Eyeworld

73 July 2018 EW MEETING REPORTER entiate between a normal unusual measurement in an unusual eye versus an error. Dr. Little said that it's important to crosscheck the IOL power calculation against the patient's refractive history. Particularly in high-risk eyes, Dr. Little said to be alert, recheck the biometry and have a low thresh- old for repeating, use appropriate and up-to-date formulae, reconcile biometry measurements against the patient's refractive history, and warn patients about the high probability of error and need for a possible sec- ondary procedure/enhancement. Dr. Little concluded by talking about correction of refractive error. He said to assess and identify the cause by doing a methodical assess- ment. Check for accurate subjective refraction, repeat the biometry measurements, and recalculate IOL power. Then, rectify the situation. He said to document stable refrac- tion prior to intervention and weigh the risks and benefits of correction. Laser vision correction, a piggyback IOL, or IOL exchange may be needed, depending on the situation. Laser correction or a pig- gyback IOL are more predictable and preferable to an IOL exchange, Dr. Little said. EW He first said to have an error, you have to have a target. What are we aiming for? In terms of bench- marking outcomes, the target is to have 85% within 1 D of the target. The normal distribution of refractive error is 66% of eyes within 1 D of emmetropia. Dr. Little focused on some of the causes of refractive error. Before optical biometry, 54% of refractive surprises were due to errors in axial length measurement, with 38% due to errors in predicting IOL posi- tion, and 8% due to keratometry errors. Now, optical biometry offers improved axial length measurement, and axial length measurement is responsible for only 17% of errors. Dr. Little noted that other causes of refractive error now are prediction of postop IOL position (36%), errors in postoperative refraction (27%), and keratometry errors (10%). Dr. Little added that it's important to identify high risk eyes. If something does happen, be sure to apologize, explain the situa- tion, and support the patient. He moved on to discuss preven- tion of refractive error and noted that enhancing the accuracy of measurements can help with this. Modern software protocols recheck any measurements with low prob- ability, but it's difficult to differ- the eye. Poor surface quality impacts visual acuity and patient satisfac- tion, especially in premium IOL patients. She offered a number of tips to avoid trouble with dry eye. Make the diagnosis before you operate, she said. Patient education is key, Dr. Colby said, and you need to stress that this is a chronic disease and that patients may need daily inter- vention. It's important to manage patient expectations and to optimize the tear film before surgery, often continuing to do so after surgery as well. Cataract surgery can decom- pensate a borderline dry eye patient. Dr. Colby also spoke about the mechanism of dry eye and high- lighted features, medical manage- ment, and surgical management of the different types of dry eye disease. Charles Kelman Lecture Takayuki Akahoshi, MD, Tokyo, Japan, gave the meeting's Charles Kelman Lecture. Dr. Akahoshi's lecture focused on phaco prechop. He also discussed his experience in Brazil, noting that it was nearly 20 years ago when he first visited the country and was asked to share his phaco prechop technique. He shared his history of cataract surgery using phaco prechop, which he described as a "mechanical nucleofracture performed prior to phacoemulsifi- cation." He said he first began the technique in 1992 in Japan. The femtosecond laser can now prechop, however, it has some limitations because the posterior plate will remain undivided using this technology. Therefore, a manual method may be preferred. Dr. Akahoshi detailed the phaco prechop technique, noting that before performing it, you should ensure corneal protection, have a complete CCC, and perform suffi- cient hydrodissection. Target refractive error Brian Little, MD, London, U.K., discussed target refractive error and causes, prevention, and manage- ment of this. stability, and using a CTR if the IOL seems mobile. Toric IOLs and astigmatism Bruna Ventura, MD, Recife, Brazil, discussed using toric IOLs and other considerations for astigmatism. She first discussed the popula- tion of patients with astigmatism and cataracts. She noted the prev- alence of astigmatism in cataract patients and said that around 6% of patients present with less than 0.5 D of astigmatism, 58% with between 0.5 D and 1 D, and 36% with greater than 1 D. Greater than 0.75 D of astigmatism can affect the quality of life of the patient. To optimize results with toric IOLs, Dr. Ventura shared several tips. She first discussed mapping the cornea and stressed the importance of having at least two devices to obtain measurements. She said phy- sicians should pay attention to the quality of the exam. Dr. Ventura highlighted the im- portance of including the posterior corneal astigmatism and specifically mentioned Dr. Koch's work in this field. She also noted that you can use devices to evaluate the posteri- or astigmatism, nomograms, toric calculators, adjustment coefficients, and the Abulafia-Koch formula. In addition to the posterior corneal astigmatism, Dr. Ventura stressed the importance of calculating SIA. She also mentioned the impor- tance of axis marking and maintain- ing the IOL at the correct axis. Editors' note: Reporting on Dr. Ventu- ra's presentation was based on a trans- lation from Portuguese to English. Phaco and special cases Kathryn Colby, MD, PhD, Chica- go, discussed optimizing the ocular surface prior to cataract surgery. Dry eye is common in the cataract age range, and several studies estimate that around 80% of patients are affected. Many of these patients are asymptomatic and undiagnosed. Dr. Colby said that the air-tear film interface is the most important component of the refractive state of View videos from the 2018 BRASCRS: EWrePlay.org Douglas Koch, MD, discusses the nuances of the double-needle technique for scleral IOL fixation.

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