Eyeworld

Comparing the two in a practice I ntraoperative aberrometry can help a surgeon in determining factors such as spherical power, toric power, and alignment power. It is particularly helpful in cases that are more complicated than a standard cataract procedure, like those with higher degrees of toric power, higher astigmatism, and post-LASIK cases. In a presentation at the 2013 American Academy of Ophthalmol- ogy meeting, Kathryn Hatch, MD, Talamo Hatch Laser Eye Consult- ants, Waltham, Mass., and assistant clinical professor, Warren Alpert Medical School of Brown University, Providence, R.I., discussed toric IOL selection and positioning with and without the use of intraoperative aberrometry. "Intraoperative aber- rometry gives us real-time aphakic and pseudophakic readings and can assist with IOL choice, including both toric and spherical power cal- culation, as well as assist with astig- matism management with LRIs and toric IOL alignment," Dr. Hatch said. She referenced a study she worked on to determine the value of intraoperative aberrometry in cases of toric IOL implantation. The study was a non-randomized, retrospec- tive, comparative trial in a private practice setting with two surgeons, Dr. Hatch said. In the aberrometry group, cylinder power and axis of place- ment was determined by an ORA system (Optiwave Refractive Analy- sis, WaveTec Vision, Aliso Viejo, Calif.) aphakic refraction. With the traditional method, the cylinder power and axis of placement was determined by standard biometry and the use of an online toric calcu- lator. The primary outcome meas- urement was mean postoperative residual refractive astigmatism. The mean preoperative kerato- metric astigmatism in the aberrome- try group was 1.83 D with a range of 0.74 D to 3.77 D. Meanwhile, in the non-aberrometry group, the mean was 1.59 D, with a range of 0.69 D to 4.1 D. Intraoperative aberrometry, including the ORA machine that Dr. Hatch uses, can help physicians make decisions in the operating room. She said that when using this tool, there was a change for toric and spherical IOL power 24% and 35% of time, respectively, in the operating room. "We can also decide whether we need to rotate the lens," Dr. Hatch said. Two-thirds of the time, there was no need for additional rotation after the initial insertion, and 92% of the time less than three rotations were needed. This study showed statistical significance between the ORA group and the non-ORA group. She added there was a lower residual refractive astigmatism in the ORA group. "Across the board, the chance of patients being in lower postopera- tive residual refractive range increases when intraoperative aber- rometry was used, and this was sta- tistically significant," Dr. Hatch said. She said that when conducting the tests on effectiveness of the in- traoperative aberrometry, the results compared to the Alcon (Forth Worth, Texas) FDA trial, which tested for similar results. Results indicated a 57% reduc- tion in cylinder in the non-aberrom- etry group, and in the aberrometry group there was a 75% reduction in cylinder. There was a higher percent- age of patients with better vision in the ORA group than in the non-ORA group, Dr. Hatch said. "You don't always get it right the first time, and in our hands the ORA allowed us to make changes," she said. "We did change one in four patients, we did change the power of the toric lens, and we did do a rotation in one in three patients." Intraoperative aberrometry reduces absolute postoperative residual refractive astigmatism and improves uncorrected vision, Dr. Hatch said. "The take-home [point] is in our hands, patients were two-and-a-half times more likely to have less than half a diopter of astigmatism with the use of aberrometry," Dr. Hatch said. She added the study has found that toric patients and those with higher degrees of astigmatism as well as post-LASIK patients tend to reap the benefits of ORA more than standard cataract patients and those who have had no prior surgery or have minimal astigmatism. Dr. Hatch said there can be some disadvantages of the ORA sys- tem, and it can take some getting used to. "It certainly does add oper- ating room time," she said. Cost is also a factor, as it is not covered by insurance. The system has a learning curve. Dr. Hatch said a surgeon has to be- come familiar with it and know when to trust the information that it's giving. She started by using in- traoperative aberrometry on routine cases, making sure that the measure- ments matched with her measure- ments. EW Editors' note: Dr. Hatch has no finan- cial interests related to her comments. Contact information Hatch: kmasselam@gmail.com EW REFRACTIVE SURGERY 47 May 2014 by Ellen Stodola Toric IOL selection with and without intraoperative aberrometry However, he stressed that cur- rently in the U.S., this approval only applies to "normal virgin eyes" be- cause all data from the clinical trial is from eyes that had not undergone previous surgery. "There may be surgeons who use this off label, but they should know there is no data in the U.S. clinical trials to support that," he said. Pearls Dr. Cummings said that surgeons must make sure that patients are well informed about the technology. Tell patients you are trying to make the cornea more regular, which will lead to better vision once you have corrected with glasses, contacts, or another treatment option, he said. "I think you need to spend time going on a training course where you can learn more about how to predict what the refractive effect is going to be of the regularizing procedure," Dr. Cummings said. He added a warning that "it's a very powerful tool, and the laser's going to do exactly what you ask it to do." It's important to know what it is going to do and be sure you have read the ablation profile, he said. The key pearl that Dr. Durrie of- fered is "if it's a topography-driven treatment, surgeons need to make sure they have excellent topogra- phy." Normally topography is used as a diagnostic screening tool, and now it is being used as a therapeutic tool. Make sure you have the right topography and that it is done properly, he said. Compared to wavefront The main difference between wave- front and topography data is that wavefront is based on the optics just through the pupil, while topography data is based on the corneal surface. It may be hard to get good wave- front data for complicated patients because the corneal aberration is so high; it might be necessary to use topography-guided in these patients, Dr. Cummings said. The U.S. clinical trial did not look at any head-to-head compar- isons of topography-guided abla- tions and wavefront. Because there have been trials on wavefront-opti- mized, wavefront-guided, and to- pography-guided, Dr. Durrie said there is data to be reviewed in the future on this topic. EW Editors' note: Dr. Cummings has financial interests with Alcon (Fort Worth, Texas). Dr. Durrie was an investigator in the topography-guided ablation U.S. clinical trial. Contact information Cummings: abc@wellingtoneyeclinic.com Durrie: ddurrie@durrievision.com The current state continued from page 46

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