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158 Cards in this Set
- Front
- Back
Australian definition of legally blind |
VA 6/60 or worse, VF +/- 10 degrees of fixation in better eye |
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Economic Blindness |
Cannot perform work for which sight is essential |
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WHO Definition of Low Vision |
6/18 or worse, VF Restriction within 10 degrees |
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Preventable causes of vision impairment (2) |
Trachoma and Cataract |
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Trends in Blindness Prevalence (First world) |
Decreased poverty-related blindness, Increase in age related blindness |
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Role of Optometrist and Low Vision (4) |
Identify Vision Difficulties, Treat where possible, Discussion, counselling and education, Refer where appropriate - ophthal, social worker, etc. |
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Central VA Defect; Functional Consequences (3) |
Peripheral functions and mobility in tact Central Vision - TV, reading, detailed tasks Mobility decreased in reduced contour environment |
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Central VA Defect Adaptation (2) |
Eccentric fixation Increase angular magnification (some environments) |
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Peripheral VF Defect; 3 types |
General Depression (opacities, pupil abnormalities, albinism) Peripheral constriction (glaucoma, RP) Visual pathway disease (hemianopia, quadrantanopia) |
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Peripheral VF Defect; Functional Issues (2) |
Reading (can't keep place) Mobility |
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Near Magnification (General) |
Relative magnification; bring things closer (pre presbyopes) Specs (high add bifocal, SV specs +/- prism) Magnifiers (hand/stand, loupes, near telescopes, telescope caps, electronic magnifiers) |
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Distance Magnification (General) |
Relative Magnification; bring things closer Telescopes (hand-held/spec-mounted, binocular/monocular) Electronic Magnifiers |
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Non-optical Vision Enhancement (2) Assists with? |
Lighting, contrast enhancement Glare reduction, colour adjustment Activities of Daily Living (ADL) |
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Demographic of blindness |
Ageing population Genetic vs environmental ageing |
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Senses and age |
Hearing (presbycusis) - talk low and slow Proprioceptive loss - posture, falls risk Decrease in taste and smell Very common disease - cardiac, hypertension, NIDDM |
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Normal Age-related Optical Changes; Pupil Size |
Senile mitosis, implicates media changes, benefits of high illumination, DFE |
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Age-related Optical Changes; Media changes |
decreased transmission, increased internal scatter, largest deficit at short wavelengths, increased glare sensitivity, CV changes, CS loss |
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Age-related Optical Changes; Decreased Retinal Illumination |
Scatter, absorption and miosis |
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Age-related Optical Changes; Neural changes |
fewer foveal photoreceptors and GC's |
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Age-related Optical Changes; VF |
depressed static perimetry, VF constriction, decr retinal illumination, neural loss, test - age matched normals |
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Age-related Optical Changes; Dark adaptation |
Decreased retinal illumination, implications - changing from light to dark (Falls), VA post DFE, ophthalmoscopy, etc |
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Age-related Optical Changes; VA |
Expect BCVA 6/6 even at 70 (lose <0.2 log units from young adulthood) |
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Age-related Optical Changes; Rx changes |
Hyperopic shift (changes in accom, latent hyperopia manifests) Myopic shift (PSCC< slow vs rapid) Incr ATR astigmatism (Steepening cornea in H meridian, astigmatic axes shift to ATR, reduced eyelid tension/pressure) Incr anisometropia (breakdown of BV, neural control?) |
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Age-related Optical Changes; Ocular Disease |
More prevalent in elderly, dilate annually/biannually, baseline fields, ARM, Cataract, glaucoma and diabetic retinopathy |
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Exam Tips (6) |
Emphasise general health, assist where needed, hearing issues, information processing, simple advice, time management |
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Case History; PC |
Define specific goals early (motivation), quantify task and how to implement it |
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Visual status with Current devices |
D and N bailey-lovie VA, consider condition (central vs peripheral loss), measure to threshold, contrast sensitivity |
