Congenital cataracts are present at birth but may not be identified until later in life. Prenatal and family history is helpful.
Some cataracts are static, but some are progressive. This explains why not all congenital cataracts are identified at birth.
Anterior polar cataract and nuclear cataract are usually static, although they may rarely progress.
Cataracts that typically progress include posterior lenticonus, persistent hyperplastic primary vitreous, lamellar, sutural, and anterior or posterior subcapsular. They usually have a better prognosis because they only usually begin to obstruct the vision after the critical period of visual development has passed.
Not all cataracts are visually significant. If a lenticular opacity is in the visual axis, it usually is considered visually significant and requires removal.
Cataracts in the center of the visual axis that are greater than 3 mm in diameter are generally considered visually significant. This principle is furthermore correlated with the clinical ophthalmological examination of the patient.
A study by the Department of Pediatric Ophthalmology of the Wills Eye Hospital concluded that, in terms of the risk factor for amblyopia, more important than the cataract size is the anisometropia induced by the congenital anterior lens opacities (CALOs).  Patients with CALOs who have anisometropia of 1 diopter (D) or more are 6.5 times more likely to develop amblyopia. 
A lenticular opacity is called a cataract. Not all cataracts are visually significant.
Description of a congenital cataract must include location, color, density, and shape for purposes of identification.
An irregular red reflex is the hallmark of visual problems. If an irregular red reflex is detected at the initial screening, this is usually an indication that a congenital cataract might be present and an ophthalmology consultation is warranted.
Leukocoria or white reflex can be the presenting sign of a cataract. In fact, in a 2008 study by Haider et al, 60% of patients who presented with leukocoria had congenital cataracts (18% unilateral and 42% bilateral).  Other causes included retinoblastoma (11% unilateral and 7% bilateral), retinal detachment (2.8% unilateral and 1.4% bilateral), bilateral persistent hyperplastic primary vitreous (4.2%), and unilateral Coats disease (4.2%). 
Slit lamp examination of both eyes (dilated pupil) not only may confirm the presence of a cataract but also may identify the time when the insult occurred in utero and if there is other systemic or metabolic involvement.
Dilated fundus examination is recommended as part of the ocular examination for both unilateral cataract cases and bilateral cataract cases.
The most common etiology includes intrauterine infections, metabolic disorders, and genetically transmitted syndromes. One third of pediatric cataracts are sporadic; they are not associated with any systemic or ocular diseases. However, they may be spontaneous mutations and may lead to cataract formation in the patient's offspring. As many as 23% of congenital cataracts are familial. The most frequent mode of transmission is autosomal dominant with complete penetrance. This type of cataract may appear as a total cataract, polar cataract, lamellar cataract, or nuclear opacity. All close family members should be examined.
Infectious causes of cataracts include rubella (the most common), rubeola, chicken pox, cytomegalovirus, herpes simplex, herpes zoster, poliomyelitis, influenza, Epstein-Barr virus, syphilis, and toxoplasmosis.
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