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Tackling the challenges of paediatric cataract surgery

Innovations address existing difficulties

Cheryl Guttman Krader

Posted: Thursday, November 1, 2018

Paediatric cataract poses a number of challenges. At the World Society of Paediatric Ophthalmology and Strabismus Subspecialty Day preceding the 36th Congress of the ESCRS in Vienna, Austria, speakers described techniques and technologies for enabling successful outcomes.

A good anterior capsulotomy is critical for success in any cataract surgery, but can be particularly difficult to achieve in children. Ramesh Kekunnaya MD described the new technique of precision pulse capsulotomy (PPC; Zepto, Mynosys) as a method for allowing safe and predictable capsulotomy creation by all surgeons.

“If you can get the capsulotomy right in paediatric cataract surgery, the next steps are relatively easy. But because cataracts in children are rare, many surgeons only perform these procedures infrequently. Using PPC helps surgeons to achieve the ultimate goal of being able to place the IOL in the bag,” said Dr Kekunnaya, Head, Child Sight Institute, LV Prasad Eye Institute, Hyderabad, India.

Dr Kekunnaya reported his experience with the Zepto in 21 eyes of 14 children (mean age 6 years). All but one child was older than age 2. Mean time for PPC was 76 seconds, and average capsulotomy size was 5.72mm.

“Interestingly, and in contrast to adults, the capsulotomy tends to be a bit bigger than planned when using PPC in children,” Dr Kekunnaya said.

As another difference compared to adults, the margin of the capsulotomy created in children using PPC has a serrated appearance, but the edge remains very strong.

Dr Kekunnaya noted the need for data from more cases and longer follow-up.

PREVENTING VISUAL AXIS OPACIFICATION
Marie-José Tassignon MD, PhD, Professor Emeritus and Immediate Past Head, Department of Ophthalmology, Antwerp University, Antwerp, Belgium, discussed implantation of the bag-in-the-lens (BIL) IOL as a safe and effective technique for maintaining a clear visual axis after paediatric cataract surgery.

After creating identically and specifically sized anterior and posterior capsulorhexes, the rims of the anterior and posterior capsule are placed in apposition into the BIL IOL’s circumferential interhaptic groove. Fusing of the capsular blades traps lens epithelial cells, preventing their escape and proliferation.

In her own series of 46 eyes of 31 children followed for five years, Dr Tassignon found an 8.7% rate of visual axis opacification (VAO). Corrected distance visual acuity (CDVA) of 0.5 or better was achieved in 31.2% of unilateral cases and 86.7% of patients having bilateral BIL IOL implantation. Glaucoma developed in one eye (2.2%).

More recently, Nyström et al. reported outcomes of BIL IOL implantation in 109 eyes of 84 children. After a median follow-up of 2.8 years, five eyes (4.6%) required treatment for VAO, CDVA was 0.5 or better in 37.5% of unilateral cases and 55.6% of children who had bilateral surgery, and glaucoma developed in 15 (13.8%) eyes.

Dr Tassignon commented: “The higher rate of VAO in my report includes my earliest cases where I was still learning. Nyström and colleagues benefited from tips I taught them for minimising VAO.”

She attributed the higher rate of glaucoma in the series by Nyström et al. to their operating on some patients just two-to-four weeks after birth.

“I stopped operating on such young children because the surgery is very difficult and results in very marked inflammation. Now, I wait until a child is at least 2-to-3 months old,” Dr Tassignon said.

IN-THE-BAG IMPLANTATION AFTER TRAUMATIC CATARACT
In cases of traumatic cataract where there is partial rupture of the anterior capsule, a novel technique developed by Ken Nischal MD allows IOL implantation in the capsular bag, maintains the implant in a stable position, and reduces the risk for lens-iris capture.

He refers to the approach as the ‘banded technique’ because it converts the edge of the ruptured anterior capsule into a band of tissue that restrains the IOL.

“The banded technique gives surgeons confidence to place the lens in the bag,” said Dr Nischal, Professor of Ophthalmology, University of Pittsburgh Medical Centre, Pittsburgh, United States.

“The beauty of the technique is that the band holds the optic back, but it also retracts away from the visual axis over a period of months. For that reason, I have not yet had to do an Nd:YAG capsulotomy to the band in any eye where I have used this technique.”

The banded technique is done by using a two-incision push-pull approach to create a capsulorhexis in the intact anterior capsule proximal to the rupture.

“The two-incision push-pull approach is ideal for facilitating creation of an oval opening, which is the key to the banded technique,” noted Dr Nischal.

After aspirating the crystalline lens, the posterior capsule, if it is intact, is opened with a two-incision push-pull capsulorhexis, followed by anterior vitrectomy. If the posterior capsule is also ruptured, then anterior vitrectomy is performed carefully to avoid further damage to the remaining posterior capsule.

A three-piece hydrophobic IOL is introduced into the capsular bag, entering through the rupture site if the opening allows or else through the capsulorhexis. The leading haptic is put underneath the edge of the anterior capsule and the trailing haptic is placed so that the IOL is underneath the band.

Ophthalmologists can find more information about the banded technique in a paper that will be published soon in the Journal of Cataract and Refractive Surgery.

Ken K Nischal: nischalkk@upmc.edu
Ramesh Kekunnaya: rameshak@lvpei.org
Marie-José Tassignon: 
marie-jose.tassignon@uza.be