EyeWorld Asia-Pacific December 2011 Issue

24 EW CATARACT/IOL December 2011 Views from Asia-Pacific Abhay R. VASAVADA, MS, FRCS (England) Director, Raghudeep Eye Clinic Iladevi Cataract & IOL Research Centre Gurukul Road, Memnagar, Ahmedabad – 380052 Tel. no. +91-79-27490909, 27492303 Fax no. +91-27411200 icirc@abhayvasavada.com D uring dense cataract emulsification, the surgeon is likely to encounter difficulties such as incomplete division of the leathery lens fibers, increased risk of endothelial damage, wound site thermal injury (WSTI), and posterior capsule rupture. I adhere to the following paradigms to make dense cataract emulsification safe and reproducible: Incision A clear corneal incision ranging between 2.4 and 2.6 mm is made in the temporal quadrant to allow microcoaxial cataract surgery. Anterior capsulorhexis If the visibility is compromised, staining the anterior capsule with trypan blue helps visualization. I make a 1-mm paracentesis incision, and paint the capsule with trypan blue under air bubble. Subsequently, I use a high viscosity cohesive viscoelastic (Healon GV/Healon 5, Abbott Medical Optics, Santa Ana, Calif., USA), and complete the rhexis through the paracentesis incision using a microincision-compatible rhexis forceps. Creation of a small rhexis confines the floating of the hard fragments within the capsular bag and facilitates posterior plane emulsification. Hence, the technique of creating an initial small rhexis that is widened after nucleus removal to achieve a definitive large rhexis is preferred. In intumescent cataracts, I make a nick on the anterior capsule and aspirate some fluid before beginning the capsulorhexis. Cortical cleaving hydrodissection During hydrodissection, there is the possibility of a sudden blow-out of the posterior capsule, because of a bulky nucleus. In these eyes, immediate decompression of the nucleus upon its forward bulge can prevent an intraoperative capsular block. Dense cataracts often resist rotation because of corticocapsular adhesions. Multi-quadrant hydrodissection helps to cleave the corticocapsular adhesions, making rotation easier. Sculpting A central space is created that acts as a recess for emulsifying fragments safely within its confines. While carrying out sculpting, it is advisable not to push the nucleus but just to scrape the layers gently. We prefer to use a bent Kelman tip as the bend allows us to sculpt deep without causing stress to the zonules. Division A dense cataract characteristically has tenacious and cohesive leathery fibers that are difficult to separate. Incomplete separation results in multiple fragments held together like the petals of a flower. Fragments attached centrally make posterior plane emulsification extremely difficult and risky and also increase the possibility of anterior capsular split, posterior capsular rupture, and prolonged energy dissipation close to the endothelium. Our technique of division involves a judicious combination of chop in situ and lateral separating movements. We call it the “Step-by-step chop in situ and separation technique”. The division technique consists of five steps: Step 1: Achieving a vacuum seal Step 2: Chop in situ: Initiating a crack Step 3: Lateral separation Step 4: Repositioning the chopper Step 5: Lateral separation Step 6: In very tenacious dense fibers, the phaco tip is repositioned posterior to the previous site to achieve a vacuum seal. The chopper is then repositioned close to the tip in the depth of the extended crack. This divides the posterior plate (Multi-Level Chop). The end result is creation of multiple small fragments, that are easy to emulsify at the posterior plane. Fragment Removal It is vital to emulsify fragments in the posterior plane to avoid energy dissipation close to the endothelium and mechanical damage to the endothelium by the hard fragments. On the other hand, emulsification in the posterior plane increases the risk of inadvertent posterior capsule rupture because of the high parameters that are preset, particularly for dense cataracts. To achieve posterior plane emulsification we introduced the step down technique. In this technique, we reduce all the parameters in a step-by-step manner as more and more fragments are removed. Emulsification is achieved by constant repositioning or carouselling of the lens material at the phaco tip. The torsional ultrasound (Ozil Technology, Alcon, Fort Worth, Texas, USA/Hünenberg, Switzerland) has an advantage because it appears to naturally reposition and emulsify the fragments by surface shearing with its unique side-to-side ultrasonic movement of the phaco tip. To summarize, adhering to the following pearls will make dense cataract a safe, effective and predictable procedure: • Capsular staining with Trypan Blue • Creation of multiple small fragments • Posteior Plane Emulsification • Step-down technique • Use of torsional ultrasound Editors’ note: Dr. Vasavada has no financial interests related to his comments.