A third category targets the suprachoroidal space. These include the Alcon CyPass, the Allergan iStent Supra and the SOLX Gold Shunt.
These devices are providing new options for treating pseudoexfoliation glaucoma. Pseudoexfoliation stems from a generalized disorder of the extracellular matrix. The most-strongly associated genetic variants are found in the lysyl oxidase-like 1 (LOXL1) gene. It is associated with pelvic organ prolapse, atrial fibrillation, emphysema, chronic obstructive pulmonary disease, hernias, and aneurysms.
"It shouldn't be a surprise that there are other issues with pseudoexfoliation," said Dr. Crandall. "It's all part of a systemic disease so we need to be more holistic with diagnosis."
Although it is classically associated with northern European heritage, Dr. Crandall has encountered it in Ethiopia, Guatemala, and Mongolia, he said.
Patients with pseudoexfoliation may present with small pupils, capsule, rhexis and zonular issues, sticky cortex, capsule phimosis and late subluxation, he said.
In capsule phimosis, the interval between implantation and explantation is shorter. The capsular contraction exerts tractional forces on the capsular bag and this is transmitted to the zonules.
Lens management in patients with metabolic disorders, especially Marfan syndrome, presents special problems, said Dr. Crandall. He advised taking care to maintain the natural bag and vitreous space.