EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
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February 2011 June 2013 Presbyopia probably going to like true laser vision monovision even better,'" he said. Dr. Chu said his practice employs several methods of determining dominance in patients, including targeting through a small aperture and asking the patient to point. "We use one of the standard ways—we do it a couple of different ways on a couple of different visits to confirm, especially for these patients who can switch dominance, if possible," he said. Dr. Hovanesian said in his practice, he uses a disposable film camera to determine dominance. Patients are asked to hold up the camera to simulate taking a photo of themselves in a mirror, which allows them to show which eye is dominant without thought, he said. "It's simple and it's quick, and patients don't think twice about it. Patients almost always show you their dominant eye that way. But if we choose their dominant eye to do certain tasks, we basically force them to pick an eye," he said. Pearls Dr. Hovanesian said that in monovision, measurements for refractive accuracy are important, especially in the dominant or distance eye because of the importance of uncorrected distance vision. "One of the pearls we learned from any type of refractive/cataract surgery is that without good, clear uncorrected distance vision, patients are generally not happy," he said. "No matter what you give them as near, you've got to give them distance." He recommended that when performing monovision, the near eye could be a quarter to half a diopter off, as slight error can be tolerated in the near eye. But the distance eye must be as perfect a possible. "In the distance eye, you've got to hit emmetropia, you've got to correct the astigmatism, because that's the only eye they're depending on to see the television clearly, to see road signs clearly," he said. He said that when the target is not in monovision, physicians should be aware that an enhancement will most likely be necessary. Contact information Chu: 952-835-0965, yrchu@chuvision.com Hovanesian: 949-951-2020, drhovanesian@harvardeye.com VISIONBLUE EW FEATURE 35 Thompson: 605-361-3937, vance.thompson@vancethompsonvision.com TM (TRYPAN BLUE OPHTHALMIC SOLUTION) BRIEF SUMMARY OF PRESCRIBING INFORMATION A patient in Dr. Chu's office is tested for her dominant eye. Source: Y. Ralph Chu, MD "If they say, 'I can't see road signs. I had this surgery so I could see far, and I could see near,' they are going to be unhappy," he said. Dr. Chu said establishing patients' needs with a preoperative discussion about lifestyle is critical. He said patients need a great deal of education on monovision's strengths and weakness. One potential strength of monovision is improved near vision, while two weaknesses are a slight loss in depth perception and an intermediate blur zone, he said. Dr. Thompson said bothersome blur at a distance from the near eye that may require distance lenses is not the only problem patients might face with monovision—the distance eye might also create near blur for some patients. If they can't ignore this near blur they may need reading glasses for longer, more intense reading times. "That is why I tell monovision patients that the goal is to minimize dependency on glasses, but when they need both eyes at a distance or both eyes up close, having their bifocals to help when necessary is very acceptable. If they can accept this fact, they are more likely to be good candidates to start the monovision journey," he said. "This is all about setting up preexperience expectations and then being willing to repeat postop what you said preop [because] they often do not remember everything you said," he continued. "Being patient and a quality educator sets you up for great success in monovision care." EW Editors' note: Drs. Chu, Hovanesian, and Thompson have no financial interests related to this article. Indications and Usage VisionBlueTM is indicated for use as an aid in ophthalmic surgery by staining the anterior capsule of the lens. Contraindications VisionBlueTM is contraindicated when a non-hydrated (dry state), hydrophilic acrylic intraocular lens (IOL) is planned to be inserted into the eye because the dye may be absorbed by the IOL and stain the IOL. Precautions General: It is recommended that after injection all excess VisionBlueTM be immediately removed from the eye by thorough irrigation of the anterior chamber. Carcinogenesis, mutagenesis, impairment of fertility: Trypan blue is carcinogenic in rats. Wister/Lewis rats developed lymphomas after receiving subcutaneous injections of 1% trypan blue dosed at 50 mg/kg every other week for 52 weeks (total dose approximately 1,250,000-fold the maximum recommended human dose of 0.06 mg per injection in a 60 kg person, assuming total absorption). Trypan blue was mutagenic in the Ames test and caused DNA strand breaks in vitro. Pregnancy: Teratogenic Effects: Pregnancy Category C: Trypan blue is teratogenic in rats, mice, rabbits, hamsters, dogs, guinea pigs, pigs, and chickens. The majority of teratogenicity studies performed involve intravenous, intraperitoneal, or subcutaneous administration in the rat. The teratogenic dose is 50 mg/ kg as a single dose or 25 mg/kg/day during embryogenesis in the rat. These doses are approximately 50,000- and 25,000-fold the maximum recommended human dose of 0.06 mg per injection based in a 60 kg person, assuming that the whole dose is completely absorbed. Characteristic anomalies included neural tube, cardiovascular, vertebral, tail, and eye defects. Trypan blue also caused an increase in post-implantation mortality, and decreased fetal weight. In the monkey, trypan blue caused abortions with single or two daily doses of 50 mg/kg between 20th to 25th days of pregnancy, but no apparent increase in birth defects (approximately 50,000-fold maximum recommended human dose of 0.06 mg per injection, assuming total absorption). There are no adequate and well-controlled studies in pregnant women. Trypan blue should be given to a pregnant woman only if the potential benefit justifies the potential risk to the fetus. Nursing mothers: It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when trypan blue is administered to a nursing woman. Pediatric use: The safety and effectiveness of trypan blue have been established in pediatric patients. Use of trypan blue is supported by evidence from an adequate and well-controlled study in pediatric patients. Geriatric use: No overall differences in safety and effectiveness have been observed between elderly and younger patients. Adverse Reactions Adverse reactions reported following use of VisionBlueTM include discoloration of high water content hydrogen intraocular lenses (see Contraindications) and inadvertent staining of the posterior lens capsule and vitreous face. Staining of the posterior lens capsule or staining of the vitreous face is generally self limited, lasting up to one week. Rx ONLY Revised: July 2005 Manufactured by: © Dutch Ophthalmic Research Center International b.v. Scheijdelveweg 2, 3214 VN Zuidland The Netherlands Distributed in the United States by: Dutch Ophthalmic USA 10 Continental Drive, Bldg 1 Exeter, NH 03833, U.S.A. Phone: 800-75-DUTCH or 603-778-6929 U.S. PAT. 6,367,480; 6,720,314