Risks and outcomes associated with primary intraocular lens implantation in children under 2 years old with congenital and infantile cataract: the UK and Ireland IoLunder2 cohort study

Background Public health initiatives to prevent childhood blindness have emphasised the importance of effective intervention for congenital cataract. Primary intraocular lens implantation, an important recent management innovation, has been rapidly adopted despite the absence of robust supporting evidence. The IoLunder2 study aimed to provide much needed insights into visual and adverse outcomes after surgery with and without primary intraocular lens implantation in children aged under 2 years. Methods Active surveillance case identification of cataract surgery and systematic data collection were undertaken through the British Congenital Cataract Interest Group (comprising 173 ophthalmologists who manage affected children in the UK and Ireland), which identified more children undergoing surgery for cataract than were reported to the National Health Service statutory databases. Multivariable regression analysis was used to estimate associations of intraocular lens use with visual outcome (assessed with standard hospital-specific but harmonised protocols) and incidence of adverse events at 1 year after surgery, with adjustment for all relevant confounding factors (eg, ocular comorbidity or age at surgery), which were agreed a priori on the basis of previous research or biological plausibility. All reported odds ratios (ORs) are fully adjusted. Findings Of 221 children, 56 of 131 with bilateral cataract and 48 of 90 with unilateral cataract had primary intraocular lens implantation. Implantation was independently associated with better visual outcome in bilateral (OR 5·4, 95% CI 1·09–26·4, p=0·04) but not unilateral disease, and with increased odds of reoperation (bilateral OR 5·5, 95% CI 2·3–13·2, p=0·002; unilateral 16·7, 4·1–68·9, p=0·009). Intraocular lens use did not reduce the odds of postoperative glaucoma, the key sight-threatening complication, after surgery in bilateral or unilateral cataract. Interpretation Use of intraocular lenses in young children, particularly in settings where follow-up is limited, should be critically reassessed. The absence of visual benefit and the lack of a previously postulated protective effect against postoperative glaucoma question the value of intraocular lens implantation in unilateral disease. The association between intraocular lens implantation and better early visual outcomes in bilateral disease needs to be balanced against the risk of reoperation and exposure to general anaesthetics during a key neurodevelopmental period. Funding Ulverscroft Vision Research Group, Great Ormond Street Hospital/UCL Institute of Child Health National Institute for Health Research Biomedical Research Centre, and Moorfields Eye Hospital NHS Foundation Trust/UCL Institute of Ophthalmology National Institute for Health Research Biomedical Research Centre.