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Colour and Vision

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Colour and Vision Sylvie Cringle Orthoptist ... used at home for reading Offered referral for Colorimetry assessment with possibility of precision tinted lenses. – PowerPoint PPT presentation

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Title: Colour and Vision


1
Colour and Vision
  • Sylvie Cringle
  • Orthoptist

2
Orthoptists What we do!
  • Diagnosis and management of disorders of visual
    development, binocular vision and ocular motility

3
Orthoptists an extended role.
  • Treatment of patients with Specific Learning
    Difficulties, other reading difficulties and
    other visual disturbances

4
Background
  • Degree Research Project
  • Pursuit of interest at Heart of England NHS Trust
  • Courses/study
  • BIOS SLD SIG

5
Reading Difficulties
  • General Learning difficulty
  • Low intelligence
  • Medical reason
  • Specific Learning difficulty
  • Dyslexia
  • Meares Irlen Syndrome (Visual Stress)
  • Other causes
  • Physical disabilities such as poor vision or
    hearing
  • Lack of knowledge of the English language
  • Lack of exposure to printed material
  • Lack of important pre-reading skills such as the
    ability to recognize letters and the ability to
    attach sounds to letters.

6
Dyslexia What is it?
  • Literally Word Blindness
  • 4 of GB population severely affected
  • Affects boys 3 times more than girls
  • Genetic component
  • Normal or above average intelligence
  • Difficulty in reading/writing
  • Often not diagnosed and children left to struggle

7
Dyslexia General signs and symptoms
  • Difficulties with
  • Reading, writing and spelling
  • Sequences
  • Short term memory
  • Copying
  • Mental arithmetic
  • Directions Left and Right
  • Reverses numbers and letters
  • Cant put ideas onto paper
  • Frustration
  • Lack of confidence
  • Likes practical not academic subjects
  • Dislikes reading

8
Meares Irlen Syndrome (Visual Stress) Signs and
Symptoms
  • Some of the main symptoms are
  • Glare from the page
  • Headaches when reading
  • Sore eyes when reading
  • Movement/blurring of print
  • Signs include
  • Rubbing eyes when reading
  • Excessive blinking
  • Tiring/inability to read for long/ poor
    concentration
  • Loses place
  • Dislike of reading

9
What causes the visual disturbances?
  • Two theories
  • Hyper-excitability in Visual Cortex (Pattern
    Glare)
  • Disorder of Visual Magnocellular system

10
Pattern Glare
  • Exaggeration of normal phenomenon
  • Visual symptoms when viewing stripes depends on
    spatial frequency of the stripes
  • Spatial frequency of 3 cycles per degree
  • Uncomfortable patterns visual distortions
  • Symptoms alleviated by coloured filters

11
Visual Magnocellular System
  • Directs visual attention and eye movements to
    identify letter order
  • Visual magnocellular weaknesses may cause visual
    perceptual instability, hence letter position
    confusions
  • Magnocells maximally activated by medium and long
    wavelengths (yellow)

12
Assessment of patients with reading difficulties
at H of E NHS Trust
  • Referrals received
  • Questionnaire sent to bring completed to
    appointment along with book
  • Orthoptic assessment with additional tests
  • Observation/assessment of reading
  • In line with the BIOS SLD clinical guidelines

13
Orthoptic Assessment
  • Accommodation
  • Fusion
  • Stereopsis
  • Measurement
  • Observation of reading
  • Posture and movement
  • Eye movements
  • Types of Errors
  • Dominant eye
  • Assessment with Coloured Overlays
  • Detailed history
  • From child as well as parents
  • Visual Acuity
  • Distance
  • Near
  • With un-crowded test?
  • Cover Test
  • Ocular Movements
  • Convergence

14
Management
  • Appropriate Refractive correction
  • Orthoptic Exercises or other treatment
  • Convergence
  • Accommodation
  • Fusional reserves
  • Tracking
  • Occulsion
  • Coloured overlay trial
  • Practical advice
  • Movement whilst reading
  • Font type and colour
  • Coloured pens/paper/computer screen colour
  • Position in class
  • Liase with class teacher/SENCO
  • Colorimetry and Precision Tinted lenses

15
Case One The Double Whammy
  • 70 year old Male
  • ARMD
  • RVA 6/38 LVA 6/24
  • Unable to drive
  • Struggling to read
  • Magnifier helps
  • Additional symptoms of movement of print
  • Orthoptically satisfactory
  • Chose purple overlay which relieved symptoms
  • Known Dyslexic

16
Case Two Unexplained visual symptoms
  • 30 year old female, Librarian
  • Referred from main clinic
  • Normal Ophthalmological examination
  • Low myopic/astigmatic correction
  • Symptoms
  • Uncomfortable in bright light
  • Movement of print
  • Shadowing/halo around print
  • Tired Eyes
  • Frontal Headaches

17
Case Two Unexplained visual symptoms
  • VAs R and L 0.3 (6/12) great discomfort
  • Eyes more comfortable with unilluminated chart
  • Orthoptically satisfactory, just Slight CI
  • Chose lime green and mint green overlays
  • VAs immediately improved with these to
  • R and L 0.1 (6/7.5) and symptoms decreased.

