Congenital cataracts and childhood blindness

[caption id="attachment_5228" align="alignnone" width="750"] Ken Nischal MD[/caption]   Congenital cataracts account for as much as 20% of childhood blindness around the world, with half of these cases being unilateral. So, is it better to do the cataract surgery as early as possible, or wait? The Infant Aphakia Treatment Study (IATS), a clinical study designed to answer that question, produced results that remain controversial. EuroTimes met with Ken Nischal MD to discuss the controversy at the 2016 WSPOS Subspecialty Day in Copenhagen, Denmark. IATS sought to determine which treatment for aphakia is better for infants between the ages of four weeks and seven months who were born with a unilateral cataract. Specifically, it compared implantation with a primary lens implant with leaving the child aphakic and using a contact lens, looking at visual outcomes, surgical complications, or complications after the surgery was done. The study included 114 patients from centres around the world. The five-year outcomes came out recently, with numerous publications reporting and discussing the results. The primary finding was that patients who received an implant had the same visual outcome as those who remained aphakic, but were more likely to require additional surgery, and to have more complications such as anterior membranes, membranes behind the implant, and glaucoma. “This was the first prospective, randomised controlled trial of paediatric cataract surgery. It used the best methodology possible, since this is not a common disease. To enrol a sufficient number of patients they had to involve a large number of centres. This can make it difficult to get a consensus. Moreover, the study tried to answer an important question, but it did it in a way that tried to create a perfect situation, not matching real-world conditions,” said Dr Nischal, Chief, Paediatric Ophthalmology and Strabismus, Children’s Hospital of Pittsburgh, USA. Consensus was challenging because of a diverse range of approaches around the world. “In many ways IATS has not affected my practice in a big way because I already had very tight criteria as to when I would put an implant in an infant and when I would not,” added Dr Nischal. He explained that the most common cause of unilateral congenital cataract he sees involves persistent foetal vasculature. These are challenging cases with a number of pros and cons. The decision needs to be based on the particular anatomy and other factors for each patient. The personal and economic circumstances of the patient can also affect the decision-making process. If a child comes to his US clinic with inadequate insurance coverage, that patient may only be covered for one contact lens per year, or may not have access to an optometrist. “I have to very careful not to leave that child aphakic even in one eye. I don’t want to put a contact lens in, only to find that it has been chewed by the dog, and they can't afford another contact lens. I have to avoid creating a case of deprivation amblyopia. You have to make this decision based on the circumstances of the child, and the eye itself,” he said. “My decision-making has served my population well. Nothing that IATS added has changed my decision-making for the children I look after. It is not as if every child who walks in with unilateral congenital cataract gets an implant. They all get carefully vetted and evaluated. Even in those where I thought we could put a implant in, 43% don’t get an implant. IATS hasn’t changed that.” In IATS, the rate of putting an implant in was 80% in a randomised group. While IATS reported complication rates as high as 78%, other series have reported rates as low as 25%. “What IATS has done is to raise doubts among people who were considering doing implantations. My concern is that there may be children in parts of the world who may end up severely visually disabled, because they didn’t get an implant when perhaps they should have,” emphasised Dr Nischal. Ken Nischal: nischalkk@upmc.edu