Bag-in-Lens for Ectopia Lentis

Children with ectopia lentis treated with an adapted Tassignon bag-in-lens technique had good refractive results and no lens decentration one year after surgery in a study conducted by Lyubomyr Lytvynchuk MD, PhD.

The procedure typically requires no vitrectomy and preserves ocular anatomy, Dr Lytvynchuk said. It provides an alternative to watching and waiting for lens subluxation to advance—which risks uncorrectable refractive error and amblyopia—or treating advanced cases with lens and capsular bag extraction and aphakic contact lenses or spectacles. Generally, he added, iris-fixated or intraocular lenses (IOLs) sutured to the sclera are unsuitable for children.

Multiple implants

The procedure involves bag-in-lens IOL implantation supported by a capsule tension ring. The lens is fixated by fitting the edges of both posterior and anterior capsulorhexes into a groove around the lens edge—helping prevent posterior capsule opacification since there is no posterior capsule behind the lens, though lens opacities develop in about 5% of cases, Dr Lytvynchuk noted.

Since patients with ectopia lentis lack zonular support for the capsule, two bean-shaped ring segment implants anchor the lens implant. The exterior convex side of each ring is placed in the sulcus, and the interior concave side is placed in the lens groove, holding the lens in place. The lens is then centred in the eye using a 6-0 polypropylene loop around its groove, fixated to the sclera with a flange similar to the Canabrava technique. Dr Marie-José Tassignon developed the procedure—having also invented the bag-in-lens IOL and the bean-shaped ring segments in collaboration with Dr Luc Van Os and Dr Darius Hildebrand.¹

Favourable outcomes

Dr Lytvynchuk reported on a consecutive series of paediatric cases, including 11 eyes of 7 patients aged 2–16 years diagnosed with ectopia lentis. Molecular genetics helped diagnose Marfan syndrome in 5 patients. In all cases, lenses were severely subluxated upward with preserved but stretched ciliary zonules. Preoperative refraction revealed high astigmatism in all eyes, with a risk of amblyopia.

Surgery was successful in all patients without severe adverse events. In 3 eyes of 2 patients, anterior vitrectomies were performed to remove vitreous strands in the anterior chamber seen before surgery. Optimal centration of the bag-in-lens was achieved in all cases.

Postoperative refraction was considerably improved for both visual acuity and astigmatism in all patients. A minimal displacement of the polypropylene loop was observed without decentration of the lens in one case. In about 50 cases performed at 4 centres, approximately 10% of patients developed anterior uveitis, which was successfully treated with steroids, Dr Lytvynchuk said.

“This is quite a complex surgery,” Dr Lytvynchuk noted. However, it is minimally invasive, and the learning curve is not steep for surgeons experienced with bag-in-lens IOL implantation for cataract treatment.

“In our clinic, this is standard procedure for treating paediatric cataract starting from age 6 or 8 weeks.”

Further studies are needed to prove the efficacy of this technique in a larger patient cohort, he concluded.

Dr Lytvynchuk spoke at ARVO 2024 in Seattle, US.

Lyubomyr Lytvynchuk MD, PhD is acting director at the Justus-Liebig-University, Department of Ophthalmology, University Hospital Giessen, Germany. Lyubomyr.Lytvynchuk@augen.med.uni-giessen.de

1. Van Os L, Hildebrand GD, Tassignon MJ. Klin Monbl Augenheilkd. 2021 Oct; 238(10): 1058–1064.