Childhood, Blindness and Low Vision
Conditions causing childhood blindness and low vision.
Albinism is caused from a hereditary deficiency of pigmentation, that may involve the entire body or part of the body. It is believed to be caused by an enzyme deficiency involving the metabolism of melanin during prenatal development and inherited as a recessive trait. There are 4 medical types of albinism. Diagnosis of albinism is based on visual diagnostic testing.
- Nystagmus: regular horizontal back and forth movement of the eyes
- Strabismus: muscle imbalance of the eyes, “crossed eyes” (esotropia), “lazy eye” or an eye that deviates out (exotropia)
- Photophobia: sensitivity to bright light and glare, far-sighted, near-sighted and possible astigmatism
- Foveal hypoplasia: the retina develops atypically during pregnancy and in infancy
- Optic nerve misrouting: the nerve signals from the retina to the brain follow atypical nerve routes
- The iris has insufficient pigment to screen out stray light coming into the eye. Light can pass through the iris as well as the pupil.
Visual Educational Accommodations for Students with Low Vision:
Students with low vision may benefit from any or all of the accommodations listed below:
- Implement strategies suggested by a vision itinerant.
- Provide copies of notes.
- Use auditory cues to get the attention of the class.
- Provide oral instructions with visual instructions.
- Use assistive technology (i.e., CCTVs, and computers to enlarge and increase contrast in print) according to the student's needs.
- Provide enlarged hand-outs, texts, etc. and/or access to computer equivalents, i.e., map on laptop with enlargement options.
- Frequently check with the student to ensure understanding.
- Reduce visual distractions.
- Encourage self-advocacy to meet his/her own needs.
- Encourage use of magnifiers and other accommodative tools.
- Provide preferential seating near the front of the class and near assistive technology.
- Dim or brighten the classroom lighting according to the needs of the student.
- Consider the proximity of the student to the windows.
- Develop a plan for evacuation and safely moving throughout the school.
- Use assistive technology/computers/near and distant camera systems for enlargement.
- Provide enlarged copies of tests in print and/or on the computer.
- Allow for extra time.
- Allow scribing and/or oral tests.
- Allow breaks to rest eyes/refocus.
CHARGE syndrome occurs in approximately one in every 9-10,000 births worldwide and is a very complex syndrome involving extensive medical and physical difficulties unique to each child. Babies with CHARGE are frequently born with life-threatening birth defects, including complex heart defects and breathing problems. After spending many months in the hospital undergoing surgeries and treatments, swallowing and breathing problems can continue to make life difficult. Most children with CHARGE have hearing loss, vision loss, and balance problems which can delay their development and communication. Although CHARGE children face many obstacles often far surpass their social, physical, educational, and medical expectations. A characteristic feature of CHARGE syndrome is the determination and strong character the children often display. Strong character and determination can be seen in the following video of students with CHARGE: “We Have CHARGE, So What!” http://www.chargesyndrome.org/resources.asp.
Coloboma of the eye (sort of like a cleft) of the iris, retina, choroid, macula or disc (not the eyelid), microphthalmos (small eye) or anophthalmos (missing eye) are causes of vision loss in persons with CHARGE and are present in 80%-90% of cases.
Visual Educational Accommodations:
Students with CHARGE may be Deafblind. The low vision accommodations listed above under Albinism may benefit students with CHARGE keeping in mind that vision loss may be accompanied by hearing loss and possible developmental delays. Deafblindness is a unique disability that exists as its own exceptionality and not as two separate disabilities co-existing.
Cortical Vision Impairment
Cortical visual impairment (CVI) is a term that refers to visual impairment that occurs due to brain injury. CVI is not due to physical problems with the eyes and is caused by damage to the visual centers of the brain. Damage to the visual centres interferes with communication between the brain and the eyes. The brain is not interpreting what the eyes may be viewing. Other terms for Cortical visual impairment (CVI) include: cerebral visual impairment, neurological visual impairment and brain damage related visual impairment.
Some children with CVI are undiagnosed and do not receive treatment. Doctors such as Dr. Roman-Lantzy believe that CVI can be treated successfully and divides CVI into three phases. Most children start in Phase I, the phase in which most of the CVI characteristics are present. With treatment characteristics begin to resolve as a child progresses through the three phases. With persist treatment over several years children in the thrid phase may approach near normal vision to varying degrees and possibly result in literacy.
