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Updated: Aug 7, 2026
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Glaucoma-inducing Procedure in an In Vivo Rat Model and Whole-mount Retina Preparation
Published on: March 12, 2016
Clinical implications of reported timolol-induced side effects
Summary
Timolol is widely used for glaucoma but can cause ocular and systemic side effects, including CNS effects. About 20% of patients experience side effects, with many discontinuing treatment.
Area of Science:
- Ophthalmology
- Pharmacology
Background:
- Timolol is a common treatment for open-angle glaucoma approved by the FDA.
- Post-approval reports indicate potential ocular and systemic side effects not fully detailed in pre-approval trials.
Purpose of the Study:
- To review the reported ocular and systemic side effects of timolol.
- To discuss the implications of these side effects for patient care and contact lens wearers.
- To note optometric findings regarding timolol's effect on the electro-oculogram (EOG) ratio and its potential use in acute angle closure.
Main Methods:
- Review of clinical trial data and post-approval reports on timolol side effects.
- Analysis of systemic effects attributed to beta-adrenergic antagonism.
- Examination of ocular side effects, including pain, blurred vision, and keratitis.
- Inclusion of optometric findings on EOG ratio and acute angle closure management.
Main Results:
- Systemic side effects (cardiovascular, respiratory, gastrointestinal) are linked to beta-adrenergic antagonism.
- Central nervous system (CNS) effects are also reported but less clearly explained.
- Ocular side effects like instillation pain and blurred vision are frequent, often leading to discontinuation.
- Superficial punctate keratitis and reduced corneal sensitivity pose risks for contact lens wearers.
- Two prospective studies reported a 20% incidence of side effects, with 40% of those discontinuing timolol.
- Timolol may increase the EOG ratio (Arden Index) and can be used in acute angle closure when pilocarpine fails.
Conclusions:
- Timolol, while effective for glaucoma, presents a significant incidence of ocular and systemic side effects.
- These side effects, particularly CNS and ocular issues, necessitate careful patient monitoring and may lead to treatment discontinuation.
- Optometric findings suggest potential impacts on visual function and a role in managing specific glaucoma types.
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