Cataract Surgery in the Glaucoma Patient

Abstract

According to Research to Prevent Blindness, 20.5 million US citizens have cataract, and two million are visually impaired with glaucoma. Today, we operate on approximately three million cataracts a year, and 10% of these patients have co-existing glaucoma; so, 300,000 times a year, a US surgeon must decide how to treat a patient with co-existent cataract and glaucoma. Treatment Has Changed for Co-existent Cataract and Glaucoma During the Past 70 YearsFrom 1940 to 1975 the predominant method of cataract removal was intracapsular surgery. Since intracapsular surgery entailed removing the lens capsule, the lens capsule could no longer serve as a barrier between the anterior vitreous and aqueous. Without this barrier, vitreous mixed with aqueous in the anterior chamber in many aphakic eyes, and caused many fistulas of glaucoma operations to fail if glaucoma surgery was performed after the cataract was removed. Also, the limbal incision through conjunctiva and sclera made with intracapsular surgery created scleral/conjunctival scarring that increased the failure of subsequent glaucoma operations. Therefore, when patients had co-existent cataract and uncontrolled glaucoma, glaucoma surgery was always carried out before the cataract was removed. Glaucoma Bleb SurgeryThe first successful operations for open-angle glaucoma created an alternative channel for aqueous egress from the eye that bypassed the eye's failing trabecular meshwork (TM) and Schlemm's canal (SC). The operation created a fistula at the limbus through corneal-scleral tissue that drained aqueous from the anterior chamber, and created a bleb beneath Tenon's capsule and conjunctiva. The bleb drained posteriorly into the orbital lymphatics. AbstractThis article describes the changing treatment of co-existent cataract and glaucoma over the past 70 years. Seventy years ago, the cataract was removed using an intracapsular technique. Glaucoma was always controlled with a scleral fistulizing operation before the cataract was removed.In 1975, Charles Kelman introduced phacoemulsification. When clear corneal incisions were introduced for phacoemulsification, glaucoma surgery no longer needed to precede cataract surgery. The combined procedure of phacoemulsification/lens implantation and trabeculectomy became popular 10 years ago. Recently, non-bleb treatments for glaucoma have emerged that eliminate the problems associated with trabeculectomy. These procedures include phaco/intraocular lens (IOL) alone, trabectome, iStent ® , and canaloplasty. A major cause of adult glaucoma, the enlarging crystalline lens as it ages, was recognized in 2007. Greater IOP reductions following phaco/IOL alone were discovered at this time. Phaco/IOL may emerge as the preferred treatment of co-existent cataract and glaucoma. Trabectome can be added to phaco/IOL if greater IOP reduction is needed.