1. Session : Wednesday, October 13, 2015: CVI

2.  Housekeeping ◦ Discussion ◦ Quiz ◦ CVI Assignment/CVI Quiz  CVI ◦ Overview ◦ Causes of CVI ◦ Ophthalmological exam ◦ CVI Characteristics ◦ CVI Assessment

4.  CVI: Cortical Visual Impairment or Cerebral Visual Impairment  Interference in visual function exists in the visual processing centers and visual pathways in the brain  Describes a condition when an individual is visually unresponsive, but has a normal eye exam ◦ May have abnormal MRI or CAT scan showing damage to the areas of the brain containing the visual pathway

5.  The term cortical blindness was first used in the early 20 th century to describe the temporary or permanent loss of vision in adults who experienced ◦ Hypoxia ◦ Circulatory or inflammatory disease ◦ Traumatic injury  This term is not appropriate in describing the visual dysfunction in children who have damage to the visual centers of the brain

6.  The ability of cortical cells to interpret messages sent from the retina develops in infancy ◦ Even short lapses in light and pattern exposure can permanently impair vision  Development of vision is dependent on: ◦ An intact ocular system ◦ Exposure to stimuli  Specific visual functions are dependent on corresponding experiences

7.  There are various opinions about the specific time frame surrounding the brains period of plasticity ◦ There is agreement that visual development occurs early in life and that there is a finite amount of time to expose children to appropriate visual inputs  Even children with a serious brain injury at a young age, may be able to benefit from this critical period ◦ Rerouting neurons from damaged areas to healthy areas of the brain responsible for visual functions

9.  A delay in identifying children with CVI prevents us from taking advantage of the critical period  Children with CVI require: ◦ Prompt identification ◦ Careful assessment ◦ Planned interventions

10.  CVI is the most common cause of visual impairment in children in the US  Most common in children: ◦ Born prematurely ◦ With neurological disorders ◦ With acquired brain injury

11.  Asphyxia and Perinatal Hypoxic-Ischemic Encephalopathy ◦ When the brain is deprived of oxygen and glucose, there is a chance of long-term brain dysfunction ◦ Damage depends on the severity and duration of the episode  If severe, cell death is the result  Can cause organ damage, CP, Seizures, hearing loss, CVI

12.  Intraventricular Hemorrhage ◦ Bleeding that occurs in the germinal matrix, ventricles and surrounding tissues of the brain  Premature infants are at a higher risk of this  Periventricular Leukomalacia ◦ Injury to or death of the white matter of the brain ◦ Occurs when low blood flow injures the vulnerable cerebral white matter of the brain in premature infants (prior to 32 weeks gestation)

13.  Cerebral Vascular Accident/Cerebral Artery Infarction ◦ Stroke ◦ Occurs when blood capillaries in the brain are ruptured  Obstruction  Abnormal increase in blood pressure  Problems with clotting ◦ Usually seen in full-term infants, but occasionally in premies ◦ Infants are more likely to have seizures (esp. in the first few days of life), CP, Dev. Delay and CVI

14.  Infection ◦ Infections can be passed from mother to fetus in utero and can cause damage to the brain  Toxoplasmosis  Rubella  Herpes simples ◦ Bacterial infections (Strep B, E. coli) can cause sepsis and meningitis in infants  Meningitis can cause hearing deficits, CP and CVI

15.  Structural Abnormalities ◦ Alterations in the normal progression of the brain development may result in structural abnormalities that can cause developmental and neurological consequences ◦ Chromosomal abnormalities, infections, or idiopathic incidents can cause:  Meningomyelocele (Spina Bifida)  Dandy Walker Syndrome (cyst in brain)  Primary Microcephaly (small brain)  Hydrocephalus  Agenesis of the corpus callosum (no connections between hemispheres of the brain)

