Eyeworld

EW RESIDENTS 66 July 2017 by Dan Gong, MD, Joaquin De Rojas, MD, Priya Mathews, MD, Sanjai Jalaj, MD, Bryan Winn, MD, Royce Chen, MD, and Leejee Suh, MD I n the prospective study titled "Effect of manual capsulorhexis size and position on intraocular lens tilt, centration and axial position," the authors exam- ined various features of the manual continuous curvilinear capsulorhex- is (mCCC), including size, shape, and position, to determine if these features impact final axial position, tilt, and centration of the IOL in the immediate postoperative period as well as 3 months postoperatively. By describing the ways that mCCC can vary among surgical cases and correlating them with variations in monofocal IOL position, the authors shed light on possible inconsisten- cies with the manual approach that could lead to suboptimal refractive outcomes. Such an investigation is import- ant in an age when the automated approach to capsulotomy provid- ed by femtosecond laser-assisted cataract surgery (FLACS) is gaining popularity. FLACS' ability to create a Review of "Effect of manual capsulorhexis size and position on intraocular lens tilt, centration and axial position" Bryan Winn, MD, residency program director, Department of Ophthalmology, Columbia University Medical Center How important is capsulotomy shape and diameter on the effec- tive IOL position and centration? The Columbia residents review this important study published in this month's JCRS. —David F. Chang, MD, EyeWorld journal club editor From left: Bryan Winn, MD, Priya Mathews, MD, Dan Gong, MD, Leejee Suh, MD, Sanjai Jalaj, MD, Joaquin De Rojas, MD, and Royce Chen, MD Source: Columbia University Medical Center rounder capsulotomy 1 that adheres precisely to the specifications set by the surgeon provides a theoret- ical advantage over the traditional manual approach that is susceptible to human error or variability. For ex- ample, prior research has found that all eyes undergoing FLACS achieved a capsulotomy diameter within 0.25 mm of the intended size, whereas such precision occurred in only 10% of manual capsulorhexes. 2 More precise capsulotomies are thought to result in better IOL centration, im- proved IOL optic coverage, and less IOL tilt. 3 Indeed, prior empirical re- search has found improved IOL cen- tration 4 and less IOL tilt 5 in FLACS capsulotomies compared to manual capsulorhexes. As the authors note, however, studies to date have not shown a clear advantage of FLACS over traditional cataract surgery in terms of complications, visual out- comes, or refractive outcomes. 6,7 In their study, the authors used modern technology and geometric calculations to determine (1) ante- rior chamber depth (determined by partial coherence interferometry me- ter lens), (2) IOL decentration, and (3) IOL tilt (the latter two calculated by Purkinje meter). Retroillumina- tion photos were used to measure the size and shape of the rhexis. The rhexis data was used to classify patients into one of three groups: (1) "control rhexis" if they had a sym- metric rhexis between 4.5 and 5.5 mm, (2) "small rhexis" if they had a rhexis smaller than 4.5 mm, and (3) "eccentric rhexis" if they had a rhexis larger than 5.5 mm or an asymmetric rhexis with incomplete overlap of rhexis with the IOL edge. Additionally, the rhexis-IOL overlap was calculated with an objective scoring software developed by the first author. The rhexis shape factor is a novel metric introduced by the authors representing the degree of deviation from a perfect circle. Although this value has not been EyeWorld journal club

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