EyeWorld India March 2014 Issue

23 EWAP CAtArACt/IOL March 2014 D. RAMAMURTHY, MD Chairman, The Eye Foundation 582-A, D.B. Road, R.S. Puram, Coimbatore, India 641002 Tel. no. +91 422 4242000 Fax no. +91 422 4242099 drramamurthy@theeyefoundation.com T here are few technologies in anterior segment surgery that have brought about a paradigm shift in the way we practice ophthalmology. In the 1980s, it was IOLs, in the 1990s, phacoemulsification, and in the first decade of this millennium the excimer laser. Though these technologies were available earlier it was in these specific decades that the technologies gained widespread acceptance, especially in the Asia-Pacific region. Whether the present decade will belong to the femtosecond laser is something that remains to be seen. Femtosecond lasers have become established in corneal laser vision correction but still have to gain universal acceptance for cataract surgery. Significant data is emerging to prove their utility in creating a perfect capsulorhexis, reducing the amount of phaco power needed in all grades of cataract, improving incisions and in addressing corneal astigmatism. Integrating with premium IOLs, the two technologies have complemented each other, incrementally improving outcomes. Perfection in biometry with preoperative and intraoperative diagnostic aids like the ORA (WaveTec), VARION (Alcon), CALISTO (Carl Zeiss Meditec, Jena, Germany), and iTrace (Hoya, Tokyo) are further enhancing outcomes to hitherto unimagined levels. For the hype surrounding the femtosecond technology to become a reality, there has to be not only developments in the laser and the imaging systems alone, but also in the ancillary technologies which seem to be keeping pace with it. With more players coming into this evolving arena, there is also scope for this to become more cost- effective and gain wider acceptance. This would lead to more surgeons adopting this technology, more procedures being performed and more significant data emerging to fine tune femtosecond lasers for cataract surgery, which is still in its infancy. In parallel, its utility in refractive surgery, glaucoma treatment and oculoplasty may also increase. Going hand in hand with the speed with which information is shared across the globe in today’s tech savvy world, there is every hope that femtosecond technology would live up to the hype much faster than its predecessors. Editors’ note: Dr. Ramamurthy is a consultant for Alcon and AMO but has no financial interests related to his comments. John S. M. CHANG, MD Director, Guy Hugh Chan Refractive Surgery Centre Hong Kong Sanatorium and Hospital 8/F Li Shu Pui Block, Phase II 2 Village Road, Happy Valley, Hong Kong Tel. no. +852-2835-8885 Fax no. +852-2835-8887 johnchang@hksh.com T he Femto Cataract Laser is here to stay, many papers have shown its advantages over phacoemulsification. We are in its early stages—like the Femto LASIK 15Hz which took longer to perform, cost a lot, had problems with DLK, etc. There have already been significant improvements: an average case now only takes about 3 minutes to perform. There were also concerns about anterior capsular extension 1,2 but since we decreased our energy and spot separation, the incidence is now the same as with the manual technique. In our experience, apart from grade 1 cataracts which hardly require any phaco energy, Grade 2 and 3 required statistically significant less phaco energy. The other grades did not have enough numbers to confirm that. This is in line with other publications. 3 We used simple 2-chop and reduced 2–3 Circle for mature cataracts and multiple cubes for less mature cataracts (grades 2 and 3). In choosing a Femto Laser, we must keep in mind the smaller Asian eyes, the suction ring must be small enough to fit into the smaller palpebral fissures. The ORA, can further enhance the refractive result of IOL implantation. However, intraoperative change of IOL power selection would require extra IOLs with different powers to be immediately available, so IOL inventory may be a practical issue. This is only possible for non-toric IOLs because it is nearly impossible to keep a full stock of toric IOLs. Prolonged surgical time, of course, is expected with the use of ORA. Additionally, if the IOL power implanted measured by the ORA is unsatisfactory, should the IOL be exchanged immediately? One would expect the ORA to give a perfect result before it is worth damaging the endothelium to exchange the lens. There have not yet been any papers published on this. Despite all the possible “practical problems”, the ORA, without doubt, can be a very useful supplementary tool on top of the IOLMaster with multiple formula calculations (without the ORA we are already achieving UCVA of 76% 20/20, 85% 20/25 and 100% 20/40 for our Prelex patients), especially for patients with parameters way beyond normal range, e.g., very long or very short eyes, and it may also be very useful for post refractive patients. However, there is a lack of peer-reviewed studies. Only one published paper by Canto et al. 4 can be found related to intraoperative aberrometry for post refractive cataract surgery. The postoperative data showed that ORange performed better than IOLMaster, Average K and the ASCRS website (without statistical test provided). References 1. Abell RG, Davies PE, Phelan D, Goemann K, McPherson ZE, Vote BJ. Anterior capsulotomy integrity after femtosecond laser-assisted cataract surgery. Ophthalmology. 2014 Jan;121(1):17-24. 2. Chang JS, Chen IN, Chan WM, Ng JC, Chan VK, Law AK. Initial evaluation of a femtosecond laser system in cataract surgery. J Cataract Refract Surg. 2014 Jan;40(1):29-36. 3. Abell RG, Kerr NM, Vote BJ. Toward zero effective phacoemulsification time using femtosecond laser pretreatment. Ophthalmology. 2013;120:942–948. 4. Canto AP, Chhadva P, Cabot F, et al. Comparison of IOL power calculation methods and intraoperative wavefront aberrometer in eyes after refractive surgery. J Refract Surg. 2013 Jul;29(7):484-9. Editors’ note: Dr. Chang has no financial interests related to his comments. Views from Asia-Pacific