الفهرس 
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Abstract
Cataract means opacification of the crystalline lens of the eye. Opacities vary in morphology and are often confined to a portion of the lens, and may be static or progressive. Cataract is the commonest treatable cause of visual disability in childhood with an incidence of 0,6 to 6 per 10,000 live births. Childhood cataract is classified as congenital, infantile and juvenile depending on age of onset of the lens opacity. Congenital cataract is present at birth; however it may not be obvious and therefore can go unnoticed until it is observed to have an effect on the child’s visual function. Human congenital cataract has a diverse aetiology. There are many different causes including intrauterine infections, metabolic disorders and chromosomal abnormalities. There are large variety of chromosomal and dysmorphic syndromes, in which the child will have a high risk of having congenital cataract.
Cataract may also be inherited either as an isolated ocular abnormality or as part of a syndrome. It is important to notice any abnormal features in children presenting with cataract, such as unusual facial features, extra digits, unusual skin, short stature, developmental delay, microcephaly or hydrocephaly, as it is essential that the child’s diagnosis is made so that any necessary treatment is given to the child because if a cataract goes undetected in an infant, permanent visual loss may ensue, also the parents should undergo genetic counseling for estimation of possible risks of recurrence in subsequent offsprings.
Genetic counseling in congenital cataract is an important task for the genetic counselors as many families have a case of congenital cataract need to know the percent of recurrence of the disease in their offsprings. Firstly, both parents and any sibs should undergo dilated slit lamp examination to exclude mild congenital opacities; the presence of such opacities will confirm the familial nature of the cataract and allow accurate counseling of recurrence risks. When counseling adults with congenital cataract about the risk to their offsprings, it is important to review other relatives and if possible clinical records of all family members should be examined to exclude any syndromic forms of cataract or non-genetic aetiology.