WHAT EXACTLY IS FIELD PERSONALISATION?
Personalisation involves adapting/designing fields to suit a patient's lifestyle or preferences. It is by no means a "magic wand" to produce better lenses.
It's important to remember that adjusting one area of the lens mapping will have an impact on the other fields. It doesn't matter which lens brand you favour, when adapting visual fields to suit patient lifestyle there is always a compromise to be made.
Let's look at it this way: If I want the best possible vision for any particular distance then I will choose single-vision lenses every time. If I want vision across multiple distances then I require a vari-focal and that, unfortunately, requires a level of compromise as there will be a degree of lateral astigmatism to accommodate.
- Personalisation achieves a slight adjustment of the visual fields (i.e. a redistribution of the lateral astigmatism) with the objective of providing greater comfort and breadth-of-vision where the patient feels he/she needs it. However, an improvement in one area will result in a reduction elsewhere.
WHEN IS FIELD PERSONALISATION VALID?
Contrary to what some over-zealous sales reps may claim, personalisation is NOT an exact science by any means. The theory of adapting field placement to better suit a patient's individual needs is undoubtedly sound; however, ascertaining exactly where to enhance vision and by how much is far from straightforward. This is because it is the patient him/herself who is providing the anecdotal feedback.
And remember, as we've already established - when one visual area is enhanced there is ALWAYS a compromise to be made.
So when is personalisation valid?
Let's take a patient who does a large amount of driving but very little reading. In this scenario it would make sense to accentuate vision in the distance at the expense of the near (or "reading") area. And the liklihood is that the patient will instantly appreciate the greater breadth of long-range vision whilst hardly noticing the more confined area for 'up close' focus.
In another example, let's consider a patient who spends the vast majority of time indoors with just the occasional walk to the local shopping parade. This patient likes to do the daily crossword, and enjoys reading books, playing cards and watching TV. In this scenario it would make sense to accenuate vision in the near ("reading") area at the expense of the distance area whilst retaining full "intermediate" for television viewing. And the liklihood is that the patient will not miss the slight loss of distance panorama but will appreciate the wider reading area.
Both these examples would appear to justify a significant degree of personalisation. However, the best design software technicians understand that with field personalisation a little goes a long way, and should NOT be too drastic but should rather result in subtle field adjustment (usually only a few percentiles). So, just to reiterate, the quality of the software is vital.
PROBLEMS WITH PERSONALISATION
Whilst the examples above support the argument for personalisation, there are many examples where personalsiation can prove problematic.
The first thing to consider is PATIENT EXPECTATION.
After all, what patients want is simple: MAXIMUM distance, MAXIMUM intermediate, MAXIMUM reading.
Whilst many patients might like the idea of an improved reading area, will they be happy when they put on their new glasses and realise that the distance is slightly reduced from their previous pair? Invariably the answer is a definitive "no".
And the reality is that most patients (our trials show between 80% and 85%) use the full range of distances extensively. They spend time both outdoors and indoors; they watch TV, socialise, cook, clean, tidy; they go to the cimema, concerts, events; they do sports, play games; they have hobbies; they use computers, mobile phones, kindles etc.
Our honest opinion is that the majority of patients will receive the ideal "user experience" from a carefully optimised design that has been EVENLY (intelligently and intuitively) balanced to provide the maximum BREADTH and COMFORT of vision throughout EVERY STAGE of the prescription: DISTANCE, INTERMEDIATE, NEAR and UP CLOSE.
What we then recommend (if the Eye Care Professional wishes to incorporate a well-structured Patient Profile) is the extremely subtle adjustment of field parameters to very slightly favour the most used zones.
Going too far with personalisation will result in adaptation issues, hence the problems many practitioners experience with even the most expensive lenses.
VERDICT ON PERSONALISATION
Personalisation is by no means a revolutionary leap forward guaranteed to deliver "better" vision to the patient. Nor is it the "emperor's new clothes" of optics, as some have claimed.
The truth, as ever, lies somewhere in between. Personalisation has its place, provided the technology is suitably intuitive and applied conservatively.
The most beneficial aspect of freeform technology is not personalisation - it's the enhanced precision of freeform generation that, with the BEST design software, can significantly improve patient acuity, comfort and depth/colour perception.
OPTIK MIZEN AND PERSONALISATION
At OPTIK MIZEN we would recommend completing the Patient Profile when ordering any lens from our ELITE SERIES as this enables us to understand the patient's individual needs.
With EQUINOX HD and SOPHOS HD we will - only where appropriate - provide very subtle adjustment of the field parameters to deliver just the right amount of benefit without any meaningful (i.e. perceptible) compromise.
And with LIFE SYNCHRONICITY and MATRIX ASSIMILATE we can potentially use the Patient Profile to apply a more significant level of adjustment in accordance with the patient's informed choice/preference.
We also have proven optimised designs for specific use such as our "driving" design (AUTOBAHN) and our "sports" design (LE SPORTIF).
So, to summarise:
- EQUINOX HD and SOPHOS HD are intuitively balanced to provide exceptional optics. Very subtle field adjustment will be applied when the Patient Profile is completed.
- Dispensing of LIFE SYNCHRONICITY or one of our SPECIFIC USE series can be very beneficial in cases where the patient particularly favours one or two visual fields over the others.
As always, please don't hesitate to contact us if you have any questions about how we use our technologies to deliver more natural vision to your patients.