colour and vision
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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. - PowerPoint PPT PresentationTRANSCRIPT
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
affectedAffects boys 3 times more than girlsGenetic componentNormal 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 SymptomsSome 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
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 receivedQuestionnaire sent to bring completed
to appointment along with book Orthoptic assessment with additional
testsObservation/assessment of readingIn 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 symptoms30 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)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
Case Three: Unexplained reduced VAs3/12 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 Symptoms14 year old girlSymptoms of difficulties including ‘eye
strain’ and headaches when readingCI and Accommodation insufficiency
treated with exercisesSymptoms remained despite
satisfactory Conv and AccommAll symptoms relieved when issued
with coloured overlay
Which patients can be helped?
DyslexiaMeares Irlen Syndrome/Visual StressMigraineAutistic Spectrum DisorderMSParkinson'sOthers?
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.