Glaucoma, a disease that affects between 1 and 3% of the population above the age of 60, is most commonly treated by topical beta-adrenergic blockers. Although effective in lowering intraocular pressure and helping to preserve sight, beta blockers also may have adverse influences on the cardiac, pulmonary, and central nervous systems, and on endocrine functions. Clinicians' awareness that their patients may be treated with topical beta blockers will help them to elicit this information and the history, prescribe the medicine correctly, and be cognizant of a possible role this medicine may have in any deterioration of a patient's systemic clinical status.