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Colour and 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.

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Colour and Vision

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  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. 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 Dyslexia – General signs and symptoms

  8. 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 Meares Irlen Syndrome (Visual Stress) – Signs and Symptoms

  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. 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 Orthoptic Assessment

  14. 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 Management

  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 • Didn’t 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. CaseThree: 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. CaseThree: 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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