Bilateral congenital cataracts are often inherited as an autosomal dominant trait, however, recessive and x-linked patterns have also been described. Approximately 5-10% of bilateral cataracts are associated with a systemic disorder. Unilateral infantile cataracts are rarely caused by a systemic disease, except in some cases of intrauterine infections such as rubella. About 20-30% of rubella cataracts are unilateral. Thus, the presence of a unilateral cataract does not completely rule out the possibility of an associated systemic disorder, but it is highly suggestive that the cataract is caused by local dysgenesis. Asymmetric bilateral lens opacities may be misinterpreted as a unilateral cataract.
The first part of the consultation is the history. The parents will be asked questions regarding the onset of the cataract and developmental milestones of your child. The family history is also critical. Then, a complete ophthalmic evaluation shall be done. If a hereditary type of cataract is suspected, both the parents should be examined. Laboratory workup is not necessary if the cataracts can be positively defined as hereditary without other systemic abnormalities. The required laboratory tests for congenital cataract include serum TORCH titer and VDRL. A urine test for reducing substance (sugar) after a milk feeding is necessary for bilateral cases. The blood exam is costly but important, particularly if the examination does not clearly reveal a specific diagnosis. The serum TORCH titer will help rule out an intrauterine infection.
Children with congenital cataracts, particularly those with questionable inheritance pattern and possible systemic conditions, are referred to clinical geneticists for co-management.
The main goal for treating congenital cataract is to provide a clear retinal image as soon as possible to avoid irreversible amblyopia, the most common cause of poor vision after cataract surgery in children. Amblyopia may occur whether only one eye or both eyes are involved, so visually significant congenital cataract must be visually rehabilitated as soon as possible. Treatment is urgent because bilateral congenital cataracts that obscure the visual axis will often result in sensory nystagmus and a bilateral poor visual outcome if not treated by 2 months of age.
The use of intraocular lenses is the accepted method for treating aphakia (absence of a natural lens) in children that underwent cataract surgery. Because of the significant change in eye size during the first year of life, implantation of ocular lenses in infants is controversial. By 2 years of age, however, the eye is almost adult size. For the most part, intraocular lenses are becoming the standard in children older than 2 years old. Since the posterior capsule invariably opacifies after a lens implantation, a secondary YAG capsulotomy or secondary procedure is usually necessary. Complications of cataract surgery are unusual, but late complications include retinal detachment, immediate or late glaucoma, retinal hemorrhages, and endophthalmitis.
The treatment does not stop after the surgery. Visual rehabilitation continues by the use of spectacles and contact lenses and amblyopia therapy.
Spectacles are an option to correct bilateral aphakia in children. However, they do not provide constant correction. They are not used for monocular aphakia because of the unilateral magnification of the aphakic lens. Contact lenses are the standard treatment for either unilateral or bilateral aphakia in newborns. Aphakic spectacles can be used as a backup for contact lenses in bilaterally aphakic children.
Occlusion therapy is a must after surgery in monocular congenital cataract in order to treat amblyopia. The amount of patching should be based on the severity of the amblyopia. The role of the parents in the treatment of amblyopia is critical. They should be educated about the importance of a clear retinal image, and the need for occlusion therapy.
Unlike adult cataract, the management of cataracts in children is a big challenge because the role of early visual rehabilitation is critical in the prevention of irreversible amblyopia. Until two decades ago, many ophthalmologists would not even attempt to do surgery on unilateral congenital cataracts because of the poor prognosis associated with this condition. Ophthalmologists today operate as early as the first few weeks of life, and the prognosis is much improved.
In general, patients with monocular cataracts have a very poor prognosis for obtaining fusion, and almost all cases eventually develop strabismus. However, if surgery and optical correction are provided by 2 months of age, good visual acuity and good binocularity with stereopsis are possible. The important point in the management of these cases is that very early surgery (less than 2 months of age) is performed with immediate contact lens fitting, and part-time monocular occlusion for amblyopia is initiated during the first few months of life.
Binocular cataracts can also cause amblyopia. It is important that binocular cataracts are treated with urgency and are operated during the first few weeks of life. If visually significant bilateral congenital cataracts are not cleared by 2 months of age, patients will develop sensory nystagmus and very poor visual acuity in most cases. Surgery by 2 months of age is definitely the treatment of choice. However, older children who present late should still be considered for cataract surgery, even though they present with bilateral cataracts and nystagmus. The exceptions to this are those patients with an abnormality of the retina or optic nerve, such as aniridia. Cataract surgery usually does not improve vision in these cases because the anatomic abnormality of the optic nerve or macula limits the visual acuity potential of the child.
Yes, there are several links between these two conditions. All children who undergo cataract surgery, especially in infancy, are at life long risk for developing glaucoma after surgery. Although this risk is not very high, the serious visual effects of glaucoma can be detected even at the earliest stage. This is why regular follow-up with the pediatric ophthalmologist is important, even after the surgery. Some eyes with congenital cataract are also at risk for glaucoma even if no surgery is done yet. This only means that there are other problems in the eye other than just the cataract. Some eye conditions that are associated with glaucoma would include eye and body syndromes such as aniridia (absent iris), anterior segment dysgenesis, congenital rubella syndrome, and persistent hyperplastic primary vitreous (PHPV). These eye conditions sometimes present initially with cataract and glaucoma.
The following conditions present with infantile cataract and glaucoma:
Lowe syndrome (oculocerebrorenal syndrome)
This is an x-linked disorder that presents with bilateral congenital cataracts and often with bilateral congenital glaucoma. Infants show severe developmental delay, hypotonia, and renal failure with aminoaciduria. The visual prognosis is poor since there is progression of neurological and renal deterioration. Death occurs in late childhood. A dilated slit lamp examination of the patient’s mother shows multiple punctate white snowflake opacities of the lens periphery.