Chapter 11 Vision and Visual Impairment Chapter 11 slides in Children with Disabilities, Seventh Edition, Online Companion Materials. Copyright © 2013 Paul H. Brookes Publishing Co., Inc. All rights reserved.

https://www.youtube.com/watch?v=6rbHOAtBNew https://www.youtube.com/watch?v=7rzmMiIT3Ao Chapter 11 materials in Children with Disabilities, Seventh Edition, Online Course Materials. Copyright © 2013 Paul H. Brookes Publishing Co., Inc. All rights reserved.

Introduction Impaired vision in childhood Can have detrimental effect on physical, neurological, cognitive, emotional development Can occur as isolated disability or associated with other developmental disabilities Must be identified and treated with effective medical and special education interventions Chapter 11 slides in Children with Disabilities, Seventh Edition, Online Companion Materials. Copyright © 2013 Paul H. Brookes Publishing Co., Inc. All rights reserved.

Structure and Function of the Eye Structure problems can result in vision impairment or loss Visual loss divided into disorders impacting Transmission of light Central visual field Peripheral visual field Refraction Combination of issues Ocular support problems can result in glaucoma Ocular motility problems can result in strabismus (misalignment of the eyes) Chapter 11 slides in Children with Disabilities, Seventh Edition, Online Companion Materials. Copyright © 2013 Paul H. Brookes Publishing Co., Inc. All rights reserved.

Ocular Development Structures that become eyes first appear at 4 weeks’ gestation Chapter 11 slides in Children with Disabilities, Seventh Edition, Online Companion Materials. Copyright © 2013 Paul H. Brookes Publishing Co., Inc. All rights reserved.

Visual Development Children with disabilities Causes of developmental disabilities often influence visual system One half to two thirds of individuals with developmental disability have significant occular disorder Pediatric ophthalmologist should conduct exam as part of overall assessment for child with developmental disability Amblyopia Visual regression in healthy eyes Must be identified and treated or the visual use is reduced, which can lead to educational disability Chapter 11 slides in Children with Disabilities, Seventh Edition, Online Companion Materials. Copyright © 2013 Paul H. Brookes Publishing Co., Inc. All rights reserved.

Common Disorders of the Eye in Children with Disabilities Cataract—a defect in lens clarity, appearing as a white spot in pupil, that can cause amblyopia Can require surgery Isolated abnormality or part of syndrome or disease Optic nerve hypoplasia—an optic nerve transmits impaired information Decreased vision uncorrectable with glasses Common cause of visual disability Often associated with other developmental disabilities Chapter 11 slides in Children with Disabilities, Seventh Edition, Online Companion Materials. Copyright © 2013 Paul H. Brookes Publishing Co., Inc. All rights reserved.

Common Disorders of the Eye in Children with Disabilities (continued) Retinopathy of prematurity (ROP)—vascular damage from incomplete blood vessel growth Can result in vision loss Screening for premature infants Treated with laser application, but visual impairments often remain Other retinal disorders—other disorders that affect the retina Nonaccidental injury (shaken baby syndrome) Congenital infections Inborn errors of metabolism Retinal tumors Chapter 11 slides in Children with Disabilities, Seventh Edition, Online Companion Materials. Copyright © 2013 Paul H. Brookes Publishing Co., Inc. All rights reserved.

Disorders of the Visual Cortex Cortical visual impairment (CVI) Caused by oxygen deprivation, infections of central nervous system, or traumatic brain injury One of most common causes of visual impairment in the developed world Behavior: mildly impaired to absent visual attention Requires full ophthalmologic exam to rule out treatable causes Delayed visual maturation (DVM) Presents like CVI, but visual function improves spontan-eously in infancy as child’s overall development progresses By 6–12 months, DMV infants often have normal or near-normal visual function Visual stimulation important Chapter 11 slides in Children with Disabilities, Seventh Edition, Online Companion Materials. Copyright © 2013 Paul H. Brookes Publishing Co., Inc. All rights reserved.