The following characteristics of CVI are quoted from the website, Little Bear Sees:
- Preference for a specific color. You may have noticed that your child seems to prefer looking at a certain color. Bright red and yellow are often favorite colors, but some children prefer other bright colors such as blue, green, or pink.
- Need or preference for movement. Many children with CVI require movement in order to see an object. For example, it may be easier for them to look at a pinwheel or a swaying balloon.
- Delayed response when looking at objects (visual latency). It may take time for a child with CVI to look at an object. Often they will look at an object and then look away. For this reason it is important to give your child enough time when presenting an object.
- Difficulty with visual complexity. Children with CVI need simplicity. First, it is important that the object presented is simple. For example, a single colored stuffed animal, like Elmo, is preferable to one with multiple colors. Likewise, it is important that the background and the environment are simple. For example, putting a solid black cloth behind a single colored toy helps to reduce visual clutter. Creating a simple environment is a matter of eliminating noise and anything else that might distract from the visual task.
- Light-gazing and nonpurposeful gazing. Often, children with CVI will stare at light. They may be seen gazing out the window or up at a ceiling light. They may also appear as if looking at things that are not there, or looking at things without intent.
- Visual field preferences. Most children with CVI will prefer to look at objects in a particular direction. For example, they may see an object better when it is presented in their periphery, or may turn their head to see an object.
- Distance vision impaired. Some children with CVI have trouble seeing far away. This is related to the preference for visual simplicity. Objects far away may be lost in visual clutter.
- Visual blink reflex is absent or impaired. When an object comes too close to the eyes, or touches the bridge of the nose, many CVI children have an absent or delayed protective blink response.
- Preference for familiar objects. Because it is difficult for CVI children to process the information that the eyes see, they often prefer familiar objects that the brain easily recognizes and has processed before.
- Impaired visually guided reach. The ability to look at an object while reaching for it is impaired. Often CVI children will look away from the object and then reach for it.
Visual Educational Accommodations:
Children with CVI may be provided with any of the accommodations cited for low vision listed under the Albinism heading. Students with CVI benefit from reducing visual noise in their environments, instruction and assessment. Providing opportunities for visual discrimination through highlighting contrast, thereby allowing ease of the visual perception of foregrounds from backgrounds may aid students with CVI greatly.
Down syndrome is a chromosomal condition associated with intellectual disability, weak muscle tone (hypotonia) and characteristic facial characteristics in infancy. All affected individuals experience cognitive delays with mild to moderate intellectual disability. People with Down syndrome may have a variety of birth defects. About half of children with Down syndrome are born with a heart defect. Digestive abnormalities, such as a blockage of the intestine, are less common. Individuals with Down syndrome have an increased risk of developing several medical conditions.
The eye problems which may affect children with Down’s syndrome are those
which may occur in any group of children, however, they tend to occur more frequently and sometimes to a more marked degree. Visual conditions that may be present in individuals with Down Syndrome include the following:
- Squint- Many children squint because they are far-sighted or near-sighted and consequently need glasses.
- Astigmatism-About 30% of pre-school children with Down’s syndrome have astigmatism. An astigmatism causes the image to be distorted because the image is more out of focus in one direction than the other. The astigmatism can be either far-sighted or near-sighted or a mixture of the two.
- Focusing Difficulty (Weak Accommodation)-Many children with Down Syndrome have difficulties focusing well on near tasks, and this applies whether they are far-sighted or near-sighted.
- Nystagmus-Approximately 10% of children with Down’s syndrome have nystagmus. Nystagmus is a condition in which the eyes make small, involuntary, jerky movements. Often these movements are more noticeable when the child is looking sideways. If this happens the child should not be discouraged from adopting the head posture as this is likely to be the position where the vision is at its best.
- Eye Infections-Eye infections and watering eyes tend to be more common in people with Down’s syndrome. Normally tears, which are formed continuously to keep the eyes moist and healthy, drain down a duct which connects the corner of the eye with the back of the nose. This tube in persons with Down Syndrome, this tube is often quite narrow and so it easily becomes blocked. This leads to watering of the eye and because clean tears are not rinsing through the system effectively.