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Distance Refraction (8) |
Prelims - preferred rx, Keratometry, Retinoscopy and objective rx, Radical Ret (alter WD for opacities), Larger steps, slower presentation times, health exam first, decr working dist and convert acuity |
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When to prescribe? (3) |
Quality of specs/device, significant improvement in VA, <1DS or <2DC unlikely to sig improve VIP VA |
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Near VA (5) |
Record monocular, speed and WD, start at +4.00D at 25cm, measure with increased illumination, Amsler grid, advise "good eye" for D and N |
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VF (6) |
Amsler grid (routine when reading, raw perception), confrontation (Gross assessment), Bjerrum screen, automated, hemianopias (LHS; affects mobility and reading - can't find next line, RHS affects mobility and reading - next word, turn page 90 deg), hemiplegia (hemi-neglect; loss of function without awareness) |
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Other tests (3) |
CV (not ishihara or central defects, Panel D15), BV (usually absent unless interocular diff >3lines VA, wandering 'blind' eye - discuss patching/frosting), Glare testing (photostress test, OCT) |
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OT role (9) |
Advice, assistance or devices, social and personal skills, everyday activities, communication, self-care, household activities, handling money, shopping, time and orientation, social and recreational activities |
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Social worker role (6) |
Assesses needs of VIP, info regarding resources and assistance, counselling (individual and family), lifestyle history, medical and VIP history, goals and referral |
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Orientation and mobility; GDQ (6) |
Free to VIP and their carer/colleagues, Skills assessment, O&M training, information on living with VIP, education for carers, mobility devices - canes, dogs, electronic devices, telescope training |
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Pensions and Travel Subsidies; Age or Disability Support Pension Responsibility? Criteria? |
Optom or Ophthal Snellen BCVA 6/60 or worse BE, VF Constriction to central 10 deg in better eye (or both) |
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Pensions and Travel Subsidies; DVA Blind Pension Responsibility? Criteria? |
Ophthal Same as Age/Disability CCTV's for free if eligible |
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Pensions and Travel Subsidies; VI Travel Pass Responsibility? Criteria? |
Optom, Ophthal or Medical Practitioner Same as blind pension Free public transport for VIP (not carer) |
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Pensions and Travel Subsidies; Taxi Subsidy Scheme Responsibility? Criteria? |
Ophthal Category 3; Total blindness or severe VI Half Price taxi vouchers |
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Assessing fitness to drive; VA |
Private; VA at least 6/12 in one or both eyes Commercial; 6/9 one eye and 6/18 fellow eye - flexibility with task Conditional licence if specs required Snellen or logMAR chart equivalent (5 letters on 6/12) 2+ mistakes - FAIL 3+m testing dist |
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Assessing fitness to drive; Private conditional licence Responsibility Criteria; VA and VF |
Ophthal or optom
VA and VF just below standard, px is alert, normal reaction times, good physical coordination |
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Assessing fitness to drive; VF |
Private; Horizontal extent of at least 110 and 10 degrease about midline Commercial; precluded if any defect, condition if binocular field >140 degrees and no scotomas, quadrantanopias, or hemianopia - no flexibility Screened by confrontation - defect assessed by automated peripmetry, fail --> Estermann Binocular Field Test (HFA) |
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Jet's Law |
Patient is required to inform authority if condition that affects ability to drive is diagnosed Fines and licence cancelled, insurance and legal implications |
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Responsibility to report fitness to drive |
Responsibility to report condition to drivers licence authority if condition affects ability to drive safely and refusing to stop. Mandatory at 75+yo |
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Telescopic lens (bioptic telescopes) and electronic aids |
No standards set; may reduce peripheral vision, individual assessment by opthal/optom |
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Practical Driving Assessment |
OT driving assessor |
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Licensing advice |
Maintain standards Px's legal responsibility; risk to self/others/property... |
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Medicare items and LV; Normal codes (9) |
10910, 10911, 905, 907, 915, 916, 918, 940, 941 |
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Medicare Items for Comprehensive Assessment (3) |
