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Dr. Natasha Healey PhD BSc ( Hons ) MCOptom 31 st May 2014

The NINA Study. The Northern Ireland Nystagmus & Albinism Study. Dr. Natasha Healey PhD BSc ( Hons ) MCOptom 31 st May 2014 Dr Julie McClelland, Dr Kathryn Saunders, Prof Jonathan Jackson, Ms Eibhlin McLoone. Contents. Albinism - Background and subtypes - Ocular Features

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Dr. Natasha Healey PhD BSc ( Hons ) MCOptom 31 st May 2014

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  1. The NINA Study The Northern Ireland Nystagmus & Albinism Study Dr. Natasha Healey PhD BSc (Hons) MCOptom 31st May 2014 Dr Julie McClelland, Dr Kathryn Saunders, Prof Jonathan Jackson, Ms EibhlinMcLoone

  2. Contents • Albinism - Background and subtypes - Ocular Features - Visual Symptoms • Northern Ireland Nystagmus & Albinism (NINA) Study - Background - Results

  3. Background • Albinism term used to describe a group of disorders with absent or reduced melanin production • Results in hypopigmentation of the hair, skin and eyes • Prevalence: 1 in 20,000 worldwide 1 in 10,000 **N. Ireland ** NEW Results

  4. Albinism 2 broad categories exist:

  5. OCA1A

  6. OCA1B

  7. OCA2

  8. OCA 3 • Common in African & Papua New Guinean populations. • Brick reddish skin, hair and iris. OCA 4 • Mainly found in Japanese / Korean populations • Physical appearance often indistinguishable from OCA1B or OCA2. Secondary OCA • Blood clotting or immune disorders, more frequent in Puerto Rico, Holland & Switzerland.

  9. The Eye Fovea Eye muscle

  10. Characteristic Ocular Features • Iris transillumination*

  11. The Eye Fovea Eye muscle

  12. Iris Transillumination

  13. Characteristic Ocular Features • Iris transillumination* • Foveal hypoplasia* **NEW FINDINGS

  14. The Eye Fovea Eye muscle

  15. Foveal Hypoplasia Foveal Hypoplasia ‘absent fovea’ ‘typical’ fovea

  16. Characteristic Ocular Features • Iris transillumination* • Foveal hypoplasia* • Fundal hypopigmentation*

  17. Fundus Hypopigmentation Typical fundus colour fundus hypopigmention

  18. Characteristic Ocular Features • Iris transillumination* • Foveal hypoplasia* • Fundal hypopigmentation* • Macular transparency • Optic nerve hypoplasia • Anomalous retinal vessel presence in the foveal avascular area

  19. Fundus Hypopigmentation Typical fundus colour fundus hypopigmention

  20. Characteristic Ocular Features • Iris transillumination* • Foveal hypoplasia* • Fundal hypopigmentation* • Macular transparency • Optic nerve hypoplasia • Anomalous retinal vessel presence in the foveal avascular area • Abnormal misrouting of retinal ganglion cell axons at the optic chiasm (VEP asymmetry)

  21. ‘Typical’ Visual Pathway: 60% fibres cross, 40% remain uncrossed

  22. Typical Visual Pathway: 60% fibres cross, 40% remain uncrossed Albinism: Higher percentage of fibres cross (95%), 5% uncrossed

  23. Characteristic Visual Symptoms • Reduced visual acuity

  24. Characteristic Visual Symptoms • Reduced visual acuity • High refractive errors

  25. No Refractive Error • Eye that does not need glasses

  26. No Refractive Error • Eye that does not need glass • Light / image rays focused perfectly on fovea / retina

  27. Long Sighted Eye • Hypermetropia • Light/image focused behind retina

  28. Long Sighted Eye • Hypermetropia • Eye needs PLUS lenses to focus light/image on retina

  29. Short Sighted Eye • Myopia • Light / image is focused in front of the retina

  30. Short Sighted Eye • Myopia • Eye needs MINUS lenses to focus light/image on retina

  31. Short Sighted Eye • Myopia • Eye needs MINUS lenses to focus light/image on retina

  32. Characteristic Visual Symptoms • Reduced visual acuity • High refractive errors • Reduced contrast sensitivity

  33. Characteristic Visual Symptoms • Reduced visual acuity • High refractive errors • Reduced contrast sensitivity • Nystagmus

  34. Characteristic Visual Symptoms • Reduced visual acuity • High refractive errors • Reduced contrast sensitivity • Nystagmus • Photophobia

  35. Characteristic Visual Symptoms • Reduced visual acuity • High refractive errors • Reduced contrast sensitivity • Nystagmus • Photophobia • Reduced or absent stereoacuity

  36. Characteristic Visual Symptoms • Reduced visual acuity • High refractive errors • Reduced contrast sensitivity • Nystagmus • Photophobia • Reduced or absent stereoacuity • Amblyopia

  37. Characteristic Visual Symptoms • Reduced visual acuity • High refractive errors • Reduced contrast sensitivity • Nystagmus • Photophobia • Reduced or absent stereoacuity • Amblyopia • Strabismus

  38. The Northern Ireland Nystagmus & Albinism (NINA) Study

  39. The NINA Study Autumn 2008- Spring 2012 Location: Royal Group of Hospitals Altnagelvin Area Hospital Recruited: 105 participants (age range 4.5 months-47 years) Albinism n=73 ICN n=32 (control group) Retrospective analysis (n=147 medical files, 1986-2010)

  40. Control GroupIdiopathic congenital nystagmus (ICN) • Nystagmus may also occur in isolation • Onset prior to 6 months of age • Normal ocular and neurological anatomy

  41. Method • Refractive Error: strict cycloplegic protocols

  42. Method • Refractive Error: strict cycloplegic protocols • Visual acuity: age appropriate tests

  43. Method • Refractive Error: strict cycloplegic protocols • Visual acuity: age appropriate tests • Nystagmus assessment : video recorded/graded

  44. Method • Refractive Error: strict cycloplegic protocols • Visual acuity: age appropriate tests • Nystagmus assessment : video recorded/graded • Corneal curvature: Nidek Hand-held keratometer

  45. Fovea Eye muscle

  46. Method • Refractive Error: strict cycloplegic protocols • Visual acuity: age appropriate tests • Nystagmus assessment : video recorded/graded • Corneal curvature: Nidek Hand-held keratometer • Axial Length: IOL Master (NC) Biometer

  47. Fovea Eye muscle

  48. Method • Refractive Error: strict cycloplegic protocols • Visual acuity: age appropriate tests • Nystagmus assessment : video recorded/graded • Corneal curvature: Nidek Hand-held keratometer IOL Master (NC) Biometer • Axial Length: • Contrast Sensitivity & Straylight: -Pelli Robson Chart - Straylight meter

  49. Method • Refractive Error: strict cycloplegic protocols • Visual acuity: age appropriate tests • Nystagmus assessment : video recorded/graded • Corneal curvature: Nidek Hand-held keratometer • Axial Length: IOL Master (NC) Biometer • Contrast Sensitivity: Pelli Robson Chart • Foveal imaging: SD-OCT

  50. Fovea Eye muscle

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