EyeWorld Asia-Pacific March 2011 Issue

March 2011 8 EW FEATURE even greater caution. She cracked the nucleus carefully, holding on to it so it would not drop. Using a bimanual technique, maintaining the anterior chamber depth with viscoelastic throughout, she managed to bring the cracked nucleus out of the bag, into the anterior chamber. She extended her incision, slipped a sheets glide in to support the cracked nucleus—now two heminuclei—and went on to phacoemulsify the cataract with suitably lowered parameters. Having removed the two main fragments of cataract, she found the tear: unusually, it was not centrally located; rather, it was positioned where the cataract had been most dense. On close examination, she found that she had dropped a fragment, and a vitreoretinal colleague went in to perform a vitrectomy. With a torn posterior capsule, Dr. Chee wondered whether she should proceed with the toric implant; she decided to give it a go. Since the lens would not be supported by a posterior capsule, she decided to perform an optic capture, placing the optic over the anterior rhexis. By recognizing the pupil snap—a sign of posterior capsular rupture—Dr. Chee knew to proceed with lowered parameters, reducing the risk of further complications. The optic capture technique allowed her to continue with the toric lens, and she was able to position it to optimize the refractive outcome. This case, she concluded, further emphasizes the importance of a properly constructed, well- centered CCC. A simple cornea problem? Renowned cornea surgeon Shigeru Kinoshita, MD (Japan), began a case of DSAEK expecting it to be a simple, uncomplicated procedure. In fact, the case may not have seemed so simple to your average cornea surgeon: the patient, he said, had some form of bullous keratopathy, and had previously undergone scleral buckling for retinal detachment and several trabeculectomy procedures for glaucoma. Moreover, he said, the patient had connections to the Japanese mafia; he was, he admitted, “a little bit scared”. Nonetheless, Dr. Kinoshita was initially able to perform standard DSAEK, injecting air to position the graft at the end of the procedure. Because of the scleral buckling and bleb, he secured the flap with a 10-0 nylon suture—the only thing, he said, that was unusual about the procedure at the time. Three hours later however, the air had escaped, and Dr. Kinoshita decided to increase the intraocular pressure of the soft eye with irrigating solution, and once again injected air through a 30-gauge cannula to keep the graft in position. The following day, the graft was found to be in the middle of the anterior chamber; the unusual corneal architecture seemed to be preventing the graft from attaching. In the end, Dr. Kinoshita had to place sutures at five different locations to attach the graft and to keep it from distorting. Six months later, the graft retained an endothelial cell count of 1,948 cells/mm2. If the DSAEK flap will not attach, Dr. Kinoshita found, it is possible to suture it. “So why not suture?” he said. In the end, the patient achieved an improved visual acuity of 20/40 in the grafted eye and, Dr. Kinoshita assured his audience with a smile, is no longer a threat to him. Fighting for life and vision Dedicated to Barry and Michelle Wylie, and the staff who took care of Michelle during her stay at SNEC Donald Tan, MD (Singapore), is one of a handful of surgeons around the world currently performing osteo- odontokeratoprosthesis (OOKP)— “one of the most challenging and arduous procedures in ophthlamology”, used only in the most severe cases, he said. The staged procedure involves taking a patient’s tooth, drilling a hole into it for the insertion of a bolt- shaped PMMA optic, and using the resulting complex as an implant. OOKP represents the last hope for restoring vision to patients suffering from conditions that include Stevens–Johnson syndrome, severe burn and chemical injuries, and multiple failed corneal grafts. Dr. Tan and his team have been able to use the procedure to restore functional monocular vision in 27 of the worst cases to be seen in any cornea subspecialty clinic. Michelle Wylie had been the team’s 18th patient; at the time, said Dr. Tan, they had been “getting cocky”, gaining confidence in the procedure; Mrs. Wylie’s case taught the team a sobering lesson. In September 2006, Mrs. Wylie was referred to SNEC for OOKP. She suffered from toxic epidermal necrolysis (TEN), a severe, often fatal reaction to certain antibiotics. After multiple organ failure resulting in an inordinately long stay at an intensive care unit, she also acquired a very rare condition called critical illness polyneuropathy, leaving her quadriplegic with severe dysphasia. The two stages of the OOKP procedure are spaced two to four months apart, with the tooth–optic complex initially implanted under a patient’s cheek to allow the body to surround it with a living fibrotic capsule before the second stage, during which the complex is finally implanted into the eye to restore vision. In Mrs. Wylie’s case, Dr. Tan and his team were able to complete both stages of the procedure. The trouble began soon after completion of the second stage. On the first day post-op, Mrs. Wylie complained of severe eye pain; because she had a relatively low pain threshold and at the time she was covered with parenteral antibiotics, Dr. Tan and his team decide to observe her condition. By the second day, the mucosa surrounding the implant became pale and swollen. Suspecting infection, the team switched her to vancomycin, amikacin and azithromycin on the advice of an infectious disease specialist. By the third day, the problem emerged: Mrs. Wylie now had a mucosal abscess, the tooth–optic complex protruding through an ulcer. Reviewing her history, the team found that she had been a nasal carrier for multidrug resistant Staphylococcus aureus (MRSA). The team immediately brought her back to the operating table, removed the tooth and debrided all the infected, purulent and necrotic tissue. After soaking the tooth– optic complex in vancomycin solution, all surrounding infected tissue removed, the team re-implanted it under Mrs. Wylie’s chin. The infection resolved, and two months later they were able to repeat the second stage procedure. Mrs. Wylie gained 20/200 vision, correctible to 20/150—a reasonable outcome given her condition. Her vision was stable up to her last follow up at SNEC in May 2009. Sadly, in October the same year, Mrs. Wylie passed away from pneumonia complicating her quadriplegia. Minefields in refractive surgery Minefields, said refractive expert Chan Wing Kwong, MD (Singapore), lull you into a false sense of security. “If you do not heed the sometimes very subtle signs that are put there to warn you—if there are warning signs— then you may end up stepping on something and at best you lose a foot, at worst you can lose your life,” said Dr. Chan. “Armies all over the world take a lot of effort in detection of mines, because psychologically and physically they inflict the heaviest damage on people.” Minefields continued from page 7