912 - Significant change in visual function - 2 line drop VA, incr in VF loss, or previously undetected VF loss (seen previously) 913 - New signs and symptoms, unrelated to previous consult 914 - progressive disorder (twice per year) |
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Medicare item 10942 |
Specifically for LV; twice/year, claim with 10910/10911, testing residual vision to optimise using specs, CS, glare sensitivity, magnification aids, BCVA < 6/15 or N12 in better eye, or H VF loss <120deg (10deg about H midline) |
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Medicare iten 10926 |
CL as part of telescopic system CL Consult if VA 6/30 or worse in BE and telescopic CLs 1/36, gives ~2.5x mag |
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10931-10933 |
Domiciliary visits In conjunction with comprehensive/subsequent consult Outside of consult room; home, aged care.... |
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Distance Magnification (Acuity); 2 types |
Relative enlargement; reduced WD Telescopes (angular enlargement) |
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VF Manipulation (4 types) and purpose |
Reverse telescope, negative powered lenses, prismatic specs, mirrored specs Orientation and Mobility |
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Disadvantages of Telescopes |
Reduced FOV; can't use whilst mobile, use for spotting Light lost at each surface; image is dimmer |
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Magnification of a telescope (equation) |
M = -F eyepiece/F objective |
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3 numbers to describe telescope |
Magnification, aperture size (mm), field extent visible through telescope (FOV) |
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Keplerian vs Galilean Telescopes |
Keplerian; Astronomical, 2 convex lenses, inverted image rectified with prisms, longer and greater FOV than Galilean Galilean; Convex objective, concave eyepiece, eyepiece closer than focal length of objective, rays exit parallel erect image, no prisms - cheaper, smaller, more robust |
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Distance Magnification Equation |
Mag = (angular height of object through magnifier, image)/(angular height of object to eye, object) |
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Prescribing Distance Magnification (3 steps) |
eg. BCVA 6/60 1. Estimate required acuity (+ some reserve, 6/9.5) 2. Calculate magnification required (e.g. 60/9.5 = 6x) 3. Trial Device |
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Estimated VA for everyday tasks; Blackboard Watching TV Driving |
6/12-6/15 6/12-6/15 6/12-6/18 |
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Assessing telescope of unknown power |
Magnification; compare one eye mag and normal images; ratio = approx mag FOV; how much of known object you see at known distance; eg. 60cm at 5m - field in radius = 0.6m/5m radians = 0.12 radians = 6.9 deg |
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Bioptic telescope |
Telescope mounted on carrier rx lens Dip head to incr mag Hands-free drivin |
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Distance electronic magnifiers; Autofocus |
Attach to VDU to enlarge test Adjustable magnification, good FOV, auto focussing. Can increase image brightness/contrast, revers contrast. Head-mounted/hand-held, binocular/monocular Very expensive, not as portable |
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CL + Specs |
High minus CL (eyepiece) and high plus spec lens (objective). Give erect, magnified image Increase FOV ~ -30 to -45D RGP with +22D Specs (12mm BVD) gives ~2x mag |
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Limitations of Telescopic CL + Specs (5) |
Ocular intolerance of CL
Cosmetic appearance of high + specs Limited functional field Rapid and opposite movement of VF with head movement Difficult to adapt to extended periods of magnification |
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VF Manipulation; reverse telescope or neg powered lens How it works? What it's used for? What condition requires it? |
Incr FOV, decr VA (minification) High neg lens held 10-30cm from eye; Lens = objective, accom = eyepiece, potentially spec mounted (Reverse telescope) Useful for navigating around objects, doorways, landmarks, hazards Used in; RP, end stage glaucoma Require GDQ training |
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VF Manipulation; Prismatic Specs How it works? What it's used for? What condition requires it? |
Right angled prism; base towards defect, apex to usable field, mounted in front of non-seeing field. Stick on peripheral Fresnal prisms. Vertical separation gives greater peripheral expansion. Reduced eye/head movements required to scan environment Hemianopic field loss Require training and adaptation period |
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Gottleib VF Awareness System (VFAS) |
One prism only on side of VF loss |
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Non-optical aids (3) |
Improving contrast Lighting and other non-optical systems Refer to other rehabilitation services |
