Alphaselective Agonists

The alpha-selective agonists available clinically include clonidine, apraclonidine, and brimonidine. Key differences between these agents include therapeutic index, clinical safety, penetration, level of alpha-2 selectivity, and side effects. Clonidine was the first relatively selective alpha-2 agonist available it lowers IOP well, but its narrow therapeutic index, particularly its propensity to cause sedation and systemic hypotension, has made it unpopular in glaucoma therapy. Apraclonidine...

Reasons For Noncompliance

Each mentally and physically competent patient has ultimate responsibility for compliance, but how a patient arrives at the decision to comply or not to comply with medical treatment is based on many factors. A patient's beliefs about health and disease, influenced by personal, societal, cultural, and financial factors, as well as the amount of information he or she has about the disease, play a significant role in this decision. In addition, other factors, such as the nature of the disease,...

S175

Latanoprost-induced iris color darkening a case report with long-term follow-up. J Glaucoma. 2000 9 95-98. Yamamoto T, Kitazawa Y. Iris-color change developed after topical isopropyl unoprostone treatment. J Glaucoma. 1997 6 430-432. Zhan GL, Toris CB, Meza JL, Camras CB. Unoprostone isopropyl ester darkens iris color in pigmented rabbits with sympathetic denervation. J Glaucoma. 2003 12 383-389. Albert DM, Gangnon RE, Zimbric ML, et al. A study of iridectomy...

Glaucoma Treatment Trials

Treatment of POAG and other forms of open-angle glaucoma has been addressed by several large clinical trials comparing medical, laser, and surgical intervention. Two of these trials assessed early surgical intervention. In the Scottish Glaucoma Trial,20 99 patients with newly diagnosed glaucoma were randomly assigned to initial trabeculectomy (46 patients) or conventional medical therapy followed by trabeculectomy if medical therapy failed (53 patients). After a 3- to 5-year follow-up, a...

Bioavailability In Ocular Compartments

The pharmacokinetics of a drug can be mathematically modeled using a technique called compartmental analysis to develop descriptive and predictive information about a drug's concentration at different times in different locations.4 A compartment is an anatomic or physiologic space within an organ that is separated by a barrier to drug transfer (figure 1.1). The drug is assumed to be homogeneously distributed within a compartment, and exchange of the drug between adjacent compartments occurs at...

Info

Calcium channel blockers were introduced for use in the management of patients with angina pectoris and have had a major impact in the therapy of patients with cardiac and vascular disease. These agents affect blood vessels by reducing their resistance and preventing vasospasm, which reduces systemic blood pressure. In addition, calcium channel blockers also have a moderate ocular hypotensive effect.27,28 Calcium channel blockers are a heterogeneous group of...

Ocular Use Of Steroids

Most of the known effects of the glucocorticoids are mediated by widely distributed glucocorticoid receptors. Glucocorticoid enters a target cell as a free molecule. In the absence of the hormonal ligand, intracellular glucocorticoid receptors bound to stabilizing proteins are incapable of activating transcription. When a molecule of glucocorticoid binds to the receptor, the complex undergoes conformational changes that allow it to dissociate from the stabilizing...

Angleclosure Glaucoma

Angle closure is an anatomic disorder comprising a final common pathway of iris apposition to the trabecular meshwork. By recent convention, the term glaucoma is applied to eyes with visual field and or optic nerve damage, analogous to the differentiation between ocular hypertension and glaucoma in eyes with open angles. Angle closure results from various abnormal relationships of anterior segment structures. These, in turn, result from one or more abnormalities in the relative or absolute...

Drug Delivery Systems

Ocusert Pilo System

Commonly used ophthalmic drug formulations, such as solutions, gels, suspensions, and ointments, deliver drugs at rates that follow first-order kinetics, in which the concentration of the drug transferred to the eye decreases exponentially with time. To achieve a constant concentration of the drug in the precorneal tear film and create a steady-state concentration in the tissues, an ophthalmic drug delivery system needs to be designed to deliver a specific drug at a zero-order kinetic rate. At...