Rudy Project Lightflow B Prescription Sunglasses | Extreme Eyewear
The Rudy Project Lightflow B RX combines understated style and lightweight performance with prescription-ready flexibility. Crafted using sustainable Rilsan® Clear a bio-based polymer this frame offers durability, lightness and a refined silhouette that suits everyday wear or active use. With a moderate lens size and classic shape, Lightflow B is ideal for those seeking a subtle but sporty look, comfortable enough for daily use while still suitable for outdoor activity.
Designed for comfort and adaptability, Lightflow B comes with adjustable anti-slip temple tips and rubber nose pads, ensuring a secure and stable fit whether you’re walking, cycling or commuting. The frame’s sculpted ventilation details and ergonomic design help reduce fogging and maintain comfort during extended wear.
Prescription Lens Options
At Extreme Eyewear, your Rudy Project Lightflow B can be custom-fitted with prescription lenses according to your needs:
Single-Vision Prescription Lenses - Lightflow B supports single-vision RX lenses, ideal for everyday vision correction.
Lens Material Options - You can choose polycarbonate lenses (impact-resistant and light) or Trivex lenses (premium clarity and lightness), depending on your prescription strength and visual needs.
UV Protection & Optical Quality - Lenses provide full UV protection. The frame and lenses together deliver clear vision and stable visual performance suitable for outdoor use and everyday wear.
Built for Comfort, Fit & Everyday Wear
Lightflow B offers a combination of practical comfort and refined design, making it suitable for daily use as much as for active outdoor use:
Lightweight comfort: At just 29g, Lightflow B is easy to wear all day.
Sustainable & durable frame material: Rilsan® Clear provides strength, flexibility, and a lighter environmental footprint.
Adjustable fit: Anti-slip temple tips and rubber nose pads ensure a secure, personalised fit.
Good for slimmer/average faces: The softer lines and moderate lens size make Lightflow B especially suitable for smaller to medium face shapes.
Why Choose Extreme Eyewear?
Official UK retailer of Rudy Project prescription eyewear
Custom RX lens fitting (single-vision), with choice of polycarbonate or Trivex materials
Expert support and guidance from our UK-based optical specialists
Quality frame material and build with sustainable Rilsan® polymer
Comfortable, lightweight frame suitable for everyday use and outdoor wear
Perfect For:
Users needing prescription sunglasses with a discreet, versatile frame
People looking for lightweight, comfortable eyewear suitable for daily wear or light outdoor use
Riders, cyclists or commuters wanting prescription lenses with UV protection and durable frame
Those who prefer a more classic sunglasses look rather than aggressive sporty or wrap-around designs
Rudy Project Prescription sunglasses – 3 to 4 weeks
Uvex Prescription sunglasses – 2 to 3 weeks
Serengeti Prescription Sunglasses – 2 to 3 weeks
Oakley Prescription Sunglasses fitted with Digital custom lenses – 3 to 4 weeks
* If you have a required by date in mind during checkout please leave a note in the ‘comments’ box to advise your date and we will pass it onto the manufacturer. If your date is before the lead times we can’t promise the sunglasses will be delivered in this timescale however the brands will aim to hit your dates.
Prescription Help Understanding your prescription
Your prescription is split into three sections, Sphere, Cylinder and Axis. You will most commonly see this written as, Sph, Cyl and Axis.
There are simple rules for each part of the prescription
Sphere – Is always a number in 0.25 jumps (i.e. 0.25, 0.50, 0.75, 1.00, 1.25). This can either be written in minus or plus (- or +).
IMPORTANT: You must select the correct symbol when ordering (minus or plus, – or +) as selecting the wrong sign will create the completely wrong prescription required to correct your vision.
Cyl – Is always a number in 0.25 jumps (i.e. 0.25, 0.50, 0.75, 1.00, 1.25). This can either be written in minus or plus.
IMPORTANT: You must select the correct symbol when ordering (minus or plus, – or +) as selecting the wrong sign will create the completely wrong prescription required to correct your vision.
Axis – Is a number between 0 and 180, it can also be written to point five (0.5) of a degree. This simply happens if the optometrist can’t decide wether you prefer for example 79 or 80 so they simply write your axis as 79.5. In this case lets get your glasses as accurate as possible so please provide us with the 79.5.
