Vigilance is required particularly in early infancy
"It is not yet clear if we can do anything to prevent the development of glaucoma in paediatric patients following congenital cataract surgery," declared Dr Allen Beck (glaucoma specialist at Emory University, Atlanta, Georgia, USA) when discussing the first year results of the study examining glaucomarelated adverse events in patients of the Infant Aphakia Treatment Study (IATS).1
"IATS is a prospective, randomized study comprising two surgical approaches with congenital cataract surgery - no intraocular lens (IOL) and subsequent contact lens correction versus an IOL placed at the time of surgery," explained Dr Beck. "A protocol for these two approaches was followed for the randomized patients."
Standardized definitions for glaucoma were created within the IATS to ensure consistency. "We established standard definitions for glaucoma and glaucoma suspect. Previous studies have used differing definitions, so it is hard to compare the rates of glaucoma," added Dr Beck. "I am working with an international paediatric glaucoma group to further refine definitions and classification of paediatric glaucoma."
In addition to standardized definitions, examinations under anaesthesia were used to confirm diagnosis of patients and a standard examination protocol was employed for additional evaluations by the investigator if suspected glaucoma was noted.
It was found that current surgical procedures did not prevent early development of glaucoma post congenital cataract surgery either with or without lens implantation. "It is important to note, that this paper represents the one year results," stressed Dr Beck. "Some investigators had postulated that improvements in cataract surgery or that using an IOL would reduce the number of early cases of glaucoma. Unfortunately, that is not what we found."
The results were a moderate surprise to the team. "The 1 year results showed more complications in the IOL group but no statistically significant difference on visual outcomes (again the 5 year results will be very important)," Dr Beck said. "Patient age still appears to play a role in the development of glaucoma. IATS investigators operated at a slightly older age (optimally 4–6 weeks, but a number of patients were older than that) in an effort to reduce early glaucoma cases, yet younger patient age was still a risk factor for the development of glaucoma." These odds decreased by 1.6 times every month the child aged.
It was also demonstrated that the chances of a child, with persistent foetal vasculature, developing a glaucoma-related adverse event was 3.1 times higher than those without persistent foetal vasculature.