Contact lenses to slow progression of myopia

Posted by eye exam | eye care doctor exam vision | eye exams | optometrist 24/03/2018 0 Comment(s) Eye Treatment,

The prevalence of myopia has been steadily rising, with 28 per cent of the global population said to be affected in 2010 and to rise to affect nearly 50 per cent by 2050.

 

The use of soft contact lenses as a platform for myopia control offers an exciting and effective avenue to manage myopia but there is a need for further research on issues such as the mechanism underlying control of myopia, improving efficacy with lenses, and understanding rebound on discontinuation. More significantly, although contact lenses are generally safe and improve quality of life in older children, one of the major challenges for improved uptake and acceptance of contact lenses centres on the perceived risk of complications with lens wear.

 

Owing to the vast global population affected and the burden of visual disability imposed by the condition, myopia is considered to be a pressing public health issue. With an estimated 1.5 billion people affected in 2010, myopia is the most common cause of distance vision impairment and is expected to rise to nearly five billion by 2050.

 

CONTACT LENSES FOR MYOPIA CONTROL

The idea that contact lenses might play a role in slowing myopia progression was considered as early as 1975 with a finding that rigid contact lens wear slowed myopia progression compared to spectacles but not compared to atropine.21 However, the lack of use of a controlled clinical trial approach makes it difficult to put the results into perspective. It is also not clear if corneal flattening seen with rigid lens wear may have influenced the result.

 

A later study from the 1990s found day‐time wear of rigid gas‐permeable (RGP) contact lenses (as opposed to orthokeratology lenses) slowed myopia compared to matched spectacle lens wearers. Some corneal flattening was found with rigid lens wear but the refractive power change attributable to corneal flattening did not fully explain the significant difference in progression between rigid lens and spectacle lens wear.22 However, this finding was not supported by later evidence that found no difference in progression between those wearing RGPs versus spectacles.

 

The use of soft contact lenses as a platform for myopia control offers an exciting and effective avenue to manage myopia but there is a need for further research on issues such as the mechanism underlying control of myopia, improving efficacy with lenses, and understanding rebound on discontinuation. More significantly, although contact lenses are generally safe and improve quality of life in older children, one of the major challenges for improved uptake and acceptance of contact lenses centres on the perceived risk of complications with lens wear.

IMPROVING PERFORMANCE OF MYOPIA CONTROL LENSES

The performance of myopia control contact lenses so far has spurred thoughts and questions on various aspects, such as, for example, improving efficacy with myopia control contact lenses, rebound on discontinuation of lens wear, efficacy with long‐term wear and use of combination treatments to improve efficacy.

 

With respect to improving efficacy, evaluating the response of an individual to treatment with any myopia control option, including contact lenses, continues to challenge researchers and practitioners alike. Although the efficacy as reported from the various clinical trials, that is, a range of 20 to 72 per cent, is encouraging, the result is an average and therefore some eyes are likely to derive greater benefit from the treatment compared to others.

 

A significantly higher level of myopia control was achieved in a clinical trial that was limited to children with near esofixation disparity,45 but other than this risk factor, there are no other reliable indicators identified of who is likely to respond to myopia control strategies. Conducting further clinical trials might shed light on factors related to improved efficacy but the lack of understanding of the underlying mechanism limits our ability to maximise the chance of obtaining positive responses.

 

References:

     https://onlinelibrary.wiley.com/doi/full/10.1111/cxo.12584
     http://www.highprairieeyecare.com/
     http://slavelakeeyecare.com/

    

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