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Occupational Therapy Role in Low Vision

Occupational Therapy Role in Low Vision. By Serena Speaker OTR SCLV November 8, 2013 TOTA Mountain Central Conference. Objectives. 1. Participant will understand basic anatomy of the visual system and primary low vision conditions affecting older adults.

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Occupational Therapy Role in Low Vision

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  1. Occupational Therapy Rolein Low Vision By Serena Speaker OTR SCLV November 8, 2013 TOTA Mountain Central Conference

  2. Objectives 1. Participant will understand basic anatomy of the visual system and primary low vision conditions affecting older adults. 2. Participant will be able to describe how low vision conditions influence occupational performance. 3. Participant will be able to compare and contrast the role of the occupational therapist specialist and generalist in low vision rehab. 4. Participant will demonstrate techniques to improve ADLS function with low tech devices.

  3. What is low vision? • Definition of low Vision -a visual impairment severe enough to interfere with occupational performance but allowing some usable vision • Legal Blindness (used to qualify persons for benefits and services) Best corrected visual acuity of 20/200 or less in better eye (BE) or visual field of 20 degrees or less in the better eye Source: Warren, Mary, MS, OTR/L, FAOTA (2008) Low Vision: Occupational Therapy Evaluation and Intervention with Older Adults, Revised Editin. Bethesda, M. AOTA Press.

  4. Low vision is primarily an acquired condition that is an issue of aging • 2/3 are over age 65 • 30% over age 75 • Most are caused by 3 age related conditions-Macular Degeneration, Glaucoma, Diabetic retinopathy • These account for 90% of low vision referrals

  5. Visual Perceptual HierarchySeven levels of visual processing Permission From Mary Warren PhD, FAOTA, OTD

  6. Foundation Level 1. visual acuity 2. visual field 3. oculomotor control

  7. Second Level Attention 1. Alert 2. Attending

  8. Third Level • Scanning-ability to look side to side

  9. Level Four-Pattern Recognition • CNS must have high quality, accurate visual input to complete object recognition. 1.Visual acuity ensures the clarity of visual input 2.Visual field integrity ensures the presence of vision-that all of the visual input from the environment is represented 3.Oculomotor control ensure that visual information is acquired rapidly and accurately when the body is in motion or at rest for perceptual stability

  10. Level Five • Visual memory-the ability to recall or match the visual object to one’s memory. When an R is an R and is the first letter in Run. Or a picture or viewing a water glass means that there is a memory that means this glass of water will be able to quench my thirst.

  11. Level Six • Visuocognition- the ability to use the visual memory and then relate to past experiences on a cognitive level. The ability to recognize a bank check register and then be able to record the check, determine the balance in the check book and then reconcile the balance with the bank statement. Visual tasks that require cognitive input on a high level of processing from the initial visual input.

  12. Level Seven • Adaptation through Vision 1. Solve Problems 2. Formulate plans 3. Make decisions Source: Warren, Mary, MS, OTR/L, SCLV.FAOTA and Elizabeth Barstow, MS, OTR/L, SCLV (2011). Occupational Therapy Intervention for Adults with Low Vision, Bethesda, Md, AOTA Press.

  13. Low vision is issue of aging • Older adults associate low vision with normal aging process • 2/3 have at least one other chronic medical condition (LV with diabetes=6X greater likelihood of problems shopping and socializing, LV with CVD=7X) • Woman’s Issue-more likely to live alone, 75% of men with low vision are married and have in-home support compared to 30% for women

  14. ICD-9 CMS Definitions of Low Vision and Blindness table. • Individuals will not meet CMS medical necessity requirements unless Visual Acuity is worse than 20/60 in the better seeing eye or visual field less than 20 degrees. • OTs provide services under Part A-acute care, Part B or Home Health umbrella. • Additional credentialing is encouraged: SCLV by AOTA and or CLVT by ACVREP.

