EyeWorld Asia-Pacific June 2021 Issue

REFRACTIVE 34 EWAP JUNE 2021 He mentioned that sometimes there may be a break in suction or another situation where a femtosecond laser can’t be used. In these cases, he will use a manual technique. If a surgeon doesn’t have access to a femtosecond laser, they can easily practice on pig eyes or artificial eyes and incorporate manual LRIs into their surgical routine, Dr. Weinstock said, adding that the technique for doing manual incisions is not difficult. Nomograms Going back 30 years, Dr. Weinstock said that Dr. Donnenfeld, Louis Nichamin, MD, and Richard Lindstrom, MD, were among those doing AKs using a diamond blade. They developed nomograms depending on how much astigmatism there was and what optical zone the arc would be at, and how long the arc would be and how deep the cut would be in the cornea depending on the localized pachymetry of the cornea. The longer arc length, the more astigmatism was being corrected. “If you don’t have access to a femtosecond laser, [you can fall] back on the Donnenfeld or Nichamin nomogram with a diamond blade during surgery at the beginning or end of the case,” Dr. Weinstock said. Dr. Donnenfeld said he uses the Donnenfeld nomogram and that this is available on the CATALYS femtosecond laser platform (Johnson & Johnson Vision). Dr. Donnenfeld also said a good place to learn about limbal relaxing incisions is www.lricalculator.com , which he designed about 10 years ago. It gives doctors the nomogram and allows them to populate their patients’ treatments, so they know where to place the incisions, he said. Dr. Donnenfeld stressed that LRIs are tools to take patients’ results from good to great. “I often will offer patients LRIs for even small amounts of astigmatism,” he said. “My goal for refractive cataract surgery is not to make people happy but to exceed their expectations, and limbal relaxing incisions are one of the most important ways that I can exceed patients’ expectations by reducing astigmatism to lower levels.” EWAP Editors’ note: Dr. Donnenfeld practices with the Ophthalmic Consultants of Long Island, Garden City, New York, and has relevant interests with Johnson & Johnson Vision. Dr. Weinstock practices at Weinstock Laser Eye Center, Largo, Florida, and has relevant interests with Alcon, Bausch + Lomb, Johnson & Johnson Vision, and LENSAR. Ronald Yeoh, FRCS, FRCOphth, DO, FAMS Consultant Eye Surgeon & Medical Director, Eye & Retina Surgeons Adj. Associate Professor Duke-NUS Grad Med School, Singapore Eye Centre ASIA-PACIFIC PERSPECTIVES 2 0 years ago, astigmatic keratotomies (AK) and limbal relaxing incisions (LRI) were the preferred techniques for correcting corneal astigmatism. That they worked was indisputable. What was challenging was that they could be variable in outcome and the corrections achieved were unstable over a period of time. Hence, when modern well-designed toric IOLs arrived on the scene in the mid-2000s, they were very well received by cataract surgeons who were then able to align the toric correction built into the IOL with the desired steep meridian on the cornea. This was like a breath of fresh air as the outcomes were predictable and stable. However, there were still some inaccuracies due to errors in acquisition of keratometry data, measurement of axial length, and limitations of toric calculators. With better swept-source biometers and the refinement of the latest generation toric calculators such as the Barrett Toric Calculator (available on www.apacrs.org) , toric IOLs are now delivering outstanding results. Indeed, the precise results obtained have led to many refractive cataract surgeons implanting toric IOLs for preexisting corneal astigmatism as low as 0.5 D. It is interesting that this article highlights the use of AKs and LRIs today when one might have expected these techniques to have faded into the sunset. I believe that they still have a role to play, but mainly for economic reasons and this is true only if the added cost of a corneal incisional astigmatic correction is less than the added cost of a toric IOL over a non-toric IOL. Users also need to remember the limitations of incisional astigmatic correction as mentioned above. Editors’ note: Dr. Yeoh is a consultant for Alcon, Johnson & Johnson, and Zeiss. correction and you don’t have to open them,” Dr. Weinstock said. “But sometimes you need to open them.” He prefers to not open the incisions during surgery but waits to see the patient in a month. “If the astigmatism is not gone, I’ll open the incision up at the slit lamp and check them,” he said. “Sometimes I’ll even augment it manually at the slit lamp with a diamond blade and either extend the incision or make another incision.” If patients are signing up for premium cataract surgery, it’s the responsibility of the surgeon to not just do great surgery but also to follow them postop and do the enhancement that may be needed, Dr. Weinstock said.