18
Case Two Unexplained visual symptoms
  • 3/12 review
  • RVA 0.3 (6/12) LVA 0.4 (6/15) BL
  • RVA 0.1 (6/7.5) LVA 0.2 (6/9.5) u/c Keeler
  • Overlays do help but impractical for her job
    used at home for reading
  • Offered referral for Colorimetry assessment with
    possibility of precision tinted lenses.

19
Case Two Unexplained visual symptoms
  • On discharge
  • RVA -0.1 (6/4.8) LVA 0.0 (6/6) BL
  • Read with ease, no discomfort
  • Symptoms now less
  • Eyes less tired
  • Overlays help with reading at home
  • Not keen for Precision tinted lenses - cosmetic
    issue

20
Case Three Unexplained reduced VAs
  • 5 year old Male (A)
  • Referred by community optician
  • Age 3 years 8 months
  • Parents/nursery concerned re Vision
  • RVA 1.0 (6/60) LVA 0.9 (6/48) Kays
  • Surprisingly low VAs
  • Straight eyes
  • Normal Ophthalmological examination
  • Refraction
  • R 7.00 DS L 7.50 DS
  • Reduced prescription issued R 5.00 L 5.50

21
Case Three Unexplained reduced VAs
  • 3/12 Review
  • Glasses worn full time
  • R and LVA 0.65 (6/24-2) Kays
  • Straight eyes
  • Seen regularly to monitor VA
  • Full prescription of R 6.00 L 6.50 issued at
    annual refraction
  • Cooperation/concentration with VA test always
    noted to be poor
  • VAs remained reduced for age
  • Didnt appear to be overplussed

22
Case Three Unexplained reduced VAs
  • Age 5 years
  • R and LVA 0.5 (6/19) BL
  • (sgls R and LVA 0.7 (6/30))
  • Still no increase in VA if lenses decreased.
  • Glasses still worn fulltime
  • A comments that VA better cgls.
  • Still no Ophthalmological abnormalities
  • Age 5 ½ years
  • Now has small RCS and R amblyopia
  • RVA 0.62 (6/24-1) LVA 0.44 (6/15-2) BL

23
Case Three Unexplained reduced VAs
  • Electrodiagnostic Tests performed
  • VEPs and ERGs entirely normal in each eye
  • So normal, retinal, macular and optic nerve
    function in each eye
  • Parents commented that VA had also been tested
    and found to be normal
  • Single optotype test used
  • A now struggling at school
  • Almost 6 years old
  • Reading difficulties
  • Difficulties seeing whiteboard

24
Case Three Unexplained reduced VAs
  • Age 6 years
  • RVA 0.7 (6/30) LVA 0.3 (6/12) Keeler cr
  • RVA 0.4 (6/19) LVA 0.1 (6/7.5) Keeler ucr
  • Reading assessed
  • Guesses words
  • Rubs eyes
  • Blinks excessively
  • Difficult for A to describe if symptoms present
  • Coloured Overlay
  • Appeared to prefer orange and acqua overlays

25
Case Three Unexplained reduced VAs
  • Age 6 ½ years
  • R amblyopia being treated
  • RVA 0.54 (6/19-2) LVA 0.34 (6/12-2) BL
  • RVA 0.45 (6/15-2) LVA 0.15 (6/7.5-2) K ucr
  • Doing much better at school
  • Now has extra help at school and home
  • Uses orange overlay
  • Uses bigger print
  • Sits closer to whiteboard
  • Review ongoing

26
Case Four Asthenopic Symptoms
  • 14 year old girl
  • Symptoms of difficulties including eye strain
    and headaches when reading
  • CI and Accommodation insufficiency treated with
    exercises
  • Symptoms remained despite satisfactory Conv and
    Accomm
  • All symptoms relieved when issued with coloured
    overlay

27
Which patients can be helped?
  • Dyslexia
  • Meares Irlen Syndrome/Visual Stress
  • Migraine
  • Autistic Spectrum Disorder
  • MS
  • Parkinson's
  • Others?

28
Vision Tests
29
Coloured Overlays
30
Coloured Overlay Spectrum
31
Coloured lenses
32
Conclusions.
  • Reading difficulties and visual symptoms can
    present at all ages
  • Be aware of other possible diagnoses
  • Importance of observation
  • Detailed questioning re reading skills/ability at
    school
  • Patients may not just have one problem
  • Keep an open mind Think outside the Box

33
  • Any questions?

34
  • Thank You.
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