Risks of IOL replacement in children under age of 2 exceed benefits

The risks of intraocular lens (IOL) replacement in children under 2 years of age may exceed the benefits, researchers say.

The procedure doesn’t appear to improve vision on average in unilateral cataract, and IOL use increased the odds of reoperation requiring general anaesthesia, according to Ameenat Lola Solebo and colleagues from the British Isles Congenital Cataract Interest Group (BCCIG).

The researchers published their findings in the British Journal of Ophthalmology.

Congenital and infantile cataract is responsible for the blindness of more than 280,000 children worldwide, they report, and most developed countries now screen everyone for these conditions.

IOLs have caught on rapidly as an alternative to aphakic contact lenses, Dr. Solebo and her colleagues write. Advocates argue that the IOLs offer better visual rehabilitation, especially in children with unilateral cataract because amblyopic deprivation is particularly strong when there is rivalry from an unaffected eye.

Advocates also say that IOLs would be particularly useful in developing countries to reduce the challenge of regular clinic visits to update contact lenses, and the risks of infection where clean water is hard to find.

Finally, advocates hope that the IOLs could reduce the risk of postoperative glaucoma as a complication of glaucoma surgery.

Yet, systematic studies of the outcomes of this procedure are lacking.

NEXT: BCCIG study IoLunder2

To fill that gap, the BCCIG undertook a cohort study, IoLunder2. For this study, 69 surgeons at 43 hospitals across the United Kingdom and 3 in the Republic of Ireland identified and reported data.

The surgeons identified 306 eligible children, and families provided consent for the participation of 254. Of these 48% were female, 75% were white, and 27% were in the worst quintile of socioeconomic deprivation.

Surgeons undertook primary IOL implantation in 61 of 151 children with bilateral and 55 of 103 with unilateral cataract.

Data was available 1 year postoperatively for 350 eyes of 221 children. The researchers compared preoperative and postoperative characteristics to look for attrition bias and didn’t find any.

The median age at diagnosis of cataract was 1.8 weeks. At surgery it was 9.2 weeks. Many children had ocular comorbidities. Twenty-four percent of the children had persistent foetal vasculature and among those with unilateral cataract this proportion rose to 47%

Children who received IOL implantation were older, had larger eyes, and were less likely to have other ocular abnormalities at the time of surgery when compared with children with aphakia.

Peroperative complications occurred in 36 of the 350 operated eyes, including multiple complications in 2 eyes. Among the IOL-implanted eyes, 26 (16%) had complications compared to 12 (6%) of the aphakic eyes. This difference was statistically significant (P < 0.01). The most common complication was iris prolapse.

In analysing visual outcomes, the researchers excluded 18 children whose preoperative ocular or cerebral abnormalities precluded good vision.

They found vision within the normal range for age in the better eye, or with both eyes open, in 35 children (36%) with bilateral cataract and 10 (20%) operated eyes of children with unilateral disease. IOL implantation increased the odds of being in a better visual category, though not necessarily of normal vision, with bilateral cataracts (odds ratio 4.6, P = 0.004).

IOL implantation did not result in better vision for children with unilateral cataract, though good concordance with occlusion therapy and the absence of postoperative glaucoma were associated with better visual outcome in them.

Overall, younger age at surgery was also associated with better visual outcomes.

After excluded children with preoperative glaucoma, the researchers found that 28 of 216 (13%) were diagnosed with glaucoma during the first postoperative year. Among children with bilateral cataract, age at surgery was the only factor associated with glaucoma. And in children with unilateral cataract, significant microphthalmia was the only factor.

Out of the 350 operated eyes, 105 underwent reoperation. IOL implantation increased the odds of postoperative intervention 550% (adjusted OR 5.5) in bilateral cataract and 1670% (adjusted OR 16.7) in unilateral cataracts.

 “We are able to suggest that the use of IoLs should be reconsidered in all children under 2 years of age with unilateral congenital and infantile cataract,” Dr. Solebo and colleagues concluded. For children of this age with bilateral cataract, they recommend that the potentially better visual outcome be measured against the increased risk of reoperation, which exposes children to general anesthesia at a key period in neurodevelopment.

Their finding that glaucoma and better visual outcomes are both associated with younger age at surgery reveals a complicated question of time in surgery for this population, they added.