EyeWorld India June 2021 Issue

to spherical power and lens rotation. Dr. Barrett’s Barrett Rx provides a solution for these scenarios in one single formula. Once implanted IOL power data, post-operative refraction data, and the lens constant are entered into the calculator, the Rx formu- la can provide the recommend- ed spherical IOL, toric cylinder, and alignment required for an IOL exchange. Selecting the piggyback IOL option provides spherical power, toric power, and alignment values. Finally, the Rx formula displays a graph pro- viding the rotation values for the existing lens to minimize residual astigmatism. The Rx formula is a comprehensive formula that provides all the required calcu- lations to manage unexpected refractive outcomes in terms of IOL exchange, piggyback lens implantation, or Toric IOL rotation with both an IOL and effective lens position (ELP) option. If a surgeon wishes to rotate the lens a week after the initial surgery, both Dr. Oshika and Dr. Barrett recommend using the online calculator to recalculate the axis alignment values since it provides an opportunity to get the patient’s astigmatism as close to 0 as possible. “Precise postoperative refraction in these cases is key,” says Dr. Barrett. Clinical Tips and Pearls with Toric II Dr. Ronald Yeoh offered his clinical tips and pearls for us- ing the TECNIS ® Toric II IOL in cataract surgery. The main challenges in achieving high toric lens implant rates in cataract surgery are inertia in adoption of new implants and variation in implantation technique. For toric IOLs, the usage around the world has been quite variable, from 50% in Australia to 10% in other countries. The main challeng- es of successful toric IOL use in cataract surgery involve the inertia of acclimating to this new technology and the implantation technique. These two challenges pose extra work for surgeons in learning how to implant IOLs as well as the supposed burden of placing the toric implant in the correct desired meridian. Additionally, surgeons may fear inaccurate refractive outcomes due to poor biometry. The most common fear, though, is malro- tation of toric IOLs after implan- tation. With today’s technology and the TECNIS ® Toric II IOL, fear of malrotation is mitigated, providing surgeons with greater accuracy and improved patient outcomes. In 2018, a comparison study done by Lee et al 1 showed that the AcrySof ® Toric IQ IOL had a significantly lower mean rotation at 2.72 degrees postoperative compared with the old TECNIS ® Toric IOL at 3.79 degrees. The old Tecnis ® Toric implant had a higher repositioning rate. It was also noted that the malpositions were usually in an anti-clock- wise position. With less than desired rotational stability, the TECNIS ® Toric II IOL was created to improve this factor. After many redesigns, the simple solution of frosted haptics worked well enough to increase rotational stability. In Dr. Yeoh’s practice, he has had great success using the TECNIS ® Toric II IOL with ease of implanting the IOL at the desired position as well as the ability to back-rotate lens if necessary. Dr. Yeoh provided useful tips for implanting any toric IOL while presenting three patient case videos of IOL insertion. Surgeons should make sure to inject the IOL and align the axis 10 de- grees shy of the desired position, remove ophthalmic viscosurgi- cal devices (OVDs) behind the IOL (to maintain stability of the lens), and then dial the IOL to the intended position. Whilst being careful to not over-rotate the IOL, surgeons should also press the IOL onto the posterior capsule using the side port. Dr. Yeoh finally advises patients to avoid sudden movements in the first hour after surgery and to avoid jogging and rubbing the eyes for 2 weeks after surgery. Another advantage of the new TECNIS ® Toric IOL is that the A constant is the same for all single piece Tecnis lens implants. Upon selecting the lens in the Barrett Toric Calculator, the lens factor and A-constant will automatical- ly populate for the calculation. For Dr. Yeoh, he believes the TECNIS ® Toric II IOL holds great promise, finding the lens “have stayed exactly where I’ve placed them and the outcomes have been very good.” Laser Cataract Surgery: Unmet Needs in Astigmatism Management for Cataract Patients Dr. Hungwon Tchah discussed how unmet needs for astigma- tism in cataract patients can be managed using a different approach: femtosecond laser-as- sisted surgery. Astigmatism, or the imperfection in the curva- ture of the eye’s cornea or lens, results in blurry vision, eyestrain, headaches, and eye discomfort. After cataract surgery, uncorrect- ed astigmatism significantly com- promises a patient’s vision, es- pecially in the case of multifocal IOL insertion. Dr. Tchah offered a range of reasonable residual postoperative astigmatism val- ues. For monofocal IOLs, astig- matism should range between less than 0.5 to 1.25 diopters (D), whereas bifocal IOLs require a tighter range between less than 0.5 to 0.75 D. Extended depth- of-focus (EDOF) IOLs allow for more tolerance than bifocal IOLs, while trifocal IOLs allow for less It's aToricWorld Frosted haptics (right) in the TECNIS ® Toric II IOL display a rough texture, designed to increase friction and rotational stability Polished haptics Frosted haptics