Prescription Lens Inserts vs Diopter Adjustment: Which is Better?
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Time to read 6 min
Seeing the Future Clearly AR Glasses for Nearsighted Users
Imagine this: You've made the leap into AR gaming by picking up some awesome AR glasses to pair with your trusty Steam Deck, but you're a little worried about the possibility of straining or hurting your eyes (especially if you already wear regular prescription glasses).
Well, you're not alone. Considering that about 40% of the population requires some form of vision correction, AR and XR companies are painfully aware of the potential that their groundbreaking visual tech might have on their everyday users. Given the size, shape and form-factor of these AR and XR devices, companies creating in this field have developed two major solutions to make this technology accessible for nearsighted users.
Table of content
The Two Most Common Solutions
1. Solution 1 Prescription Lens Inserts
One solution is prescription lens inserts, with brands like XREAL having embraced this method from the very beginning. Here’s how it works:
Just like regular prescription glasses, these inserts are customized based on an eye exam conducted by an optometrist. This ensures that the lenses match your needs, whether you have myopia, astigmatism or any other conditions. Once your lens inserts have been professionally customized to fit your exact prescription, you simply insert them into the AR glasses, as demonstrated in this video:
2. Solution 2 Diopter Adjustment
The other most common method is a diopter adjustment built into the glasses. This involves adjusting the optical module's position to bring virtual screen closer to your eyes. By turning the knobs, you can change the distance of the screen until it becomes both clear and comfortable.
A built-in diopter adjuster may sound like a no-brainer, especially for folks with nearsightedness. It's simple, convenient, and supposedly cost-effective. However, it's not as popular as people would assume. Built-in dials are noticeably absent from bigger name devices like Apple's Vision Pro and Meta's Quest line of headsets. With this in mind, let's take a closer look at the pros and cons of both:
5 Key Aspects to Consider
1. Effectiveness
Users will undoubtedly question the efficacy of these vision correction solutions, considering how the experience might change and if these solutions can ensure a clear, crisp screen.
Prescription Lens Inserts：
Myopia Correction：⭐⭐⭐⭐⭐
After having an eye exam, your custom lenses will be tailored based on what needs to be corrected - myopia, astigmatism, etc. This precision fit means your AR gaming adventures will be clear and crisp every time you put the AR glasses on.
Lens inserts can generally accommodate for a wide range of prescriptions, varying by optician, often supporting up to -10.00 diopter.
Astigmatism Support：⭐⭐⭐⭐
Astigmatism is also effectively corrected with prescription lens.
Anisometropia AKA "Different prescriptions in each eye"：⭐⭐⭐⭐⭐
If you have a different prescription in each eye, this is refered to as "Anisometropia". This can be quite common, so there's no need to worry. Once tested and the issues have been identified, optometrists will scientifically adjust the degree the lenses for both eyes to ensure a seamless visual experience. This precise balance guarantees that your vision correction is consistent, delivering the best possible fit and clarity for your AR adventures.
Diopter Adjustment：
Myopia Correction:⭐⭐⭐
Less precise.
Picture this: you're lounging on your couch, ready to embark on an augmented reality adventure, and you grab your trusty AR glasses. You set the diopter adjustment to what "feels" right— At first, the virtual landscapes seem sharp, but you may have gone slightly over and adjusted to -2.50 when your actual prescription is -2.25.
Just because your screen feels crisp doesn't mean your lenses are set to the correct level. Over time, this slight difference could cause your eyes to actually worsen.
Now imagine sharing your AR glasses with friends; they adjust the diopter for their vision and hand it back, leaving you to fiddle with the dials again. These constant tweaks, if off the mark, risk straining your eyes and possibly worsening your vision.
Limitations of Diopter Adjustment
An important limitation is the degree range. The maximum diopter adjustment typically supports up to -5.00. This means users with severe myopia have been left out.
Astigmatism Support ：⭐
There is no Astigmatism Support.
Anisometropia AKA "Different prescriptions in each eye" ：⭐⭐
Since the two eyes adjust independently, it's easy for one eye to achieve a corrected vision of 20/20 while the other remains at 20/25, resulting in an imbalance between the two. This imbalance is tough to spot with the naked eye in the short term, but prolonged wear with mismatched degrees can lead to a defocused state, damaging the users' vision further.
