Bifocals and Progressives in XR

When designing or assessing solutions in XR, you need to ensure that people who wear corrective lenses are able to have a quality experience. This includes people who wear reading glasses, bifocals or progressive lenses.

Not all headsets on the market allow room for prescription glasses, so it is important to look at both the design of the experience AND the design of the physical headset. If the headset doesn’t allow room for glasses, the user may be losing either near or far sight — especially with Mixed Reality.

After extended use, people needing bifocals, reading glasses or progressives may experience eyestrain, headaches, and possibly migraines.

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Prescription lens inserts are not a viable solution

One of the first things people say when I mention needing glasses to see in a headset is that I could just wear contacts. People who wear contact lenses should be fine and that would be an ideal solution. However, keep in mind that not everyone is able to wear contact lenses for various reasons.

Custom prescription lenses are available, but they are costly for the individual and impractical for shared devices. Remember that those of us who need these prescription lenses also have to pay for our everyday eyeglasses.

Depending on the medical condition, many people need prescriptions updated more frequently than once a year. It’s not sustainable to have to buy new prescription lenses for each XR headset in addition to everyday glasses each time the prescription changes.

When you go to the eye doctor and get fitted for new lenses, the shape and size of your face, pupil distance, shape of the eyeglass frames, and more is taken into account when positioning the lenses in the glasses.

The importance of the lenses being properly positioned is even greater for those who wear bifocals and progressives, due to the custom placement of the multiple prescriptions being unique to each individual.

This means that optometrists and hardware vendors have to work together to get the appropriate positioning within the headset for each person — adding more complexity and longer wait times before they’re even able to use the headset for the first time. Hopefully they like the headset and don’t have to return it…

Until resolved, this issue will greatly impact hardware adoption rates.

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The difference in issues with VR and MR

With VR, users are focusing on a screen depicting a fully digital environment, but that screen is positioned in very close proximity to your eyes while simulating distance virtually. This could be an issue for people who need corrective lenses since the brain is trying to focus the eyes in a way that wouldn’t happen with real-life objects.

It gets even trickier when you get into AR and MR environments since users need to be able to switch their view between the content on the head-mounted display, which is close to the eyes simulating distance, and real-world objects that are at varied distances.

Depending on where the content is placed in relation to the location of the progressive or bifocal portions of lenses, the digital content may not be visible or legible at all. This re-emphasizes the need to avoid sticking UI elements to a HUD that moves when you move your head.

Scientists are working on lenses that will digitally adjust to the user’s prescription, but this technology is not available on the market yet.

So what do we do in the meantime?

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Hardware recommendations

• Evaluate the hardware to ensure a person can wear their own eyeglasses comfortably within the headset.
• Ensure the hardware does not cause a risk of damage to the eyeglasses while wearing, putting on, or taking off the headset.

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UI recommendations

• Avoid designing solutions that stick UI elements to a HUD that moves when you move your head since this is counterproductive to people who wear bifocals or progressives.
• Research the target user group to determine how this will affect their ability to use the solution.
• When launching a solution, have someone available who can work with individual users to ensure the optimal experience for their vision needs — including testing with and without their prescription glasses in the head-mounted display.
• Watch closely for signs of eyestrain or headaches within your user group. They will often say it’s fine, when they’re actually just trying not to inconvenience others.

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Areas of uncertainty

• Physical distance of headsets from people’s faces vary by the physical design of the technology.
• Lens types differ by headset.
• Pupil width adjustment limits vary by headset.
• People have different visual impairments and corrective lens needs, which will affect how their eyes focus and switch between content that is near and far.

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This will change as the technology advances

As mentioned in a previous article, these guidelines will change as the technology advances, resolutions increase, and the lenses are able to digitally correct depth of field and vision more effectively.

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Learn more

• Vision by Oculus
• Comfort Heads-Up Displays – Mixed Reality by Microsoft
• Apple Invention Details a Prescription Lens System for a Future Head-Mounted Display Device by Patently
• Apple Invents a Vision Correction System for Headsets that eliminates the need for a user to wear prescription glasses to enjoy MR Content by Patently

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I’m an Immersive Tech UX Design Professional with over 22 years of experience designing for kiosks, websites, mobile apps and desktop software for many well-known and not-so-well-known companies.

I’m not speaking on behalf of or representing any company. These are my personal thoughts, experiences and opinions.

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