Strabismus and Ocular Motility Disorders https://www.youtube.com/watch?v=jMPjSFe7Dys Strabismus (misalignment of eye) 3%–4% of all children; 15% of former premature infants; 40% of children with cerebral palsy Two forms: esotropia (cross-eyed) and exotropia (wall-eyed) Causes amblyopia in children younger than 8 years of age; resulting neurological problems can be treated by surgery Nystagmus (rapid jiggling back and forth of eyes as result of inability to fixate on objects) Evaluation can include comprehensive pediatric ophthalmologic exam, electroretinogram, and neurological evaluation https://www.youtube.com/watch?v=Ey-UD5Vzu_Q Chapter 11 slides in Children with Disabilities, Seventh Edition, Online Companion Materials. Copyright © 2013 Paul H. Brookes Publishing Co., Inc. All rights reserved.

Strabismus and Ocular Motility Disorders (continued) Anomalous head postures (tilted or turned head) Can be caused by strabismus and nystagmus Should see ophthalmologist as part of evaluation Strabismus surgery can reposition eyes Chapter 11 slides in Children with Disabilities, Seventh Edition, Online Companion Materials. Copyright © 2013 Paul H. Brookes Publishing Co., Inc. All rights reserved.

Refractive Errors in Children Myopia—nearsightedness The eye is too long or refracting mechanisms are too strong Severe myopia requires eyeglass correction from infancy to expand vision Hyperopia—farsightedness The eye is too short or refracting mechanisms are too weak Most common refractive error of childhood Most children require no correction, but hyperopia of more than 4 diopters may require glasses Astigmatism—eye does not focus on single point and image is blurred because surface of cornea is misshaped Chapter 11 slides in Children with Disabilities, Seventh Edition, Online Companion Materials. Copyright © 2013 Paul H. Brookes Publishing Co., Inc. All rights reserved.

Vision Assessment Multidisciplinary vision assessment is critical in determining best interventions  Parent perception Clinical examination Infants and nonverbal children Blinking to a light “Eye-popping” reflex Directed vision Red reflex testing Fixating on and following objects Toddlers and older children Wall charts and picture cards Matching games Vision-testing machine Chapter 11 slides in Children with Disabilities, Seventh Edition, Online Companion Materials. Copyright © 2013 Paul H. Brookes Publishing Co., Inc. All rights reserved.

Blindness Different definitions of blindness and low vision, but from functional standpoint: Acuity or field numbers aren’t all-important Individuals function differently with vision they retain Care providers should avoid making judgments based solely on clinical measures Important to talk to parents and school staff Critical to understand the extent of limitations from the visual impairment Causes of blindness Cortical visual impairment, ROP, optic nerve hypoplasia Other: traumatic brain injury, severe infections, tumors Chapter 11 slides in Children with Disabilities, Seventh Edition, Online Companion Materials. Copyright © 2013 Paul H. Brookes Publishing Co., Inc. All rights reserved.

Severe Visual Impairment Clues: Inability to visually fixate on parent’s face or brightly colored objects Abnormalities in eye movements Lack of blinking or response Developmental delays appear dependent on amount of residual vision and the presence or absence of associated developmental disabilities Chapter 11 slides in Children with Disabilities, Seventh Edition, Online Companion Materials. Copyright © 2013 Paul H. Brookes Publishing Co., Inc. All rights reserved.

Interventions Early interventions include clinical, rehabilitation, and educational aspects that increase skills in other senses, improve body concept and awareness, and promote locomotion and active environmental exploration Home-based sessions with early childhood educator School-based preschool programs Optical aids and devices, braille, computers, audio Assistive technology: voice recognition software, close circuit television, global positioning system Genetic advances (e.g., gene-replacement therapy) Multidisciplinary approach for children with multiple disabilities Chapter 11 slides in Children with Disabilities, Seventh Edition, Online Companion Materials. Copyright © 2013 Paul H. Brookes Publishing Co., Inc. All rights reserved.

Outcome for Children with Visual Impairment Visual impairment can be progressive or nonprogressive Outcome depends on Amount of residual vision Presence of associated disabilities Motivation of child and family Skills of child’s teacher and therapists Chapter 11 slides in Children with Disabilities, Seventh Edition, Online Companion Materials. Copyright © 2013 Paul H. Brookes Publishing Co., Inc. All rights reserved.