Which IOL for child in paediatric cataract surgery?

Primary intraocular lens (IOL) implantation is not always possible in paediatric cataract surgery, but when it is, the bag-in-the-lens IOL (BIL, Morcher) is the only implant that can be used in every case, said Marie-José Tassignon MD, PhD, FEBO. Dr Tassignon was speaking at a joint session of the 3rd World Congress of Paediatric Ophthalmology and Strabismus and the XXXIII Congress of the ESCRS in Barcelona, Spain.

Reviewing the ranges of age (one to 119 months), axial length (16.71-28.40mm), and corneal curvature (36.00-54.25D) from her series of paediatric eyes implanted with the BIL IOL, Dr Tassignon noted that no traditional one-piece or thee-piece IOL could be used in all of those cases.

“With a total length of 7.5-8.0mm, the BIL implant can fit even the smallest eye. Moreover, the long-term results are beautiful,” said Dr Tassignon, Professor of Ophthalmology, Antwerp University, Belgium.

The BIL implant is designed to prevent posterior capsular opacification (PCO). Published long-term results show it performs well. Among 46 paediatric eyes having at least five years of follow-up, 42 (91 per cent) maintained a clear visual axis (J Cataract Refract Surg. 2015;41(8):1685-1692).

The BIL IOL prevents PCO by trapping lens epithelial cells within the capsule. Dr Tassignon suggested that this principle of the BIL IOL also explains the very low rate of glaucoma that has occurred in her paediatric cataract series.

Implantation of the BIL IOL requires making identically and specifically sized anterior and posterior capsulorhexes. The capsule becomes sealed through apposition of the anterior and posterior capsulorhexis rims, which are placed into the implant’s circumferential interhaptic groove.

POSTERIOR LIP

Dr Tassignon said that the posterior lip of the BIL haptic lies in Berger’s space. After objectification of the space by Jan Worst MD, Dr Tassignon developed the idea of using it to accommodate the BIL haptic. “We are not just putting the lens somewhere, we are putting it into an existing space,” she said.

Dr Tassignon noted finding anomalies at the anterior vitreolenticular interface in a high proportion of paediatric eyes with congenital cataract (46 per cent). By presenting videos of surgeries in eyes with posterior capsule plaque and anterior persistent foetal vasculature, she demonstrated that it is still possible to implant the BIL IOL in such cases.

In addition, with the use of bean-shaped rings as auxiliary support devices, the BIL IOL can also be used in eyes without good capsular and zonular integrity. The rings are placed into the sulcus and fit into the BIL IOL interhaptic groove.

Marie-José Tassignon: marie-jose.tassignon@uza.be