Eyeworld

EW CATARACT 21 capsulotomies be as strong?" Both the manual and femtosecond images in these pig eyes looked the same, he recalled. However, there is a big difference between human and pig eyes. "A dead pig capsule is thick and hard, so it's different from a human capsule, and these eyes do not move," he explained. When the femtosecond laser docks onto a human eye, he said, it does not hold the eye completely. Some misfiring due to move- ment is unavoidable, with packets of laser light 200 micrometers long being fired, he said. "If the eye moves, there is no way a computer is going to detect the movement and signal the laser to change its firing or stop it because the light has already released," he noted. "I believe that intuitively, the capsule is not going to be as strong if it's cut by a micro-postage stamp mechanism of mini explosions," he said. "I think our clinical data sup- ports that." "Most importantly, in our data, there is no difference in visual re- sults or refractive outcomes between the laser and manual groups," Dr. Davies said. "We have more than 1,000 patients in each group now." "A common argument for the laser is that the results improve be- yond the learning curve. We did not observe a learning curve. The com- plications kept occurring. We feel there is a fundamental issue of cap- sule strength that has not been ad- dressed with good quality studies." "For now, our paper abolishes the concept of universality of bene- fit for all surgeons. The laser did not benefit our patients, and cannot be considered the gold standard until large, good quality studies are done," Dr. Davies said. "We have 6-month data that does not show significant corneal benefit either." The 6-month data is being prepared for publication. Dr. Safran pointed out that even if you assume the laser is more effi- cient, it's only cost effective for the doctor if the patient pays for it. "No doctor is going to want to take $500 out of his fee," he said. In addition, there are click fees and maintenance costs. "The problem is you cannot charge a patient for a 'golden scalpel.' As a result, it comes down to charging patients for limbal relax- ing incisions, which many patients don't need, and others are better served with a toric IOL," he said. Overall, Dr. Safran views the push for the femtosecond laser for cataract surgery as marketing driven. "I don't see the technology as a springboard—I see it as a crutch," he said. "What I'm looking for is a trampoline, something that's going to help me jump higher, go further, do better—not something that's going to automate and reproduce what I can already do." EW Reference Abell RG, Vote BJ. Cost-effectiveness of femtosecond laser-assisted cataract surgery versus phacoemulsification cataract surgery. Ophthalmology 2014;121(1):10-6. Editors' note: Dr. Davies has no financial interests related to his comments. Dr. Safran has financial interests with Bausch + Lomb (Rochester, N.Y.) and Heidelberg Engineering (Heidelberg, Germany). Contact information Davies: pejd@bigpond.net.au Safran: safran12@comcast.net April 2014 by Vanessa Caceres EyeWorld Contributing Writer Postmenopausal hormone use: A protective effect against cataracts? No dice continued from page 20 Meta-analysis leaves room for further research A recently published study reported that post- menopausal hormone use might have a protective role in the formation of cataracts. 1 However, ophthalmologists who reviewed the analysis cautioned that it is not the definitive word on the topic. The meta-analysis was led by Kairan Lai of the Eye Center, Second Affiliated Hospital, Hangzhou, China. The investigators analyzed four cohort and five case-control or cross-sectional studies, all related to postmenopausal hormone replace- ment therapy (HRT) use and cataract development. All of the studies ana- lyzed were published prior to March 2013. Although the investigators found 96 citations in PubMed and EMBASE, they excluded those that did not meet their specific criteria, which led to the final nine studies analyzed. The studies were set in the United States, Europe, and Asia. Sample sizes in the studies ranged from 242 women to 20,000 women, the latter in a U.K. population-based case-control study. Some of the well- known studies included in their analysis were the Salisbury Eye Evaluation, the Framingham study, the Blue Mountains Eye Study, and the Beaver Dam Eye Study. Study findings Overall, the studies indicated a decreased risk of cataract associated with postmenopausal hormone use, regardless of cataract type. The in- vestigators also found an association between current HRT use and nu- clear cataract in the case-control and cross-sectional studies, but they did not find an association between cortical cataract risk and posterior subcapsular cataract in women who had used HRT at any point. "The current HRT users had a decreased risk of developing any type of cataract, nuclear cataract, and cortical cataract, but neither any type of cataract nor subtypes were correlated with the past HRT," the investigators wrote. They added that these results should be interpreted with caution because of the limited number of studies in the subgroup analysis. Investigators also found the women currently using HRT had a slightly lower risk for cataracts com- pared with past users. "Each article, which evaluated current and past HRT use separately, reported the same tendency," they wrote. "One possible reason is that the exposure time and concentrations of estrogen in current users may be higher than those in past users." Investigators wrote that they are not entirely sure why the results indicate a protective effect between HRT and cataracts, but they said that previous research suggests that estro- gen has antioxidant properties and preserves mitochondrial function and cell viability. This may help pro- tect the lens from oxidative damage. The research also noted the possible involvement of several other biolog- ical mechanisms. Limitations of the study as cited by the investigators include the use of self-report questionnaires in most of the studies, varying definitions of HRT use in each study, and different study designs. For these reasons, they recommend follow-up studies. Analyzing the results This research should provide some reassurance to patients and ophthal- mologists regarding the use of HRT, said David R. Hardten, MD, Min- neapolis. "This gives us advice on our patients who may be concerned about the eye effects; they can make the decision about HRT with their gynecologist without fearing, and maybe benefiting from, the effects on the eye," Dr. Hardten said. Evan Lewis Waxman, MD, University of Pittsburgh Medical Center, Pittsburgh, was surprised that the results seemed to contradict a popular 2010 report that showed women in Sweden on HRT were more likely to have cataract surgery than women who had not been on HRT. 2 That study, which involved more than 30,000 women from the Swedish Mammography Cohort, concluded that long-time HRT use put women more at risk for cataracts, especially if they had more than one alcoholic drink daily. However—"As I looked further into both papers, I started to see that the effect of HRT in each paper was small and that factors leading to un- certainty were so many that it was hard to come to any conclusion other than that women should not make a decision about HRT based on whether or not it will have any ef- fect on cataracts," Dr. Waxman said. Nancy A. Tanchel, MD, Liberty Laser Eye Center, Vienna, Va., was somewhat surprised by the protec- tive effect of HRT as found in the analysis, but noted that hormones seem to help skin and other tissues, continued on page 22

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