EyeWorld Asia-Pacific June 2017 Issue

June 2017 70 EWAP NEWS & OPINION APACRS highlights – from page 69 Richard Hoffman, MD , Eugene, Oregon, representing ASCRS, was up first, discussing his practical solutions cataract surgery in short eyes (less than 20 mm in axial length). The clinical spectrum of the small eye is divided into four groups—simple microphthalmos, complex microphthalmos, nanophthalmos, and relative anterior microphthalmos— Dr. Hoffman said. Simple microphthalmos constitutes 83% of hyperopes and are without complications related to the condition unless surgically induced. Complex microphthalmos is similar to simple in terms of short axial length and normal anterior chamber, but anatomic malformations (coloboma, for example) are present. Nanophthalmos needs to be distinguished preoperatively due to the complications that could occur, which need to be prepared for or treated ahead of time. A preoperative assessment with ultrasound biomicroscopy is helpful, Dr. Hoffer said. Accurate axial length measurement is critical, “because even a small error can lead to a larger refractive error,” Dr. Hoffer said. Modern IOL calculators (Hill-RBF, Barrett II, Olsen, Hoffer Q, Holladay II, and Haigis) were advised, as well as piggyback IOLs for eyes needing more than 40 D of correction. As for surgical approach, Dr. Hoffer said topical and intracameral anesthesia should be used rather than a block, which could increase posterior pressure and vortex vein occlusion. If the IOP is more than 24 mmHg, Dr. Hoffer advised 20% mannitol. It’s also important to avoid hypotony, use a dispersive viscoelastic, and he said he finds microincision forceps helpful for the capsulorhexis. If an anterior chamber doesn’t exist, a limited pars plana vitrectomy can be performed, but Dr. Hoffer cautioned against it in nanophthalmos eyes as they may be too short. Ronald Yeoh, MD , Singapore, representing APACRS, gave his pearls for cataract surgery in long eyes (30 mm or more). Dr. Yeoh said optical biometry is essential for precise axial length measurements. When it comes to formulae, he said the SRK-T is widely used, but in very large eyes, you can get errors due to change in lens configuration from convex to meniscus as IOLs of lower and lower dioptric power are selected. As such, Dr. Yeoh recommended the Barrett Universal II, which factors in lens shape. In terms of operative issues, he said it’s important to minimize chamber shallowing. Complications could include pseudophakic retinal detachments, which he said can be prevented by maintaining the chamber and avoiding abrupt shallowing. “Before removing the I/A tip, inject viscoelastic,” he said. He said you can press a cotton bud on the wound as you withdraw. Even if an eye is indicated for a zero power IOL, Dr. Yeoh said this IOL should still be implanted in case a YAG capsulotomy is needed. YAG on an aphakic eye, he said, can result in pupil block and IOP rise. Wang Zheng, MD , Guangzhou, China, and Vance Thompson, MD , Sioux Falls, South Dakota, discussed their thoughts on refractive surgery for the –10 D myope. Dr. Wang said there are several papers that show LASIK is safe and effective for high myopes. In contrast, he said intraocular procedures are riskier, the long-term safety has not been established, and follow-up is longer compared to that for laser vision correction patients. Dr. Wang noted new technologies as bringing additional safety to corneal refractive surgery— small incision lenticule extraction (SMILE), combined LASIK and crosslinking, and combined SMILE and crosslinking—but said he thinks phakic IOLs do have some advantages in this category and is “probably the future for high myopes.” Dr. Thompson considers –10 D a very high myope, and he’ll start thinking of phakic IOLs more quickly in this category than in lower myopes. Choosing the best procedure for the patient is about preserving best corrected visual acuity and best corrected image quality, he said. Dr. Thompson said he finds wavefront analysis, HD Analyzer (Visiometrics, Terrassa, Spain) and Pentacam (Oculus, Wetzlar, Germany) helpful in determining candidacy for certain procedure. He considers corneal refractive procedures when the patient is not an eye rubber, they have a healthy ocular surface, quality cornea and topography, minimal higher order aberrations, and other factors. For lens-based procedures, Dr. Thompson said there is less risk of retinal detachment with a phakic IOL vs. a refractive lensectomy. Graham Barrett, MD , Perth, Australia, and Mitchell Weikert, MD , Houston, dispelled myths related to toric IOLs. Dr. Barrett said that less than a diopter of astigmatism should be the standard for all patients. In order to achieve that, he presented various points as to why. He said, there is no benefit to actively measuring the posterior chamber, incisions are not as good as toric IOLs for astigmatism correction, and one should target 0 residual astigmatism in all patients. Dr. Weikert dispelled myths that keratometry is good enough, that the posterior cornea mirrors the front, that preop refraction doesn’t matter, that there’s one perfect calculator for toric lenses, and that IOL toricity is “one size fits eye,” among others. Other presentations included Gregory Ogawa, MD , Albuquerque, New Mexico, and Chee Soon Phaik, MD , Singapore, presenting different IOL fixation techniques, and Stephen Slade, MD , Houston, and Abhay Vasavada, MD , Ahmedabad, India, presenting their advice on breaking up dense nuclei with femtosecond laser and using other approaches, respectively. EWAP Editors’ note: Drs. Hoffman, Wang, Thompson, Chee, and Slade have financial interests related to their comments. Drs. Yeoh, Barrett, Weikert, Ogawa, and Vasavada have no financial interests related to their comments.