Are today’s Head-Mounted Displays (HMDs) for low vision more hype than sight?

I expect that you’ll think that as a manufacturer of optical bioptic telescopes writing about Head- Mounted Displays (HMDs), I’m just carping on what might be considered our competition.

But, in reality HMDs are not yet compelling competition to optical bioptics. And that’s not just my opinion (as a clinician providing low vision care for 40+ years), but also that of most experts in the field. That’s not to say that head-mounted digital displays for low vision won’t someday offer vision rehab opportunities. They likely will. There are, after all, limits to what conventional optics can do. It’s just that they’re not there yet. And it’s due largely to the limits of the technology currently available to HMD manufacturers.

So then why all the hoopla? Marketing. HMD manufacturers have great emotive testimonials: they can make the blind see; he could see her eyes for the first time in years; she can read, play piano, play cards; they can do things they never thought they’d be able to do again! But one cannot ignore the social acceptability issues of a device that hides the user’s eyes—both for the user, for their companions, and for the general public they may encounter. Since distance vision is a social sense, users seek, among other goals, to make eye contact, read body language, and feel socially connected. Devices as socially disruptive as present HMDs will certainly undermine this interactive functional goal.

HMD manufacturers claim that they are registered with the FDA. Registered is not the same as approved by the FDA. Fill out the form, pay your money and your device can be registered too! It’s false credibility. Every manufacturer of any type of medical device is required by law to be registered with the FDA. The FDA is firm in its position that registering a product with the agency does not confer the FDA’s approval nor prove its efficacy. What confers efficacy? Independent clinical trials, not testimonials or marketing.

Of course, new can be appealing and exciting. But new isn’t automatically better just because it’s new. New is better when it’s clinically proven and well received by the patient. Tried and true as optical bioptics are, they may not be as exciting as HMDs, but you won’t hear that from long-term users. Bioptics users will tell you that their devices have changed their lives. Ocutech’s prescription return rate is less than 0.1%, instead, we receive products to be cleaned and refurbished almost daily. That’s because they are used. Many are returned to have the carrier lens prescriptions updated. Patients wouldn’t bother spending the money if their bioptics weren’t helpful.

What questions should we be asking? Which patients might benefit from HMDs? Which diagnoses might respond best? What range of visual acuities are most appropriate? What

display settings are most helpful? While the HMDs are capable of very high magnification, what is the highest magnification that a user can tolerate? It’s usually no higher than 6 or 7x. So, what’s the benefit of claiming higher powers? What is the abandonment rate? HMD manufacturers don’t answer any of these questions.

Why do most HMDs completely surround the user’s eyes? It’s because the display isn’t bright enough to be visible outdoors without enclosing the user’s eyes. Try looking at the screen on your phone or your digital camera outdoors. Can’t see it, can you? HMDs have a similar problem.

What is the breadth of functionality of HMDs? Can users drive with HMDs? No. Can users walk with HMDs? Only if they are lifted out of the way or have their magnification readjusted to zero. So, where’s the benefit then? Can users wear them all day? No, they only run for a few hours. Are they comfortable to wear? No, they’re much heavy than optical bioptics, and you may perspire underneath them. Are they easy to use? They’re supposed to get easier over time, but there are controls to learn to use.

What about optical bioptics? Lightweight, great outside, drive with them (where legal and appropriate), walk with them, and socialize with them. They don’t enclose the user. They are indicated for central vision loss with best-corrected acuities of 20/300 or better. The clinical data and methods are well established. And, they’re easy to use—all you do is look. Do they work for everybody? Nothing works for everybody. They’ve been around a long time, haven’t they? What’s wrong with that? It means they work and are well accepted. Low vision specialists prescribe them all the time. They wouldn’t continue to do that if their patients weren’t successful with them.

HMDs were not originally designed for the visually impaired. They were intended for gamers and tech folks, a much larger market. Their image resolution is not high and worsens as the image is magnified. HMD manufacturers claim very wide fields of view—40 degrees, 60 degrees, even more. If it’s 40 degrees at 1x, it’s only 10 degrees at 4x. By comparison a 4x Keplerian optical telescope provides 12.5 degrees– arguably not much wider, but not narrower, as HMD manufacturers imply. So, one must be careful to interpret the technical specifications HMD manufacturer’s present in terms of how it relates to our clinical purposes.

Another salient point is that HMD firms frequently use salespersons to demonstrate and sell their products directly to the consumer. No matter how sympathetic, supportive, and engaged these reps are, they are pursuing a one-time sale, not a long-term relationship. As such, they have little or no investment in the customer after the sale is made. They are not eye care professionals who provide ongoing care for their patients and as a result are personally invested in their patient’s long-term support and the appropriateness of the devices they recommend.

Will Ocutech develop a digital bioptic? We have been studying and testing digital technology for over 10 years. We have expert consultants to help guide us. At this time, we feel strongly that digital HMD technology is not yet appropriate for a compelling low vision aid, and we will not produce a device and place it on the market until it can be proven effective in independent clinical trials. Starting too soon and investing a lot of money puts pressure on firms to place a product on the market before it’s ready. Ocutech is committed to developing products that offer tangible benefits and improvements to the low vision community.