The in instances when a prescription doesn’t have a value for the Cyl section please leave the Axis blank (or some opticians write this as 0.00), the Axis is indicating what degree the Cyl figure sits at so if there is no Cyl there is no Axis required.
Other symbols which are often seen written in a glasses prescription
Infinity Symbol ∞ – this is another way of writing zero (no prescription) so simply select 0.00 into the corresponding section for either sphere or cyl.
Plano – this is another way of writing zero (no prescription) so simply select 0.00 into the corresponding section for either sphere or cyl.
Varifocals - What is the Add (Addition) part of my prescription?
You typically start to get the add part to a prescription when you hit 40+ and it is a measure of the amount of magnification you require to read.
The add is a plus (+) power which identifies how much extra addition (magnification) a glasses wearer requires (on top of their distance prescription) in order to read comfortably at close up distances, such as reading.
NOTE: Sometimes an optician will write your prescription for reading as a full prescription rather than simply supplying your reading add.
Example:
Distance
Right: -2.50 / -0.50 x 180
Left: -2.00 / -0.75 x 175
Near
Right: -1.00 / -0.50 x 180
Left: -0.50 / -0.75 x 175
Reading Add = +1.50
In this case to get your reading add take your distance Prescription Sphere off your reading Shere. The difference between the two figures is your reading add used for Varifocals.
Pupil DistanceLet our Dispensing Optician Measure your Pupil Distance accurately
For the Pupil Distance options on the ordering pages select 'Let Extreme eyewear measure your PD' and we'll post you our specially designed glasses.
(Note: On some projects the PD option will state 'send ruler' this option will still get you the new PD Measuring Glasses)
All you have to do is take a simple photo of you wearing our glasses and emailing your photo to us.
Our Dispensing Optician will then accurately take your mono pupil distances. Our PD glasses allows our dispensing opticians to gain all the details they need to set up single vision and varifocal sunglasses / eyewear accurately.
Let us supply you with perfect vision.
This service is free for all prescription eyewear orders.
What is your PD?
Your Pupil Distance is the measurement between the centre of your right and left pupils in mm.
How can you find out your Pupil Distance?
You may be lucky enough to have been given this by your optician
You can select to have our Pupil Distance measuring glasses posted to you. These will leave us on the same day you place an order 1st class post.
Why have we gone to the trouble of supplying PD Glasses?
Prescription glasses and sunglasses always work better when the centre of the optical lens is over your pupil. Not having this set up correctly can cause head aches and limit how well the glasses will work.
Varifocal Wearers
If you don't know your Mono Pupil Distances (this is two separate measurements for your right and left pupils) we strongly advise you select to have our PD Glasses posted to you. Varifocals with out mono pupil distances will not work correctly.
If you know your Mono Pupil Distances during the checkout there is a comment box, please write your right and left mono pupil distances in this comment box.
Examples
A pupil distance of 65 may have mono pupil distances of
Right 33
Left 32
Your total PD is still the same (65) But by using the separate mono pupil distances the centre of the varifocals will be positioned over your pupils making sure the clear corridor leading to your reading is in the correct position.
How do I receive PD Measuring Glasses?
In the PD options select ‘Let Extreme eyewear measure your PD’. The Digital ruler will be posted out on the same day as your order is placed to your shipping address supplied. (If your order comes in after 4.00pm the ruler will leave us the next day).
Abroad Orders
We will post the PD Measuring Glasses abroad but please allow a little more time to complete your order. The PD measuring glasses may take up to a week to get to abroad addresses.
Reviews
I messed up and they still put it right...
Great service from the guys at extreme Eyewear. I goofed up and ordered the wrong thing. What I wanted was something they did not even sell. But, this was no problem. They ordered in what I wanted and sent it out with a postage bag to send back the wrong product. I messed up and they still put it right. Highly recommended.
Marcus Miller - Google Review
Nothing is too much trouble...
Excellent service. Got a pair of Oakley prescription glasses with Oakley varifocal lenses which I couldn't get from any local opticians . Struggled to get Oakley lenses anywhere to be honest. Two week delivery time turned out to be less than a week and included May bank holiday. Nothing is too much trouble for these guys. Glasses are spot on and you won't find the bloke next to you wearing the same!
