EyeWorld Asia-Pacific December 2017 Issue

December 2017 EWAP FEATURE 29 learning curve, Dr. Chee feels that the true value of femto “may be more evident in the management of complex cases.” Femto and complex cases Dr. Chee discussed a number of such cases that benefit from femto. Among these are brunescent cataracts, which require increased effective phacoemulsification time (EPT), thereby also increasing the risk for thermal and mechanical injury to the cornea. The meta- analyses by Chen and Popovic both found EPT to be significantly lower with femto. Further, a brunescent cataract together with a shallow anterior chamber makes creating a manual capsulorhexis difficult; not such a problem for a femtosecond laser. Intumescent cataracts are a similar challenge to manual capsu- lotomy, with the high intralenticu- lar pressure due to cortical lique- faction risking capsular rupture indicated by the Argentinian flag sign. Femto, Dr. Chee said, enables the creation of a circular, optimally sized capsulotomy. This isn’t always perfect, as illustrated by a case of Morgagnian cataract explosion, in which the rapid egress of fluid prevented com- pletion of the capsulotomy even using a femtosecond laser, and con- tinuing with manually resulted in a number of tags. Nevertheless, the femtosecond laser was able to com- plete half the capsulotomy and the surgeon achieved good outcomes. A case with dense fibrosis of the capsule further highlights the advantage of femto in complex capsulotomies. A few tags aside, the capsulotomy was complete—“only femto can do this,” Dr. Chee said. Posterior polar cataracts also benefit from femto. Vasavada et al. 8 reported increased safety with reduction of PCR rates—only 4.4% in the study—using a multiple cyl- inder femto pattern, with and with- out radial cuts. Unpublished results from the most recent audit at the Singapore National Eye Centre, Dr. Chee said, achieved similar results, with a PCR in just 4 out of 103 cases (3.9%). Femto is also useful for severely subluxated cataracts with Marfan’s syndrome. Citing a study she and her colleagues published in January 2017 9 , looking at 47 eyes with great- er than 6 clock hours of zonulysis, they found using femto was easier while being as safe as manual. However, 19 eyes had cataracts that were simply too displaced to be treated with femto, thus also demonstrating a limitation of the technology and so a situation in which manual phaco remains the ideal option. Contraindications, new indications Severely displaced lenses, Dr. Chee said, are among eye features that are contraindications to femto. Others eye features include previ- ous glaucoma or cornea surgery and severe corneal scars. Facial features such as deep-set eyes, prominent noses and eyebrows, and body structure issues such as obesity, skeletal anomalies such as pronounced kyphosis, tremor, and restless leg syndrome are also con- traindicate femto. Balancing out these contrain- dications, femto also has some new indications, including posterior capsulotomy to prevent PCO; rescue capsulotomy to enlarge a markedly smaller than required capsulotomy and to treat capsular phimosis; and for an IOL that is fixated to the capsular bag rim leading to negative dysphotopsia. In any case, economics remains a stumbling block for femto, as the current technology is simply not cost-effective, with issues related to location, logistics, scheduling, length of procedure, and cost of the patient interface. In fact, despite reduced theater utilization, Abell and Vote 10 found that phaco was still 8.7% cheaper than femto in the UK National Health Service. Moreover, femto also has to compete with new technologies such as the Zepto (Mynosys, Fre- mont, California), which produces a smoother edge and is cheaper. FEMTO OR PHACO FOR YOUR PATIENT? FEMTO • Low endothelial cell count • Capsular fibrosis • Big eye • Thick hard nucleus • Shallow AC • Subluxated lens • Create arcuate incisions AVOID FEMTO • Eyes difficult to dock • Advanced glaucoma • Small pupil • Significant corneal opacity • Large pterygium • Significant conjunctival chalasis • Uncooperative, fearful patient • COST concern • For standard cases, the visual outcomes are not different • Ultimately, it is surgeon preference & conviction Dr. Chee made the case for femto and phaco being complementary rather than competing technologies. Source: Chee Soon Phaik, MD 2017 APACRS – from page 27 continued on page 30 and e