Low Vision News

For low vision specialists and those who consult them

Telescope training: is there evidence?

At the moment there is lots of interest in implanted miniature telescopes for people with low vision (where the lens inside the eye is surgically replaced with a magnifying telescope). I will discuss these in another post, but this topic started me thinking about conventional, hand-held monocular telescopes, and the relative benefits of these.

In particular, I am interested in the role of training people to use these telescopes. There are three key things telescopes can be used for: spotting (“what is the name on this street sign?”); tracking (“what is the number on this moving bus?”); and scanning (“I know there is a sign somewhere near here, where is it?”).

Most people can probably manage to spot something with a telescope with practice and no training, as long as the principles of telescopes are explained to them (eg. you need to adjust the length of the tube to focus it; you need to make sure you’re standing still when you’re using it; you need to hold it as close to your eye as you can). However, more complex tasks such as tracking and scanning are difficult to perform without some guided practice or training.

In the UK, some local charities for the visually impaired perform this training, but there are still plenty of people who do not receive training and who just “pick up their telescope” and go home and use it. In the USA telescope training is commonly performed by rehabilitation workers, but there are still people with telescopes who have not received training.

Unless my quick literature search didn’t find it, it doesn’t seem that there has been a systematic study on telescope training to answer some key questions such as:
– what can people with low vision do with a telescope without training?
– how much training is needed to be able to perform certain tasks with a monocular telescope?
– how much better is performance with a telescope once training has been performed?

Once we have answers to questions like these, we can make a much stronger case to funding agencies that device training should be made available to more people. This would also make a nice project for someone looking to do a Masters or PhD in vision rehabilitation too.

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One response to “Telescope training: is there evidence?

  1. La'Shandra Russell November 9, 2009 at 7:01 pm

    First, let me begin by saying thank you for posting this site. It is definitely a much needed forum in the vision rehabilitation field.

    I am a CLVT with the VA Hosptial in Washington, DC where I provide low vision therapy w/ and w/o magnification devices in the new Vision Rehabilitation Clinic. Our program is an intense 10 day program in which I have to provide training in the use of handheld mag, stand magnifies, binoc ts, monoc ts, and CCTV. So as you can see, we to really target our training. When training with the monoc ts, training and efficient use is accomplished approx 3-4 days. Day 1 is spent on identification and focusing targets presented centrally to the patient. Day 2 is spent on localization technique for objects not presented centrally. Day 3 is spent on tracking and tracing. Day 4 is a culmination of days 1-3. Training for days 1-3 is generally at 10ft and then on day 4 training in done @ 10-40ft. Training is also coupled w/ the O&M specialist who will incorporate training with outdoor travel skills. On day 4 performance is significantly better by both self report and observation. For objective assessment of performance, it can timed as to how long it takes the individula to locate and identify objects. Depending on the functioning and understanding of the individual, training can be completed w/i 3 days.

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