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EW NEWS & OPINION 22 Abhay R. Vasavada, M.S., F.R.C.S., director, Iladevi Cataract & IOL Research Centre, Raghudeep Eye Clinic, Ahmedabad, India, details steps for achieving successful outcomes in these complicated eyes M anagement of co-exist- ing cataract and glau- coma can often be quite complex. In pre- viously trabeculec- tomized eyes, special considerations need to be made pre-operatively, in- traoperatively, and post-operatively. Assessing glaucoma pre-op In the presence of a cataract, the as- sessment of glaucoma becomes diffi- cult, as the cataract precludes reliable optic nerve imaging or vi- sual field examination. The patient needs to be counseled pre-op about a guarded visual outcome, possibility of early hypotony and late filtration failure, as well as a lifelong monitor- ing of glaucoma. If the patient is on glaucoma medication, the periopera- tive use of prostaglandin analogues needs to be titrated with respect to post-op inflammation. Intravenous mannitol may be given just prior to surgery in cases of raised IOP. Intraoperative challenges The surgeon faces unique intraoper- ative challenges due to the presence of a filtering bleb (often a thin, cys- tic bleb), shallow anterior chamber, and poorly dilating pupils (Figure 1). Sometimes these eyes also have co- existing corneal endothelial compro- mise and zonular weakness. The pearls for a successful out- come include avoiding damage to the bleb, observing the principles of the closed chamber technique, using the appropriate ophthalmic visco- surgical devices (OVDs), and main- taining low fluidic parameters. To avoid damage to the bleb, I take extra care while inserting the speculum. Additionally, the bleb site can be coated with HPMC to pre- vent bleb site desiccation. Surgery is initiated with the creation of two paracentesis incisions of 0.9 mm each. Avoid the bleb site while mak- ing the paracentesis. Using the soft- shell technique, a dispersive OVD (Viscoat, Alcon, Fort Worth, Texas) is injected to coat the corneal endothe- lium, followed by a high viscosity cohesive OVD (Provisc, Alcon) to maintain space in the anterior chamber. I prefer a 2.2-mm temporal, sin- gle-plane, clear corneal incision. In cases of poorly dilating pupils, stretch pupilloplasty or iris retract- ing devices (iris retractors, Malyugin Ring, MicroSurgical Technology, Redmond, Wash.) can be used. Trypan blue-assisted anterior capsulorhexis is often helpful. A thorough, cortical-cleaving hy- November 2011 Phacoemulsification in previously trabeculectomized eyes handle of this instrument has been mounted perpendicular to the direc- tion of the two-sided hook designed specifically for this purpose, the su- ture may be snared easily by sweep- ing the hook either to the right or left, drawing the suture out of the eye. The hook, which is curved a lit- tle backward and rounded off atrau- matically, has a small groove that prevents suture slippage when the surgeon is negotiating the paracen- tesis on retrieving the suture. Using the drawn-out loop of the suture, 2- 3 clockwise throws are made to form the first step of the knot, pulling the other suture end, which is cut, through this loop. The knot is grad- ually tightened without fixing it by drawing the suture ends. I prefer to do the same for the other haptic then center the optic before tighten- ing the knots. The knots are com- pleted with additional loops of suture, and the suture ends of the knots are cut using intraocular scis- sors. The IOL optic is gently pro- lapsed through the pupil without undue lateral displacement with the aid of a Kuglen hook to retract the iris and widen the pupil as the Sinskey hook pops the optic back- ward. The incisions are hydrated. Fi- nally, OVD is carefully removed by irrigation and aspiration. EW Editors' note: Dr. Chee has no financial interests related to the products discussed in this article. Contact information Chee: +65 6227 7255, chee.soon.phaik@snec.com.sg Managing continued from page 18 Figure 1 Source: Abhay R. Vasavada, M.S., F.R.C.S. U ncomplicated cataract surgery frequently results in a post-op lowering of intraocular pressure. The magnitude of the reduction is usually equivalent to the amount produced by a single glaucoma medication. Eyes with- out a history of glaucoma, ocular hyper- tensive eyes, and most eyes that are under treatment for glaucoma experi- ence this benefit. A difference between the groups is at what time point the pressure reduction is realized. In normal eyes, it is almost immediate. In ocular hypertensives, the IOP may be un- changed for a day or a week, but after- ward it goes down. In eyes with glaucoma, there is often an initial rise in IOP, followed by a gradual reduction to a lower level after a week or two. Of course, reduction in IOP is not a univer- sal outcome of cataract surgery. Eyes with glaucoma filters present unique challenges to the cataract sur- geon. Intraoperative hyperfiltration is seldom a problem, but accelerated fail- ure of a filter following cataract surgery is. All of these eyes have had at least one previous operation, and some have had several. They may have compro- mised corneas or iris issues. The loca- tion of the bleb or tube shunt may interfere with placement of the cataract incision. In this article, Dr. Abhay Vasavada discusses his approach to cataract sur- gery in the post-trabeculectomy eye. Kevin Miller, M.D., complicated cases editor Complicated cataract cases 11-23 News Update_EW November 2011-DL-3_Layout 1 11/4/11 11:51 AM Page 22

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