"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
Background
"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."
It is known that there is a high rate of glaucoma following congenital cataract surgery so in his recent study, Dr Beck led
a team to evaluate the incidence of glaucomarelated adverse events in IATS patients. The study group consisted of 114 patients
aged between 1 and 6 months old who all had unilateral congenital cataract.
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.
Results
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."
Of the patients studied, 10 developed glaucoma and 4 were glaucoma suspect. A glaucoma-related adverse event was recorded
in 14 patients during the first year of follow-up. Lensectomy and anterior vitrectomy was only completed on 57 patients. Of
those patients, 5 developed a glaucoma-related adverse event. Of the 57 patients who were also implanted with an IOL, 9 presented
with a glaucoma-related adverse event.
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.
