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Weighing up the evidence for myopia control

Professor Augusto Azuara-Blanco examined the research in favour of different myopia control methods at 100% Optical

25 Jan 2019 by Selina Powell

Atropine may be the most effective method of controlling myopia, but further research is needed before the treatment can be recommended, Professor Augusto Azuara-Blanco told delegates at 100% Optical (12–14 January, ExCeL London).

Assessing the evidence that has been accumulated on myopia, Professor Azuara-Blanco highlighted that more than 580 randomised controlled trials have been completed on the topic.

However, Professor Azuara-Blanco observed that trials can be inconclusive or may involve a high risk of bias. 

A well-designed trial will incorporate several factors, including allocation concealment, control treatments that resemble interventions and a low attrition rate.

Selective reporting can also influence what research becomes publicly available, he shared.

“If you are a researcher and you do a trial where you don’t find a difference that trial is less likely to be published,” Professor Azuara-Blanco said.

“If you have a vested interest you may not want to publish,” he added.

A trial should have external and internal validity, Professor Azuara-Blanco shared.

He suggested that clinicians should ask themselves, ‘How similar is the population in this trial to the patients in my practice?’

Professor Azuara-Blanco observed that many myopia trials are carried out in South East Asian populations.

He emphasised the importance of systematic reviews in ascertaining that a treatment is effective.

It is possible that an effect may be found in a single trial by chance, Professor Azuara-Blanco shared.

“It is only the accumulation of single trials that will give you the confidence to say that an effect is true,” he emphasised.

Turning to the available evidence on myopia, Professor Azuara-Blanco shared the results of a Cochrane Review on myopia in children.

He highlighted that the review found both under-correction and rigid gas permeable contact lenses had no effect, while multifocal lenses do slow myopia progression but only slightly.

The most effective intervention was found to be anti-muscarinic agents.

Professor Azuara-Blanco mentioned a 2011 assessment of orthokeratology that analysed the results of 13 studies.

He shared that only one of those studies was high-quality. The evaluation suggested that while orthokeratology may work, the effect is not very large, Professor Azuara-Blanco said.

Finally, a 2016 meta-analysis involving 30 myopia trials concluded that the most effective intervention may be pharmacologic.

Professor Azuara-Blanco said there are no large studies in European populations using atropine, and, at present, there is insufficient evidence to recommend it as a treatment.

He is leading a multicentre randomised trial evaluating low dose atropine eye drops for children with myopia.

This involves 289 myopic children, with 96 receiving a placebo and 193 administering one drop of 0.01% atropine in each eye every day for two years.

The trial will also measure compliance, Professor Azuara-Blanco shared.

A five-year follow up will follow the two-year treatment period. 

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