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Introduction
The County Resourse Center for The Visually Impaired, DK-Vordingborg, has wished to test the utility of a newly developed auto focus telescope spectacles.
The basis of our assessment is the user's estimate of the new telescope spectacles: an estimate in which groups of visually impaired people compare the new spectacle to their customary visual aids.
Test Groups
Two groups of test persons were selected among the 2.000 journals at the Centre.
Test group 1: 14 visually
impaired people from 60 to 75 years of age,
all suffering from Age Related
Macula Degeneration.
Random selection.
Test group 2: 17 visually
impaired people from 24 to 68 years of age
suffering from a variety
of congenital or contracted eye
diseases. Selection criteria:
the test persons should be
younger than those in group
1, and suffer from different
visual handicaps. People
engaged in active employment
were preferred to those
not working outside their
homes.
The eye diseases in test group 2:
User number: 01) Opticus
Atrofi
02) Cataract cong / Nystagmus
03) Juvenil macula degeneration
04) Juvenil macula degeneration
05) Febroplasia retrolentalis
06) Cataracts cong ou
07) Rentinoblastoma ou
08) Glaukom sec / afaci
artificialis
09) Cataract cong ou
10) Juvenil macula deg.
/ colour-blind / nystagmus
11) Juvenil macula degeneration
12) Nystagmus cong /astigmatismus
ou / exo tropi
13) Lebers cong Amaurose
/ nystagmus
14) Trombose
15) Cataract cong / Nystagmus
16) Atrofi nervi optica
od / Neuritis os
17) Stargardt's
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Visus in the best eye, both test groups:
Visus Number of patients
6/12 1
6/18 1
6/24 1
6/36 4
6/48 1
6/60 6
3/36 6
3/60 5
2/60 1
1/36 1
1/60 1
Total: 28
The aim of the research party was to include patients with a visus between 6/18 and 3/60, and particularly those with a visus between 6/36 and 3/60. 90% of the test persons were monocular.
Of 31 test persons, 3 were dismissed. In group 1, two were dismissed: one because his sight was too much reduced, and the other because the distance between his pupils was so short that it would not be possible to adjust the ABL Auto Focus Telescope Spectacles properly. In group 2, the patient suffering from Stargardt's was dismissed because his low visual acuity rendered the optimum testing of the ABL Auto Focus Telescope Spectacles impossible.
The test persons' customary visual aids
Zeiss telescope spectacles, Nicon telescope spectacles, CDCX magnifying spectacles, hand held optical instruments in both test groups.
Technical data about the
ABL Auto Focus Telescope Spectacles
The ABL Auto Focus Telescope
Spectacles consist of a frontlet on which a binocular telescope system
is mounted. The telescope oculars are parallel when looking at things at
long distance and they converge progressively when looking at things at
a shorter distance. Adjustment and ocular convergence are automatically
controlled by a small motor which receives impulses from an infra-red sensor
which is mounted above the oculars.
Optical elements made by
: Zeiss
Long distance magnification
: 3 X
Short distance magnification
: 5 X
Visual field on a 2 m.'s
distance : approximately 30 cm.
Visual field on a 20 cm.'s
distance : 3 cm.
Total weight : 685 g.
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Method of measurement
We tested the long, medium, and short distance visus of each test person using his customary visual aids. Then an objective skiascopy and a subjective refraction were made.
We tested the customary aids and registered long distance visus and reading visus (Snellen and pkt value). Subsequently, we tested the ABL Auto Focus Telescope Spectacles on long, medium and short distance. During the medium distance test, the test persons did things like peeling an apple, driving a nail into a board of wood, or watching television.
Afterwards we interviewed the test persons about the utility of the ABL Auto Focus Telescope Spectacles.
We asked them three questions:
Question no. 1: subjective
estimate of the ABL Auto Focus Telescope Spectacles
This question included an
estimate of the visual convenience at long, medium, and short distance.
Test persons re-tested their customary aids in order to compare these to
the ABL Auto Focus Telescope Spectacles.
They had to choose between
the following three answers:
1. Better than customary
visual aid
2. Worse than customary
visual aid
3. Neither better nor worse
than customary visual aid.
Question no. 2: field of
vision in the ABL Auto Focus Telescope Spectacles
The test persons made an
estimate of the visual field in the ABL Auto Focus Telescope Spectacles
compared to that of their customary telescope and magnifying spectacles.
