EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
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52 EW FEATURE February 2011 Refractive challenges and innovations September 2013 Refractive continued from page 51 the "chop and cylinder" pattern to disassemble the cataract. However, he said this part of the femtosecond laser procedure did not affect the posterior capsular bag. Toric lens? The topography showed 4.3 D of with-the-rule astigmatism in the right eye. Source: John Berdahl, MD increased risks in the face of a posterior polar cataract with a higher possibility of a posterior capsule tear needs to be had." Dr. Wortz said a patient with amblyopia and vision of 20/150 makes it difficult to track visual changes. However, if the patient has noticed a marked decrease in vision, that could signify that better vision is possible, he said. Another way to know if this case is ready to undergo surgery is by examining the patient's history, he said. "If you can at least give yourself reasonable assurance that the vision has gotten worse—if you've seen the patient over the course of years, [you can] look back at the chart and see where the vision used to be; if you have a convincing story, and the cataract looks bad enough, then yes, I wouldn't have a problem operating on someone like this," Dr. Wortz said. Femtosecond laser? Drs. Garg, Wiley, and Wortz said that they would perform femtosec- ond laser-assisted cataract surgery on this patient, if the option were available, because the patient had a posterior polar cataract. In those cases, there is an estimated 25% rate of vitreous loss, Dr. Wortz said. He said he would use the laser to create a capsulorhexis that was perfect in centration and diameter, which is key in this patient. "In this case, a perfect capsulorhexis can make the difference between a posterior chamber and an anterior chamber lens, especially if you've got a toric lens. So in this case, particularly, I think the laser has value there," he said. Dr. Garg said a perfect capsulorhexis in this case decreases the possibility of radialization. "Additionally with prechopping the nucleus in this young patient, you can avoid hydrodissection, which is where there is the highest risk for [posterior capsule] tear in this case, with potential dropping of the nucleus," he said. Venturi fluidics are helpful in a case such as this to remove the nuclear fragments, without needing occlusion of the phaco tip to generate vacuum, he said. Also, venturi fluidics enhance followability of the fragments, which can keep the phaco tip in the center of the eye, away from the capsule, Dr. Garg said. Dr. Wiley said he would perform femtosecond laser in this case with a caveat—"I would likely just do the capsulorhexis and would refrain from using lens softening in fear that the softening bubbles would lead to pressure that may cause an early bag tear. The 'perfect' capsulotomy can prove useful, as Dr. Berdahl experienced," he said. The physicians warned to be careful of gas expansion stretching the posterior capsule. Dr. Wortz explained that during the laser procedure, the lens fragmentation increases intracapsular pressure because of the tiny gas bubbles that are inserted into the capsule. This could lead to tearing because of the weak posterior capsule often seen in posterior polar cataract cases. Dr. Berdahl said he did perform lens fragmentation in this case using The physicians interviewed agreed that a toric lens is appropriate in this case. Dr. Wortz agreed with Dr. Berdahl's decision on where to place the haptics. "As long as the haptics are in the capsular bag and you've got the optic in the sulcus, I think that's appropriate management," Dr. Wortz said. A toric IOL is an especially good choice in this case because of the patient's high amount of regular corneal astigmatism, as it offers the possibility of uncorrected good visual acuity, Dr. Garg said. He said it is important that the surgeon focuses on the corneal astigmatism instead of the refractive astigmatism found on the axial map. "Even though [the patient's] cornea measures a large amount of cylinder, the patient is not used to it," he said. "In this patient, her lenticular astigmatism is negating her corneal astigmatism. If this is not corrected, even in the setting of amblyopia, the patient may be disappointed in the need for high astigmatic correction in spectacles or the need for a rigid gas permeable contact lens, as removal of her cataract will 'unmask' her pre-existing corneal astigmatism," Dr. Garg said. EW Editors' note: Dr. Garg has financial interests with Abbott Medical Optics (AMO, Santa Ana, Calif.). Drs. Berdahl and Wortz have financial interests with Alcon (Fort Worth, Texas). Dr. Wiley has financial interests with AMO and Wavetec (Aliso Viejo, Calif.). Contact information Berdahl: johnberdahl@gmail.com Garg: gargs@uci.edu Wiley: drwiley@clevelandeyeclinic.com Wortz: 2020md@gmail.com