It is standard for adults and children who undergo cataract surgery to be implanted with an artificial lens in their eye. But a clinical trial funded by the National Eye Institute suggests that the ideal treatment for infants should be surgery followed by the use of contact lenses for several years, and then an eventual lens implant.
A cataract is a cloud on the lens of the eye. Removal of cataracts involves a quick, safe surgical procedure, which is usually followed by the artificial lens - called an intraocular lens (IOL) - being implanted.
Most people would associate cataracts with elderly people, but infants can also be born with cataracts. About 1,200 to 1,600 babies are diagnosed each year with cataracts.
The implantation of an IOL can also be considered as an option for infants. Previous studies have suggested that using an IOL to treat cataracts during infancy improves the long-term visual outcomes for the child. There is also less of a risk of introducing germs into the baby's eye with IOLs, compared with contact lenses, so it is easy to understand why doctors and parents may prefer this option.
It is difficult for surgeons to judge the correct focusing power of IOLs, though, because babies' eyes grow and change a lot during this time. Also, there are more postoperative side effects for infants than there are for adults.
Contact lenses 'as effective' as IOLs
This is confirmed by the results of the new trial - published in JAMA Ophthalmology - which suggests that contact lenses are not only as effective as an IOL, but they are safer.
Cataracts can occur in both eyes, but the new study only looked at cataracts in infants that affect one eye, which are called "congenital unilateral cataracts."
The trial took place across 12 clinical centers and enrolled 114 infants with a congenital unilateral cataract who were between 1 and 6 months old. The parents visiting these clinics were informed about the potential risks and benefits of surgery before participating in the study.
Half of the infants were randomized into receiving an IOL and the other half received contact lenses.
When the babies reached toddler-age, the researchers used a visual acuity test using flash cards imprinted with finer and finer patterns. The idea is that patterns that are visible to the toddlers will grab their attention, while cards that appear blank will not.
At ages 1 and 4.5 years old, there were no differences in visual acuity between the IOL and contact lens groups. But the IOL group did have more post-surgical complications.
Comparing side effects of both treatments
The most common complication was "lens reproliferation," which is when leftover lens cells from the surgery end up in the pupil where they interfere with vision. By the age of 5, lens reproliferation was 10 times more common in the IOL group - it occurred in 40% of infants in the IOL group, compared with 4% in the contact lens group.
Because of lens reproliferation, 72% of infants in the IOL group and 12% in the contact lens group required additional surgery.
In the contact lens group, nine children developed minor eye infections by age 5. These were treated using antibiotic drops, and none of the infections had permanent effects on vision. Three of the infants in this group also had IOLs implanted before age 5, as their families found the day-to-day maintenance of contact lenses challenging.
Overall, the researchers found that, when used in infants following cataract surgery, there are less complications involved with contact lenses, compared with IOLs.
"We think that for most infants with unilateral cataract, contact lenses are a better option than an IOL," says Dr. Scott Lambert, the study's lead investigator and a professor of ophthalmology at Emory University in Atlanta, GA.
"However, in some cases, the parents and their physician may decide that contact lens wear proves to be too challenging, and ultimately not in the child's best interests," he adds.
In December 2013, Medical News Today reported on new discoveries in mapping the molecular process of cataracts.