OCT 2012

EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.

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Page 96 of 168

94 EWINTERNATIONAL Panel continued from page 93 Dr. Zacharias: Certainly the number of premium IOL implantations is growing in Brazil, and it will in- crease over time because the patients are becoming more informed and confident with this technology, and even asking for this kind of lens. The reason why some eye surgeons still prefer standard IOLs is because they are not confident with their own results and don't want to risk them with such an expensive lens. The need for premium biometry and premium surgery makes them reluc- tant to adopt these special lenses. Dr. Ghanem: I completely agree with Dr. Zacharias. Dr. Trindade: Premium IOL implan- tation is growing everywhere, and the cost of the lens is funded by the patient in many countries, including Brazil. I think patient cost is the major reason that limits wider ac- ceptance of premium IOLs over the standard lens. Also, it is well estab- lished that all presbyopia treatments involve a visual compromise of one sort or another, and most likely, surgeons who have not yet adopted premium lenses in their practices are in their comfort zone and satisfied with their results. Dr. Soriano: I believe that is growing as a function of improving the economic condition of the country. Also, there is always a learning curve with the use of new lenses, leading to a time of "maturation." On the other hand, after the euphoria with the launching of the new lenses, there is an adjustment, where the real results begin to appear and sur- geons choose the lenses that they trust. As I mentioned before, con- ventional lenses are suitable for most patients and many, like me, do not believe that visual quality is the price to be paid for independence from glasses. Dr. Nosé: The number of premium IOLs is growing fast in Brazil, espe- cially the toric aspheric lenses and the multifocal diffractive toric. As the inclusion criteria for the multifocal is very restricted, most of the patients either do not qualify for those types of lenses, or lens selec- tion is limited by patient choice and price. Dr. Casanova: For sure, it's growing in Brazil as our economy is getting better. These premium IOLs mean additional costs for the patients. Besides, many doctors do not migrate to diffractive multifocals because they have good results with The use of toric lenses has gained widespread acceptance due to their unequivocal excellent outcomes. Industry provides us with some models, and indications are expanding Fernando Trindade, M.D. monofocal IOLs and do not want to take risks, have no access to more precise biometry, and because of the learning curve (getting used to chair time, handling the patient profile, self-assurance with a new technol- ogy, and choosing a good candi- date). Dr. Padilha: I think all of us agree that toric lenses are here to stay. But what is your main concern when planning to implant a toric IOL? Dr. Soriano: An important chal- lenge, in my view, is to implant the lens exactly in the planned axis. This process includes two steps: a) marking precisely the meridian of insertion, since the markers have some degree of inaccuracy, and b) positioning the lens at the planned axis at the end of surgery. However, there is still some imprecision in the determination of the power and axis of astigmatism. This can occur espe- cially in corneas with astigmatism less regular and symmetrical. Although the toric lens corrects corneal astigmatism, the observation of the relationship between the ker- atometry and the patient's refraction enters in the rationale of the use of toric lenses. It helps in the under- standing of the refractive state of the eye, pointing to the role that the cornea and other elements such as the lens and the retina could play. Dr. Trindade: The use of toric lenses has gained widespread acceptance due to their unequivocal excellent outcomes. Industry provides us with some models, and indications are expanding. My preference is to rely on toric lenses for patients with more than 1 D of regular corneal astigmatism. Accurate IOL power calculation, correct alignment of the lens, and post-op rotational stability are the main issues. Dr. Ghanem: Placing it in the right axis is the main issue with this IOL. Usually I combine the information from various devices, including the IOLMaster (Carl Zeiss Meditec, Jena, Germany), topography, Galilei (Zeimer, Port, Switzerland), and automated keratometry. The IOLMaster provides central corneal (2.5 mm) power and axis, thus being my main guide. In patients with regular astigmatism it is usually easy to determine the right axis. In keratoconus eyes, however, it may not always be the case. Usually I draw a line through the middle of the skewed axes on the topography map to find the steepest meridian. I also combine information from the IOLMaster. I think toric IOLs are an excellent indication for cataract pa- tients with keratoconus up to grade 3, when the patient is not a rigid contact lens user and is not likely to require a corneal transplant in the future. Dr. Zacharias: The evaluation of the corneal power and axis of astigma- tism are our main concern in plan- ning a toric IOL. It is common to have different results from different devices, making it difficult to decide which to adopt. Despite the toricity, the power of the lens can be decided easily and the surgical axis to be im- planted is shown by the calculator with good precision. Dr. Nosé: If we have regular astigma- tism with normal topography, our main concern is ensuring proper lens alignment. This is even more important with higher-power toric lenses because even a few degrees could have a significant effect on the refractive outcome. If the cornea has had previous surgery and the topography is not regular, we need to pay special attention to the power and cylinder axis. We do not use simulated keratometry values to get the cylinder axis and power in these cases. Dr. Casanova: Toric IOLs should be implanted in patients with regular corneal astigmatism. Defining the correct axis is the main issue. I also compare different devices with focus in corneal topography. If the ker- atometry is not matching, I check the corneal image at the topography. If the image quality is not good or inconsistent, the exam must be repeated. I personally perform the ocular biometry and IOL power calculation for my all cases. I can evaluate the tear film and consis- tency of measurements. Blepharitis and dry eye can frequently change these measurements. On the day of surgery, I mark the cornea using the slit lamp and enhance the marks in the OR. At the end of the surgery, the OVD removal is made with the toric IOL rotated a little bit counter- clockwise. I always remove all of the viscoelastic from behind the lens, making it less likely to rotate. When finishing the case, double check the axis position comparing the paper and the image of the video screen or microscope. Dr. Padilha: When managing toric lenses, what kind of special care do you take to mark the right axis? If you notice post-op that the IOL is not well centered or not at the right position, how do you fix the problem? Dr. Ghanem: I mark the right axis directly at the slit lamp with an insulin needle. I scrape the corneal epithelium in the 6-7 mm zone along the axis of implantation and near the limbus in the axis of the main incision according to the cal- culator. With the patient under the microscope I just paint the markings with a gentian blue pen. This way, there is no need to use additional alignment instruments intraopera- tively. Dr. Zacharias: After trying different devices to mark the axis, I go back to the pendulum to mark the 6 o'clock point with the patient seated. To avoid fading of the mark, I ask the patient to sit at the slit lamp, then I scrap the point with an insulin needle and paint it with a methyl- ene blue pen. This way, the mark remains visible during the surgery to guide the axis gauge. Post-op, if the vision isn't as good as I expect it to be, I submit the patient to a refractive exam and dilate his pupils to examine him at the slit lamp and confirm if the axis is well positioned, comparing with the pre-op plan. If the lens is out of axis, I take the patient to the OR and rotate the lens to the right position easily, just with a Lester hook through a paracentesis under topical anesthesia. continued on page 96 October 2012

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