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Near magnification |
By convention, reference distance ~25cm M = height image viewed through mag/height object at 25cm M = F/4 (or M = 1 + F/4, assumes 4D accom) Fe is equivalent power for thick lens - manufacturers supply BVP or FCP not Fe >+6D is inaccurate |
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How to prescribe for near |
1. Dist rx 2. Current, increased and +4.00D near add (25cm) VA 3. Determine good print size and reserve 4. Calculate EVD (log progression or ratios) 5. Test most appropriate device for the EVD 6. Revise device, trial different devices, loan 1/12 7. Review |
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Reading Performance (wpm); Acuity Reserve (logMAR lines) and FOV (# characters) for scrolled and static Spot (40) Fluent (80) High fluent (160) Optimum |
Acuity Reserve - FOV scrolled - FOV static 1 - 1 - 2 3 - 2-5 - 5 5 - 4-6 - 12 8-12 - 4-6 - 16-20 |
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Approx print sizes; Snellen (40cm), logMAR (25cm), Uses N5 N6 N8 N10 N12 N16 |
6/9.5 - 0.4 - Small ads, bibles 6/12 - 0.5 - telephone book 6/15 - 0.6 - Newspaper 6/19 - 0.7 - Magazines/books 6/24 - 0.8 - typed print 6/30 - 0.9 - Children's books |
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Calculating EVD |
equivalent viewing distance - similar to focal distance in optical system (inverse of power). EVD (cm) = (req'd print size/current print size) x curr WD (cm) Or cross multiply By log steps |
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Determining Near Mag |
1. Define goal; specify performance objective 2. Measure current near VA and WD with appropriate add 3. Calculate EVD |
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Calculating High Near Addition |
Pick an add to allow them to see EVD from spec; total add for pre-presbyope Need to calculate for pre-presbyope - 1/2, 1/3, no reserve amps |
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Issues with near adds (5) |
Single vision or adds in specs up to 50D Better in young pxs than old Postural and psychological issues Try as first option Binocularity; Adds >8D need BI prism, rule of thumb: 1∆ for every D over 4D, Prism = near rx - 4 |
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Hand magnifier; How it works How to alter What it depends on |
Object at focal length; bring eye closer to magnifier to increase FOV, emergent vergence = 0 (light is not collimated) If magnifier too close to page; 1 - need to accommodate (emerging light divergent), 2 - magnification is less, but FOV Is increased Magnification depends on eye-lens distance (EVD varies), Px needs to be focussed on image - requires near add; Near add = 1/(eye-image distance) |
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Stand magnifier; |
Look up tables (old), calculations based on WD, EVD, most manufactured for +2.50 or +4.00 Add (based on eye-image distance) |
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Calculating Stand magnifier Add |
Try appropriate add (1/eye-image distance), Existing near rx |
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Stand vs Hand Magnifiers |
Hand; smaller, flexible, but require steady hand, can augment with spec add Stand; fixed distance, bulkier but steady, may have to augment with spec add |
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Near telescopes |
Modify distance telescope by screwing on plus lens (lens cap), can use diet and near task with same telescope - usually small EVD (4-5cm)
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EVD of near telescope |
Treat lens cap as hand magnifier or add and calculate EVD, then take into account magnification of telescope; EVD system = EVD lens cap/M telescope |
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FOV considerations of near magnification |
eye-lens distance approx inversely proportional to FOV. FOV approx proportional to lens diameter Specs and adds should have best FOV - then loupes |
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Magnifiers FOV |
Increased Eye-lens distance - more comfortable, smaller FOV High power mags - need to get close to magnifier to get usable FOV Power increased, overall diameter decreases, FOV decreases |
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CCTV |
Desktop/computer connected, 2-70xmag, variable, large FOV, distortion free. Pos and Neg contrast enhancement, flexible viewing distance, use for near tasks - one hand to move xy platform/camera, expensive $3-10k |
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Portable hand-held electronic magnifiers |
D/N, portable, distortion free, contrast enhancement, glare reduction, colour adjustment Expensive $500-$4000 |
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VDU-Connected Digital Camera |
Camera on flexible arm, D/N viewing, high levels mag, save images to VDU, magnified and enhanced images, lightweight, slightly portable, some models and software enable test to speech, refreshable braille, expensive $5000 |
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Software |
Inbuilt, enlargement (Free-$1k), text to speech ($2-5k) |