16.  Metabolic Conditions ◦ Condition that may cause significant neuronal damage  Severe Hypoglycemia (low blood sugar)  Acquired Causes ◦ Traumatic injury to the brain in the perinatal period can cause CVI  Acquired apoxia (near-drowning, near-SIDS Blows or gunshot wounds to the head  Head injuries from auto accidents  Shaken baby syndrome  Tumors  Optic radiation damage

17.  Normal eyes!!!  May show abnormality of the optic nerve ◦ Not enough to explain the visual impairment  Strabismus  Not usually nystagmus  Normal pupil reactions  Light gazing OR photophobia  Avoidant social gaze  Brief fixation  Intermittent tracking  Poor visual acuity  Visual field loss

18. Cortical Visual Impairment is the primary cause of visual impairment in children in the “first world countries”

19. “It is estimated that over 40 percent of the brain is devoted to visual function, so it is not surprising that a large proportion of children with damage to the brain have visual problems” (Christine Roman)

20. CVI Resources  Proceedings of the Summit on Cerebral/Cortical Visual Impairment: Educational, Family, and Medical Perspectives, April 30, 2005 (APH)  https://www.emeraldeducationsystems.com/

21. The CVI Experts  Christine Roman- Lantzy  Dr. Gordon Dutton  Lea Hyvarinen

22. Visual Agnosia  Inability of the brain to recognize visual stimulus even though the eye sees it.  May not recognize common objects until they are held, but is aware they are there and can reach for them.  Oliver Sacks  Facial agnosia

23. CVI terms  CVI range/scale  CVI characteristics  Resolved characteristics

24. CVI  A Normal eye exam or the existence of a visual impairment that does not explain the functional visual behaviours.  Unique visual behaviours related to CVI.  Existence of other neurological disabilities, prematurity.  CVI can improve or worsen depending on the environment and/or health of child.

25. CVI Characteristics  Distinct colour preferences  Attraction to movement  Visual latency  Visual field preference  Difficulties with visual environmental complexity  Light-gazing  Difficulties with distance viewing  Absent or atypical visual reflex responses  Difficulties with visual novelty  Absence of visually guided reach

26. CVI Assessment  Traditional FVA methods are not useful for most students with CVI.  CVI range  Often CVI range with FVA.

27. Colour preference  According to a study from the Pediatric VIEW Program of Western Pennsylvania Hospital : 55% red, 34% yellow, 11% other or no colour.

28. Colour Preference  There is disagreement that it is a true colour preference or related to something else: brightness of object, contrast/surroundings, familiarity, etc.

29. Colour Preference  Although it is unclear as to the reason for the colour preference, it is an important factor to consider when working with a child with CVI.  “Use of the preferred colour can serve as a sort of visual “anchor,” a way to attract attention toward specific objects or symbols” (Roman, 2010, p. 22)

30. Preferred colours can be used to introduce new materials/activities

31. Preferred objects in preferred colours can be used to help introduce more complex objects or different colours.

32. Preferred colour can help highlight letters when first learning UUsing the preferred colour to write the ABC’s OOr use highlighters to highlight or underlining words in their preferred colour, i.e. word wall words or the students name. CChanging the background colour on a sheet or creating a colour block for where they are meant to write.

33. Colour Preferences  Colour preferences are helpful in presenting new information or for attracting a child’s attention. However, the use of the preferred colour should be phased out as they become more able to look at new objects and only be used when needed.  The goal is to use the colour preference to teach new materials and colours, so eventually the need for the colour will resolve.

34. Need for Movement MMany children with CVI will need movement to see an object or person, especially if it is unfamliar. This may mean that the object is moving or that the child themselves are moving.

35. Reaction to movement CChildren may react differently to movement depending on their experiences and/or the environment. TThey may startle, look away, become quiet, smile or turn to look at the object.

36. How to use movement MMost children are attracted to movement. It can be in the form of a moving object or in a shiny object. The light moving over a shiny object can give the impression of movement.

