Ortho-K Lenses Not Working?

If you or your child is wearing Ortho-K sleep contacts and they aren't working as well as expected, perhaps we can help.

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​Fitting Ortho-K lenses is much more complex than regular contact lenses and requires a high level of professional skill, expertise and technology to get right. At this practice I have seen some patients with Ortho-K lenses fitted by other practitioners who may not have the best equipment or knowledge, resulting in sub-optimal vision and unhappy experiences.

​Below is an example of a 9 year old girl (-4.00 short-sighted) who was fitted with Ortho-K lenses by another Melbourne practice. She had never been satisfied with her vision from her lenses, experiences a large drop in vision from morning to evening, and despite her previous optometrist trying 4 different sets of lenses from 3 lens manufacturers she was unable to achieve 20/20 vision, hindering her vision at school. So her mum decided to seek a second opinion.

The right side images show the effect of well-centred lenses and defined treatment zones for good Ortho-K outcome. Left images show poorly fitted and de-centred Ortho-K lenses.

At her first visit to this practice I measured her eye surface topography and it was quite obvious that her Ortho-K lenses were not fitting her eyes properly, hence the poor visual outcome and short treatment holding time during the day. Her treated vision was 20/40, that's 3 lines worse than 20/20 vision on the letter chart. Her lenses were unstable and de-centred on her eyes (especially the left eye) as she slept with her lenses on at night.

​Lens centration and treatment zone centration are key to achieving good results with Ortho-K. A well-centred Ortho-K lens places even pressure and forces across the eye surface for optimum moulding effect — essential for good vision and myopia control.

I asked her to discontinue her lens wear for one week, by which time her cornea (the front surface of the eye) had completely reversed to its normal, non-treated shape. I then designed a new set of Ortho-K lenses for her using our advanced corneal topography technology and lens design software. This more sophisticated lens design approach allows me to create fully-customised lenses to suit all individual eye shapes and prescriptions. Having full control of every parameter of the lens shape, curvature and size means better fitting lenses and vision outcomes than older, trial lens-based Ortho-K fitting systems that some optometrists use.

Within 2 weeks the new Ortho-K lenses were presented to her. At her first review, after one night of wear, she was already seeing better than her previous troublesome lenses, and one week later (when the above right-side topography maps were taken) she was achieving 20/20 vision and much happier with her vision at school. It is expected that the quality of her vision will improve further still as she wears her Ortho-K lenses into her second and third weeks and the corneal moulding and treatment zone areas stabilise.

So a very happy patient and mum and well worth the visit to see us!
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Dr Philip Cheng — Melbourne Optometrist & Orthokeratologist
Member of the Orthokeratology Society of Oceania (OSO)