Leiber’s Congenital Amaurosis_ybowermanSPE 516

Summer 2011

Leiber’s Congenital Amaurosis

Definition:

Leiber’s Congenital Amaurosis (LCA) is an inherited retinal degenerative disease characterize by severe loss of vision at birth. A variety of other eye-related abnormalities including roving eye movements, deep-set eyes, and sensitivity to bright light also occur with this disease. Some patients with LCA also experience central nervous system abnormalities.

According to the website, LCA is “Inherited condition, probably caused by degeneration of the retina, in which an infant is born blind or develops severe vision loss soon after birth. Children with Leber's Congenital Amaurosis typically also have nystagmus, and some also have mental retardation and hearing disorders. At present, there is no treatment for this condition”.

Causes, Incidence, And Risk Factors

Individuals with LCA have very reduced vision at birth. Within an infant’s first few months of life, parents usually notice a lack of visual responsiveness and unusual roving eye movements, known as nystagmus. Many children with LCA habitually press on their eyes with their fists or fingers. This habitual pressing on the eyes is known clinically as oculo-digital reflex. The eyes of individuals with LCA also usually appear sunken or deep set. In some cases, LCA is associated with central nervous system complications such as developmental delay, epilepsy, and motor skill impairment. Because LCA is relatively rare, the frequency of central nervous system complications is unknown.

Symptoms

Signs and Tests

Within an infant’s first few months of life, parents usually notice a lack of visual responsiveness and unusual roving eye movements, known as nystagmus. Eye examinations of infants with LCA reveal normal appearing retinas. However, electroretinography (ERG) tests, which measure visual function, detect little if any activity in the retina. A low level of retinal activity, measured by ERG, indicates very little visual function. ERG tests are key to establishing a diagnosis of LCA.

Treatment/Expectations (Prognosis)

Clinical trials of gene replacement therapy for LCA caused by mutations in the RPE65 are now beginning. It is the same therapy that gave vision to 50 dogs, including the world-famous Lancelot, born blind from LCA. These studies provide extraordinary promise for eradicating LCA caused by RPE65, and eventually, LCA caused by other genetic variations.

Some individuals with LCA, who have remaining vision, may also benefit from the use of low-vision aids, including electronic, computer-based and optical aids. Orientation and mobility training, adaptive training skills, job placement, and income assistance are available through community resources.

Complications

Abnormal cornea and cataracts often present

Academic Recommendations

Vision stimulation activities may be beneficial. Braille materials

High contrast line markers or templates may be helpful for reading, finding math problems, or locating other important information. Teachers should not stand in front of a window or light source when teaching or speaking to the student. Lights with rheostats and adjustable arms are helpful for close work. Fatigue can become a problem.

Notes to Remember:

  • Congenital or hereditary
  • Progressive
  • Abnormal cornea and cataracts often present
  • Poor visual acuity
  • Excessive rubbing of the eyes is a characteristic behavior (produces the sensation of light in front of the eyes)

References:

Lueck, A. (Ed.) (2004). Functional vision: A practitioner’s guide to evaluation and

intervention. NY: American Foundation for the Blind.

Levack, Nancy, 2nd Ed. (2004) Low Vision: A Resource Guide with for Adaptations for Students with Visual Impairments

Bulla, Nan, M. ED, Ed Diag, (1996) Assessment of the Visually Impaired, Compiled and Presented by Texas School for the Blind and Visually Impaired

Another-retinal-diseases Leber-Congenital-Amaurosis [Online July 2, 2011]

Leber’s Congenital Amaurosis [Online July 2, 2011]

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