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The importance of accurate K readings

In the last post I gave you a taster of the new SynergEyes iD lens and the exciting early results. This time I hope to explain the importance of accurate measurements and a bit about how it works, especially the EDOF technology in the multifocal option.

SynergEyes iD hybrid lenses are Individually Designed to each patient’s unique ocular measurements utilising keratometry, horizontal visible iris diameter (HVID) readings and spectacle refraction, to personalise precise lens parameters – so these must be accurate!

Accurate K readings are essential because the back optic zone of the GP centre is manufactured to accuracy levels of 0.01mm – calibration on a regular basis is key here.
What about fitting the skirt? This lens has twelve linear skirts so accuracy is the key to patient comfort and a great fit.

Getting the HVID correct to 0.1mm can prove difficult without the use of equipment like a topographer however using a simple ruler, like the SynergEyes one pictured, held over the patient’s eye and photographed using a smart phone can be a simple, cost effective and accurate method. Order a SynergEyes ruler here.

Once we have those crucial measurements, we can get the fit of the lens designed exclusively for that patient’s eye, all we need now is the prescription to calculate the power of the lens.


The new SynergEyes iD lenses are available in single vision and multifocal, powered by the proprietary Extended Depth of Focus (EDOF) design from the Brien Holden Vision Institute (BHVI). With proven multifocal optics providing patients with a clear visual experience that transitions smoothly through all distances.

Higher order aberrations create a continuously varying power profile that is non-monotonic (varying power profile) and aperiodic (i.e. no discrete zones).
This results in:

  • Elongated focal point i.e. extended focus instead of a distinct focus (e.g. single vision) or foci (e.g. bifocals)
  • More robust for pupil changes, aberrations and decentration

If you are keen to get started with these innovative lenses, that are not available on the internet, contact us on support@positiveimpact.co.uk

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