LOW VISION VISD241. MODULE LEADER: DR G WALSH B.Sc. OPHTHALMIC DISPENSING

Transcription

1 DIVISION OF VISION SCIENCES SESSION: 2006/2007 DIET: 1 ST LOW VISION VISD241 LEVEL: TWO MODULE LEADER: DR G WALSH B.Sc. OPHTHALMIC DISPENSING MAY 2007 DURATION: 2 HOURS CANDIDATES SHOULD ATTEMPT FOUR QUESTIONS ONLY QUESTION 1 MUST BE ANSWERED PLEASE READ THE QUESTIONS CAREFULLY MATERIALS TO BE SUPPLIED/ALLOWED: Question Paper (Supplied) } Lined Examination Script (Supplied) } Calculator (Allowed) } Page 1 of 9

2 THIS QUESTION MUST BE ANSWERED 1. a) Patient details: Age 75, female, living alone Receiving income support. Prescription -8.00DS add R&L 1.74 plastics varifocals. Last GOS eye examination 6 months ago. Present specs made up following this examination. Visual acuities with spectacles 6/36 R & L; N12 R&L Dry age-related macular degeneration (ARMD) i) The patient is having difficulty seeing her television. What is the most cost-effective way to make the television picture easier to see? (1) How much magnification would you expect the patient to need to be able to read newsprint for short periods of time? How did you arrive at this answer? (2) i What is the most cost-effective way to obtain enough magnification? How much magnification would be obtained this way? Explain how you arrived at this answer. (3) iv) What are the most significant OPTICAL problems with the spectacles she is wearing for a patient with low vision and how would you resolve these? (2) v) Is the condition from which she is suffering stable, slowly progressive or rapidly progressive? Does this give her a good or poor prognosis for success with low vision aids? (2) b) on next page Page 2 of 9

3 b) Patient details: Age 25, male, living alone In full time employment as a travelling sales representative. Prescription -1.00DS, anti-reflection coated CR39 single vision Last GOS eye examination 6 months ago. Present specs made up following this examination. Visual acuities with spectacles 6/5 R & L; N4.5 R&L Retinitis pigmentosa diagnosed following referral after last eye examination i) What is the effect of retinitis pigmentosa on the visual field? (1) What other effect might the patient notice on his vision in the early stages of the disease? (1) i Which part of the patients job is likely to be affected first by the condition and why? Briefly name and explain how ONE UK law or regulation may be directly relevant to this. (3) iv) Which types of optical aid may be of value to the patient whilst he retains good visual acuity? Briefly describe ONE device of this type. (2) v) Is the patient suitable for eccentric viewing training? Give an explanation of your answer. (2) vi) The patient s uncle (his mother s only brother) also had retinitis pigmentosa. His great uncle (his mother s, mother s only brother), but he is uncertain of any other cases in his family. His mother and grandmother each had two sisters. Is it likely that his son will develop the disease? Give a brief explanation of your answer. (2) Page 3 of 9

4 2. For each of the multiple choice elements in this question there is only ONE correct answer. i) Which of the following IS an accepted way of calculating magnification in low vision? a) Angular subtense of the object without the device Angular subtense of the object with the device b) Retinal image size without the device Retinal image size with the device c) Diaoptric power of magnifier 2.0 d) New distance of object from eye Original distance of object from eye e) (Dioptric power of magnifier/4) Each of the incorrect answers is very similar to an accepted method of calculating magnification under some conditions. Briefly explain how you arrived at your answer. (5) Which of the following is NOT a suitable modification method for a distance telescope to be used at near? a) Changing the eyepiece and objective separation b) Using an extra plus lens in front of the objective lens c) Changing the objective lens to one designed for near use d) Wearing the patient s usual reading spectacles e) Changing the eyepiece and objective separation AND using an extra plus lens in front of the objective lens Briefly explain how you arrived at your answer. (2) i A distance Gallilean telescope has a magnification of 4x. If the power of the objective is +10DS, what would you expect the power of the eyepiece to be? a) -20DS b) -40DS c) +20DS d) +40DS e) -400DS Show briefly how you arrived at this answer. (2) iv) on next page Page 4 of 9

5 iv) How long would you expect the telescope in part (i to be if you assume the lenses to be thin? a) 2.5cm b) 5cm c) 7.5cm d) 10cm e) 12.5cm Show briefly how you arrived at this answer (2) v) A patient has a near visual acuity of N40 with a +4.00D reading addition. What is the addition that would be needed to see N8? a) +80DS b) +30DS c) +10DS d) +40DS e) +20DS Show briefly how you arrived at this answer (2) vi) A patient is currently using a reading lamp with a 25 Watt incandescent lamp 1m from the reading material. What change is needed to MOST NEARLY DOUBLE the amount of light incident on the page. a) Move the lamp to 70cm from the page b) Increase to a 40 Watt lamp and move to 40cm from the page c) Move the lamp to 50cm from the page d) Increase to a 40 Watt lamp e) Increase to a 60 Watt and move to 60cm from the page Show briefly how you arrived at this answer. (3) v Which of the following IS a low vision aid? a) Epidiascope b) Mantoscope c) Pseudoscope d) Typoscope e) Synoptophore Briefly describe the main forms of the real low vision device and indicate how they are used. (4) Page 5 of 9

