EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
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March 2013 the IOL shift somewhat, it's nice to have that in there, because you can suture around it to stabilize the capsule bag," Dr. Steinert said. Patients with early to moderate open angle glaucoma are candidates for minimally invasive glaucoma surgery (MIGS), which doesn't rule out further surgeries to control IOP, according to Joel S. Schuman, M.D., Pittsburgh. "Except for canaloplasty, MIGS doesn't preclude future trabeculectomy or glaucoma drainage device implant," he said. "In fact, you can convert the canaloplasty in the office. I've done this a number of times where I haven't achieved low enough pressure with canaloplasty, and the conversion allowed me to get a pressure of 10 mm Hg or less." L. Jay Katz, M.D., Philadelphia, said results with one device, the iStent (Glaukos, Laguna Hills, Calif.), have been favorable either as a procedure on its own or during cataract surgery. The iStent device resulted in patients with mild to moderate open angle glaucoma having "long-term IOP control through 4.5 years with reduced medication burden," he said. Those patients with more severe forms of glaucoma may be controlled with multiple stents, Dr. Katz added. In his talk, Malik Y. Kahook, M.D., Aurora, Colo., offered clinical pearls for performing microbypass trabecular shunt surgery. For instance, surgeons should make the corneal incision as limbal as possible so it doesn't interfere with the gonioprism and visualization during the procedure. Dr. Kahook said surgeons should avoid implanting the iStent at too steep of an angle. "Pushing against the sclera will cause rotation of the eye," he said. "It is important to tap the back or heel of the iStent to ensure that it sits better in Schlemm's canal. "When you enter into the eye and put the gonioprism on, make sure that you go up to the trabecular meshwork and tap the trabecular meshwork with the device. You're not piercing. You're just making sure you understand the dimensions and the relationship between the device and the trabecular meshwork. I've found that very helpful." Wednesday, January 23 There have been important advances in the field of genetics for glaucoma over the past year, according to a speaker during Hawaiian Eye's Glaucoma Day on Wednesday. Genetic research has shown that the genes that cause elevated intraocular pressure (IOP) are not the same as those that cause optic nerve susceptibility, said Janey L. Wiggs, M.D., who recently was named the Paul A. Chandler associate professor of ophthalmology at Harvard Medical School, Boston. "That's important in terms of understanding the biochemical and biological pathways that are responsible for IOP elevation in optic nerve disease and also will help us use those pathways to develop new therapies," Dr. Wiggs said. Researchers also have found that genes influencing optic nerve disease can suggest neuroprotective strategies and that cerebral spinal fluid (CSF) pressure may be an important risk factor for glaucoma. Finally, research is showing that primary open angle glaucoma (POAG) is not just one disease from a genetic standpoint. "It's not just apples and oranges, either," Dr. Wiggs said. "It's probably a whole fruit basket. As we go on to identify additional genes that are responsible for POAG subtypes, we will be able to fully delineate all the genetic risk factors for this important cause of blindness." Several very large genome-wide association studies over the past year and a half for POAG as well as normal tension glaucoma have discovered predictive genes. "When we add these to the genes for early-onset glaucoma, we can begin to separate these genes into those that cause elevated IOP and those that cause optic nerve disease," Dr. Wiggs said. "These genes also point to important clues in neuroprotection. The results suggest that modulating the TNF-alpha pathway is one way we can begin to develop neuroprotective therapies for glaucoma." The TGF beta also influences optic nerve disease and modulating it could lead to neuroprotective therapies, she added. Detrimental translaminar cerebral spinal fluid pressure gradient is a susceptibility factor for optic nerve disease in glaucoma, especially in those patients with normal tension glaucoma, Dr. Wiggs continued. EW MEETING REPORTER 157 "When the CSF pressure is low, that causes the same sort of adverse translaminar pressure gradient that there is when the IOP is high," Dr. Wiggs said. Editors' note: Dr. Wiggs has no financial interests related to this talk. continued on page 158