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Presentation on theme: "G UIDELINES FOR PRESCRIBING OPTICAL DEVICES AND TRAINING 23 February 2012."— Presentation transcript:


2 S ESSION OUTCOMES At the end of the session, each student is expected to: Discuss the factors which need to be considered before choosing an appropriate device Discuss guidelines and factors to consider before prescribing telescopes Discuss guidelines and factors to consider before prescribing near magnifiers

3 Discuss problems which may be encountered with devices Discuss the training of a prescribed device

4 S PECIAL CONSIDERATIONS 1. Patient’s level of motivation The examiner may pick-it up during examination Other patients may require encouragement. 2. The size and working distance of the task 3. Hands-free Does the patient require to have hands free to hold a book/paper? Can he/she have the text mounted on a stand?

5 4. Ability to hold steadily Does the patient has ability to hold material steadily Will the hand-held device be appropriate for this patient? 5. Ease of handling 6. Need for a flat surface E.g. reading newspapers needs a flat surface, but reading a can won’t require fixed focus stand magnifier.

6 7. Acceptable cosmesis Does the patient like the cosmesis of the device? Will the patient mind using the device in public? 8. Training involved High reading addition? Is eccentric viewing necessary? 9. Environment 10. Close working distance It is more acceptable to younger or highly motivated patients.

7 11. Portability Does the aid need to be portable? Or it should not be too bulky 12. Integral lighting Devices which require electricity cannot be prescribed for a patient who lives in a village where there’s no electricity. 13. Cost Affordability should be considered.

8 O THER FACTORS INCLUDE Age of the patient Preference VA of the patient

9 D ISTANCE OPTICAL DEVICES ( TELESCOPES ) They provide an increase in the retinal image size- better resolution Magnification should be as low as possible To avoid limitations of field To avoid aberration The amount magnification depends on best VA and target acuity.

10 S EQUENCE FOR PRESCRIBING TELESCOPES 1. Determine the best distance correction 2. Measure the best corrected acuity 3. Determine the goal acuity 4. Calculate the magnification needed 5. Demonstrate the appropriate telescope to the patient 6. Explain the available options 7. Loan a device for home trials 8. Design the final prescription

11 P ROBLEMS WITH THE USE OF TELESCOPE MAY BE DUE TO THE FOLLOWING : May be improperly focused May be misaligned with the eye May be due to the patient’s poor localization skills May be causing insufficiency of brightness May be too close to or too far from the patient’s eye

12 T RAINING INCLUDES The use of the device (s) effectively in terms of: Working distance Posture Handling of the device How to take care of device

13 Head and eye movement Eye hand coordination

14 T RAINING WITH THE DISTANCE DEVICES 1. Familiarization with focusable devices 2. Focusing 3. Locating the object 4. Fixating the object 5. Spotting the object 6. Tracing the object 7. Tracking the object

15 8. Scanning 9. Integration

16 H AND - HELD TELESCOPES Have px to look at the object without the telescope, Then move the head down along straight line to look at their own feet. Then raise the head slowly in the direction of the object with telescope before the eye. The back-and-fourth motion along a straight line will bring the image into focus.

17 The poorer eye may be covered with a patch to allow concentration. Do not try to walk around while looking through the telescope. If there’s a problem with lighting or glare, the px must try to reposition him/herself. Practice for about 5-10 (mins)

18 S EQUENCE FOR PRESCRIBING HAND - HELD AND STAND MAGNIFIERS 1. Determine the best distance correction 2. Measure the best corrected acuity through appropriate add 3. Determine the goal acuity 4. Calculate the magnification needed 5. Demonstrate the appropriate telescope to the patient 6. Loan a device for home trials 7. Demonstrate different options in which it can be prescribed.

19 O THER IMPORTANT FACTORS WHICH NEED TO BE TAKEN INTO CONSIDERATION Working distance Field of view Illumination Device manipulation

20 Working distance Train the patient to position and maintain the material at the proper distance. The use of reading stands may have to be considered Most low vision aids impose working distances to which the px is not accustomed.

21 H AND - HELD MAGNIFIER Place the aid on the reading material and slowly and slowly move it towards you until words get blurred, and then push the aid away you get focus. View from the centre of the magnifier- for good field of view Adjust the light to properly illuminate material.

22 Hold material in vertical position. A reading stand or clipboard may help to keep material flat and steady. Practice for 5 to 10 minutes several times a day in the beginning. Asthenopia may be experienced

23 S TAND MAGNIFIER Reading portion may be used for patient who have bifocals. Place the base of the stand flat against the reading material. The print is automatically in focus when the stand magnifier rests on the page. Moving closer to material will allow the px to see a larger area at one time.

24 View from the centre The px must move the stand magnifier across the page as he/she reads.

25 T HE IMPORTANCE OF TRAINING AND EDUCATION To ascertain how the patient is adjusting to the use of the device/s. To establish if the patient has any problems with the use and care of the device/s The patient must demonstrate the use of the device/s and comment on the his/her vision with the device/s.

26 G ENERAL GUIDELINES FOR THE TRAINING 1. Motivation 2. Explanation 3. Demonstration 4. Practice 5. Transfer

27 Motivation The patient must be well motivated to perform certain visual skills He/she must understand the purpose of the skill And how it relates to the desired task.

28 Explanation How does the device work? At what distance does the device have to be use.

29 Demonstration Clearly demonstrate how the device must be used by the patient. Make sure that the patient understands and stay motivated by choosing the relevant material.

30 Practice This is preferably done under the supervision of the examiner or the. The patient must be given clear instructions and guided accordingly.

31 Transfer The skill learned in the clinic setting must be transferred to the patients home or at work situation. Practice must therefore takes place in the “real life" setting.

32 TRAINING SESSION REQUIREMENTS 1. Comfortable room 2. Good central lighting 3. Additional desk lighting for near work 4. Variety of print 5. Different charts 6. Reading exercises 7. Reading stands

33 Typoscope or bar readers Other necessary devices- Material must resemble the desired task set by the patient. E.g. if the desired task is to sew, use sewing material, not reading cards.

34 F OLLOW - UP VISITS First visit is after a week or two weeks. After three months After six months

35 S UMMARY SLIDE Case history VA measurements Refraction Magnification/ power calculation Special considerations Device Prescription Training with a device Loan Follow up visits


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