EyeWorld India September 2018 Issue

by Stefanie Petrou Binder, MD EyeWorld Contributing Writer The dropping and dropped nucleus A cataract expert gives best course of action in cataract cases involving a torn posterior capsule M anaging compli- cated cataract sur- gery that involves a dropping or dropped nucleus requires experi- ence. According to Paul Rosen, MD , Oxford Eye Hospital, Oxford, U.K., who spoke on the topic at the 22nd ESCRS Winter Meeting, these unwanted events happen to both highly practiced and less practiced cataract surgeons with an incidence of 0.18%. Knowing how to handle the situation in the moment is key, he said. “You need a planned treat- ment pathway,” Dr. Rosen noted. “Primary management involves an anterior vitrectomy, without IOL implantation. Secondary manage- ment should happen within 3 weeks, but best within 10 days, and include a vitrectomy, nucleus re- moval, and IOL implantation. The key is early intervention, especially if there is raised IOP or uveitis. We can prevent sequelae with prompt surgery and achieve nearly normal outcomes.” How does the nucleus drop? A dropping or dropped nucleus has a number of etiologies, including an anterior capsule rim tear that can extend posteriorly to become a posterior tear, a posterior capsule tear that can occur during phaco, and zonular disinsertion. Posterior capsule tears are as- sociated with a number of tell-tale signs that indicate something is wrong, such as a deepening an- terior chamber, an unstable lens, pupil contour changes like dila- tion or an irregular shape caused by vitreous coming through the wound, and when the phaco ap- pears to stop working or vibrates. Management of events during phaco When the posterior capsule is torn during phaco, the surgeon needs to stop and observe the nucleus. What the surgeon does next depends on the position of the nucleus, whether it is dropping or has dropped into the vitreous. “If the nucleus is anterior enough to enable the surgeon to stabilize it, clear the vitreous from the anterior chamber, then consider how to remove the nucleus,” he explained. “Options to remove the nucleus are phaco, convert to extracapsular cataract extraction (ECCE), or letting the nucleus drop and thereby causing as little dam- age as possible and referring the patient to a vitreoretinal surgeon.” According to Dr. Rosen, the technique of posterior assisted levitation (PAL) is somewhat con- troversial. It involves inserting a needle 2.5 mm behind the limbus via the pars plana into the poste- rior chamber and injecting OVD behind the lens to support the lens and prevent it from falling. This method provides a cushion that keeps it from dropping any deeper. “Some people say PAL is a bad choice because it will cause vit- reous traction and potentially risk retinal detachment,” he said. “I think it is useful if you don’t have immediate access to a vitreoreti- nal surgeon. Its use depends on a facility’s availability for secondary repair, risk of vitreous base/retinal damage, or if the surgeon prefers to allow the nucleus to drop and plan a secondary procedure. PAL raises the lens material and lets the surgeon retrieve it via the anterior chamber.” Management of events if the nucleus has dropped Once the nucleus has dropped, it is a different scenario. Management begins with clearing any vitreous, demarcated with triamcinolone, from the anterior chamber. The surgeon needs to manage post- operative inflammation and IOP rise. A referral to a vitreoretinal surgeon should be done for a pars plana vitrectomy. “What you never do is put the phaco probe into the vitre- ous cavity or even the anterior chamber when vitreous is present to try and remove the fragments of nucleus because you will cause vitreoretinal traction and poten- tially a retinal tear/detachment, Dr. Rosen said. “Also, you should not put an infusion fluid into the vitreous cavity in an attempt to flush the fragments out into the anterior chamber. Doing this will risk producing a retinal tear and detachment.” The potential problems of a dropped nucleus include corneal failure, uveitis, vitritis, glaucoma, cystoid macular edema, retinal detachment, and endophthalmitis. Before nucleus removal, the surgeon must check IOP and uvei- tis. The corneal edema should be allowed to clear and dexametha- sone taken every 1–2 hours. Sur- gery to remove the nuclear frag- “ The key is early intervention, especially if there is raised IOP or uveitis. We can prevent sequelae with prompt surgery and achieve nearly normal outcomes. ” - Paul Rosen, MD 38 EWAP CATARACT/IOL September 2018