EyeWorld India March 2019 Issue

10 EWAP FEATURE • September March 2019 keratometry and total corneal astigmatism measurements being done via color LED and swept- source OCT. In addition, more topographers are beginning to noninvasively measure tear breakup time and other dynamic tear film-related variables, “which may help us know when to trust our Ks and when not to, as well as better monitor our dry eye treatments.” In any case, Dr. Donaldson said, “in the shorter term, cataract surgery is becoming more customized, requiring extensive attention to detail and high-level, time-consuming preoperative evaluations to help meet the expectations of a population that thinks that cataract surgery will provide them vision that compares with LASIK and other corneal refractive procedures of the 21st century.” EWAP Editors’ note: Dr. Donaldson has financial interests with Alcon (Fort Worth, Texas), Johnson & Johnson Vision, and Bausch + Lomb (Bridgewater, New Jersey). Dr. Raviv has financial interests with Cassini Technologies and Johnson & Johnson Vision. Dr. Thompson has financial interests with Johnson & Johnson Vision, Alcon, Avedro (Waltham, Massachusetts), Bausch + Lomb, RxSight, and Carl Zeiss Meditec. Dr. Gupta has no financial interests related to her comments. Contact information Donaldson: kdonaldson@med.miami.edu Gupta: preeya.gupta@duke.edu Raviv: TalRaviv@EyeCenterofNY.com Thompson: vance.thompson@vancethompsonvision.com 9LHZV IURP $VLD 3DFLÀF I t is timely that Drs. Thompson, Donaldson, Gupta, and Raviv discuss the issue of preoperative astigmatism measurements prior to toric lens implantation. One of the biggest revolutions in recent years has been the greater understanding in how to achieve accurate post-cataract surgery refractive outcomes in our patients. For this, we have much WR WKDQN 'RXJ .RFK ZKR LQ KLV ,QQRYDWRU·V /HFWXUH RI DW $6&56 taught us the importance of the hitherto neglected posterior corneal DVWLJPDWLVP 3&$ We have all seen the graphs that show the percentage of cataract SDWLHQWV ZLWK D GLRSWHU RU PRUH RI FRUQHDO DVWLJPDWLVP LV DERXW ,I we accept that a diopter of astigmatism is where we should be using WRULF ,2/V WKHQ WKH LQFLGHQFH RI WRULF ,2/ XVDJH LQ DQ XS WR GDWH SUDFWLFH VKRXOG EH DURXQG +RZHYHU WKH IDFW LV WKDW LQ $XVWUDOLD WKH LQFLGHQFH RI WRULF ,2/ LPSODQWDWLRQ LV DERXW RI DOO FDWDUDFW VXUJHULHV RI DOO P\ RZQ FDWDUDFW SDWLHQWV DUH LPSODQWHG ZLWK D WRULF PRQRIRFDO or multifocal lens implant and I know that many of my cataract surgeon FROOHDJXHV LQ $VLD DUH DW WKH ² WRULF ,2/ XVDJH OHYHO Why is this so? This is because the conventional wisdom of only doing toric calculations when there is a diopter or more of corneal astigmatism is fundamentally incorrect. Based on what Doug Koch taught us, whether astigmatism is with-the-rule or against-the-rule is more important than the DEVROXWH DPRXQW RI DVWLJPDWLVP )RU H[DPSOH D SDWLHQW ZKR KDV ' ZLWK WKH UXOH FRUQHDO DVWLJPDWLVP ZLOO QRW QHHG D WRULF ,2/ EXW LI LW LV ' DJDLQVW WKH UXOH KH ZLOO DEVROXWHO\ QHHG D WRULF ,2/ :H DUH IRUWXQDWH LQ $VLD WKDW ZH KDYH DFFHVV WR ORZ GLRSWULF SRZHUV RI WRULF ,2/V WKDW FRUUHFW HYHQ ' RI DVWLJPDWLVP DQG FHUWDLQO\ XS WR RI DOO P\ WRULF ,2/V implanted are of these low corrections. One of the most useful tools to help ensure accurate toric outcomes is WR XVH WKH RQOLQH %DUUHWW 7RULF &DOFXODWRU %7& ZKLFK FDQ EH IRXQG DW www.apacrs.org 7KH %7& IDFWRUV LQ WKH KLGGHQ 3&$ DQG JHQHUDWHV D UHFRPPHQGHG ,2/ VSKHULFDO DV ZHOO DV WRULF SRZHU :KLOH WKLV LQ LWVHOI ZDV DOUHDG\ D UHPDUNDEO\ DFFXUDWH IRUPXOD SRVWRSHUDWLYH UHVLGXDO F\OLQGHUV RI ' WKH LQWURGXFWLRQ RI WKH LQWHJUDWHG . FDOFXODWRU LPSURYHG WKLV WR 7KLV LV ZKHUH WKH GLIIHUHQW ZD\V RI FDOFXODWLQJ . YDOXHV DV GHVFULEHG LQ WKLV DUWLFOH DUH RI YDOXH 7KH %7& RSWLPL]HV WKH data from three different devices capturing K values by using the median YDOXHV WR FRPSXWH WKH WRULF ,2/ SRZHU ,I RQO\ WZR GHYLFHV DUH XVHG DQ average value is derived, not the more accurate median value. By the VDPH WRNHQ KDYLQJ ÀYH RU VHYHQ GHYLFHV PHDVXULQJ WKH . YDOXHV LV D ODZ RI GLPLQLVKLQJ UHWXUQV +DYLQJ WKUHH GHYLFHV LV WKH VZHHW VSRW 7KH QH[W VWHS IRUZDUG ZLOO EH ZKHWKHU PHDVXULQJ WKH 3&$ DQG LQSXWWLQJ this information into our formulas will lead to even more precise outcomes. (GLWRUV· QRWH 'U <HRK LV RQ WKH VSHDNHU SDQHOV RI $OFRQ -RKQVRQ -RKQVRQ 9LVLRQ DQG &DUO =HLVV 0HGLWHF Ronald YEOH, FRCS, FRCOphth, DO, FAMS $GM $VVRFLDWH 3URIHVVRU 'XNH 186 *UDG 0HG 6FKRRO 6LQJDSRUH 1DWLRQDO (\H &HQWUH &RQVXOWDQW (\H 6XUJHRQ 0HGLFDO 'LUHFWRU (\H 5HWLQD 6XUJHRQV &DPGHQ 0HGLFDO &HQWUH 2QH 2UFKDUG %RXOHYDUG 6LQJDSRUH 7HO QR )D[ QR ry@ers.clinic The true - from page 9