First they tried the ABL Auto Focus Telescope Spectacles, then their customary
aids, and finally they compared the two.
They had to choose between
the following three answers:
1. Better than customary
visual aid
2. Worse than customary
visual aid
3. Neither better nor worse
than customary visual aid.
Question no. 3: the comfort
and ergonomical convenience of the ABL Auto Focus Telescope Spectacles
Test persons were asked
the following questions about the comfort and ergonomical convenience of
the ABL Auto Focus Telescope Spectacles:
1. Is the weight of the ABL
Auto Focus Telescope Spectacles a nuisance?
2. Is the frontlet too tight?
3. General estimate of comfort
and ergonomical convenience
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Subsequently the test persons
were asked to give an overall estimate of the comfort and ergonomical convenience
of the ABL Auto Focus Telescope Spectacles, choosing between the following
answers:
1. Good
2. Medium
3. Bad
Test persons' subjective estimate of the ABL Auto Focus Telescope Spectacles
Test group 1:
Age : 60-75 years
Sex : 6 males, 6 females
Ocular trouble : Age Related
Macula Degeneration
67% find the ABL Telescope
Spectacles better than their customary visual aids
16,5% find the ABL Telescope
Spectacles worse than their customary visual aids
16,5% find no difference
between the ABL Telescope Spectacles and their customary visual aids.
The test group 1's estimate of the field of vision in the ABL Auto Focus Telescope Spectacles expressed in percentages:
67% find the field of vision
in the ABL Telescope Spectacles better than in their customary visual aids
8% find the field of vision
in the ABL Telescope Spectacles worse than in their customary visual aids
25% find no difference between
the fields of vision in the ABL Telescope Spectacles and in their customary
visual aids.
The test group 1's estimate of the comfort and ergonomical convenience of the ABL Auto Focus Telescope Spectacles expressed in percentages.
42% find the comfort and
ergonomical convenience of the ABL Telescope Spectacles good
25% find the comfort and
ergonomical convenience of the ABL Telescope Spectacles medium
33% find the comfort and
ergonomical convenience of the ABL Telescope Spectacles bad.
Test group 2:
Age : 24-68 years
Sex : 11 males, 5 females
Ocular trouble : see page
1.
The test group 2's estimate the visual comfort of the ABL Auto Focus Telescope Spectacles expressed in percentages:
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61% find the ABL Telescope
Spectacles better than their customary visual aids
8% find the ABL Telescope
Spectacles worse than their customary visual aids
31% find no difference between
the ABL Telescope Spectacles and their customary visual aids.
The test group 2's estimate of the field of vision in the ABL Auto Focus Telescope Spectacles expressed in percentages:
69% find the field of vision
in the ABL Telescope Spectacles better than in their customary visual aids
8% find the field of vision
in the ABL Telescope Spectacles worse than in their customary visual aids
23% find no difference between
the fields of vision in the ABL Telescope Spectacles and in their customary
visual aids.
The test group 2's estimate of the comfort and ergonomical convenience of the ABL Auto Focus Telescope Spectacles expressed in percentages:
31% find the comfort and
ergonomical convenience of the ABL Telescope Spectacles good
38% find the comfort and
ergonomical convenience of the ABL Telescope Spectacles medium
31% find the comfort and
ergonomical convenience of the ABL Telescope Spectacles bad.
Evaluation of Test Results
On the basis of these tests,
the optometrist considers the ABL Auto Focus Telescope Spectacles a suitable
visual aid for approximately 50% of the test persons in both test groups.
The prospects of a successful adjustment to the ABL are the same in both
test groups which means that they do not depend on age. Other factors,
however, must be taken into account when considering a patient's possibility
of adjustment to the ABL Auto Focus Telescope Spectacles.
It takes a fair amount of personal involvement to become used to a visual aid which is as different and as comparatively advanced as are the ABL Auto Focus Telescope Spectacles, and the patient's motivation and adaptability are crucial to a successful adjustment to the ABL Auto Focus Telescope Spectacles. As regards the patient's psychological comfort, we find it necessary that the patient should have a serene and composed attitude to his or her own handicap in order not to feel bad using an aid which is as conspicuous as the ABL Auto Focus Telescope Spectacles.
