![]() In dogs, timolol applied in combination with dorzolamide 2% has a greater IOP-lowering effect than either drug alone. Although more effective, higher concentrations may lower heart rate. Timolol maleate BID leads to a modest IOP reduction at available concentrations (0.25 and 0.5%). Cats may show signs of inappetence and hyper-salivation, perhaps related to an unpleasant taste.īeta-blockers: These reduce IOP by inhibiting aqueous secretion and, to a lesser extent, enhance aqueous production. Local side effects, including conjunctivitis and blepharitis, have been reported following application of CAIs. These drugs have now been superseded by topical CAIs, dorzolamide 2% and brinzolamide 1% that effectively lower IOP in normal and glaucomatous dogs and cats (both applied TID). Oral CAIs (acetazolamide, methazolamide and dichlorphenamide) historically played a key role in the medical management of canine glaucoma but significant systemic side-effects were common, in part related to hypokalemia and metabolic acidosis. Medical Therapy to Reduce Aqueous ProductionĬarbonic Anhydrase Inhibitors (CAIs): These drugs reduce aqueous humor formation and IOP by reducing the secretion of bicarbonate ions (with sodium ions and water) into the posterior chamber. Is the cost of therapy acceptable to the owner?ĭoes the drug actually work in this individual? What is the likelihood of owner and patient compliance? What is the potential for vision in the affected eye? What are the specific mechanisms for IOP elevation?Īre these mechanisms reversible or irreversible? When selecting a treatment strategy, the following are important considerations: ![]() Glaucoma Treatment Should be Tailored for the Individual ![]() Combining treatments that reduce aqueous production, with treatments that increase outflow generally have a greater impact on IOP than targeting either alone. Particularly in the management of acute congestive glaucoma in dogs, more than one component of aqueous humor dynamics should be targeted in order to maximize IOP reduction. Currently available therapies generally either reduce aqueous production or increase aqueous outflow. Dorzolamide reduced pupil size, while timolol reduced both pupil size and maximal contraction to red light, but the effect was minute and not of clinical importance.The major goal in glaucoma management remains the lowering of IOP, to a point that prevents or slows loss of vision and eliminates pain. CONCLUSION:Īnti-glaucoma medications did not interfere with the blue light elicited PIPR. Intraocular pressure was significantly reduced by all three drugs after 3.5 h (p < 0.01), while it remained unchanged during the control day (p = 0.3). Timolol also reduced the maximal contraction amplitude significantly during red light (p = 0.02). Pupillary size decreased slightly with timolol (0.1 mm, p = 0.03) and dorzolamide (0.2 mm, p < 0.001), but not with latanoprost. ![]() During the control day, the only significant variation over time was observed for the red light PIPR0-10s (p = 0.02). We found no drug effect on the blue light PIPR10-30s or any other blue light pupil parameters. Intraocular pressure (IOP) was measured before and 3.5 h after drug instillation. Additionally, pupil size, maximal contraction, and the early post-illumination pupillary response (PIPR 0-10s ) to blue and red light were investigated. Main outcome was the PIPR10-30s to blue light. Stimulus was blue (463 nm) and red light (633 nm) of 2 log (lux). In this randomized, double-masked, crossover trial, pupillometry was performed before and after topical administration of latanoprost, dorzolamide, and timolol in 20 healthy subjects. Since animal studies have indicated that common anti-glaucomatous agents affect the iris muscle, we investigated the short-term effect of the anti-glaucoma drugs on the pupillary light reflex and in particular on the PIPR10-30s. The late post-illumination pupillary response (PIPR 10-30s ) to blue light is reduced in glaucoma, suggesting that pupillometry can be used in clinical glaucoma evaluation. ![]()
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