1. Christina Gasse
Anatomy and Diseases of the Eye
In-Service Presentation
Leber’s Congenital Amaurosis (LCA) is “an inherited retinal degenerative disease
characterized by severe loss of vision at birth” (“Foundation Fighting Blindness”, 2012.) Simply
put, it is a disease that affects the retina, the tissue lining the back of the eye, typically beginning
in infancy. The retina is the area lining the back of the eye that processes images by carrying
information to the brain through the optic nerve. The absence of these signals in the retina is
what is known as Leber’s Congenital Amaurosis.
Since Leber’s Congenital Amaurosis is a retinal degenerative disease, it causes vision
problems including an increased sensitivity to light (photophobia), involuntary movements of the
eyes (nystagmus), and extreme farsightedness (hyperopia). Additionally, the pupils, which
usually expand and contract in response to the amount of light entering the eye, do not react
normally to light. Instead, the pupils of a person with LCA expand and contract more slowly than
normal, or might not respond to light at all.
Leber’s can result from gene mutations. Some of these genes contain the instructions for
development and function of the retina, while other genes are necessary for the normal
development of light-detecting cells called photoreceptors. What happens is the genes involved
in Leber’s disrupt the formation and function of the retina, a key role in vision, which results in
loss of vision.

2. Leber’s Congenital Amaurosis is genetically passed through families. In order for
offspring to inherit this disease, both parents must be carriers of a gene with the disease. So
basically a child with Leber’s has inherited a copy of the same gene from each parent with a
misprint for making photoreceptors.
LCA’s impacts on the visual system can be found specifically in the retina. “Light
aversion and nystagmus are common features, and some colour discrimination is usually present
(Keith, p.278)” Additionally, the cornea, or the clear covering on the front of the eye, may be
cone-shaped and abnormally thin, a condition known as keratoconus.
Leber’s is also associated with photophobia or an increased sensitivity to light. The
pupils, which usually expand and contract in response to the amount of light entering the eye, do
not react normally to light. Instead, they expand and contract more slowly than normal, or they
may not respond to light at all. How a child’s eyes react when shown bright lights are a huge
indicator if Leber’s is present.
This eye condition affects functional vision differently for each child. Some children with
Leber's can see the top letter on an eyesight chart from 3 meters (3/60) while others may only be
able to see larger objects. Many children with Leber's can only see very little and for the
purposes of education will read braille (Blaikie).
The following resources contain further information related to Leber’s congenital
amaurosis and may be found helpful. These materials are written for the general public.
For Patient Support:
 Foundation Fighting Blindness

3.  Foundation for Retinal Research
 National Federation of the Blind
 Leber’s congenital Amaurosis Forum
(Familyconnect.org)
For parents:
Resources for Parents of Blind Children
(http://bvi.growingstrong.org/)

4. References:
Blaikie, D. A. (n.d.). Visually impairing conditions. Retrieved from
http://www.ssc.education.ed.ac.uk/resources/vi&multi/eyeconds/LebCA.html
Cotlier, E., Maumenee, I. H., & Berman, E. R. (1982). Genetic eye disease: Retinits
pigmentosa and other inherited eye disorders. (Number 6 ed., Vol. volume 18, p. 278).
New York: Alan R. Liss, Inc.
Elsevier Health Sciences (2010, April 7). Leber congenital amaurosis: Gene therapy for
blindness works only when specific mutation present. ScienceDaily. Retrieved October
27, 2013, from http://www.sciencedaily.com
Genetics Home Reference. (n.d.). Retrieved from http://ghr.nlm.nih.gov/condition/leber-
congenital-amaurosis
Manning, A. (n.d.). Retrieved from http://www.nei.nih.gov/lca/blindness.asp
Simonelli, F. (n.d.). Retrieved from
http://www.nature.com/mt/journal/v18/n3/full/mt2009277a.html
(n.d.). Retrieved from http://www.blindness.org/index.php?view=article&id=253:leber-
congenital-amaurosis&option=com_content&Itemid=88