Cylinder, written CYL on your prescription, is the number that measures astigmatism. When that number is large, an optician calls it a high cylinder prescription and a patient usually calls it strong astigmatism, high astigmatism, or severe astigmatism. All four phrases describe one condition: a cornea shaped closer to a football than a sphere, bending light along two different meridians at once.
A large cylinder value changes how the lens has to be made. Practically all large lens manufacturers make stock lenses that go to ±6.00, very few go higher than that. You've probably noticed that yourself on your hunt to fill your prescription.
Nerdy Frames is a self service boutique optical. It's the quality and custom lens work from a storefront optical but from our lab so we control the quality of our product.
The maximum cylinder each retailer accepts, checked against their own order forms and published help pages in August 2026:
A stock lens is pre-made in standard powers and standard thickness. Ours are surfaced from scratch to the exact prescription, achieving the thinnest lens possible for your prescription, which helps your vision while looking aesthetically pleasing.
High cylinder orders come through our lab every month. In a typical month the strongest prescription we surface falls between ±5.00 and ±6.50 of cylinder. The strongest we have filled recently was a -8.50, made from scratch like every prescription from ±2.00 up. Our order form accepts to ±10.00; the fastest way to check us is to enter yours. Updated August 2026.
Your prescription includes a CYL value that indicates the degree of astigmatism. Here is a general reference:
The short answer is that your lens is custom made. We surface it from scratch, which means the lens begins as a blank puck of material and your prescription is cut into its curve on a lens generator, to your exact prescription.
Our competition uses stock lenses to complete your order. Stock lenses are easier to use because common prescriptions sell in volume. A high cylinder prescription is not common, and a stock lens isn't designed for the frame you're using nor the base curve it should have to maximize your vision. Almost all online retailers use stock lenses except for us. We make your lenses from scratch.
So there is a charge for creating your lenses, and it reflects the work done by an Optician. At a chain or a storefront optical, frames alone commonly start near $200 before a single lens is added, and high cylinder carries a surcharge on top of their already expensive lenses.
Custom digital lenses suit high cylinder prescriptions well, offering sharper vision. These lenses use digital surfacing to reduce the distortion known as the swim effect, the sensation that the room tilts or slides when you turn your head. Adaptation is achieved faster, even at high astigmatism corrections, and the periphery of the lens stays usable and clear.
With strong prescriptions, order the thinnest lens available to you. Higher index material bends light more efficiently, adding a premium coating also helps with clearer vision.
Frame choice doesn't really matter since the lenses are custom but a well fitting frame that centers your eyes is ideal. Feel free to use our virtual try-on or our at home try-on program.
A CYL value of ±2.00 or above is generally considered high cylinder. Up to ±1.00 is mild and suits polycarbonate. Between ±1.00 and ±2.00 is moderate and calls for polycarbonate or high index depending on the rest of the prescription. From ±2.00 upward the lens is custom made.
Yes. High cylinder, high astigmatism, strong astigmatism, and severe astigmatism all describe the same thing. Cylinder, written CYL on a prescription, is the number that measures astigmatism, so a large cylinder value and strong astigmatism are two ways of saying the same fact.
At Nerdy Frames, yes. Our range runs to ±10.00 of cylinder in single vision, anti-fatigue, and progressive lenses. Much of the online eyewear market stops around ±6.00, which is why a strong astigmatism prescription is often rejected at checkout elsewhere.
As of August 2026, checked against each retailer's order form: GlassesUSA stops at ±5.00. Zenni Optical, Payne Glasses, and EyeBuyDirect stop at ±6.00. Warby Parker accepts to ±10.00 using stock lenses. Nerdy Frames accepts to ±10.00 with lenses custom surfaced from scratch.
±10.00 of cylinder, in single vision, anti-fatigue, and progressive lenses, with sphere accepted from -20.00 to +20.00. Prescriptions from ±2.00 upward are custom made, and the upper end of the range is surfaced individually.
Because the lens is custom made rather than pulled from stock. Common prescriptions exist as pre-made stock lenses held in inventory. A high cylinder prescription does not, so the lens is surfaced from scratch, cut to your exact numbers one lens at a time. There is a charge for that work.
Custom made digital lenses, surfaced from scratch. Digital surfacing and behavioral AI reduce distortions such as the swim effect, giving wider and sharper vision zones and faster adaptation at high astigmatism corrections.
A strong prescription puts more material in the lens, and with astigmatism the thickness sits unevenly, heavier along one meridian than the other. Choosing the thinnest lens available reduces it, since higher index material bends light more efficiently and reaches the same power with less mass.
Unfortunately, we don't have any direct partnerships with vision insurance providers, but we can assist you in getting a reimbursement for your purchase after you have paid in full at the time of purchase. In order to be reimbursed, you will first need to fill out a form from your insurance provider. After you fill out their reimbursement form, you will need to provide an itemized receipt, which we can provide you with once you have completed your purchase. We've provided some links below of popular vision insurance providers to help you get started.
Please contact your vision insurance for more information on how to file for a reimbursement.
If you have any question or you need an itemized receipt, please email us at [email protected]
We accept both FSA and HSA payments, as long as they are in the form of a credit or debit card. After you have had completed a purchase with your FSA/HSA, you can then file for a reimbursement with your vision insurance provider.
