Overview
Definition:
Congenital cataract refers to opacity of the lens present at birth or developing within the first year of life
Amblyopia, or "lazy eye," is a condition of reduced visual acuity in one or both eyes that can result from a congenital cataract if not treated promptly, as the visual cortex does not receive clear images during the critical period of visual development.
Epidemiology:
Congenital cataracts occur in approximately 1 to 4 per 10,000 live births
The etiology is diverse, including genetic factors (hereditary or new mutations), metabolic disorders (e.g., galactosemia, Lowe syndrome), chromosomal abnormalities (e.g., Down syndrome, trisomy 13), intrauterine infections (e.g., rubella, cytomegalovirus), and exposure to teratogens.
Clinical Significance:
Untreated congenital cataracts are a leading cause of preventable childhood blindness
Early detection and intervention are crucial to prevent irreversible amblyopia, ensuring normal visual development and long-term visual function, which directly impacts a child's learning, development, and quality of life.
Clinical Presentation
Symptoms:
Parents may notice a white reflex (leukocoria) in the pupil
Poor visual fixation or tracking
Nystagmus (involuntary eye movements)
Strabismus (misaligned eyes)
Poor visual development or delayed milestones related to vision
The infant may present with rubbing of the eyes.
Signs:
Ocular examination reveals opacity of the lens, varying in size, density, and location
Red reflex examination may be diminished or absent
Fundus examination might be obscured
Refractive assessment may show significant myopia, hyperopia, or astigmatism
Pupillary light reflexes may be abnormal.
Diagnostic Criteria:
Diagnosis is primarily based on clinical observation of lens opacity and confirmed by a comprehensive ophthalmological examination
Associated findings may include features of underlying genetic syndromes, metabolic disorders, or intrauterine infections
Visual evoked potentials (VEPs) can objectively assess visual pathway function when subjective responses are unreliable.
Diagnostic Approach
History Taking:
Detailed family history of eye conditions or consanguinity
Maternal history of infections or drug/alcohol use during pregnancy
Any concerns raised by parents regarding the child's vision or eye appearance
Birth history and developmental milestones
Associated medical conditions.
Physical Examination:
A thorough ocular examination in a well-lit environment, often requiring specialized pediatric equipment and techniques
Assessment of visual acuity (using age-appropriate methods like preferential looking or visual evoked potentials)
Examination of the anterior segment (cornea, iris, lens) and posterior segment (retina, optic nerve) with a dilated pupil
Assessment for nystagmus, strabismus, and pupillary reflexes.
Investigations:
Slit-lamp biomicroscopy is essential for precise localization and grading of the cataract
Cycloplegic refraction to detect significant refractive errors
Ultrasound biomicroscopy (UBM) can visualize the anterior segment structures
Genetic testing may be indicated if a specific inherited syndrome is suspected
Blood tests for metabolic disorders like galactosemia (GALT assay) and TORCH screening for intrauterine infections if indicated.
Differential Diagnosis:
Retinoblastoma (most critical differential due to leukocoria and life-threatening potential)
Persistent hyperplastic primary vitreous (PHPV)
Retinal detachments
Toxocariasis
Coat's disease
Uveitis
Norrie disease
Phthisis bulbi.
Management
Initial Management:
Urgent referral to a pediatric ophthalmologist is paramount upon suspicion of congenital cataract
The goal is to preserve visual potential and prevent amblyopia
Management is tailored to the type, density, and location of the cataract, and the visual acuity of the affected eye(s).
Medical Management:
Medical management is primarily supportive and involves managing underlying systemic conditions
Topical steroids may be used cautiously in some inflammatory conditions mimicking cataracts but are generally not the primary treatment for congenital cataracts themselves.
Surgical Management:
Surgical intervention is indicated for visually significant cataracts that cause amblyopia
Options include lensectomy (removal of the lens), often combined with intraocular lens (IOL) implantation or contact lens correction, and optical correction for aphakia
Surgery is ideally performed within the first few weeks to months of life, especially for bilateral dense cataracts, to minimize the duration of visual deprivation.
Supportive Care:
Postoperative care includes antibiotic and steroid eye drops, cycloplegic drops to prevent synechiae, and meticulous follow-up
Spectacle correction or contact lenses are crucial for optical rehabilitation after cataract removal, especially if an IOL is not implanted or if refractive errors remain
Patching therapy is essential to treat established amblyopia following surgery.
Complications
Early Complications:
Intraoperative: vitreous loss, dropped nucleus fragments
Postoperative: infection (endophthalmitis), uveitis, hyphema, corneal edema, increased intraocular pressure (IOP).
Late Complications:
Posterior capsule opacification (PCO), glaucoma, strabismus, nystagmus persistence or development, amblyopia if treatment is delayed or inadequate, visual impairment due to refractive errors, retinal detachment.
Prevention Strategies:
Early detection through universal newborn eye screening programs and regular pediatric well-child visits
Prompt ophthalmological referral and timely surgical intervention for visually significant cataracts
Aggressive and consistent amblyopia treatment (patching, atropine penalization) post-surgery
Careful monitoring for refractive errors and glaucoma
Genetic counseling for families with a history of congenital cataracts.
Prognosis
Factors Affecting Prognosis:
The visual outcome is highly dependent on the timing of intervention, the density and type of cataract, the presence of associated ocular abnormalities (e.g., microphthalmia, retinal dysplasia), underlying genetic or systemic conditions, and the effectiveness of amblyopia management and refractive correction.
Outcomes:
With early and appropriate surgical management and diligent amblyopia therapy, many children with congenital cataracts can achieve good visual acuity, enabling normal development and learning
However, some degree of visual impairment, refractive errors, or strabismus may persist
Bilateral dense cataracts operated on very early have a better prognosis than unilateral ones or those operated on late.
Follow Up:
Lifelong regular ophthalmological follow-up is essential to monitor for refractive changes, amblyopia, strabismus, glaucoma, and PCO
This monitoring is critical throughout childhood and adolescence, and often into adulthood, to ensure optimal long-term visual function and address any emerging issues promptly.
Key Points
Exam Focus:
Leukocoria is a critical sign requiring immediate ophthalmological evaluation to rule out retinoblastoma and congenital cataract
The primary goal of congenital cataract management is to prevent amblyopia and ensure normal visual development
Timeliness of surgery is paramount, especially for dense bilateral cataracts.
Clinical Pearls:
Always consider retinoblastoma when presented with leukocoria in a child
it is a life-threatening emergency
Use cycloplegic refraction to accurately assess refractive errors in children, as their accommodation is strong
Diligent patching therapy is the cornerstone of amblyopia management post-cataract surgery
Educate parents thoroughly about the importance of follow-up and compliance with treatment.
Common Mistakes:
Delaying referral or surgery for visually significant cataracts
Underestimating the importance of aggressive amblyopia treatment
Inadequate refractive correction post-surgery
Failing to consider and rule out retinoblastoma in cases of leukocoria
Neglecting lifelong follow-up for potential complications like glaucoma.