  15. Occupational Therapy Practice Framework (AOTA) published 2002, revised in revised in 2008 • Ecology of Human Performance Model • published 1994 by Dunn, Brown & McGuigan • describes the domain and processes that define occupational therapy practice and outlines the OT evaluation and intervention process. Investigates relationship between the person, context, tasks, performance, therapeutic intervention.

  16. Occupational Areas • Activities of DailyActivities • Instrumental Activities of Daily Living • Rest and sleep • Education • Leisure • Play • Social Participation • Work

  17. Daily Occupations Affected by Reduced Visual Acuity and Contrast Sensitivity • Self CareMeal Preparation • applying make-up setting appliance dials • applying toothpaste measuring ingredients • completing nail-care determining when food is done • selecting clothing cutting, chopping, slicing • mending clothing reading recipes, instructions • managing medications identifying foods • eating neatly pouring liquids • seasoning foods operating microwave • spreading toppings cleaning cookware

  18. Instrumental Activities of Daily Living Shopping • Accessing transportation • Locating correct aisle/item • Reading prices • Making change • Making grocery list Money management • Reading bills/financial statements • Completing check, money order • Debit transaction • Maintaining financial ledger • Addressing/mailing bills • Computer bill payment • Identifying money Leisure • Sewing, quilting, needlework • Bingo • Card games • Woodworking • Fishing • Automotive repair

  19. Reading Activities Informational Reading Pleasure Reading • Newspaper Magazines • Newspaper ads E-mails • Stock quotations Books • TV guide E-books • Recipes Daily devotionals • Food labels Cards and letters • Medication labels • Menus • Telephone directory • Address Book • Incoming mail • Bank receipts/statements • Checkbook ledger • Watch or clock face • Street signs • Aisle marker/store signage

  20. Home and Community Activities Home Maintenance • Cleaning • Setting dials on washer/dryer • Yard maintenance • Car maintenance • Minor household repairs • Ironing • Thermostat adjustment Community Activities • Accessing transportation • Recognizing acquaintances • Maintaining orientation in unfamiliar places • Locating public restrooms • Eating out in restaurants • Negotiating curbs, steps, etc • Avoiding collisions

  21. Two step process to develop an intervention plan • occupational profile • occupational analysis • OT evaluates FUNCTIONAL vision • How it hinders and facilitates occupational performance to define rehab potential

  22. Results of A Good Evaluation 1. Identify limitations in occupational performance 2. Identify factors that contribute to the limitation in occupational performance 3. Determine if intervention is necessary 4. Identify most appropriate intervention to achieve optimal outcome

  23. Anterior Visual System • Cornea • Iris • Lens • Choroid (blood supply) • Ciliary Body: 2 structures • Ciliary muscles shape lens, controlled by CN III • Ciliary process - secretes aqueous in anterior chamber

  24. Anterior Visual System • Anterior Chamber: space that is filled with clear watery fluid between the back surface of cornea and front surface of the vitreous • Aqueous: produced by ciliary body in posterior chamber and circulates through anterior chamber • continuously produced and drained away while maintaining the shape and pressure within the eye

  25. Overall function of brain is to filter, organize and integrate sensory information to make an adaptive response to the environment. • CNS is devoted to taking in sensory input, analyzing it and responding to it. • Vision is primary sensory system to acquire information about environment. • 80-90% of learning occurs through visual channel • 1/3 to 1/2 of brain devoted to visual processing

  26. Most far reaching sensory system • alerts us to danger or pleasure • enables us to be anticipatory, plan for situations • Supplies speed in informational processing • tells us exactly what is going on • instantly identify objects with vision • Can use other senses but not as quickly • Example: World Trade Towers

  27. Size up situations • first impressions are important • avoid certain people • Make decisions • where to sit in a room • what to select from salad bar • Solve problems • want to see the problem so we can solve it with visual memory of a previous event • previous problem can help solve a new one • Interpret social interactions • facial expressions • Elicit and guide movement • Maintain postural control • warn of upcoming obstacles to navigate around objects

