Why, When and How to Prescribe the Ocutech Falcon Autofocus Bioptic

femaile doctor talking with patient

Patti Fuhr, OD, PhD, FAAO
Chief, Advanced Low Vision Section, Hefner VA Healthcare System, Salisbury, NC
Henry Greene, OD, FAAO
Co-founder, President, Ocutech, Inc., Professor and Director (retired), Low Vision Service, UNC Department of Ophthalmology, Chapel Hill, NC

WHY?

Distance vision supports both our social and environmental engagement. We use it to make eye contact, read body language, and feel connected to the world around us. Distance vision helps us to derive information from our surroundings—to read signs, see signals, recognize faces and see environmental features that support independent travel. Lack of distance vision has been associated with an increased academic challenge in children, fewer vocational opportunities for working-age adults, as well as feelings of isolation leading to depression and cognitive decline in seniors.

Persons who lack central vision, generally have ample peripheral vision to avoid obstacles, enabling them to move about safely. But they lack sufficient central visual clarity to resolve details—hampering their ability to derive meaningful cues from their environment. Reduced central vision not only impacts distance seeing, but also near and midrange activities. Seeing store signs while shopping; reading labels, bills, menus, books, and newspapers; preparing medications; using the computer; performing tabletop activities at home, school and work; watching TV, and engaging in social activities all require adequate central vision resolution.

We are all creatures of habit—we tend to want to do things the way we always have.  We have muscle memory for the distances at which we normally engage in those activities.  For those born with reduced central vision, holding things close or viewing with the preferred remaining part of their retina (eccentric viewing) develops naturally over the years and becomes the individual’s habitual behavior.  But for those who enjoyed normal vision for most of their lives, adaptation to a different way of seeing can be challenging. Using sight enhancement devices, needing closer than normal working distances, or experiencing the constraints of the narrower fields of view and shallower depths of field of low vision devices can all be burdensome.

Eyecare providers organize our visual world into 3 “activity ranges”—distance (~6 feet {2 m} or beyond); midrange (~1.5-6 feet {50 cm to 2 m}); and near (~1.5 feet {50 cm}or closer).  Each range is likely to involve different types of visual engagement.  For example, we travel using distance vision; we use computers, shop, cook, eat, and play tabletop games at midrange; we read and write at near distances. And, we will often integrate several different ranges continuously such as in the classroom, at work, while shopping and even at home.

The goal in developing sight enhancing technology is to best support the user’s visual activity needs while interfering the least with their normal, habitual behavior. The more natural the device’s functioning, and the less the user needs to engage with the device, the more effective and efficient the user will be.

Ocutech’s new Falcon Autofocus bioptic has been designed to address the challenges inherent in conventional telescopic vision enhancing devices. Bioptics are miniature telescopes usually mounted toward the top of the eyeglass frame so as to not interfere with the user’s regular line of sight. This allows the user to conveniently switch their view between the regular eyeglass lens (carrier) and the telescopic view with just a slight downward head tilt. Bioptics are a convenient way to magnify objects at normal working distances. They are most frequently prescribed to support distance and midrange visual activities for individuals with best-corrected visual acuity in the 20/70 to 20/300 range.

Bioptic telescopes need to be refocused when the user looks at different distances, requiring the user to continually manipulate the device. This is especially relevant with the shallower depths of field encountered at closer distances and with higher magnification power devices. The benefit of the Falcon Autofocus is that the image is in focus immediately at virtually any distance. No manipulation of the device is required. All the user has to do is look at the object of interest, making the Falcon’s user experience as close as possible to natural vision. And, as an additional benefit, as the user moves closer to an object, the image size will increase clearly and seamlessly, providing a helpful zoom effect.

