What is a Visual Impairment?
According to the Centers for Disease Control and Prevention (CDC), approximately 6.8% of children younger than 18 years in the United States have a diagnosed eye and vision condition and 3% of children younger than 18 years are blind and visually impaired. Visual disability is one of the most prevalent disabilities disabilities among children.
According to IDEA’s definition, visual impairment is defined s including blindness means an impairment in vision that even with correction, adversely affects a child’s educational performance. The World Health Organization (WHO), classifies visual impairment as occurring when an eye condition affects the visual system and one or more of its vision includes both partial sight and blindness
Classifications
The World Health Organization uses the following classification based on visual acuity in the better eye:
- 20/30 to 20/60- mild vision impairment
- 20/70 to 20/160- moderate visual impairment
- 20/200 to 20/400- severe visual impairment
- 20/500 to 20/1,000- profound visual impairment
- More than 20/1,000- considered near-total visual impairment
- No light perception- considered total visual impairment or total blindness
Types of Visual Impairment
- Strabismus– a condition when the eyes do not align with each other (crossed eyes)
- Congenital cataracts– a clouding of the eyes natural lens present a birth.
- Retinopathy of prematurity– a blinding disorder that affects prenatal infants that are born before 31 week of gestation.
- Coloboma- a condition where normal tissue in or around the eye is missing at birth.
- Cortical visual impairment– a visual impairment that occurs due to brain injury.
Signs of Visual Impairments
- Appears “clumsy” in new situation
- Shows signs of fatigue or inattentiveness
- Does not pay attention when information is on the chalkboard or reading material
- Is unable to see distant things clearly
- Squints
- Eyes may appear crossed
- Complains of dizziness.
Causes
The causes of childhood blindness or visual impairment is often caused by Vitamin A deficiency which is the leading cause of preventable blindness in children. Other causes include genetics, diabetes, injury and infections such as congenital rubella syndrome and chickenpox before birth.
Cortical Visual Impairment (CVI)
Cortical Visual Impairment in children is attributed to brain dysfunction rather than issues with the eyes. Causes included hypoxia, traumatic brain injury, neonatal hypoglycemia, infections and cardiac arrest.
References