by Jamie Bartlett July 21, 2021 6 min read
Single vision lenses? Easy peasy.
Varifocals? A little more tricky.
“If only I had a less complicated prescription…”
But fret not, because I’ve put together 4 helpful tips which should hopefully make buying varifocals online much much easier. Here's a quick overview.
The key to ordering varifocals online is accurately communicating two vital details; Your ocular centre height and your dual pupillary distance. With these, your resultant lenses are likely to be more accurate, reducing the chances of misalignment.
Ok, but what exactly is your ocular centre and how do you find it? And what is your pupillary distance when it’s at home?
Using the links below, you can;
First up, let’s talk about your optical centres.
In simple terms, this is where your pupils are located, directly behind each of the lenses of your new glasses.
Knowing where your pupils are behind your lenses means they can be aligned to give you the truest and most accurate vision. These positions are measured vertically and horizontally, similar to longitude and latitude.
Your optical centres are the most crucial detail for ordering any kind of glasses online, especially varifocals. This is because progressive lenses are more intricate, containing multifocal lens powers.
Because of this intricacy, varifocal lenses are more sensitive to their positioning over your eyes. Your unique facial structure and how your frame fits you needs to be taken into account to make your lenses as accurate as possible.
In other words, when glasses rest on your nose and ears, their positioning is unique to you.
Oh yea, and different glasses have different sizes of lenses, frame shape and temple thicknesses which all affect how they fit you.
To asses where your optical centres are, you need two measurements.
Your ocular height (OC or OCH) determines the vertical height between your pupil and lowermost part of your lens.
In order to find your OC height, the best method is to have the glasses on your face. Yep, you need to try them on before you order your lenses.
The internet can only go so far.
At Banton Frameworks, this is how we know how your glasses fit you, without having to book an appointment with you in your living room…
Instead, we very simply recommend marking where your pupils are on the demonstration lenses (demos) fitted in your new glasses frame. Here’s how;
On your own
OC height tips
We use this method to make your lenses as accurate as possible. For the extra time, this method will prevent any vertical misalignment of your pupils behind your lenses.
According to a recent article by “Which?” many online retailers rarely consider ocular centres for their varifocal customers.
Unsure how varifocals actually work?
Check out this article which explains the workings of progressive lenses.
This refers to the horizontal position of your pupils behind your lenses.
Dual PD accounts for the distance from the centre of your nose to the centre of each of your pupils in each eye. As a varifocal wearer, it’s vital you measure both PD's for both eyes.
The trouble is, your dual pupillary distances might be missing from your prescription paper. Which is super annoying, because it’s vital for ordering varifocal glasses online.
You’d think opticians did it on purpose or something…
No big deal though, you can measure it yourself with our free printable PD ruler below.
Printed to scale, it’s got a slot for your nose and a mirror-friendly ruler for each of your eyes. The slot mimics how your glasses rest on your face and also keeps the ruler steady as your read your measurement.
Is your Dual PD missing from your prescription?
Give this PD ruler a go.
Download this free PD ruler.
In case you didn't know, there are three main vision "zones."
Depending on what you use your glasses for, varifocal lenses can assist you with any or all three of these vision zones.
Based on your glasses purpose, your can choose from two main types of varifocal lens described as Everyday Varifocals or Occupational Varifocals.
Which type suits you best?
One last tip.
Before you order your new varifocals, it’s worth mentioning your prescription details.
In order to get the most out of your new glasses, you should try to implement an up to date prescription from at least within the last 12 months.
As a varifocal wearer, your eyes are more likely to change since your last eye examination. Varifocal wearers usually undertake more frequent optical analysis at least once every year so it’s important to keep that in mind if you’re buying varifocal glasses.
You can order your varifocal glasses following the steps above.
Combined with a recent prescription paper, these simple steps can alleviate the chances of poorly aligned lenses, eye strain or dysfunctional new glasses you don't enjoy wearing.
Hopefully, you’ve found this article useful and you feel more comfortable knowing what to do when ordering your new pair of varifocal glasses.
If you have any questions about the topics written in this article, please feel free to get in touch with me here.
Thanks for reading.
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