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E-readers/tablets (4) |
Magnification, talk to text, apps, refreshable braille |
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Funding for Low Vision Aids/CCTV |
Outside Medicare, tax deductible, some health funds up to $500, QBA financial assistance, DVA, work aids fully funded |
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Onward referral (6) |
Quantum or Humanware, QBA, Lifetec, GDQ, Vision Aus, Mac Degen Foundation |
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Lighting as a non-optical aid; how it helps Advice (5) |
Big difference, intensity and position of source; inverse square law - l = 1/d^2, increased intensity, decr distance (or both). Portable/adjustable lamps +/- built in mags Advice; back to window (Reduce glare), direct lighting from behind, flexible arm (gooseneck arms), good lighting in falls risk areas, avoid looking directly at bright light |
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Contrast |
Highlight differences by optimising/enhancing contrast. Plain (white/non-patterned) b/ground and contrasting (coloured/patterned) foreground |
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Glare; Prevent with (6), relevant in (3) |
Sunnies, visor/hat, cover shiny surfaces, close blinds, adjust TV viewing position, chair near doorways to dark/light adapt Relevant in; Cataracts (PSCC), RP, albinism |
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Occupational Therapist; assist with... Home assessment |
Assist with ADL; reading/writing, phone, socialising, time, money, shopping, sewing, cleaning HACC: Home and Community Care officer - home assessment |
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Reading; (6) |
large print books, audio libraries, podcasts, text to talk, e-Books, 4RPH; 1296AM blind radio station |
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Writing |
Magnifiers, good to read, hard to write Large print, tactile address books/organisers Writing frames, signature guides Raised line/bold writing paper, thick pens Future; touch typing with magnification |
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Kitchen (4) |
Liquid level indicators, talking scales/measures, tactile markers, non-slip trays, food plate surrounds |
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Around the house |
Talking/tactile watches, clocks, tape measures, needle threaders, games, large phone, money identification, magnified mirrors, diabetes; syringe guides and magnifiers |
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Social worker (3) |
Information on community resources (Travel, pension, taxis, libraries, community groups) Counselling client and family Assess early on and follow up over time |
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Travelling, O&M; Identification Cane |
Sternum to shin, held in front not touching floor Identify that this person is VIP navigate objects in arms reach, thin and lightweight |
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Travelling, O&M; Long/Mobility cane |
Sternum to ground, rolling ball tip Held forward with tip on ground Move side to side to feel terrain and warn of objects |
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Travelling, O&M; Support cane |
Normal walking stick, painted white |
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Travelling, O&M; Cane Advice (2) and limitations |
Recommended on referral from O&M training, safety and postural issues Cane limitations; can't detect objects above waist height or 1+m away |
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Travelling, O&M; Ultrasound |
Used with cane or guide dog Can pick out overhead objects or doorways, etc. Vibration changes with distance to object, different buttons for different heights - training required. |
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Travelling, O&M; Guide Dogs |
Assist VIP travel, entitled to travel anywhere VIP with proficient mobility aid ability |
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Communication with VIP (7) |
Signal presence in a room, announce if you're leaving, speak directly at person, don't shout, ask if they need assistance, refer for O&M always, explore O&M in case hx |
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Psychosocial Implications of VI; Acquired VI Impact Coping ability depends on (4) Modern attitude |
Impact on QOL and ADL Type of vision loss (congenital, chronic, stable, etc...), personality (anxious, independent, motivated), Life stage (education, working, retired), Support network (family, friends, carers) Previously; stigma. Current; realistic, technology, awareness |
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Psychosocial Implications of VI; Patient response 5 Stages Acquired Adaptation (3) |
Denial (multiple opinions, expectations). Grief OR bargaining. Anger. Depression. Acceptance. Mourning process Skills to restore independence and control, participation and socialising overcomes depression. Redefining identity |
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Psychosocial Implications of VI; Family Involvement Advocating (4) Avoiding (4) |