- Congenital Cataracts- Cataracts, if significant early, prevent the brain from receiving messages about what images look like and the brain may not learn to see. This can be a severe form of amblyopia.
- Retinal and Optic Nerve Disorders- Rarely, in persons with Down Syndrome, infants can be born with retinal and optic nerve conditions that at this time are non-reversible.
Visual Educational Accommodations:
If students present with low vision, the accommodation strategies outlined under Albinism may be used. The following accommodations may be used for students who are blind:
- Provide copies of written texts and handouts for the student on a USB key or emailed to the student. Print or braille copies may be used by a student dependent on his/her visual need. As vision fluctuates throughout the day, the student and the vision itinerant may indicate that more than one print accommodation may be preferred.
- Use of other media sources for delivering information (i.e., audio, webcasts, video with visual captioning.
- Use of physical models and/or concrete materials whenever possible, to aid in the development of concepts.
- Consistently keep items in predictable/predetermined places (desks, hairs, scissors, etc.).
- Give the student appropriate warning of any changes to the classroom set up, and provide support for familiarizing with the new set up.
- Use preferential seating so that the student is close to the teacher for additional instructions.
- Reduce auditory noise in classroom.
- Provide easy access to Braille equipment, if appropriate.
- Provide elevator access if necessary/available.
- Develop and practice a plan for emergency evacuations to ensure safety.
- Use assistive technology and Braille materials.
- Provide extra time.
- Use oral tests/scribe.
- Provide choices for projects/assignments.
Fetal Alcohol Syndrome
Fetal Alcohol Syndrome (FAS) is a condition caused by maternal alcohol consumption during pregnancy. FAS is estimated to be the most common non-inherited cause of learning disability. Diagnosis of FAS is based on the characteristics of facial dysmorphism, postnatal growth retardation and functional or structural central nervous system deficits. Eye abnormalities having been shown to occur in over 90% of children with the condition.
Children with fetal alcohol syndrome (FAS) may have ocular abnormalities and impaired vision. All parts of the eye may be affected and anomalies such as microphthalmus, microcornea, Peters' anomaly, cataract, persistent hyperplastic primary hyaloid vitreous body, coloboma of the iris and choroid, retinal dysplasia and, most commonly, optic nerve hypoplasia and tortuosity of the retinal vessels, have been reported. Visual function may be reduced moderately or severely. Refractive errors and strabismus are common. In the management of this disorder, the early detection of impaired vision and ocular abnormalities in affected children is important.
Visual Educational Accommodations:
To accommodate students with FAS' visual needs, it should be noted that students may additionally have other special education needs in regards to cognitive processing.
Abdelrahman, A., & Conn, R. (0006, February 28). BACKGROUND. National Center for Biotechnology Information. Retrieved July 12, 2014, from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2773598/
CHARGE Syndrome Foundation - About CHARGE. (n.d.). CHARGE Syndrome Foundation - About CHARGE. Retrieved July 12, 2014, from http://chargesyndrome.org/about-charge.asp
CHARGE Association. (n.d.). CHARGE Association. Retrieved July 11, 2014, from http://www.tsbvi.edu/curriculum-a-publications/975-charge-association
What is CVI?. (n.d.). Little Bear Sees. Retrieved July 12, 2014, from http://www.littlebearsees.org/what-is-cvi/
(n.d.). Retrieved from https://www.google.ca/search?q=charge syndrome pictures&tbm=isch&ei=Pam8U7qYK4GXyATf8ICIBA
Teaching Strategies for Students with Special Needs. (n.d.). Teach Special Education. Retrieved July 11, 2014, from http://www.teachspeced.ca/teaching-strategies-students-special-needs
Vision & Down Syndrome. (n.d.). - National Down Syndrome Society. Retrieved July 12, 2014, from http://www.ndss.org/Resources/Health-Care/Associated-Conditions/Vision--Down-Syndrome/
Visual impairment and Down syndrome | Sense. (n.d.). Visual impairment and Down syndrome | Sense. Retrieved July 12, 2014, from http://www.sense.org.uk/content/visual-impairment-and-down-syndrome
What is Albinism?. (n.d.). NOAH —. Retrieved July 11, 2014, from http://www.albinism.org/publications/what_is_albinism.html