Corneal edema following argon laser iridotomy

Laser iridotomy is generally a safe and effective procedure for narrow-angle glaucoma. However, since surgical success with the argon laser depends on a focal thermal effect, a corneal burn is a possible complication. I describe five patients with occludable anterior chamber angles and bilateral corneal guttata who developed uniocular progressive corneal edema with visual loss following argon laser iridotomy. These five patients underwent iridotomy with a total laser energy of 63, 48.5, 7, 25, and 25 J, respectively, and began to lose vision due to corneal edema immediately, and 5, 2, 4, and 2 years later, respectively. Following penetrating keratoplasty with cataract surgery, histopathology of the corneal buttons showed generalized endothelial cell loss in all five. Microstructural findings of guttata and thickened Descemet's membrane implied that prior endothelial dystrophy had predisposed these patients to laser-induced damage. Risk factors for immediate or delayed-onset bullous keratopathy after argon laser iridotomy include prior angle closure, preexisting endothelial guttata, and high laser energy with multiple applications. Recognizing the potential of this complication offers opportunities for preventive strategies.