  28. Because of the importance of vision to the brain, a person with vision-no matter how limited-will ALWAYS attempt to use vision to adapt and complete activities • Biggest challenge is that low vision is a hidden disability and its symptoms are often attributed to other causes • we identify low vision if the person has a white cane or dog guide

  29. Reduced visual acuity to 20/30-20/40 • Dynamic acuity decreases • affects gaze stability • more visual blur • Loss of accommodation • AKA; Presbyopia; lens thickens and loses flexibility • bifocals • Floaters: strands of protein that float in vitreous • generally benign unless accompanied by bright flashes of light or significant increase in number • Dry eyes • lacrimal glands decrease secretion • medication exacerbates condition, treat with artificial tears

  30. Increased need for light • pupil diameter decreases, lens thickens and yellows • 80 yo needs up to10X more light than 23 yo • Glare susceptibility • lens and cornea become less smooth • protein strands cause light to scatter • increased discomfort • Reduced dark/light adaptation • more difficult to go from bright to dark than dark to bright since takes longer to reform and store visual pigments • Reduced Contrast Sensitivity • caused by changes in color, density, size of pupil • 75 yo needs 2X as much contrast as younger person • 90yo needs 6X

  31. Macular degeneration Diabetic retinopathy Glaucoma

  32. Macular Degeneration • Other names for this condition: Senile macular degeneration, Atrophic macular degeneration (AMD), Age related macular degeneration (ARMD) • Two forms-chronic and advanced (dry/wet) • Caucasians more susceptible • NEVER results in blindness-disease of central vision-cone retinal cells • 60 to 90% of referrals to low vision clinic

  33. Two types • Chronic: dry or atrophic type • 90% • Progressive: wet or hemorrhagic type • 10% • Attacks cone cells • Both types cause • macular scotomas (blind spots) • photophobia (light sensitivity) • fluctuating vision • slow dark/light adaption

  34. Vision with Macular Degeneration • Normal vs Macular Degeneration view

  35. Injected into vitreous cavity • Lucentus (40X cost of Avastin) approved in 2006-4 wks • Avastin-used off label- every 4 weeks • Macugen-approved in Germany 2006- every 6 weeks • Eylea-FDA approved November 2011 • Eliminate existing abnormal blood vessels and turn off signal for additional vessels to develop • Works for several weeks to months: repeated injections if necessary • Lost vision may be recovered if administered at first sign of new blood vessel formation

  36. Avastin and Lucentis are equivalent in treating Wet AMD • Avastin most frequently used drug for wet AMD • Two year clinical trial with results published 04-13-12 by National Eye Institute-NIH • Long term results with either drug resulted in robust and lasting improvement in vision • As needed dosing vs monthly treatment only yielded ½ line better acuity in 2 year trial • As needed dosing required 10 fewer eye injections with similar results, many pts may choose this option • Lasting improvements in vision with there two drugs is extraordinary • At two years, 2/3 of pts had driving vision (20/40 or better) while only 15% of pts retained similar visual acuity with previous tx • Source; www.nei.nih.gov/news/pressreleases/043012.asp

  37. Pathology • gradual destruction of cone cells • Drusen develops on surface of retina where atrophy is occurring • Gradual progression • Often unilateral for many years • No conclusive medical treatment-eye vitamins may help

  38. Side effect of Diabetes- most dangerous as can take vision rapidly, higher prevalence in African American, Native American, Hispanics, Pacific Islanders • Accounts for 9% of low vision referrals • Diabetes has multiple effects in eye-effects entire retina and can cause any level of vision loss including blindness • Only common eye disease causing varying patterns of vision loss because it affects blood vessels that support entire retina • 50% increased risk for cataracts for people over 50, with increased complications from cataract surgery • 2X incidence of chronic open-angle glaucoma than person without DR

  39. Disease of optic nerve although it starts in the Anterior Chamber of the eye Can result in blindness-most feared • Required good control with drops and frequent eye exams • Higher incidence in African Americans-significant visual loss • 13% of low vision referrals

