August 2018

CATARACT

Cataract editor’s corner of the world
Overcoming challenges in pseudoexfoliation cataract surgery


by Rich Daly EyeWorld Contributing Writer

In this “Cataract editor’s corner of the world,” we delve into the nuances of cataract surgery in an eye with pseudoexfoliation syndrome. As many of us are aware, these can be challenging cases intraoperatively, and they also require proper preoperative diagnostics and sometimes postoperative care. Uday Devgan, MD, skillfully drives us through these nuances. With meticulous planning and intraoperative techniques, he shows us how to take a potentially tough case and make it more manageable. It is great to be able to learn tips and tricks from our colleagues.

Rosa Braga-Mele, MD,
Cataract editor
 


Presentation of a pseudoexfoliation case for cataract surgery

Deposits of pseudoexfoliative material identified preop in a cataract patient

Range of deposits of pseudoexfoliative material identified in a preop exam

Use of bilateral choppers to manually and gently stretch the pupil

A zone of clearance on the anterior lens capsule stemming from the iris margin clearing the surface of the anterior capsule to remove pseudoexfoliative deposits in the ring-shaped area
Source: Uday Devgan, MD

One surgeon describes steps he took to overcome possible complications in a complex case

The frequency with which pseudoexfoliation 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 ophthalmology, 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 certain 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 phacoemulsification. 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 Super 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 pseudoexfoliative 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 pseudoexfoliative 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 anterior 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 prevent pupil constriction; it keeps the pupil bigger, which is what we want,” Dr. Devgan said.
Additionally, the use of stronger dilating drops in the surgery center may give additional dilation. 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 challenges 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 pupil, which is a technique Robert Osher, MD, has called viscomydriasis.
“We can then make the capsulorhexis right at the pupil margin or, even better, just underneath it,” Devgan said. “Most experienced surgeons can make the capsulorhexis larger than the pupil without directly visualizing it.”
Dr. Devgan used balanced salt solution to hydrodissect the nucleus out of the capsular bag and tilt it into the iris plane. The iris sphincter held the nucleus in place while he used a phaco chop technique to emulsify and aspirate it.
“This technique brings the nucleus out of the capsular bag in order to minimize stress on the zonules,” Dr. Devgan said “Even in cases in which there is zonular laxity, this supracapsular technique can be safer than intracapsular techniques such as divide and conquer.”
Due to the shallowness of the anterior chamber, Dr. Devgan performed as much of the phacoemulsification as possible at the iris plane.
Another key to good outcomes in this patient was to ensure that the zonules were secure when he removed the cortex. That involved watching the edge of the capsulorhexis during cortex removal for any signs of movement in the capsule or capsulorhexis.
“Take your time on this part; it should be done in slow motion even,” Dr. Devgan said.
A full instructional video with narration of this case can be seen at www.CataractCoach.com.

Postop keys

Dr. Devgan added preservative-free triamcinolone (0.5–1 mg) in the anterior chamber at the end of surgery to quell the inflammation.
Due to weak zonules, patients with pseudoexfoliation face the risk of capsular phimosis in the months or even years postop. When normal capsule contraction occurs, the opening in the capsule can become very small and the lens may dislodge.
In the postop months in such patients Dr. Devgan looks for excessive contraction on the capsule. If that occurs, he performs a YAG laser of that anterior capsule to break the phimotic ring.
Another long-term precaution is to watch for progressive zonular weakness, which could allow a complete dislocation of the lens and capsular bag into the vitreous.
“This patient had a beautiful outcome,” Dr. Devgan said. “It showed that with proper planning and certain techniques we can do a beautiful job on patients with pseudoexfoliation, and it’s not too much of a burden for us.”

Editors’ note: Dr. Devgan is a principal in www.IOLcalc.com and www.CataractCoach.com.

Contact information

Devgan
: Devgan@gmail.com

Overcoming challenges in pseudoexfoliation cataract surgery Overcoming challenges in pseudoexfoliation cataract surgery
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