EyeWorld Asia-Pacific December 2018 Issue

December 2018 EWAP FEATURE 9 Views from Asia-Paci c Hiroko BISSEN-MIYAJIMA, MD, PHD Professor, Department of Ophthalmology, Tokyo Dental College Suidobashi Hospital 2-9-18 Kandamisaki-cho, Chiyoda-ku, Tokyo, Japan 101-0061 Tel. no. +81-3-5275-1912 Fax no. +81-3-52575-1912 bissen@tdc.ac.jp A chieving emmetropia is a target for refractive cataract surgery. This is not only for the premium intraocular lenses (IOL), such as toric and presbyopia-correcting IOLs, but also for the monofocal IOL. Even with recent developments in diagnostic technology and IOL calculation formulas, postoperative refractive error within 0.5 D has been reported to be less than 75%. When the patient is not satisfied with the postoperative uncorrected visual acuity following the implantation of IOL, the choices of correction are spectacles, contact lenses, corneal refractive surgery (touch-up), add-on IOL, and IOL exchange. Most patients are not happy wearing spectacles or contact lenses, hence surgical procedures are often considered. In most cases, the correction of spherical power and cylindrical power are small amounts, and a corneal laser procedure such as photorefractive keratectomy (PRK) or laser in situ keratomileusis (LASIK) is performed. “ The light adjustable lens has the potential to change the postoperative procedure to correct residual refractive error...the FDA's approval of this IOL is just the starting point in its further development. ” - Hiroko Bissen-Miyajima, MD, PhD The light adjustable lens has the potential to change the postoperative procedure to correct the residual refractive error. From the comments of Drs. Robert Maloney, John Doane, David Chang, and Kevin Waltz, the benefit of this IOL would be as follows: (1) No need to touch the cornea; (2) can be done in the office; (3) patient-friendly under the slit-lamp delivery; (4) a secondary adjustment can be done; (5) superior accuracy; (6) ideal for low to moderate astigmatism correction. On the other hand, disadvantages would be: (1) The cost which is over US$ 5,000; (2) limitations in correctable power; (3) the need of specific UV range blocking glasses; (4) the possible influence of corneal changes over time. I think the FDA’s approval of this IOL is just the starting point in its further development. We all agree that the possibility of fine-tuning the spherical and cylindrical powers within the implanted IOL is ideal. Some of the disadvantages will be solved in the near future and long-term stability of IOL material and the visual outcomes will increase our confidence in this new IOL. Editors’ note: Prof. Bissen-Miyajima has no relevant nancial interests. John So-Min CHANG, MD Director, GHC Refractive Surgery Centre, Hong Kong Sanatorium & Hospital 8/F Phase II, Li Shu Pui Block, 2 Village Road, Happy Valley, Hong Kong Tel. no. +85-2-2835-8884 john.sm.chang@hksh.com T his procedure has a high degree of accuracy and the refractive tuning is in 0.25-D steps. Ninety-seven percent of the patients have postoperative spherical equivalent refractive error within 0.25 D 1 . It offers a high degree of safety, too. The posterior surface of the light-adjustable IOL has a 100 µm UV-blocking surface to prevent damage to the retina, leaving the anterior lens for UV adjustment. It has been shown that no damage was done to the endothelial cells during the UV-tuning and lock-in procedures 1 . It is also advantageous for cataract surgeons who do not have access to refractive enhancement. In addition to adjusting sphere and cylinder, it can: 1. Change the spherical aberration (SA) on the lens to create more negative SA for good near vision (J2@30cm and J1+@40cm) with some compromise in distance vision, or to create less SA to keep good distance vision but weaker near vision 2 . 2. Change the SA in post-LASIK patients. In patients who already have high positive SA, this procedure can adjust the optimal position of depth of focus. For post- LASIK patients with low positive SA, negative SA can be created to increase the depth of focus for reading 3 . 3. Irradiate the lens center to thicken the central part for reading. 4. Create a multifocal optic with customized power and diameter, according to an in-vitro study done by Sandstedt et al. 4 Disadvantages include: 1. Labour intensive and staff time consuming In a study by Hengerer and Dick 1 , 100% of the patients needed 1 adjustment, 46% patients needed 2 adjustments and 6% patients needed 3 adjustments. If a patient needs only 1 adjustment, he/she will need to wait for a minimum of 18 days before the second lock-in. If a patient needs 3 adjustments, he/she will need to wait for at least 18 days before the 3rd adjustment, and 22 days before the second lock-in. Manifest refraction is needed for every visit. 2. Cost US$ 6,000 to 8,000 additional per eye Cost of LASIK enhancement is at most US$ 1,500 to 2,000 per eye, and LASIK is already very safe. 3. Patient inconvenience Patients need to wear UV-blocking lenses at all times for at least 2 weeks (up to 23 days). The glasses are worn immediately after surgery even before the OT lights are turned on. They can only be removed 24 hours after the final lock-in treatment. Frequent visits to the clinic are usually required. References 1. Hengerer FH, et al. Clinical evaluation of an ultraviolet light adjustable intraocular lens implanted after cataract removal: eighteen months follow-up. Ophthalmol. 2011; 118(12):2382-8. 2. Villegas EA, et al. Extended depth of focus with induced spherical aberration in light-adjustable intraocular lenses. Am J Ophthalmol. 2014;157(1):142-9. 3. Villegas EA. Effective approach. Eurotimes 2015 Nov. Available at: http://www. eurotimes.org/effective-approach. Accessed October 20, 2018 4. Sandstedt CA, et al. Light-adjustable lens: Customizing correction for multifocality and higher-order aberrations. Trans Am Ophthalmol Soc. 2006;104:29-39. Editors’ note: Dr. Chang declared no relevant nancial interests. continued on page 13