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CATARACT removal within the first two weeks of life, although surgically challenging, appears to provide the best outcomes in paediatric patients, report Canadian researchers.

There has been a long-standing debate within the profession as to whether surgery should be done earlier or later in infants born with cataracts, said Alex Levin, MD. Evidence in the medical literature suggests that removing cataracts early results in the best visual outcome. On the other hand, performing surgery in younger babies presents certain surgical challenges, he said.

"There has been a balance in many people's minds, wanting to get in as early as possible but at the same time fearing that should they do so, their best intentions would be foiled by complications that would develop as a result of surgery done too early," Dr. Levin said.
Dr. Levin and his co-authors, Patrick Watts (now a paediatric ophthalmologist in Wales) and Mohamed Abdolell used data from their retrospective study of the records of all infants who underwent surgery for congenital cataracts between the years 1990 to 2000 at The Hospital for Sick Children, in Toronto, Canada's busiest paediatric ophthalmology centre (JAAPOS 2003;7(2):81-5).

"Our experience is the largest in Canada, and one of the largest in North America," he noted.
Researchers focused on data from infants who had undergone surgery within the first 12 weeks of life for removal of congenital cataracts. During the 11-year period, 80 eyes in 55 full-term infants were operated on. Premature infants were not included in the analysis.
A total of 25 infants had bilateral cataracts, 35 were female and 14 eyes had persistent foetal vasculature (PFV, also known as PHPV). The mean age at surgery was 31.5 days, with a range of two to 84 days.

Early treatment yields fewer orthoptic problems
CART (classification and regression trees) analysis suggests that glaucoma was more prevalent in infants who underwent surgery between 13.5 to 40 days of life than in those who received surgery earlier (CART=0.37). Nystagmus was more frequent in infants who underwent surgery 48 days or more after birth (CART=0.5), and strabismus occurred more frequently when surgery was performed after 55 days (CART = 0.4). The study did not assess visual acuity outcomes due to the presence of confounding variables.

"We found that the first two weeks of life were indeed the safest in terms of complications of surgery," commented Dr. Levin.
The study used only a small part of the information available in The Hospital for Sick Children database. Researchers are doing further analyses to determine what other factors influence outcome, and to better understand the general epidemiology and phenotypic characteristics of paediatric cataract patients.
"Our goal is to try to determine what the prevailing types and causes of cataract at the centre are, and to see if there are identifiable trends that would allow us to make predictions about visual outcome," Dr. Levin explained.

"To our knowledge, no study has been done to better understand the Canadian population of paediatric cataract patients," Dr. Levin said. Epidemiologic findings from the year 2002 were presented at the University of Toronto 45th Annual Research Day by Shehla Rubab MD, David Rootman MD and Dr Levin. The authors are collecting data over the last 10 years representing approximately 1000 cataract patients
For 2002 there were records for a total of 100 patients who presented with cataracts.
Half were male, 53% had bilateral disease, and 21% had associated ocular or systemic disease. Only 6% had a family history of cataracts.

The age of presentation ranged from two days to 16 years. A total of 23% of patients were fitted for contact lenses postoperatively, and 21% of patients were managed without surgery. Patching and dilation was advised in 7%.
The most common phenotypes in the population were posterior subcapsular cataracts, 33%; nuclear cataracts, 12%; and total dense cataracts, 10%. While the study had only short-term follow-up for the population, improvement in vision was seen in 25% of the posterior capsular cataracts, 31.5% of nuclear cataracts, 25% of anterior capsular cataracts, and 28.5% of both cortical and multiphenotypic cataracts.

Most (75%) of the patients required surgical management, but nonsurgical management was a good option in 21% of cases, Dr. Levin said.
Researchers will continue mining the database to study trends over the years.
Although this large database is exciting, retrospective reviews can reveal only so much, cautioned David Granet, MD, Anne Ratner Chair of Pediatric Ophthalmology at the University of California San Diego.

One concern is that surgical technique can evolve over time, and there can be biases. Prospective randomised studies eliminate these problems.
"For example did they operate on one kind of cataract earlier and another later changing their approach over the years? Did children with syndrome-related cataracts receive treatment at a different age?" elaborated Dr Granet.

In response to Dr. Granet's comments Dr. Levin added that "Our very large database is a treasure chest of potential insights. However, like Dr. Granet we recognise the difficulties of dealing with retrospective data and must address these weaknesses in our analysis. Over the last 10 years we have indeed developed a better ability to collect our data prospectively and will be interested to see what the next 10 years will tell us."

Alex V. Levin, MD, MHSc, FAAO, FAAP, FRCSC
The Hospital for Sick Children
alex.levin@sickkids.ca

David Granet, MD, FACS
UCSD/Ratner Children's Eye Center
University of California San Diego
dgranet@ucsd.edu

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