EyeWorld Asia-Pacific September 2012 Issue

28 EWAP CAtArACt/IOL September 2012 Abhay VASAVADA, MD Director, Iladevi Cataract & IOL Research Centre Raghudeep Eye Clinic, Ahmedabad, India Tel. no. +91-79-27490909 Fax no. +91-79-27411200 icirc@abhayvasavada.com E very step in the surgery for subluxated cataract poses a significant challenge to the surgeon. As pointed out by Dr. Miller, the best way to manage loss of significant zonular support is by carrying out a sound preoperative diagnosis. Indeed, anticipating the problem of zonular weakness is the first step in managing this condition. Further, preoperative counseling also plays a critical role and surgeons should incorporate it in their management strategy. I always stabilize the capsular bag using iris retractors to ensure safer and easier lens removal and to prevent additional zonular loss. I usually introduce these retractors during or after completing capsulorhexis to provide stability to the capsular bag complex. Needless to say, it is best to perform a small capsulorhexis that can be enlarged later. I perform multiquadrant hydrodissection using bent cannulas, followed by viscodissection with a dispersive viscoelastic (Viscoat, Alcon, Fort Worth, Texas, USA/ Hünenberg, Switzerland).This creates a plane of cleavage between the lens and the capsular bag, which is further expanded by the viscoelastic and provides cushioning that prevents the floppy posterior capsule from being aspirated. What I appreciated in the articles is the emphasis on using low fluidic parameters during emulsification. Use of low parameters causes minimal turbulence in the anterior chamber and prevents inadvertent vitreous prolapse. My technique of phacoemulsification is based on the creation of multiple small fragments. I follow this up with the step-down technique to emulsify these fragments. These techniques help to prevent inadvertent capsular touch and vitreous prolapse. Further, I recommend the use of a dispersive viscoelastic repeatedly during surgery, to push back the posterior capsule. I always use capsular stabilization devices to stabilize the capsular bag and advocate use of intracameral preservative-free triamcinolone acetonide to detect the presence of any residual vitreous strands in the anterior chamber at the end of surgery. My preference is to try and preserve the capsular bag and fixate it using Cionni modified CTR or Ahmed segments and implant an in-the-bag IOL. Alternatively, lensectomy with scleral fixation or intrascleral/glued fixation of the IOL can be performed. 9–0 prolene or gortex suture is preferable as there are no reports of suture degradation even up to 10 years after surgery. One of the biggest dilemmas in a case of subluxated lens is when to operate. Following are indications for surgery: increasing subluxation resulting in anisometropia; refractive errors that cannot be corrected with spectacles/contact lenses; disturbance in activities of daily living; signs of imminent complications. While there is no consensus regarding the appropriate timing of surgery in children with subluxated cataract, I strongly believe that surgery should be considered at an age of 4 years. Equally important is to follow these patients closely for their lifetime, particularly keeping an eye for complications such as glaucoma and retinal detachment. Editors’ note: Dr. Vasavada is a consultant for Alcon and receives travel support and research grants. Views from Asia-Pacific CHEE Soon Phaik, MD Senior Consultant and Head, Cataract Service Singapore National Eye Centre 11 Third Hospital Avenue, Singapore 168751 Tel. no. +65-62277255 Fax no. +65-62277290 chee.soon.phaik@snec.com.sg I n this two-part article, David Chang, MD, helpfully shares his surgical pearls to diagnose and manage intraoperative zonulopathy, describing them elegantly in a step-wise fashion. Herein, I describe additional tips and tricks used to manage these cases. Running intravenous mannitol at the start of the case may limit vitreous presentation. Incisions created should be appropriately sized for the task to prevent shallowing of the anterior chamber (AC) and vitreous herniation. For example, the main incision is created by partial entry of the keratome into the AC just wide enough to admit the microcapsulorhexis forceps, and widened to fit the phaco probe on completing the task. Ensuring that the AC is adequately pressurized with ophthalmic viscosurgical device (OVD) to keep the anterior capsule flat is another important maneuver that helps prevent the tendency to run outwards due to lack of anterior zonular tension. Additional challenges include difficulty in sizing and centering the capsulorhexis. However, a complete capsulorhexis is a prerequisite for the use of capsular hooks and capsular tension ring devices. In cases of severe zonulysis, using a two-handed technique may be necessary: microforceps to grasp and stabilize the anterior capsule as the microcapsulorhexis forceps tears the rhexis. Paracentesis incisions created for iris or capsular hooks should be limbal and more vertically inclined in order to avoid having the hooks lift the capsular bag too anteriorly. These hooks are best placed to take a diamond shape, with one hook at the subincisional site. 1 I insert the (modified) capsular tension ring (CTR) at this stage if one is indicated, entering the plane just under the anterior capsule, created by viscodissection. 2 Support and expansion of the capsular bag by the use of hooks and CTR are crucial to the success of the case, as irrigation fluid is prevented from entering the vitreous cavity and vitreous is tamponaded. Used together, they help prevent trampolining of the posterior capsule during phaco and cortical clean-up. Gentle multi-quadrant hydrodissection is important to free cortical/nuclear-bag adhesion. In addition, I viscodissect subincisionally. Phacoemulsification is done with reduced parameters using a cross-chop3 technique. This limits the need for nuclear rotation and zonular shear. Trapping of cortical material is not encountered if the CTR had earlier been correctly inserted in the subcapsular plane. Residual subincisional cortex can be safely approached from the side port incision. If the modified CTR requires scleral fixation, this is done after insertion of the intraocular lens. Corneal incisions are hydrated before OVD removal. References 1. Oetting TA, Omphroy LC. Modified technique using flexible iris retractors in clear corneal cataract surgery. J Cataract Refract Surg. 2002 Apr;28(4):596-8. 2. Chee SP, Jap A. Management of Traumatic Severely Subluxated Cataracts. Am J Ophthalmol. 2011 May;151(5):866-871.e1. Epub 2011 Feb 18. 3. Kim DB. Cross chop: Modified rotationless horizontal chop technique for weak zonules. J Cataract Refract Surg. 2009;35(8):1335-7. Editors’ note: Prof. Chee is a consultant for Technolas Perfect Vision (Munich, Germany), Bausch & Lomb (Rochester, NY, USA), and Hoya Medical Singapore Pte. Ltd., but have no financial interests related to her comments.