Eyeworld

EW CATARACT 37 October 2016 travels slower. When it goes through the aqueous and vitreous, it travels faster. Unfortunately, optical biom- eters make an assumption about the average speed of light through the whole eye so that you can calculate the distance from the front to the back based on the average speed. The extremely myopic eye is going to have a bigger vitreous cavity, so the amount of time light is going to spend traveling in the vitreous is much greater. However, the assump- tion is that the lens and cornea comprise a certain percentage of the overall length of the eye, which is totally off when you have a myopic eye. So the speed of light calculation is off; it doesn't measure the actual axial length of the eye. You have to compensate." Based on ultrasound measure- ments, the SRK-T formula, and his own compensation, Dr. Miller chose a –7 D lens for this patient. Calcu- lations using SRK-T alone recom- mended a –10 D lens. While the main challenge in these eyes is lens power calculation, this case specifically held some other complications as well. This patient had an irregular cornea showing 44 D in some spots and 33 D in others. This irregularity was due in part to the patient's eye being exposed more than normal and drying due to the fact that she had small orbits, which are associat- ed with Crouzon syndrome. She had previous tarsorrhaphy to allow her to fully close her eyelids, which Dr. Miller noted were extremely thin. She also had strabismus, where when her eyes were relaxed they pointed toward her nose. As such, Dr. Miller couldn't have her head turned straight toward the micro- scope for the operation. Rather, he had her turn her head to the opposite side so her eye was in the proper orientation with respect to the microscope. Surgically, Dr. Miller said long eyes also demonstrate more trampo- lining of the lens-iris diaphragm. "When you go into such an eye, you have to lower the bottle height big time—I mean, really close to the eye," he said, adding that if your machine has pressurized infusion, the IOP setting should be set very low. Another issue is that lens im- plants for highly myopic eyes come posterior capsule opacification fast because the capsule doesn't shrink wrap to the lens very well because "We prepare patients for this, and they get a laser capsulotomy to make the starburst symptoms go away somewhere down the road," Dr. Miller said. "They also develop only in three-piece designs. The haptics of these lenses are generally too short for the capsular bag, lead- ing many of these cases to develop capsular striae. BVI, BVI Logo and all other trademarks (unless noted otherwise) are property of Beaver-Visitec International ("BVI") © 2016 BVI Beaver-Visitec International, Inc. 411 Waverley Oaks Road, Waltham, MA 02452 Tel: 1.866.906.8080 Fax: 1.866.906.4304 www.beaver-visitec.com REGISTER ONLINE NOW endooptiks.com Endo Optiks In-Booth Clinical Wet Lab Now experience Endo Optiks during AAO show hours ● Discover the benefi ts of ophthalmic microendoscopy ● Explore the inside of the eye ● Practice ECP and vitreoretinal surgical techniques Endo Optiks Ophthalmic Endoscopy Course for the Vitreoretinal Surgeon* Location: Hilton Chicago, 720 South Michigan Ave.; Room: Williford A Date: Friday, October 14, 2016 Time: Registration and Refreshments at 6:00 pm ● Featuring a KOL guest speaker ● Course certifi cate upon completion of hands-on wet lab Endo Optiks ECP Surgical Course Location: Hilton Chicago, 720 South Michigan Ave.; Room: Williford A Date: Saturday, October 15, 2016 Time: Registration and Refreshments at 5:30 pm ● Featuring a KOL guest speaker ● Course certifi cate upon completion of hands-on wet lab Visit Booth 2515 at AAO to review BVI's complete ophthalmic product portfolio 3 Opportunities to Experience Endo Optiks® at our Hands-on Clinical Wet Labs! NEW At BVI Booth 2515 1 Friday, 6:00 pm 2 Saturday, 5:30 pm 3 continued on page 38

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