Day: January 28, 2019

What Are Common Causes of Blindness in Children?

Patient Presentation
An 8-year-old male came to clinic because of increased fussiness, fever to 102°F and coughing for 2 days. He had increased respiratory secretions but it was difficult to tell if he had any sputum production, as he had global cognitive delays and was cortically blind after non-accidental trauma as an 8 month old. His adoptive mother stated that he usually had increased secretions but they had become thicker and yellowish. He also had been intermittently breathing faster. The past medical history included several ear infections when he was younger, and one viral pneumonia.

The pertinent physical exam showed he was non-communicative and was doing eye-rolling which was his normal state of health. His vital signs showed 32 respirations/minute, a temperature of 101.6°F and an oxygen saturation of 97% on room air. HEENT had increased oral and nasal secretions that were pale yellow. His lungs had coarse breath sounds throughout with crackles bilaterally at the bases. His heart, abdomen and skin examinations were normal.

The diagnosis of clinical pneumonia was made and was confirmed by the radiologic evaluation of a chest radiograph which showed bilateral consolidations at the bases consistent with bacterial pneumonia. The patient was started on oral antibiotics with instructions to call if he worsened. One week later at his health supervision visit he was markedly improved with decreased secretions and improved air exchange.

Discussion
According to the World Health Organization, about 1.3 billion people have some form of visual impairment. Most people with visual impairments are >50 years old, more are female than male, and more live in resource-limited areas than resource-rich areas. Most visual impairments are avoidable (80%) in all age groups with the leading causes globally and across ages being uncorrected refractive errors and cataracts.

The most common causes of blindness are:

  • Refractive errors, uncorrected
  • Cataract
  • Age-related macular degeneration
  • Glaucoma
  • Diabetic retinopathy
  • Corneal opacity
  • Trachoma

The exact numbers vary by region and country. In general there has been an improvement in the percentage of those with visual impairments but because the global population has increased, especially the older population, the actual numbers of patients have remained steady or possibly increased over the past few years.

Visual impairment for distance vision is considered mild if worse than 6/12 in meters = 20/40 in feet or 0.3 LogMAR and for moderate impairment is 6/18 meters = ~20/60 = ~0.6 LogMAR. LogMAR stands for the Logarithm of the Minimum Angle of Resolution and is considered more accurate than other charts. Near vision is considered impaired if acuity is worse than N6 or N8 at 40 cm with existing correction. N numbers are the size of the letters on the handheld card.

Normal visual acuity development occurs over the first year of life with the average neonate being > 6/60 = 20/200 = 1.0 LogMAR at birth.

Examples of some visual acuity scale equivalents

Foot 20/16 20/20 20/32 20/40 20/63 20/80 20/100
Meter 6/4.8 6/6 6/9.5 6/12 6/19 6/24 5/30
LogMAR -0.1 0.0 0.2 0.3 0.5 0.6 0.7

Learning Point

For children it is estimated that ~ 14 million are blind. Prevalence is estimated to be 3-4/10,000 children in affluent global areas and 12-15/10,000 children in very poor areas. Children that are blind have more disordered or delayed development, more likely to have other health impairments (particularly neurological) including a dramatic increased risk of death, and poorer overall socioeconomic status. Most children with blindness are diagnosed in the first year of life and especially with signs consistent with poor vision.


For children the common causes of blindness are:

  • Cerebral and optic nerve visual impairments
  • Cataract
  • Corneal opacity due to Vitamin A deficiency
  • Glaucoma
  • Infectious – Meningitis, TORCH, Measles, Rubella, Zika
  • Retinopathy of prematurity
  • Retinal disorders, inherited
  • Trauma

*Note that almost all are avoidable or treatable causes.

Questions for Further Discussion
1. What causes color blindness? A review can be found here
2. What are presentations of child abuse/child maltreatment/non-accidental trauma? A review can be found here
3. What are potential complications of pneumonia? A review can be found here

Related Cases

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at SearchingPediatrics.com and the Cochrane Database of Systematic Reviews.
Information prescriptions for patients can be found at MedlinePlus for these topics: Pneumonia and Vision Impairment and Blindness</a.

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

To view videos related to this topic check YouTube Videos.

Stevens GA, et.al; Vision Loss Expert Group. Global prevalence of vision impairment and blindness: magnitude and temporal trends, 1990-2010. Ophthalmology. 2013 Dec;120(12):2377-2384.

Solebo AL, Teoh L, Rahi J. Epidemiology of blindness in children. Arch Dis Child. 2017 Sep;102(9):853-857.

Gudlavalleti VSM. Magnitude and Temporal Trends in Avoidable Blindness in Children (ABC) in India. Indian J Pediatr. 2017 Dec;84(12):924-929.

World Health Organization. Blindness Fact Sheet. Available from the Internet at http://www.who.int/en/news-room/fact-sheets/detail/blindness-and-visual-impairment(rev. 10/11/18,cited 11/5/18)

World Health Organization. Causes of Blindness and Visual Impairment. Available from the Internet at https://www.who.int/blindness/causes/en/ (cited 11/5/18)

LogMAR Chart. Wikipedia. Available from the Internet at https://en.wikipedia.org/wiki/LogMAR_chart (cited 11/6/18).

Author
Donna M. D’Alessandro, MD
Professor of Pediatrics, University of Iowa