EyeWorld Asia-Pacific December 2018 Issue

by Rich Daly EyeWorld Contributing Writer Overcoming challenges in pseudoexfoliation cataract surgery One surgeon describes steps he took to overcome possible complications in a complex case T he frequency with which pseudoexfo- liation cases arise in cataract surgery does not reduce the challenge that they present. “Every ophthalmologist does many of these cases every year, and they’re tough,” said Uday Devgan, MD , chief of ophthal- mology, Olive View-UCLA Medical Center, professor at UCLA, and Devgan Eye Surgery, Los Angeles. Pseudoexfoliation is present in 5–10% of cataract cases but presents more frequently in cer- tain populations, such as those of Scandinavian descent, he said. Pseudoexfoliation is associated with glaucoma, iris abnormalities, and zonular weakness, all of which can cause difficulty during phaco- emulsification. Proper preparation and early intervention can make surgery easier for the surgeon and safer for the patient. Dr. Devgan described the preop, intraop, and postop approaches he used in a recent case to minimize the risk of complications. Preop steps The 80-year-old female patient presented for cataract surgery with a best corrected vision of 20/100. A slit lamp examination of her anterior segment revealed a 3+ nuclear sclerotic cataract and a 4 mm maximum dilation after three sets of mydriatic drops. The anterior chamber was shallow at about 2 mm, and biometry showed a slightly longer axial length of 24 mm. Dr. Devgan used the Ladas Su- per Formula at www.IOLcalc.com to determine that an IOL of +18.5 (using an A constant of 119.2) would provide an emmetropic postop result. However, a higher power slit lamp magnification displayed a round area of deposits of pseudo- exfoliative material. Even higher detail showed a zone of clearance on the anterior lens capsule. That was the result of the iris margin clearing the surface of the anterior capsule to remove pseudoexfolia- tive deposits in the ring-shaped area. The patient also had deposits in the center and periphery of the anterior lens capsule. Pseudoexfoliative material can be dispersed throughout the anterior segment on the anterior lens capsule in a target manner— as found in this case—over the zonules and ciliary processes, on the iris, and in the angle of the eye. Additionally, iridodonesis or phacodonesis found at the slit lamp was an indication of severe zonular weakness. Dr. Devgan also looks for a shallow anterior chamber in patients with pseudoexfoliation because it usually means that the entire lens-iris diaphragm is loose and pushing forward, thereby shallowing the anterior chamber. “This patient had an ante- rior chamber depth of just 2 mm in the setting of a 24 mm axial length. This is a high risk for loose zonules,” Dr. Devgan said. Due to the high association with glaucoma, Dr. Devgan said such patients should be screened for optic nerve damage and treated if an elevated IOP is detected. Because pseudoexfoliation patients may be more prone to inflammation, they should receive preop topical nonsteroidal anti- inflammatory drugs, which will also help prevent intraop miosis. Dr. Devgan begins with an NSAID or steroid for a day or two preop. “We know that using NSAIDs before cataract surgery helps pre- vent pupil constriction; it keeps the pupil bigger, which is what we want,” Dr. Devgan said. Additionally, the use of strong- er dilating drops in the surgery center may give additional dila- tion. Normally, Dr. Devgan uses phenylephrine 2.5%, but a 10% version of the same drug is helpful in such cases. “That may be able to get the pupil a little bigger so you don’t have to struggle quite as much,” Dr. Devgan said. “The main chal- lenges are that the pupil is smaller and that the zonular structures holding the cataract are weaker.” Intraop techniques Dr. Devgan used bilateral choppers to manually and gently stretch the pupil. However, surgeons should be careful to avoid contact with the anterior capsule during the maneuver. He used a technique to bring the nucleus out of the capsular bag and tilt it into the iris plane so that the iris sphincter held it in place. This approach required a capsulorhexis of at least 5 mm in diameter, however, the pupil size was just 4 mm. He injected viscoelastic at the pupil margin to help push the iris and expand the continued on page 52 EWAP CATARACT/IOL 51 December 2018