Advocating; improve understanding, support, retain and reinforce ideas/strategies, Promote discussion and sense of involvement. Avoiding; hinders patient openness, over-involvement in discussions, doesn't promote independence, confidentiality/privacy issues |
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Psychosocial Implications of VI; Social interactions |
Central Vision loss especially (Facial recognition and expression, handwriting, eating, eccentric viewing) |
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Psychosocial Implications of VI; Psychological Adaptation |
Duration of VI affects acceptance/denial, increased risk of depression |
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Psychosocial Implications of VI; Depression signs/symptoms |
Mood, irritable, frustrated. Less time with family/friends/enjoyable activities, Awake through night, alcohol and drug use, fatigue and pain, rekless/risk taking |
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Psychosocial Implications of VI; Driving |
Marker of independence, warn young VIPs of options in the future Older VIPs giving up licence - plan ahead (public transport), discussion with family/firneds |
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Psychosocial Implications of VI; Assessment of QOL |
Psychological assessment tools Vision Specific Assessment tools; AVL (adaptation to age-related vision loss scale), NEI-VFQ 25 (National Eye institute Visual Functioning Questionnaire 25, most common, 3 parts), LVQOL (Developed for LV assessment, 4 parts) |
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Psychosocial Implications of VI; Charles Bonnet Syndrome (CBS) |
Visual hallucinations, psychological normal px's with significantly decreased vision (central typically), vivid, realistic, aware of non-real nature, frequency/duration varies, trigger is usually change in illumination, 10-40% VIPs |
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Psychosocial Implications of VI; Charles Bonnet Syndrome (CBS) Risk Factors Mechanism Management |
Risk; 64+yo, social isolation, poor lighting, stroke history Mechanism; Deprivation theory (reduced input, spontaneous image from cortex), Release theory (abnormal signals from pathology) Mx; reassurance, sympathy, incr illumination and socialising, refer if suspected neurological disorder |
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Psychosocial Implications of VI; Dementia Cause |
Impaired cognitive abilities interfere with occupational and social activities, progressive and degenerative. Alzheimer's Disease (50-80%), Vascular dementia (7-15%), mixed (10-20%), Other (Lewey Body, Frontal Lobe) |
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Psychosocial Implications of VI; Alzheimer's Disease 4 Stages Visual Consequences (4) |
Neurodegenerative disorder 1 - Pre-dementia (mild cognitive impairment. 2 - early-mild AD. 3 - Moderate AD. 4 - Advanced/Late AD Loss of RGCs, plaques and fibrils in LGN, visual cortex atrophy (retrograde degeneration of cortical neurons - decreased CS, stereopsis, visual hallucinations 25-50% pxs), RNFL Thinning |
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Psychosocial Implications of VI; Alzheimer's Histopathology (4) Modify consult |
Neurofibrillary tangles, amyloid plaques, gross decrease in weight and volume (hippocampus, temporal and frontal lobes), increased ventricle size Carer present, longer appointments |
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Psychosocial Implications of VI; D/Dx - depression and Alzheimer's |
Loss of mental sharpness in age can be depression or dementia - involve GP Rapid mental decline vs Slow Knows time/date/orientation vs Confused/disorientated Difficulty concentrating vs difficult short term memory Normal, slow language, motor skills vs impaired writing, speaking and motor skills Notices/worries about memory problems vs doesn't |
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Paediatric Low Vision; Prevalence Causes (4) |
Low prevalence 2-6% 0-15yo's. 28% cortical vision impairment (&organic pathology), 11% albinism/nystagmus, 7% ROP, 6% optic atrophy |
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Paediatric Low Vision; Cortical Vision Impairment Definition Tests Caused by (5) Associated impairments (5) |
Reduced VA/VF due to occipital cortex abnormality. Confirmatory (imaging/electrophysiological testing) required. Major causes; asphyxia, brain maldevelopment, head injury, infection, chromosomal anomalies Assoc; variable responses, peripheral viewing, light gazing or photophobia, preference for colours, respond well to motion |
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Paediatric Low Vision; Albinism What it is? Findings Tx |
Oculocutaneous (+/- tyrosinase); lack pigment, glare sensitive, +/- Pendular horizontal nystagmus Usually astigmatic refraction, foveal and ONH hypoplasia, VF 6/30-6/60 Pigmented CL for glare |
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Paediatric Low Vision; ROP 5 Stages Findings Tx |
1 - Demarcation line. 2 - Ridge. 3 - Fibrovascular proliferation into vitreous. 4&5 - Tractional retinal detachment, cicatrical moderate to severe myopia, VA 6/15-CF PRP, vitreoretinal surgery if detached |
