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EW FEATURE 92 Challenging and complicated cataract surgery • October 2016 AT A GLANCE • During a slit lamp investigation, surgeons should look for posterior capsule opacification or puncture. • In surgery, surgeons should be aware of the potential for zonular instability, especially in patients who have had multiple vitrectomies. • Timing of a cataract is something to note; a rapidly progressing cataract days to weeks after an intravitreal injection or vitrectomy could suggest the lens was touched. • Post-vitrectomy patients should be told that their visual outcomes will only be as good as their retinal pathology allows. by Liz Hillman EyeWorld Staff Writer Awareness of a few possible complicating factors can result in successful cataract surgeries C ataract surgery in the post-vitrectomized eye has become more common, according to Richard Tipperman, MD, Wills Eye Hospital, Philadelphia. As such, there are certain preop and intraop- erative considerations to take into account with these cases to ensure the safest outcomes. "Retina people have gotten much more aggressive about doing vitrectomies for early macular holes and macular puckers when the pa- tient's vision is dropping a bit," Dr. Tipperman said. "The other thing is that scleral buckling is falling out of favor and more people are having vitrectomies for retinal detachments, so there are a lot more vitrectomies." People who have had a vitrec- tomy, if they don't have a cataract already, will eventually form a cataract, Dr. Tipperman added. This could be due to inflammation and/ or oxygenation that occurs in the procedure, but in some more rare cases, the lens capsule is punctured from an intravitreal injection needle or a vitrector. Kevin M. Miller, MD, professor of clinical ophthalmology, University of California, Los Ange- les, said more intravitreal injections are being done now, leading to a few cataract colleagues are starting these patients on topical non-steroidal and steroidal anti-inflammatory drops before the day of their cataract surgery to preemptively address the inflammation, and have a low threshold to refer back to the retinal specialist in the postoperative period if the patient is experiencing sig- nificant inflammation (i.e., cystoid macular edema) refractory to topical therapy," he said. Intraoperative adjustments As a general rule, Dr. Henderson said she avoids hydrodissection in the post-vitrectomized eye and only hydrodelineates. "I try to minimize the rotation of the lens and prefer to remove the inner nuclear core by chopping rath- er than rotating it in the capsular bag," she said. Dr. Miller also said he would not hydrodissect in an eye where he sus- pected a capsule puncture. In such a situation, he advised pressurizing the eye with viscoelastic material before pulling instruments out of it. If zonular instability is con- firmed, Dr. Miller said first and foremost the bottle height or infusion pressure should be low. He also said surgeons should be on the lookout for reverse pupillary block, which could stress the zonules if not addressed by lifting the iris. Dr. Devgan said that a single, nasal iris hook could be placed at the begin- ning of surgery to prevent such a block as well. Dr. Devgan said he prefers to create a large capsulorhexis (5 to 5.5 mm) and prolapse the nucleus out using hydrodissection or viscodis- section, if the bag is intact. If the posterior capsule is compromised, he would lift the nucleus with a chopper. This, he said, allows him to chop it in the anterior chamber without stressing the capsule or risking an already compromised capsule. As for dense plaques that might be present on the posterior capsule, Dr. Miller said he prefers to perform a posterior capsulorhexis at the time of cataract surgery vs. a YAG laser capsulotomy later for several reasons. First, it restores visual acuity immediately. Second, he considers it "low risk" but noted that there will more lens capsule punctures. "Cap- sule punctures produce a different cataract than you get in the typical post-vitrectomy cataract eye," Dr. Miller said. "Even so, they are still the minority of post-vitrectomy cataracts." In 1998, Dr. Miller was a coau- thor of a study that found, for the most part, cataract surgery after pars plana vitrectomy resulted in favorable visual outcomes with "few unplanned intraoperative events or complications … ." 1 Keeping up on subsequent studies that have been published in more than a decade since, Dr. Miller said, aside from some studies citing more anterior chamber depth fluctuation, cataract surgery and its outcomes for the post-vitrectomized eye are "about the same as they would be for an average eye." Consider timing Timing of a cataract can say a lot in cases with retinal pathology. If a patient received an intravitreal injec- tion for age-related macular degener- ation, for example, and 4 days later developed a very mature or rapidly progressing posterior subcapsular cataract, this could indicate that the lens was touched by the needle, Dr. Tipperman said. Uday Devgan, MD, clinical pro- fessor of ophthalmology, University of California, Los Angeles, said the typical cataract that forms after an uneventful vitrectomy has central nuclear sclerosis and takes months or longer to develop. "If the patient develops a white cataract within a few weeks of the pars plana vitrectomy, there is almost certainly an iatrogenic break of the posterior capsule, and if this patient undergoes cataract surgery, there is a high risk of the entire lens nucleus falling onto the retina," he said. Timing is a factor in the sched- uling of the cataract surgery itself as well. As a retinal specialist, Ehsan Rahimy, MD, Palo Alto Medical Foundation, Palo Alto, California, says he typically advises patients to wait at least 3 months after routine vitrectomy before proceeding with cataract surgery, unless circumstanc- es warrant sooner intervention (i.e., intraoperative lens touch causing a rapidly progressive white cataract). After that time, most healing from the underlying retinal pathology has usually occurred, and other miti- gating visual factors have resolved (i.e., gas bubble has dissolved, scleral buckle has settled into place, intra- ocular inflammation has been treat- ed) to where an accurate assessment can be made about whether cataract surgery is warranted as opposed to an updated refraction. In some cases, such as a severe retinal detachment with prolifera- tive vitreoretinopathy (PVR) where silicone oil endotamponade was uti- lized, Dr. Rahimy said he would rec- ommend waiting at least 3 months and in some cases 6 months or even longer before removing the oil. "In these situations, once we determine the oil is ready for removal, the ret- inal surgeon may perform a combi- nation case in conjunction with the anterior segment surgeon to remove the oil and cataract together in order to minimize the number of trips to the operating room for a patient," he said. Preop evaluation A careful and thorough slit lamp examination, focusing on the type of cataract and posterior capsule, can prepare surgeons for what they might encounter intraoperatively, Dr. Devgan said. White opacities, or plaques, on the posterior capsule can be points of weakness and have to be addressed for visual outcomes, he said. If the cataract is not yet dense and milky, Dr. Miller said the surgeon might be able to spot a cap- sule puncture at the slit lamp and prepare for that accordingly as well. Bonnie An Henderson, MD, clinical professor of ophthalmology, Tufts University School of Medicine, Waltham, Massachusetts, said that while posterior capsule integrity can be difficult to evaluate, a vertical line in the posterior aspect of the cataract can be a warning sign, and ultrasound biomicroscopy can be helpful preoperatively as well. Then there is the possibility of zonular instability. "I compare the anterior cham- ber depths (ACD), measured with noncontact biometry, of the two eyes. If the post-vitrectomized eye has a longer ACD, this can signify zonular laxity," Dr. Henderson said. Dr. Rahimy said that post-vit- rectomized eyes may be prone to postop inflammation. "Many of our Achieving best outcomes with cataract surgery in the post-vitrectomized eye continued on page 94

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