When an individual needs to looks at a fixed near distance for an extended period of time (i.e.: the computer screen) one might assume that there would be no benefit from an autofocusing device. However, since the telescope’s depth of field is most shallow at near distances, even a slight postural change could be sufficient to blur the image. As a result the user would be forced to maintain a fixed posture to maintain image focus resulting in fatigue, lowered efficiency, and ultimately undermining the device’s long-term acceptance. As a result, autofocusing for activities at near distances can provide a more natural visual experience, lessening the user’s physical demands, lessening fatigue and increasing their performance.

When viewing objects solely beyond 20 feet (6m) (for bioptic driving perhaps), most optical telescopes used by the visually impaired will be at infinity focus.  No additional focusing for viewing beyond that distance would be required.  So, if the sole goal of the device is to support vision at 20 feet or further, an autofocusing device would offer no additional benefit. However, if the device is intended to also be used for a range of other distances, an autofocusing device may still be a compelling option.

WHEN?

Autofocusing bioptics are ideal for individuals needing enhanced vision at multiple viewing distances, for those with hands-free needs such as playing music or using the computer keyboard, and for mid-range and tabletop activities. They have been found effective for individuals with dexterity challenges and for those with mild to moderate cognitive deficits, where their ability to manipulate a manual focus device is undermined.

When traveling on public transit or at the airport, individuals will benefit greatly from the ability to see any object of interest at a glance. This visual necessity becomes less burdensome when the focus is automatic and hands-free. The classroom requires distance, intermediate, and near visual tasks all day long, as such, students can benefit tremendously from the convenience of an autofocusing device, and they are usually eager and quick adopters of such technology.

The emotional benefit of seeing a loved one’s face and expressions cannot be overstated. As mentioned in the introduction, a growing body of research demonstrates that the lack of distance vision can undermine socialization, can lead to feelings of isolation, and ultimately to depression and cognitive decline in seniors.  Efforts to support distance seeing for the visually impaired should go beyond specific task-related activities to also consider their emotional and social well-being.

HOW?

When prescribing any device, we must consider how it will be used. If intended primarily for distance-seeing, positioning the Falcon in the ‘bioptic position’ is usually the most practical option, as it will not interfere with vision through the carrier lenses for walking and other non-visually demanding activities. Individuals who intend to use it mostly for near or midrange, or in more sedentary distance activities, will likely find the straight-ahead ‘full diameter position’ to be more comfortable such as when viewing TV, movies, the computer screen or tabletop. The Falcon can be positioned at the top of the frame (bioptic position) using Ocutech’s K or U frames, or in the straight-ahead position (full diameter) using the Ocutech Sleek frame. 

The Falcon instructional videos and fitting guides will take you step-by-step through the fitting process. Designed to be easy to use, you’ll soon find just how convenient it is to demonstrate, fit and prescribe the Falcon Autofocus bioptic.

Why the Ocutech Falcon Autofocus Bioptic is important.

Image of man wearing VES Falcon and smiling

My vision rehabilitation professor taught us that in low vision care we prescribe adaptive devices, but it won’t be the device that’s doing the adapting.

The implication of this observation is that low vision aids can create a less-than-normal visual experience, and hence they place demands on the patient to learn to use them and modify their behavior to integrate them into their lives. The less natural and less convenient a low vision aid is to use, the less likely it will be adopted and incorporated into one’s daily life.

The importance of distance vision

Despite that so much of low vision care involves supporting reading, there is a growing body of evidence that shows that loss of distance vision has been associated with a greater impact on quality of life (QoL) than does the loss of reading vision. While many think of bioptics as intended solely for driving, there are very compelling reasons to prescribe bioptics for a range of other distance seeing needs. Distance vision is an important social sense. We use it to make eye contact, read body language and feel connected to the world around us. Loss of distance vision can cause feelings of isolation, can lead to depression and even contribute to cognitive decline 1,2 . Distance vision is also a vector to opportunity—it can support independent travel and both academic and vocational prospects. That’s not to say, one cannot be successful with reduced vision, but it certainly makes life more challenging.