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Paediatric Low Vision; Optic Atrophy Causes (3) D/dx (1) Hereditary forms (2) Findings (4) |
Permanent loss of function to part/all of ON Metabolic, toxic, nutritional ONH glioma Ture congenital (6/6-6/30, slow progressing, stable), Leber's (spontaneous ONH blow out, 6/60, males, late teens-20s) Disk pallor, Kestenbaum's sign, CVD, central/paracentral scotoma |
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Paediatric Low Vision; Assessment |
Involve parents/teacher Visual tasks; school work/interests/hobbies Dist VA; normal paeds Near VA; school work/writing material Objective tests; auto-rx, retinoscopy, keratometry Binocularity; <10% binocular CV; Panel D-15, City University VF: verbal children, info for parent/teacher/O&M, eccentric fixation |
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Paediatric Low Vision; Profile of Visual Behaviour Background |
Vision conditions, LV aids, Nystagmus/unusual eye movements, head tilt/turn, other conditions (intellectual, hearing, GH, meds) |
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Paediatric Low Vision; Profile of Visual Behaviour Visual responses |
Eye contact, looking at own hands, visual response with meals - irritated by touch/sight, objects that elicit visual response, favourite colours, touching own eyes/waving hands |
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Paediatric Low Vision; Profile of Visual Behaviour Observed Responses to environment |
Time of day when most responsive, familiar/unfamiliar surroundings |
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Paediatric Low Vision; Disruption of Emmetropisation Skew Onset |
Skewed towards myopia; peripheral +/-central VI - myopia, Central VI - Hyperopia. Normal distribution by 75% rx outside emmetropia. Earlier onset; increased disruption in refractive development; critical period. Birth/congenital - myopia. 1-30yo; hyperopia. 7+yo; no sig effect on Rx error. |
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Paediatric Low Vision; Prescribing Optical Devices Principles (2) Aims (3) Common Devices (4) Considerations (3) |
Same principles as adults; VT/environment, accommodation. Aim to develop abilities, maximise residual vision, develop self confidence Specs (bifocals), telescopes, Dome stand magnifiers, electronic magnification (iPad, e-reader, CCTV) Decrease working distance, enlarged notes, modified VDU's/software, etc. |
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Paediatric Low Vision; Educational Implications |
Majority of learning through vision Specialised strategies to learn new skills and more time consider; presentation format, equipment, technology, time, accessibility, mobility, preview/review material, environment (lighting/glare) |
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Paediatric Low Vision; Qld Govt Support |
Advisory visiting teachers, specialist support teachers, education programs, community/non-school organisations, Physios, OTs, Speech pathologists |
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Paediatric Low Vision; PLVC - Paediatric Low Vision Clinic |
Dept Education and training, <6-7yo, specialised vision assessment, support and information, understanding of individual VI and behaviours |
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Paediatric Low Vision; Definition of VI by Dept Education |
Mild/No VI; >6/18 Moderate VI; 6/18- 6/60 Severe VI; 6/60 - 6/120 Blindness; 6/120 and worse |
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Paediatric Low Vision; Evidence of VI (3) |
Diagnosed by ophthal, neurologist or paediatrician (CVI) Document evidence of activity/participation limitation from VI in curriculum/learning enviro by VI trained teacher Evidence of VI impact on school life by discussions with px, parents, school... |
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Paediatric Low Vision; Narbethong State Special School |
Education for VI +/- disabled, deaf students Staff; teachers, aides, therapists, nurse, guidance officer, volunteers Active learning, use all senses, encourages exploration Primary and High school |
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Paediatric Low Vision; Braille 3 Levels Modern |
Tactile writing, small raised blocks/cells arranged 3x2 3 levels - letter by letter, abbreviations/contractions, personalised shorthands Refreshable braille; linked to VDU/iPhone Diminishing use |
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Paediatric Low Vision; Diversional Therapy |
Recreation and leisure activities, encouraging participation, socialising and wellbeing |
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Paediatric Low Vision; ERG |
Electroretinography; measures electrical activity of retina when stimulated by light Active electrode in eye (foil CL), Reference electrode nearby (forehead), Earth (Ear) Isolate rod/cone response; diagnose Stargardt's etc... |
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Paediatric Low Vision; VEP Measures Detects (6) Reported as... (3) |