Similarly, the situation
and the necessities of each patient should be taken into account and tested
individually before prescribing a pair of ABL Auto Focus Telescope Spectacles.
The test persons often said that the ABL Auto Focus Telescope Spectacles
were very suitable for medium and short distance, and that they moved their
reading distance to about 20-30 cm. This means that the ABL Auto Focus
Telescope Spectacles will ease the everyday situation of many people, either
they are engaged in active employment or not working from home, since most
everyday work is done at a distance of approximately 40-80 cm.
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Similarly, several of the students among the test persons said that the ABL Auto Focus Telescope Spectacles made their daily situation much easier. They enabled the students to look directly from the blackboard and to their textbook, whereas when they used their customary aids they had to change between telescope spectacles and magnifying spectacles all the time.
We furthermore conclude that the ABL Auto Focus Telescope Spectacles is suited for patients whose visus is between 3/36 and 3/60. Those with a visus better than 6/36 are able to manage with ordinary spectacles, possibly with extra additions, and by sitting closer to the blackboard, television, etc., and this way avoiding the inevitably more troublesome solution constituted by the ABL Auto Focus Telescope Spectacles. Users whose visus is worse than 3/60 do not benefit sufficiently from the ABL Auto Focus Telescope Spectacles because their visual powers are so small that they need greater magnification than the one the ABL Auto Focus Telescope Spectacles are able to make in order to experience the optimum improvement of their vision.
Since the ABL Auto Focus Telescope Spectacles are comparatively unhandy, they must be seen generally as a supplement to ordinary spectacles and other visual aids rather than a substitute for them.
Conclusion
The ABL Auto Focus Telescope Spectacles are a new invention in the field of optical instruments for visually impaired people. The ability to focus automatically on short and medium distances can be of much help to many visually impaired people.
On the basis of this study, we conclude that patients with a visus between 3/36 and 3/60 will benefit the most from the ABL Auto Focus Telescope Spectacles. Since the ABL Auto Focus Telescope Spectacles are rather big, conspicuous, and different from ordinary visual aids, it is necessary for a successful adjustment that the patient should be motivated, show personal involvement, adaptability, and be quite composed about his or her handicap.
Approximately 50% of the total test group would benefit from the ABL. Much everyday work is done at a medium distance of approximately 40-80 cm. and the ABL Auto Focus Telescope Spectacles are able to solve this medium distance problem and, similarly, providing an ergonomically improved reading distance.
In sum, approximately 60% of the test persons found the ABL Auto Focus Telescope Spectacles noticeably better than their customary visual aids. Only 35% found that the comfort and ergonomical convenience were good: about 40% of the test persons found the ABL Auto Focus Telescope Spectacles were too heavy and troublesome.
The weight of the ABL Auto Focus Telescope Spectacles was the most frequent source of trouble for the test persons. A way of reducing this problem would be to make a monocular ABL Auto Focus Telescope Spectacle. The majority of visually impaired people are monocular. In this study, 90% of the test persons were monocular.
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In the future, auto focusing telescope spectacles will be able to ease the daily situation of many visually impaired people. But like with any other visual aid it is necessary to treat and test each patient individually, and to follow up the adjustment by after-care services in order to achieve the best possible results.
(October, 1995)
.....................................................................................
(June, 1997)
Conclusion of long-term try-out.
After the testings in October 1995 ABL has provisionally been out on loan to ten of the persons who were considert qualified, in a longer testperiod frem one week to several month.
A mumber of these persons contributed after this with comprehensive and serius evalutations, where a compile is not possible because of the individual conditions.
It is however possible to find some main causes how far the ABL is wanted or not wanted:
1 person generally refuses
headworn optics regardless the kind or objective improvement.
3 persons state the enlargement
grade to be either to big or to small.
3 persons prefered conventional
solutions
2 persons were restrainted
as a cause to a contemporary application to the municipality for edp ect.
In both cases there were positive results especially when used in spare-time
occupation: As an example one of the persons used the period of time were
the optic in question was available to paint the house - in this situation
there was automatic focus on the (paint) brush.
1 person experienced a convincing
improvement. Ever there were new experiences which confirmed that it "once
again was possible" to cut the roses, read text-tv, do ordinary everyday
things, be able to see the face of the partner and so on.
Synscentralen has up to now supported one application.