  40. Glaucoma continued • Group of eye diseases • pressure inside eye is too high • traumatic • angle closure • low-tension • or open-angle glaucoma (most common) • all cause damage to optic nerve • 50% of people with condition do not know they have glaucoma

  41. Glaucoma • Aqueous production should equal outflow to maintain pressure within eye between 9-21 mm HG • Build up of pressure in anterior chamber • only outlet is optic disc • pressure decreases blood flow to nerve

  42. Cloudiness or opacification of lens • Occurs with advancing age • Dulls color • Blurs visual detail throughout visual field • Affects distance vision before near but eventually dulls both • Cataract surgery is most common surgery in US with natural lens removed and a synthetic intraocular lens implanted through 3 mm incision.

  43. Other vision deficits; • Parkinson’s Disease-difficulty with upward gaze and convergence-necessary for reading. • Hemi Field defect with normal acuity-result of CVA, TBI, brain tumor: hemianopsia, quandrantanopsia with reading difficulty, neglect, short term memory issues with loss of letter and word recognition. • Alzheimers disease-defects in color, depth and movement perception. • Refractive errors-myopia (near sighted), hyperopia (far sighted), astigmatism (cornea problems).

  44. Usually completed by low vision ophthalmologist or optometrist • Completed not to determine what is gone but what vision remains • Functional Vision • Always assess acuity, contrast sensitivity, visual field • Informal assessment-questioning • dark light sensitivity, glare • light sensitivity (photophobia), • phantom vision • color vision

  45. Ability to see small details at specific distance • Two types • Distance/Intermediate • Reading • In USA use Snellen equivalent fracture • 20/20 is normal • what a normal person can see at 20 feet • Actually it is the ratio of the test distance at which the smallest optotype subtends 5 minutes of visual arc (or angle) or minimum angle of resolution-MAR for short

  46. Factors to be considered when Assessing Visual Acuity • Lighting • Contrast • Specific chart used • Numbers of targets at each acuity level • Spacing of targets • Difficulty of the targets being identified (ie, letters, numbers, pictures, etc) • Single letter verses reading acuity • Type of letters (ie, block, serif, etc) • Ease with which the targets are identified • Expressive as well as receptive language skills • Cognitive functioning • Eccentric viewing (body position, eye/head posture) Source: Scheiman, Mitchell, OD, FAAO (2002). Understanding and Managing Vision Deficits-A guide for Occupational Therapists. Thorofare, NJ. Slack

  47. Measurement in the normal to near normal acuity range-stops at 20/200 (big E) • No measurement for vision worse than 20/200 or anything between 20/100 & 20/200 • Subjective measurement below 20/200: count fingers x number of feet (CF at X feet), hand movement (HM or HMO), Light perception only (LPO), no light perception (NLP)

  48. Intermediate Acuity • Discrete assessment in low vision range • intermediate distance of 1 meter • can measure to 20/1200 • best chart uses logarithmic progress • ETDRS chart (lomag Chart) is Gold standard • same # of optotypes per line • spacing between letters and rows are proportional to size of letter • 1 log unit between each level • enables letter by letter measure • Test procedure: dominate eye, non-dominate, together

  49. Ability to read text • tests near acuity to 20/400 • requires accommodation • Variety of test cards • Warren reading chart • MN read acuity chart • Lighthouse Children • Test procedure: reading glasses on; use both eyes; distance of 16 inches/40 cm; center at clients midline; start at top and read down as possible; record acuity at last line of text accurately read

  50. Determine level of visual impairment for billing services-OT paid on level of acuity • Snellen of metric acuity can be used to determine minimum magnification to read 1M size print-requires 20/50 to read newspaper • reduce until denominator is 1 • EX: 20/200=1/10 • magnifier needed at least 10X • Strength of Magnifier • Size M units read divided by size of goal M unit • EX: read 50M and want to read 1M Newspaper need 50X magnifier

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