This is an important question because the scientific data increasingly points towards contact lenses as our best option for myopia control. Embracing active myopia management in practice means embracing paediatric contact lens fitting.
Is contact lens wear more dangerous than a higher level of myopia?
Ian Flitcroft, an ophthalmologist and prolific writer provides a sobering association between increasing myopia and ocular pathology in a paper that he published in 2012. Amongst other things Flitcroft compares the odds ratios of myopic maculopathy, glaucoma, retinal detachment and cataract with increasing levels of myopia, against more widely understood odds of stroke and heart attack. This truly is an outstanding paper that I thoroughly recommend as core reading for anyone interested in the full picture on myopia, but at 38 pages you might want to print it off and work at it over a few reading sessions!
In this format Flitcroft makes the case that it wouldn’t be medically acceptable to leave a hypertensive person uncontrolled, with a systolic blood pressure over 160, as this would increase the odds of stroke by 3.2x when compared to a normotensive. Yet, surprisingly these are the same odds of suffering retinal detachment for a low myope of -0.75 to -2.75D. But it doesn’t stop there, because the odds increase by a factor of three for myopes between -3.00 and -5.75D, and increase to 21.5x for those over -6.00D.
Now let’s compare this against the risk of developing microbial keratitis from contact lens wear. In the non-contact lens wearing population, the annual incidence of microbial keratitis is 0.014%. This increases to 0.02% for daily disposable soft, and 0.12% for daily wear silicone hydrogel. Wearing overnight increases the risk further to an annual incidence of 0.25% for silicone hydrogel, and 0.14% for orthok in children.
From this data we can consider contact lens wear as an avoidable risk factor, after all our patients could instead use glasses to correct their vision. This is the understandable stance of many ophthalmologists who often only see those who develop infection. However, in the presence of progressing myopia, based on current research data, the risk of using soft multifocals or orthok appears to be lower than not intervening to slow progression and the patient becoming a high myope in adulthood.
Overall this leads to some interesting comparisons:
- A paediatric daily disposable wearer who doesn’t progress past -3.00D is still three times more likely to suffer retinal detachment in their lifetime than microbial keratitis.
- A paediatric myope who progresses into the -3.00 to -6.00D bracket is equally likely to have a retinal detachment than to have a case of microbial keratitis from orthok wear in their lifetime.
- A -5.00D or over is nearly 4 times more likely to develop myopic maculopathy in their lifetime than microbial keratitis from a lifetime of orthok or daily wear of silicone hydrogel lenses.
It’s easy to see that if your paediatric myope is actively managed using contact lenses, and does not progress past -3.00D as a result, that their ocular health risks are dramatically reduced. I emphasise actively managed here as you can’t just fit these patients without giving them emergency contact numbers and information on what to do, and how quickly to act in the event of problem.
In my mind, the key here is to look beyond the immediate risks of contact lens wear to the lifetime management of the patient. Flitcroft makes the convincing argument that there is no ‘physiological’ (implying safe) level of myopia where no additional pathological risks are carried over the emmetrope. Yes, there are risks of developing microbial keratitis from contact lens wear, but when actively managed and the patient is advised accordingly, the currently available scientific evidence indicates that this risk is lower than allowing myopia to progress unchecked.