Apraclonidine Prophylaxis for Postcycloplegic Intraocular Pressure Spikes RICHARD A. HILL, MD,t DON S. MINCKLER, MD/ MARTHA LEE, PhD,3 DALE K. HEUER, MD,2 GEORGE BAERVELDT, MD,2 JAMES F. MARTONE, MD2 Abstract: A randomized, prospective, double-masked study was undertaken to determine the risk of postcycloplegic intraocular pressure spikes in patients with open-angle glaucoma and to evaluate apraclonidine prophylaxis in mini- mizing these spikes. Patients were stratified as miotic treated or untreated and each group was randomized to receive either placebo (artificial tears) or apra- clonidine in both eyes before instillation of tropicamide. In both the miotic treated and untreated groups that received placebo, there was a high incidence, (37% and 38%, respectively) of clinically significant 6 mmHg) intraocular pressure spikes after instillation of tropicamide. In both the miotic treated and untreated groups, there was a statistically significant difference in postcycloplegic intra- ocular pressure between the subgroup that received placebo and the group that received apraclonidine prophylaxis (P = 0.003 and P = 0.006, respectively). Additionally, four eyes that received placebo had a spike of over 10 mmHg (range, 12 to 27 mmHg), while only one eye had an increase of greater than 10 mmHg (12 mmHg) in the apraclonidine group. Thus, apraclonidine appears to be a useful agent for minimizing precipitous increases in intraocular pressure after cycloplegia in eyes of open-angle glaucoma patients prone to this com- plication of cycloplegia. Ophthalmology 1991; 98: 1 083-1 086 Many factors influence intraocular pressure (lOP), in- cluding mydriasis with cycloplegic agents for the purpose Originally received: January 4, 1991. Revision accepted: March 25, 1991. 1 Department of Ophthalmology. University of California at Irvine College of Medicine, Irvine. 2 Department of Ophthalmology, University of Southern California School of Medicine and the Doheny Eye Institute. Los Angeles. 3 Department of Preventive Medicine, University of Southern California, School of Medicine, Los Angeles. Presented in part at the international symposium "Pharmacology of the Eye," Wurzburg, Germany, November 1990. The authors have no commercial, proprietary, or financial interest (as con- sultant, reviewer, or evaluator) in apraclonidine or Alcon Surgical. Fur- thermore, neither the authors' spouses, minor children, or blood relatives living in their households have any financial interest in, nor are the authors aware of any financial interest held by their employers, partners, or business associates in Alcon Surgical. Reprint requests to Richard A. Hill, MD, Department of Ophthalmology, Medical Plaza, University of California Irvine, Irvine, CA, 92717. of diagnostic examinations. In 2% of a control population, a clinically significant 6 mmHg) elevation in lOP has been detected after dilation with cycloplegic agents. This incidence increases to 23% to 32% in populations with documented open-angle glaucoma,I,2 and may occur in as many as 33% to 50% of patients undergoing strong miotic therapy. 3,4 In the latter group of patients, postcy- cloplegic lOP spikes can reach extraordinary levels, equivalent to those in acute angle-closure episodes, even though the angles remain open. If the patient has a dam- aged optic nerve or is currently undergoing maximum medical therapy, the risk of aggravating existing optic nerve damage is presumed to be heightened. Apraclonidine is an alpha-adrenergic agonist that is widely used before and after anterior segment laser pro- cedures as prophylaxis against lOP spikes. 5 - 8 Before its recent approval by the United States Food and Drug Ad- ministration for this use, it had been proven safe in healthy volunteer subjects who used it continuously for a period of 4 weeks. 9 We have used this agent as an alternative to oral or intravenous hyperosmotic therapy in emergent 1083