Eyeworld Supplements

EW San Diego 2015 5 " For this type of surgery, you must be able to mark the cornea accurately preoperatively so you know where the lens axis needs to be placed. There are different ways each of us do this, but it must be done if you are going to do toric lens surgery. " Mark Kontos, MD Dr. Mah: I like this, and I also use the Barrett calculator on the ASCRS web- site to ensure my choices align with newer, better calculators regarding toric IOLs (Figures 3 and 4). Intraoperative alignment and "locking" Dr. Donnenfeld: How do you align your preoperative axis with your intraoperative axis? How important are the tools in translating your preoperative readings to surgical results? Dr. Hovanesian: As little as 15 degrees of cyclorotation in the eye can result in a 50% reduction in the astigmatic correction provid- ed by the lens. Five to 10 degrees of rotation is extremely common when patients move from a stand- ing or sitting position to the supine position. Intraoperative aberrometry probably would confirm our align- ment; however, marking the hori- zontal and vertical meridians with a pen as the patient sits upright works well for us. We do this before the pupil is dilated. Dr. Garg: We recently upgraded our IOLMaster to the Callisto Eye (Carl Zeiss Meditec) markerless system, so we align these with a preoperative reference image and the Callisto Eye provides intraoperative guidance. It is an effective way to orient the lens. Dr. Donnenfeld: Preoperative mark- ing is very important when you don't have advanced technology, but it's a step where you can ad- vance outcomes from good to great. The IOLMaster 500 finds reference marks seamlessly on the patient's eye and translates them through the Lumera microscope when using the Callisto Eye. It lays out exactly where the patient's preoperative cylinder is at the time of surgery and allows you to place the toric IOL in exactly that location. A new Catalys software develop- ment will automatically determine the steep axis of the cylinder during the femtosecond laser ablation, so surgeons can mark that axis us- ing the Catalys femtosecond laser system. In the operating room, they can find that axis so the toric IOL is placed in exactly the right location, eliminating the need to mark the eye. Dr. Garg: The iHandy, a smartphone carpenter app, has been discussed by Roger Steinert, MD. You can use it postoperatively to determine where the axis actually is by rotating your phone parallel to your slit lamp (which you orient to the marks on the toric IOL). This helps surgeons accurately identify the orientation of the lens. Preoperatively, surgeons can use markerless systems that employ reference images, or they can mark manually. When you begin this, it's important to make marks lightly or use a fine-tip marker. The more heavy-handed you are, the wider that mark becomes, creating more room for error. Dr. Donnenfeld: More than 37% of respondents to the 2014 ASCRS Clinical Survey do not use marking during surgery. Is this is a reasonable surgical technique? Dr. Kontos: For this type of surgery, you must be able to mark the cornea accurately preoperatively so you know where the lens axis needs to be placed. There are different ways each of us do this, but it must be done if you are going to do toric lens surgery. Dr. Donnenfeld: Do you remove your viscoelastic at the conclusion of your case to make certain the lens stays in the right place, and Figure 4. Tecnis Toric calculator, adding 0.7 to the against-the-rule astigmatism in the patient. This is based on the published findings of Douglas Koch, MD, et al. Note a significantly different powered toric IOL. Source: Francis Mah, MD

• Cover