2. Real World and Virtual Screen Clarity
Prescription Lens Inserts：
Real World Clarity：⭐⭐⭐⭐⭐
Virtual Screen Clarity：⭐⭐⭐⭐⭐
Excellent. You see the real world as clearly as if you were wearing regular glasses. If you're using AR glasses with a map app for navigation, you can seamlessly toggle between the augmented navigation display and the real-world view, both being crystal clear.
Diopter Adjustment：
Real World Clarity：⭐
Virtual Screen Clarity：⭐⭐⭐⭐
Through diopter adjustment, the virtual screen has effectively been moved closer to the eyes, allowing users to perceive the screen content clearly. However, this adjustment doesn't apply to the real world, rendering the glasses useless for when your attention is being pulled away from the virtual screen, even just for a moment - such as multitasking, or reaching for a drink or a snack while the glasses are on.
3. Field of View
Prescription Lens Inserts：
Field of View：⭐⭐⭐⭐⭐
These provide a full field of view, same as what a person with regular vision would see.
Diopter Adjustment
Field of View：⭐⭐⭐
With the diopter adjustment function, it's akin to zooming in on a single object at the expense of the overall view—everything becomes sharper, but your field of view is compromised. It's like physically dragging a TV closer for clarity; the closer, or in this case, the higher the adjustment, the narrower your vision.
4. Comfort Level
Prescription Lens Inserts：
Getting Started ：⭐⭐
Initial setup requires professional fitting for long-term comfort. This may be somewhat inconvenient in the beginning, but it's an important investment.
Motion Sickness：⭐⭐⭐⭐
Very effective at keeping you free from motion sickness, as the lenses are accurately matched to your prescription
Fatigue：⭐⭐⭐⭐⭐
Offers a comfortable experience for extended use as the lenses are quite literally made for your exact needs.
Diopter Adjustment：
Getting Started ：⭐⭐⭐⭐⭐
Incredibly convenient from the start, allowing for hands-on adjustment straight out of the box.
Motion sickness：⭐⭐
Less effective, inaccurate adjustments can potentially cause motion sickness, especially when playing gmaes with a high refresh rate.
Fatigue：⭐⭐⭐
Manual diopter adjustment are appealing due to their more user-friendly design, but inaccuracies in manual adjustments might leave your eyes sore, fatigued and even potentially damaged after hours of use.
5. Comfort over Extended Use
Here we need to introduce 3 concepts for measuring comfort:
Virtual Image Distance (VID)
The Virtual Image Distance (VID) is the space between the virtual image presented by AR glasses and the user's eye, typically measured per eye. When this distance is too short, the eye becomes tense, leading to fatigue over prolonged use. To mitigate this, the industry usually maintains the VID at over 1 meter; for instance, Apple's Vision Pro employs a distance of 1.1m, Meta Quest 3 sits at 1.25m, and Hololens boasts 2m. These distances are calibrated to ensure a comfortable augmented reality experience, preventing excessive eye strain.
Convergence Distance
Convergence Distance is the measurement from the point where the images for each eye converge to the eyes when wearing AR glasses.
Vergence-accommodation Conflict (VAC)
Vergence-accommodation conflict (VAC) refers to the mismatch between the VID and the binocular convergence distance. The smaller VAC, the more comfortable over extended use .
Why industry standard comfort level for VAC is set at 0.3D ？
Therefore, while diopter adjustment offers quick convenience at first, Prescription Lens Inserts provide superior comfort over prolonged use.
Conclusion
While diopter adjustment offers a quick and convenient solution for those with nearsightness, it falls short in several critical areas. Prescription lens inserts, though requiring an initial investment of time and money, provide a far superior experience in terms of clarity, comfort, and overall eye health. If you're serious about integrating AR into your daily life while requiring vision correction, it's recommended to invest in your experience and your health with prescription lens inserts.
For more insights into the best AR glasses for nearsighted users and how vision and AR technology are converging, stay tuned to our blog. Your eyes—and your future in AR—will thank you.