6 3. For each of the multiple choice elements in this question there is only ONE correct answer i) When using a conventional illuminated stand magnifier, such as an Eschenbach one, what is the best refractive correction? a) Distance spectacles b) Distance and DS addition c) Distance and DS addition d) Distance and DS addition e) Distance and DS addition Briefly explain the reason for this and explain why illuminated hand magnifiers generally have very low wattage lamps compared to anglepoise type reading lamps, yet are well liked by users. (3) Which of the following is the definition of blindness according to the National Assistance Act (1948)? a) So blind as to be unable to do any work for which sight is essential. b) Substantially and permanently handicapped by defective vision. c) With vision such as to prevent normal activities. d) Visual acuity below 3/60 Snellen. e) Visual acuity below 3/60 Log MAR. (1) i Which of the following patients would be normally considered to be eligible for registration as partially sighted? a) 6/60, complete loss of inferior (lower) visual field R & L. b) 3/60 and with a recent large peripheral visual field loss. c) 2/60 with a slight loss of superior (upper) visual field. d) 6/36 with moderate contraction of the visual field. e) 6/18 with a small central visual field loss. Without a visual field defect, what is the normal BEST visual acuity with which a patient would normally be considered for registration as partially sighted (2) iv) Which of the following is a CORRECT definition of DISABILITY? a) Deviation from normal of any bodily structure. b) An interference with a bodily function. c) Lack, loss or reduction of an individual s ability to perform certain tasks d) An individuals perceived or actual disadvantage with respect to the society in which they live. e) Registered for assistance with social services. v) on next page Briefly explain how a disability differs from a handicap. (2) Page 6 of 9

7 v) Who must agree to registration for an individual to be registered as blind? a) Patient only. b) Patient and ophthalmologist. c) Patient, optometrist and patient s own general practitioner. d) Patient and patient s own general practitioner. e) Patient and local authority social services department. Give TWO reasons why not all those eligible for registration as blind may NOT be registered as blind. (3) vi) What is the sequence of events normally considered to be the LOSS MODEL in relation to the psychological stages of coming to terms with visual loss? a) Shock, denial, anger, depression & apathy, realistic acceptance. b) Denial, shock, anger, depression & apathy, realistic acceptance. c) Shock, depression & apathy, anger, denial, realistic acceptance. d Shock, denial, anger, realistic acceptance, depression & apathy. e) Anger, denial, shock, depression & apathy, realistic acceptance. Give a brief explanation of the main problem with using this model clinically. (2) v Which of the following tests would be performed LAST in the assessment of a low vision patient with ARMD? a) Amsler visual field recording. b) Testing the effect of lighting on visual performance. c) Determining the best optical aid for reading. d) Checking the refractive correction subjectively. e) Ophthalmoscopy. Give a brief explanation of the reason for your choice of answer. (2) vi Which of the following is NOT an advantage of a Bailey-Lovie type distance chart of the type most commonly used in practice over the conventional Snellen chart? a) Easy to use at different distances. b) Even illumination. c) Equal numbers of letters per row. d) Logical gap sizes between rows and letters. e) Constant step sizes (logarithmic) between rows. Give ONE ADDITIONAL ADVANTAGE and THREE DISADVANTAGES of the Bailey-Lovie Distance chart over the conventional Snellen chart. (5) Page 7 of 9

8 4. i) A patient presents with a principal problem which is one of glare both indoors and out. Give THREE ways of reducing this effect and an indication of when they would be most useful. (3) Explain the term steady eye strategy using only terms suitable for talking to a patient with little or no optical knowledge. (2) i Indicate when steady eye strategy is likely to be of value and why. (2) iv) Describe the Amsler chart. Briefly describe how it is used and what it is used for both in the clinic and at home. Use only terms suitable for talking to a patient with little or no optical knowledge. (8) v) A patient with a hand tremor and early dry ARMD is looking for a low-cost, easy to use aid for reading the telephone directory in her entrance hall. She needs approximately 1.5x magnification. Suggest a suitable device and briefly describe it. (2) vi) An elderly patient wants to read books (N12), but can only read N18 with her present (+4.00DS add) spectacles in your consulting room. How much magnification would be required to read a novel if she wishes to read for long periods of time? Explain how you came to this conclusion. (3) 5. i) Name and briefly describe THREE pieces of equipment available to help a patient with no perception of light perform DOMESTIC activities. (3) An elderly patient with limited mobility is unable to read for pleasure any more and is seeking an alternative. Give her TWO alternatives for which sight is not needed and for which there are no major expenses involved and how they can be obtained. (3) i An patient aged 50 has just been registered as blind, but is unsure of the value of registration to her. List FIVE of the benefits which it may have for her. (5) iv) on next page Page 8 of 9

9 iv) List TWO things which the National Assistance Act, 1945 makes it mandatory for local authorities to provide for the blind and partially sighted. (2) v) Briefly describe the effect of chronic open angle glaucoma on vision and its usual timecourse. (2) vi) The majority of the blind people in the world are elderly. Briefly explain why the World Health Organisation concentrating on the eradication of blindness in younger people? (1) v Briefly explain what Trachoma is, how it spreads and what attempts are being made to eradicate it. (4) END OF PAPER Page 9 of 9