Visually Evoked Potential; electrical potential initiated by brief visual stimuli, recorded by electrodes overlying visual cortex (Scalp) Measure functional integrity of visual pathways from retina via ON to cortex Cortical blindness, optic neuritis, optic atrophy, stroke, tumours, amblyopia. Affects latency and peak, pattern VEP isolates location |
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Future of LV rehabilitation; Wet ARM - PDT |
Photodynamic therapy (Visudyne Laser) Initial tx of wet ARM and chronic CSR, visudyne injected in peripheral vein, activated by laser targeting leaky vessels, risk severe sunburn (no sun 3 days), improvement (if any) slow over months |
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Future of LV rehabilitation; IVI's - Anti-VEGF |
Wet AMD, DR, occlusive disease. Macugen (6/52, first, low stroke risk, inhibits one strain VEGF) Avastin (colorectal cancer, cheap, 1/12 until stable, then prn) Lucentis (inhibits several strains of VEGF, dose 1/12 until stable, then prn) |
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Future of LV rehabilitation; IVI's - Steroid |
Kenalog; alone or with Anti-VEGF, macular oedema, posterior uveitis, DR, RVO, slows VA loss rate, risk steroid response Ozdurec; biodegradable implant, oedema for RVO, uveitis, rapid reduction in retinal fluid post 1-12/12, remains 4/12 - risk steroid response, invasive procedure |
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Future of LV rehabilitation; IVI's - risks Minor (1) Major (4) |
Minor; SPK post betadine wash Major; infection, intraocular haemorrhage, retinal tear/detachment, IOP spike |
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Future of LV rehabilitation; IVI's - Optom Mx |
Co-manage px, commitment ($$), frequency, antibiotics, ophthal communication |
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Future of LV rehabilitation; Future of IVI |
Cheaper, disease-specific medications, fewer doses Eyelea - dose 2/12 after loading phase (3/12 IVI), comparable VA to 1/12 Lucentis, reduced Px time, cost and discomfort Combination agents; Anti-VEGF + Steroid, Anti PDGF (platelet-derived growth factor) + Anti-VEGF |
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Future of LV rehabilitation; Pre-clinical Wet ARM Diagnosis (2) |
Clinical test to predict conversion from dry to wet ARM by blood test - Endothelial progenitor cells (EPCs); rare cell populations, elevated in dry vs wet ARM, examine with fluorescence activated cell sorting (FACs). Radiation therapy (UK); expensive, 1 treatment, Side effects unexplored |
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Future of LV rehabilitation; Retinal Regeneration/Transplant Obstacles (4) |
Donor tissue/stem cells Animal studies 1940s-1980s Human studies; no improvement in objective visual function measures Obstacles; Blood supply, rejection, photoreceptor organisation, vision quality |
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Future of LV rehabilitation; Gene therapy |
Congenital blindness, key chemical from visual cycle missing, gene augmentation to correct biochemical cascade, virus vector - sub-retinal injection post vitrectomy, good short-term improvement |
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Future of LV rehabilitation; Bionic Eye 2 designs How it works |
Wide-field design; navigation, independence, identify large objects (end stage glaucoma and RP) High resolution design; face recognition, large print (AMD, Central vision loss) Combination with sub-retinal visual implant; light absorbing elements convert light to electrical impulses (req clear media, no inner-ret or visual pathway pathology) Camera; digitises image, Processor; reduces noise/image enhancement |
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Future of LV rehabilitation; Bionic Eye issues Alternative |
Biocompatability, implant size, accurate placement of implant and protection from heat of electrical current, low contrast/gaps in vision Tactile corneal stimulation |
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Future of LV rehabilitation; Microperimetry |
Comine retina function and structure; with Spectralis OCT for adequate morphology/functional prospective information |
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Future of LV rehabilitation; Adaptive Optics |
Measure and correct aberrations of eye in real time, visualise pathologies and improve VA in VIPs, count active/living cones |
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Future of LV rehabilitation; Technology LV aids |
VDU (mag, talk/text), CCTV (monitors/speech, portable), Mobile phones (mag, talk/text, colours), eReaders (kindle, iPads), Intraocular telescope (IOL-type implant), Telescopic CL, Braille Smartphone, OrCam (attached to specs, speaks to px), Glaucoma medication delivery (punctal plugs, CLs), Pharmacological CBS agents (low-dose antipsychotics, cholinesterase inhibitors, tricyclic anti-d's, serotonin reuptake inhibitors), Haptic wheelchair (GPS, laser, feedback), Haptic shoe (proximity sensor, direction, vibration), Be My Eyes App, See Eye Vest, Robotic Vision Glasses (Ultrasound, GPS, stereoscopic), Eli Pelli Specs (augmented reality, mag and contrast), Google glass and CL |