Acute pressure elevation following panretinal photocoagulation.

Intraocular pressure increased in 17 of 18 eyes treated for diabetic retinopathy with argon laser panretinal photocoagulation. All eyes had open anterior chamber angles before treatment. Fifteen eyes, continued to have open angles when first examined after treatment. The pressure elevation in these eyes averaged about 10 mm Hg, was detected soon after laser treatment, and persisted for several hours. Outflow facility usually was reduced. Three eyes had closed angles and elevated pressures when first examined after treatment. I addition, in five eyes that initially had open angles, angle closure developed later. Thus, the pressure elevation after extensive retinal photocoagulation usually begins with an open angle mechanism, but later may be due to angle closure as well. The reason for the pressure rise with an open angle is unknown.