EyeWorld Asia-Pacific December 2021 Issue

EWAP DECEMBER 2021 3 EDITORIAL Graham Barrett Chief Medical Editor EyeWorld Ƃsia‡*acific • China • Korea • India '[e9orld Asia 2acific r &ecemDer r 8ol 0o A s we approach the end of the year, there are several articles in this issue of Þe7orld Ƃsia‡*acific that will be of interest to our readers. The different options for IOL selection and the increase in the number of presbyopic solutions are highlighted as our main topic. There are several new lenses that are available for adjusting outcomes and the light adjustable lens that is available is of interest particularly in the United States. The concept has been in genesis for several decades and is somewhat less compelling than when originally proposed due to the increase in accuracy of IOL prediction based on preoperative measurements. Even patients who have had previous refractive surgery can be predicted with greater accuracy than ever thought possible. One of the key factors that have improved prediction accuracy is the refinement of methods of prediction both for spherical and astigmatic outcomes. In addition, however, biometers have improved in accuracy. The introduction of swept-source technology has allowed measurements of axial length even with dense cataracts that previously required immersion or contact ultrasound. The measurement of axial length is highly predictable and repeatable across a range of different biometers. Mean keratometry is also reproducible but not to the same extent as measurement of the axial length. The measured corneal astigmatism, however, can Ûary µuite significantly between different instruments and on different occasions. Unexpected refractive outcomes are more liŽely to reflect errors in keratometry rather than effective lens position (ELP) prediction. Measuring the cornea is akin to taking a snapshot of a corneal surface and may vary with the tear film. any surgeons routinely improve the health of the ocular surface before measurements for biometry prior to keratometry. Fast acquisition of the measurements of the corneal surface may improve the accuracy and minimize disturbance of the tear film. Ƃn alternatiÛe to Placido measurements of corneal power are those based on corneal thickness such as utlized in -cheimpflug deÛices. Swept-source OCTs are able to measure the corneal surface accurately but as yet neither option has shown evidence of better outcomes than Placido based auto keratometry. The relative lack of accuracy of keratometry can be addressed by considering multiple measurements of corneal power and then deriving an integrated medium K as incorporated in the Barrett calculator available on the Ƃ*Ƃ ,- weLsite. Ƃs discussed in the article on “Looking for a new biometer” t surgeons are faced with a variety of options in selecting a biometer for their practice. The availability of advanced formulas in a biometer is an important criterion. Formulae are available online but require careful entry of data manually. Optimization of constants are also features that are worthy of consideration when selecting biometers. Instruments that include both optical methods of axial length measurement as well as both -cheimpflug and *lacido imaging devices are attractive and worthy of consideration. There is no one device perfect for every surgeon and the discussions in this edition should prove helpful to those surgeons contemplating purchase of a new device for their practice. The COVID pandemic has obstructed our usual opportunity for in-person meetings over the past 18 months but with improved vaccinations we are hoping for travel to meetings in person to begin again in the new year. In the meantime, publications such as Þe7orld Ƃsia‡*acific have played an important role in communication and education and will continue to do so in the future. Let me take this opportunity to wish all our readers a restful and enjoyable festive season.