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

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