See also
References
Further reading
Hyatt, Keith J (February 2010). "Irlen Tinted Lenses and Overlay" (PDF). MUSEC Briefings. Macquarie University Special Education Centre (22). Archived from the original (PDF) on 29 August 2017. Retrieved 22 April 2017. Wilkins, Arnold J. (2003). Reading through color: how colored filters can reduce reading difficulty, eye strain, and headaches. Chichester: John Wiley & Sons. ISBN 0-470-85116-3. OCLC 78883050.
A person may also be a carrier of the disease and show no signs or symptoms of the disease. Late complications may result in the development of pigmented gallstones, which is secondary to the detritus of the broken-down blood cells (unconjugated or indirect bilirubin) accumulating within the gallbladder. Also, patients who are heterozygous for a hemochromatosis gene may exhibit iron overload, despite the hemochromatosis genes being recessive. In chronic patients, an infection or other illness can cause an increase in the destruction of red blood cells, resulting in the appearance of acute symptoms, a hemolytic crisis. On a blood smear, Howell-Jolly bodies may be seen within red blood cells. Primary treatment for patients with symptomatic HS has been total splenectomy, which eliminates the hemolytic process, allowing normal hemoglobin, reticulocyte and bilirubin levels. The resultant asplenic patient is susceptible to encapsulated bacterial infection, and prevented with vaccination. If other symptoms, such as abdominal pain persist, the removal of the gallbladder may be warranted for symptomatic cholelithiasis. Epidemiology
Hereditary spherocytosis is the heritable hemolytic disorder, affecting 1 in 2,000 people of Northern European ancestry. According to Harrisons Principles of Internal Medicine, the frequency is at least 1 in 5,000 within the United States of America. While HS is most commonly (though not exclusively) found in Northern European and Japanese families, an estimated 25% of cases are due to spontaneous mutations.