EyeWorld Asia-Pacific March 2021 Issue

SECONDARY FEATURE EWAP MAR C H 2021 23 by Ishtiaque Anwar, MD Femto in cataract surgery: Future or frustration? Contact information Anwar: ishtiaqueanwar1976@gmail.com On 27 November 2020, the APACRS held a webinar in conjunction with the Bangladesh Society of Cataract & Refractive Surgeons (BSCRS) annual conference 2020 on “What’s New in Cataract & Refractive Surgery.” This article was written by the author based on his presentation on “Femto in cataract surgery: Future or frustration.” F emto laser allows us to do certain steps of cataract surgery very quickly, precisely, and reproducibly. Namely wound construction (side port, main incision), limbal relaxing Incisions (LRI), capsulorhexis, and lens fragmentations. The importance of a well- architectured incision is now established and we know that a poorly constructed wound can be a major cause of endophthalmitis and astigmatism. With Femto LASER we can create incisions of our choice with precise architecture (uniplanar, biplanar, triplanar) at the exact depth and length and at our desired location. Opening of the incisions has become much more predictable with the newer generation machines. But still some surgeons are not making incisions and side ports with a femto laser, as sometimes it goes more centrally than we desire. Rhexis is one of the essential parts of phaco, and now its importance is more than ever. As with premium IOL use on the rise, effective lens position (ELP) is crucial for these surgeries. A central, circular rhexis with symmetric coverage of the optic of the IOL can ensure a well centered IOL. The edge of the femto rhexis is not as regular as manual or Zepto rhexis when observed under the electron microscope. Still, they are stronger than manual rhexes, as found in different studies. And if we minimize the femto power the edges become smoother. On the down side, micromovement of the eye during FLACS can cause incomplete rhexis. A large study by the ESCRS found that 1 in 200 FLACS rhexes was incomplete. But it is highly effective in creating rhexis in cases of white cataracts, lens subluxation, and hard cataracts where manual rhexis can be challenging. There was a fear of posterior capsule rupture during hydrodissection in FLACS. But this is something that happened in the early generation of machines; with current FLACS machines this is not observed. We have to nudge the nucleus a little to make way for the air bubble trapped under the nucleus before beginning hydro, then perform gentle multidirectional hydro. The gas generated due to the laser accumulates below the nucleus to create a space separating the posterior capsule from the nucleus making it safe and easy for hydrodissection and subsequent rotation of the nucleus. The femto laser fragments the nucleus even before the rhexis is created. The nucleus can be fragmented in different patterns as 3/4/6 sections, central cylinder, small cubes, or spiral. With the live OCT, we can pre-fix the depth of these fragmentations and leave only 800 m m of posterior plate which is easily separable using whatever technique we are comfortable with. One of the major causes of collateral damage to ocular tissues during phaco happens during removal of the fragmented nucleus. This damage, specially to the endothelium, can be minimized by making small fragments, which enables us to use less power and emulsify the pieces away from the endothelium. This can be easily achieved by femto nuclear division. The femto laser is powerful enough to easily divide even hard brunescent cataracts although it has difficulties penetrating white mature and Morgagnian cataracts. Cortical removal is different from routine phaco as the laser cuts the cortical matters along with the capsule during laser rhexis, hence they are not floating outside the capsule rim in FLACS. Thus, there is no free-floating cortical matter protruding in the anterior chamber. We have to go below the anterior capsular rim to grasp cortical matter, then with lateral movements bring them centrally and remove with vacuum. If we consider the hardware, most femtosecond laser platforms are large and take up considerable space in the operating room. Thus, most hospitals have to place the machine in a separate room. As a result, after the Ishtiaque ANWAR, Bangladesh Consultant Ophthalmologist Bangladesh Eye Hospital, Dhaka continued on page 25