37. Over stimulation from movement CChildren can be over stimulated by movement as well. Such as in a crowded gym or hallway. In this type of situation, they may appear to not use their vision. SShiny objects that produce a relfection may be difficult for the child to look at. CChildren, cars or ceiling fans moving can be a distraction for a student trying to use his/her vision.

38. Visual Latency  Visual latency is the delayed response from the time the target is presented, to the time the target is visually regarded.  Visual latency decreases as CVI resolves and can lessen when CVI accommodations are in place.

39. Visual latency  Amount of latency can vary depending on the student, the students general health, the object or environment.  It is important to wait, stay quiet and not distract the student while they are trying to use their vision.

40. Visual Field Preference  Children may ignore certain visual fields and they may have a preferred visual field for looking.  Many children will prefer to use their peripheral visual fields to see. Because the peripheral visual fields do not identify fine detail, students may react more to general form or movement.  Children may have a mixed preferred visual field preference, where they may locate the object with one eye, but examine it with the other or with one field then another.  A central preferred visual field is rare.

41. Preferred Visual fields  It is important to recognize a child’s preferred visual fields, the head postures or eye movements in order to be aware of when the child is trying to use their vision and when they may be avoiding the activity.

42. Difficulty with Visual Complexity Christine Roman identifies three types of visual complexity:  Complexity of the pattern on the surface of an object  Complexity of the pattern on the surface of a visual array (object within its surroundings).  Complexity of the sensory environment.

43. Complexity of patterns Many children with CVI can not look at toys or objects that have complex patterns. Many baby toys are bright and colourful with many different patterns, sounds and lights.

44. The most complex surface is the human face

45. Complexity of array When an object is placed against a visually complex background a child with CVI can not find the object they are looking for. This is often referred to as visual crowding. This phenomena makes organization of materials very important. Learning to read and separate letters, then words can be very difficult until this characteristic is resolved. Why can he pick up the candy on the floor, but he can’t find his bright yellow teddy bear?

46. Can you find Waldo in this picture?

48. Adapting the environment for the child with CVI

49. Complexity of Sensory Environment Some children with CVI can only use their vision when they are not being distracted by other sensory input.

50. Presenting sensory information  A student who is using his/her vision may need to stop using their vision in order to hear what is being said, i.e. “good job”  Movement, noise or too much visual information (crowding) can make it difficult for a student to use their vision.  Present sensory information sequentially. Only add other sensory information when the student is able to handle the conflicting information.

51. Light-gazing and nonpurposeful gaze  Children with CVI will often spend long periods of time fixating on light, but not on an object.  Apparent visual fixation on an object that is not there.  It needs to be determined if the child is fixating on light in order to stimulate vision or because the environment is too complex.

52. Using the attraction to light for purposeful looking

53. Difficulty with distance vision  Children with CVI often can not recognize even familiar objects beyond near vision (40 cm).  When an object is moved further from the face, the complexity is increased as the background is added to the visual scene.

54. Difficulty with Visual Novelty  Our visual systems are designed to alert to something that is novel.  Children with CVI turn away from or will not look at objects that are novel. They prefer familiarity.

55. Familiar and preferred objects Preferred objects for children with CVI are often in their preferred colour, are visually simple and/or reflect light.

56. Using visual novelty To introduce new materials or activities, use the familiar object to bridge the gap. Find materials with similar qualities.

57. Absent or atypical visual reflex responses A blink reflex or a blink in response to a visual threat are non existent or delayed.

58. Absence of Visually Guided Reach  Students with CVI will often look and touch an object as two separate actions.  They may look, look away and then reach or they may touch without looking and then release and look.

59. Many of the characteristics of CVI can resolve with intervention. According to Christine Roman, they generally resolve in the following order:  Early resolution: light gazing, atypical or absent blink reflexes.  Middle resolution: Colour preference, visual latency, difficulty with visual novelty, atypical or absent visual reflex to visual threats, need for movement.  Later resolution: Visual field preferences, absence of visualy guided reach, difficulty with visual complexity, difficulty with distance viewing.  (Roman, 2010 P. 30)