Eyeworld

EW RESIDENTS 58 April 2014 power is selected that would give the least minus target postoperative refractive outcome," he said. Dr. Chang usually relies on the SRK/T formula, as it is generally thought to be better for long eyes. However, he said it depends on what you are trying to do for patients, whether they are monofocal patients or those looking for a premium IOL. For premium IOL patients, he would use a combination of the SRK/T formula and the Holladay 2 and weigh the results of both. Intraoperative maneuvers Dr. Wortz said most agree that reti- nal detachments occur due to the dramatic chamber shallowing that can happen in highly myopic pa- tients during the various points that the irrigating handpiece is removed from the eye. "Highly myopic patients tend to have deep anterior chambers, which allow for a more dramatic shallowing effect," he said. "This shallowing can cause an abrupt force transduction from the posterior lens capsule to the vitreous and eventually to the retina, causing retinal tears in some cases." A solution to this would be to fill the anterior chamber with vis- coelastic through the paracentesis prior to withdrawing the I/A hand- piece, which can help prevent dramatic shallowing. Additionally, he said that irrigating through the paracentesis while removing the I/A after final removal of viscoelastic can cut down on the shallowing. For these types of patients, Dr. Chang tries not to break the capsule, which would be the biggest risk for retinal detachment. He aims a little smaller when performing the capsu- lorhexis because it tends to be a little larger than anticipated in myopic patients, partially due to the magnification of the cornea. Dr. Raju said that trying to make the surgery as efficient as possible could help reduce the risk of compli- cations. "I aim my paracentesis more vertically and make sure my wound isn't too long," she said. "It's impor- tant to remember that it may be hard to get the pressure up at the end of the case in a long eye, so if needed, a suture is a smart thing to use." Reverse pupillary block Reverse pupillary block occurs when the anterior chamber becomes very deep and the iris is pushed far back, Dr. Raju said. "Gently touching the iris with a second instrument may break the fluid block and allow the AC to return to a normal depth, and it won't feel like you are operating in a well," she said. "Intraoperative reverse pupillary block most often occurs in young patients, high myopes, or eyes with a prior vitrectomy," Dr. Hill said. "During surgery the iris bows posterior, the pupil dilates and forms a fluid block with the anterior lens capsule or the anterior surface of the intraocular lens." This can happen at the begin- ning of surgery or after IOL implan- tation with rapid or excessive pressurization. In order to prevent this, lowering the infusion bottle height may help, and Dr. Hill added that a single iris retractor, placed at the beginning of surgery, precludes this from happening. "If observed, a small, smooth instrument, such as a cyclodialysis spatula, can be used to lift the iris edge, which will immediately restore normal anatomic relationships with an equalization of hydrostatic forces above and below the iris," he said. Additional concerns Dr. Koch said that there are addi- tional important factors to consider when dealing with highly myopic patients. "I have found that the lens cap- sule in the myopic eye seems to be a bit more fragile and therefore at risk for rupture if capsular block occurs during ostensibly normal hydrodis- section," he said. Dr. Koch urges caution in hydrodissection with fre- quent rocking of the lens nucleus to release any trapped fluid. Additionally, there are consider- ations when fitting these patients with toric lenses. "When you're using a toric lens, these capsules tend to be larger than the capsules in normal sized eyes, and as a result there's more risk of a toric lens rotat- ing postoperatively," he said. "It's important to advise patients [of this] if you're implanting a toric lens." EW Editors' note: Dr. Chang has financial interests with Abbott Medical Optics (Santa Ana, Calif.). Drs. Hill, Koch, and Raju have no financial interests related to their comments. Dr. Wortz has financial interests with Alcon (Fort Worth, Texas) and Omega Ophthalmics (Lexington, Ky.). Contact information Chang: dchang@empireeyeandlaser.com Hill: hill@doctor-hill.com Koch: dkoch@bcm.edu Raju: rajulv@upmc.edu Wortz: 2020md@gmail.com ta Ca o to mt e F a t at C s n I ru L d n o c e s o e ge rg u S t ct ac ra ar s ts nt e m u r t st as La ry r e s a L y r e s s n I ts t nt e m u ru t st R F H V R W P ) s H S S R K & G Q R I O F X Q G S L W G H S Q H P H F Q D K Q ( , 5 / 6 X F F D V H G L Y R U S Q R L W F D V V R U & R L W D Q L P D [ H S P D O W L O V J Q L U X G isit Us at ASCRS Booth #1381 V V S H F U R ) W Q U R H U S V Q R L V L F Q L I R J Q L G D H U S V H W D U X V Q isit Us at ASCRS Booth #1381 U R \ O H Y L W D U H S R W V R S isit Us at ASCRS Booth #1381 H G Q D 6 H Q R K 3 ( isit Us at ASCRS Booth #1381 V < . Q R W J Q L [ H / G 5 H O O L Y V U H [ D ) P R F O R D # W V Q L V Q H K S H W V O L D 0 P R F W V Q L V Q H K S H W V Z Z Z isit Us at ASCRS Booth #1381 $ 6 8 isit Us at ASCRS Booth #1381 calculation formula, which will then calculate a lens of higher dioptric power—the advantage being that this almost eliminates the risk of postoperative hyperopia. Dr. Hill usually uses the Holladay 1 formula, combined with the Wang-Koch axial length adjust- ment. "As recommended by Dr. Koch, if something close to em- metropia is the objective, an IOL Cataract continued from page 57

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