Transcript The use of Colour in Vision

Colour and Vision
Sylvie Cringle
Orthoptist
Orthoptists – What we do!
Diagnosis and management of
disorders of visual
development, binocular vision
and ocular motility
Orthoptists – an extended role.
Treatment of
patients with
‘Specific
Learning
Difficulties’,
other reading
difficulties and
other ‘visual
disturbances’
Background
Degree Research Project
Pursuit of interest at Heart of England
NHS Trust
Courses/study
BIOS SLD SIG
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.
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
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
 ‘Can’t put ideas onto
paper’
 Frustration
 Lack of confidence
 Likes practical not
academic subjects
 Dislikes reading
Meares Irlen Syndrome (Visual
Stress) – Signs and Symptoms
Some of the main
symptoms are:
Signs include:
 Glare from the page
 Rubbing eyes when
reading
 Headaches when reading
 Excessive blinking
 Sore eyes when reading
 Movement/blurring of
print
 Tiring/inability to read
for long/ poor
concentration
 Loses place
 Dislike of reading
What causes the visual disturbances?
Two theories:
 Hyper-excitability in Visual Cortex (Pattern
Glare)
 Disorder of Visual Magnocellular system
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
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)
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
Orthoptic Assessment
 Detailed history
From child as well as
parents
 Visual Acuity
Distance
Near
With un-crowded
test?
 Cover Test
 Ocular Movements
 Convergence
 Accommodation
 Fusion
 Stereopsis
 Measurement
 Observation of reading
 Posture and movement
 Eye movements
 Types of Errors
 Dominant eye
 Assessment with
Coloured Overlays
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
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
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
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.
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.
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
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)
‘Surprisingly low VAs’
Straight eyes
LVA: 0.9 (6/48) Kays
 Normal Ophthalmological examination
 Refraction:
R + 7.00 DS L + 7.50 DS
Reduced prescription issued: R +5.00 L +5.50
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
Didn’t appear to be ‘overplussed’
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
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
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
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
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
Which patients can be helped?
Dyslexia
Meares Irlen Syndrome/Visual Stress
Migraine
Autistic Spectrum Disorder
MS
Parkinson's
Others?
Vision Tests
Coloured Overlays
Coloured Overlay Spectrum
Coloured lenses
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’
Any questions?
Thank You.