one week, reduced the IOP 3.9 +/- 1.0 mm Hg and decreased aqueous flow 0.84 +/- 0.23 microL/min, but produced no change in outflow facility or uveoscleral flow. When epinephrine and timolol are given in combination, the effects in lowering IOP may not be completely additive.

Retinal vascular accidents in glaucoma and ocular hypertension.

The incidence of primary open angle glaucoma in patients with central retinal vein occlusion is reported to be between 5.7 and 66%, while that of primary angle closure glaucoma is from 0 to 9%. (Corrected for the relative incidence of these two types of glaucoma in the general population, these rates are comparable). There appears to be a causal relationship between elevated intraocular pressure and central retinal vein occlusion, which does not correlate with the height to which the pressure is elevated. Other etiologic factors may be important, particularly arteriosclerosis. The association between elevated pressure and branch vein occlusion is less clear. Central vein occlusions occur in 3.5 to 5% of patients with primary open angle glaucoma. Similarly, central vein occlusions occur in approximately 3% of patients with ocular hypertension. It is recommended that ocular hypertensive patients over the age of 65 be treated to lower their pressure below 25 mm Hg.

Exercise-induced increase of intraocular pressure in the pigmentary dispersion syndrome.

A 32-year-old man with pigmentary dispersion syndrome had blurred vision and halos after strenuous exercise, associated with a release of pigment into the anterior chamber and increased intraocular pressure (IOP). Additionally, he had typical symptoms after emotional stress or exposure to dim illumination, and had a high IOP without angle closure during a darkroom provocative test. The exercise-induced symptoms and the increase of IOP were prevented by the use of pilocarpine 0.5% drops immediately before exercise.