EyeWorld Asia-Pacific June 2018 issue

June 2018 EWAP FEATURE 13 Views from Asia-Pacific Dandapani RAMAMURTHY, MD Chairman, the Eye Foundation 582-A, D.B. Road, R.S. Puram, Coimbatore 641002, India Tel. no. +914224242000 Fax no. +914224242099 drramamurthy@theeyefoundation.in T oday we have a wide choice of IOLs available to us fulfilling almost every need and expectation from both the patient and the physician. While the freedom of choice is an opportunity, it also poses a challenge in choosing the right IOL for the patient. The following are the characteristics I would look for while selecting an IOL: • Clarity: Glistenings, though they may not cause a drop in visual acuity can definitely drop quality and contrast. Today we have hydrophobic materials that remain crystal clear and this would be an important consideration. • Hydrophobic materials because of their tackiness, inherent ability to arrest PCO may be the preferred choice, although there is less propensity for dysphotopsia with hydrophilics. • The higher the refractive index, the thinner the profile of the lenses, but an index of 1.55 may be a sweet spot since beyond this the reflections from the anterior surface of the IOL would be disturbing. • A triple edge with an anterior rounded edge to reduce dysphotopsia, sloping intermediate profile and a posterior square edge to reduce PCO would be preferrable. • Asphericity of the IOL would be an important factor to improve quality of vision. Customizing asphericity to leave about –0.1 asphericity would be an ideal way to enhance the quality of vision but also increases tolerance to decentration and improves depth of focus. • Preloaded injectable IOLs would be the way to go since they reduce chances of contamination and inappropriate loading but reducing incision size to less than 2.0 mm may not be that important since it has been adequately proved that the centroid value of the astigmatism induced by a well-constructed sub-2.4-mm incision is only around 0.1 D. • Having accurate reliable IOL powers between –10 to+40 D is important. Beyond these extremes, the power calculation becomes suspect and piggyback IOLs for better refractive outcomes may be one way to go. Further IOLs beyond +40 D may have excessive spherical aberration, reducing quality. • Having IOLs in steps of 0.25 D may enhance refractive outcomes but the limiting factor would be the IOL calculation formula. • Extended depth of focus IOLs and trifocalswould take over frommultifocals since independence from glasses for all distances with minimum reduction in quality would soon become the norm and the expectation. • Accurate preoperativemeasurement, calculation should increase the adaptation and demand for low (<0.75 D) and high (>4.0 D) power toric IOLs. • Light and femtosecond adjustable IOLs could significantly enhance quality and quantity of outcomes and could be the future of IOL technology. Editors’ note: Dr. Ramamurthy is a consultant for Alcon and Johnson & Johnson Vision. Pichit NARIPTHAPHAN, MD Cataract and Refractive Surgery Specialist Rajvithi Hospital, Priest Hospital, TRSC International LASIK Center 588/12 Petchburi Road, Rajthevee, Bangkok 10400, Thailand Tel. no. +66815728787 Fax no. +6626324431 npichit@hotmail.com G listening has been a major draw back for high refractive index hydrophobic IOLs in spite of their great performance in the eye for decades. Clareon seems to be a promising material. I do agree that the tacky surface of Alcon material is a major advantage against rotation. I also do agree that J&J has excellent clarity. Its anterior peripheral surface design has less anterior capsule contraction. I would love to see a high refractive index lens with a high Abbe number in the future. European hydrophilic trifocals (from Carl Zeiss Meditec, Jena, Germany, and VSY Biotechnology, Amsterdam, the Netherlands) are hybrids in which the external shell is hydrophobic to prevent calcification. In fact, the material is bonding, not just a shell. I’ve been using these materials for a decade in bifocal design and for 4 years in trifocals without any calcification being detected. Also, dysphotopsia and glare were rarely reported. VSY has trifocals that have a high Abbe number. The plate material has the advantage of good centering and stability, especially with a toric design. The toric marker is so prominent and has great visibility even through a small pupil. The greater power of toricity allowed me to correct astigmatism higher than 4.0 D. However, the designs still have higher rates of PCO. The trifocal platform from Alcon, the Panoptix, is hydrophobic, and my Asia-Pacific colleagues have informed me of very good results; however, it is not available for me yet. I somewhat agree that the small step power in increments of 0.25 D will give us great benefits in refractive results especially for premium lOLs which need more accuracy to achieve their multifocality effect. Zeiss has had a blue-mix preload for many years for its bifocals and trifocals. Preloading will have more benefits with multifocals than with monofocals for it produces fewer scratches, which might affect the visual outcomes more than with monofocal. Preloaded IOLs from Alcon and J&J have good systems but it is only available for monofocal IOLs. Extended depth of focus IOLs have had crisp distance vision but still have near problem even with mini-monovision. The light adjustable lens seems to be promising in the coming years since the refractive results can be adjusted postoperatively. FDA will approve this lens this year but long-term studies are needed to verify the lens. The materials we have especially hydrophobic acrylics have been considered good enough for decades and are still good enough so far. As physicians, we are always searching for better material for better performance and fewer drawbacks. Editors’ note: Dr. Naripthaphan is a consultant for Alcon, Carl Zeiss Meditec, and VSY Biotechnology. continued on page 14