Bosch-Boonstra-Schaaf optic atrophy syndrome & Vision Impairment

*Overall, 90% of individuals with BBSOAS have been diagnosed with a visual impairment. Common visual impairments among individuals with BBSOAS include:

  • optic atrophy (82%)
  • alacrima (78%)
  • manifest latent nystagmus (52%)
  • optic nerve hypoplasia (49%)
  • cortical vision impairment (68%)

*The Phenotypic Expansion of Bosch-Boonstra-Schaaf Optic Atrophy Syndrome and Further Evidence for Genotype-Phenotype Correlations (2020)

What is Optic Nerve Atrophy?

*Optic nerve atrophy (ONA) is mild to severe damage to the optic nerve that can adversely affect central vision,peripheral vision and color vision.

*American Association for Pediatric Ophthalmology and Strabismus

*Symptoms of Optic Nerve Atrophy:

  • Blurred vision
  • Difficulties with peripheral (side) vision
  • Difficulties with color vision
  • A reduction in sharpness of vision

*If your ophthalmologist suspects optic atrophy, he or she will examine your eyes with an instrument called an ophthalmoscope. The doctor will look at the optic disc, the point at the back of the eye where the optic nerve enters. In optic atrophy, the optic disc will be pale because of a change in the flow in the blood vessels. There is no cure or treatment for optic atrophy.

*my.clevelandclinic.org

BBSOAS is considered a static encephalopathy and has not been shown to be progressive/degenerative. There is no progression of the eye phenotype known, including no known progression of optic atrophy.

*What is Alacrima?

Alacrima is an abnormal amount of reflex tearing (reduced tear production).

*https://pubmed.ncbi.nlm.5 nih.gov/29120068/

*Treatment for Alacrima:

Artificial tears can be used to alleviate the symptoms of alacrima. Consult your physician if you feel that a treatment plan is needed.

*https://emedicine.medscape.com/article/1210539-treatment

*What is Optic Nerve Hypoplasia?

Optic nerve hypoplasia (ONH) is a congenital condition in which the optic nerve is underdeveloped (small).

*Symptoms:

  • The development of the pituitary gland can also be affected in children with ONH. The pituitary makes and directs important hormones required for growth, energy control and sexual development.
  • Children with ONH may also experience sleep dysfunction, gastrointestinal distress, problems with hunger or thirst, difficulties with temperature regulation and autism spectrum disorder.

*Kellogg Eye Center Michigan Medicine

*American Association for Pediatric Ophthalmology and Strabismus

*Tests and Diagnosis:

ONH is diagnosed by an ophthalmologist, who will use an ophthalmoscope to look inside the eye to determine if the front surface of the optic nerve appears smaller than normal.

*https://www.chla.org/optic-nervehypoplasia

*Treatment: 

You will need to make sure your child is under the care of an endocrinologist, a doctor who specializes in hormone problems. In addition, an ophthalmologist should monitor your child’s vision on an ongoing basis.

*https://www.chla.org/optic-nervehypoplasia

*What is Nystagmus?

Nystagmus is an involuntary rhythmic side-to-side, up and down or circular motion of the eyes that occurs with a variety of conditions.

*Symptoms:

  • Fast, uncontrollable eye movements. Nystagmus can be:
    • side-to-side eye movements
    • up-and-down eye movements
    • circular eye movements

*https://www.hopkinsmedicine.org/neurology_neurosurgery/centers_clinics/vestibular/conditions/nystagmus.html

Tests & Diagnosis Patient history

  • Visual acuity
  • Refraction
  • Alignment and focus tests

Congenital nystagmus doesn’t require treatment, although the following may help improve vision:

  • eyeglasses
  • contact lenses
  • increased lighting

*What is Cortical Visual Impairment (CVI)?

  • CVI is a brain-based visual impairment where the eye’s connection to and in the brain

doesn’t work correctly.

  • Many kids with CVI often have completely healthy eyes. They simply have trouble processing what those healthy eyes are seeing.

10 Common Characteristics of CVI:

  • Color preferences (often red, yellow, saturated)
  • Need for movement (to elicit/sustain attention)
  • Visual latency (processing time)
  • Visual field preferences
  • Difficulty with visual complexity (array, target/object, multisensory, faces)
  • Need for/attraction to light
  • Difficulty with distance viewing
  • Atypical visual reflexes
  • Difficulty with visual novelty
  • Difficulty with visually guided reach

5 Facts about CVI:

  1. It is the most common cause of visual impairment in children in developing countries.
  2. It is the leading cause of congenital blindness (vision loss at birth) in the United States.
  3. It causes children with healthy eyes to have difficulty processing what they see.
  4. It causes children to display some unique visual behaviors commonly seen when there is damage to the brain’s visual system.
  5. It is typically diagnosed when abnormal visual responses can’t be attributed just to the eyes.

*Perkins School for the Blind

*Tests and Diagnosis:

In addition to a complete eye examination, objective measures of visual abilities should be done where feasible and by a pediatric neuro-ophthalmologist knowledgeable in CVI if possible.

Download Dr. Jane Edmond’s letter to eye-care providers with pertinent information specific to BBSOAS patients and eye exams.

*Rehabilitation and Education:

In all children with CVI, services of trained and experienced Teachers of the Visually Impaired are very important for the child’s development and education. Accommodations should be made to address the characteristics mentioned above that the patient lives with.

Referral of the child with CVI to state services for visually impaired children should be done promptly after diagnosis.

*Boston Children’s Hospital