There are only three ways we can improve distance vision—

  1. a better refraction;
  2. move closer; or,
  3. bring things closer using technology

A better refraction

If a new refraction were to make things dramatically better for an individual, someone probably dropped the ball way before the patient got to the low vision clinician. It’s infrequent that we can achieve a dramatic functional gain solely with a change in refraction. Remember, small changes in refraction do not beget large changes in acuity. So, an individual with lower acuity (~20/200 or less) won’t benefit from a half-diopter change, while someone with rather good acuity (~20/70 or better) might. That’s why it usually pays to check the refraction for individuals with better VAs.

Telescopes

So, when a change in glasses doesn’t help, and when moving closer is not an option, the next step is telescopes. Our goal is to prescribe a telescope power that provides approximately 20/40 though the device—an acuity level usually adequate for most all visual activities. Patients will first notice the narrower field of view through the telescope, which is why you should prescribe Keplerian telescopes whenever possible as they will provide the widest field of view at powers of 3x and higher.

The next thing they’ll notice is that they have to focus the device when looking at different distances. When you look through a telescope that’s miss-focused, you can barely see anything at all– it can be
worse than the patient’s regular vision. It’s hard to find what you want to focus on if you can’t see it. In addition, once it’s focused, if the user moves in or out, or if the target moves, you have to re-focus. This creates an unnatural user experience—it’s not ‘fluid’ because every time the user needs to refocus they have to stop what they’re doing and interact with the device. And, if they are using a fixed-focus telescope, they are ‘stuck in space’ because they can only see clearly within the shallow depth of field of
the device. In addition, if they’re focusing on an individual, it’s a rather aggressive behavior to be aiming and focusing—the user is uncomfortable doing it, and the individual isn’t too happy about being ‘aimed at’ either.

The value of Autofocus

We all have autofocus eyes. Wherever we look the image will be clear (or as clear as it’s going to get) immediately. Even presbyopes will see clearly to as close as about a meter or two before needing their reading prescription. But not so with a telescope! You’ll need to focus a 4x telescope (the most commonly prescribed power) at pretty much every distance you’d want to look, and especially as one gets closer.

And, that’s the benefit of autofocus—it provides the most natural magnification possible, because wherever you look, from optical infinity (~20 feet; 6m) to as close as 13” (0.3m), the image will be clear virtually immediately—just like normal vision.  This alleviates the major drawback of conventional telescopes—having to manipulate the device.  All you have to do is look, just like normal vision!

Supporting adaptation

The less demand there is on the patient to operate the device the easier will be their adaptation. And that is exactly what our goal should be—to make the device as easy and natural as possible for the patient to use.

Watch a manual focus bioptic wearer walk about the room. You’ll see them stop and start as they pause to refocus for different distances, raising and lowering their hand to focus the device.  Now watch the autofocus wearer—they’ll walk around the room normally, smoothly, fluidly and without hand motion to manipulate the device. They’re moving in and out naturally to examine items, in exactly the same manner that normally sighted individuals do.  Now, it’s the device doing the adapting, just like it’s supposed to be.

This is what an experienced manual focus bioptic wearer told us after receiving his autofocus bioptic:

  • “It’s so much more natural to use”
  • “I feel like I can use it without drawing attention to myself or making others feel uncomfortable”
  • “I’ll be able to use it in so many more ways”
  • “It will make my life so much easier”

Patient expectations

Patients seek the widest field of view and new, modern technology to help them maximize their vision, and that’s exactly what the Falcon Autofocus Bioptic provides.  It’s easy to demonstrate, fit and prescribe.  It provides the low vision clinician with a compelling new tool to help address the needs of their visually impaired patients.

References:

1. Low vision depression prevention trial in age-related macular degeneration: a randomized clinical trial.  Rovner, et al., Ophthalmology. 2014 Nov;121(11):2204-11

2. Longitudinal Associations Between Visual Impairment and Cognitive Functioning: The Salisbury Eye Evaluation Study. Zheng et al.JAMA Ophthalmol. 2018;136(9):989-995