Pediatric Cataract

Etiology

The etiologies of pediatric cataracts are diverse, ranging from conditions of unknown origin to those associated with genetic or systemic disorders. Cataracts may be unilateral or bilateral, with most unilateral cases and a proportion of bilateral cases classified as idiopathic.

Causes of congenital cataracts include the following:

• Intrauterine infections: T. gondii, rubella, cytomegalovirus, herpes simplex virus, syphilis (TORCHES) [13]
• Drug-induced: Corticosteroids (especially prednisolone), ivacaftor (a potentiator of the cystic fibrosis transmembrane conductance regulator, or CFTR, used to treat cystic fibrosis), and topotecan (a topoisomerase I inhibitor) [14]
• Metabolic disorders: Galactosemia, galactokinase deficiency, hypocalcemia, and hypoglycemia [15]
• Trauma, whether accidental or nonaccidental
• Radiation exposure: Laser photocoagulation
• Association with other ocular conditions: Microphthalmia, microcornea, aniridia, persistent hyperplastic primary vitreous (PHPV), Peter anomaly, corneal guttae, coloboma
• Inherited without systemic abnormalities: Autosomal dominant (most common), autosomal recessive (more common in consanguineous families), and X-linked [16]
• Association with other systemic conditions:
  • Chromosomal abnormalities: Trisomies 13, 18, and 21; Turner and Cri-du-chat syndromes
  • Cerebro-oculo-facio-skeletal syndrome
  • Mitochondrial disorders: Complex I deficiency
  • Renal disease: Lowe syndrome
  • Skeletal disorders: Smith-Lemli-Opitz, Conradi, and Weill-Marchesani syndromes
  • Digital anomalies, such as syndactyly or polydactyly: Bardet-Biedl and Rubinstein-Taybi syndromes
  • Central nervous system abnormalities: Zellweger and Meckel-Gruber syndromes
  • Cardiac disease: Hypertrophic cardiomyopathy
  • Dermatologic disorders: Cockayne and Rothmund-Thomson syndromes, atopic dermatitis, incontinentia pigmenti, progeria, ichthyosis, and ectodermal dysplasia
  • Dental anomalies: Nance-Horan and Lenz syndromes  
• Idiopathic

Bilateral congenital cataracts may arise in the following settings:

• Idiopathic cases (~60%)
• Hereditary transmission (~30%): Autosomal dominant (~75%; most common), autosomal recessive, and X-linked
• Intrauterine infections (TORCHES)
• Multisystem genetic disorders
• Inborn errors of metabolism
• Endocrinopathies
• Trauma
• Uveitic cataract
• Ocular abnormalities
• Genetic conditions: Down and Turner syndromes, myotonic dystrophy
• Metabolic disorders: Diabetes mellitus (vacuolar cataracts), hypoglycemia, hypocalcemia, galactosemia (oil droplet cataracts), Fabry disease (spoke-like cataracts), Zellweger syndrome, hypoparathyroidism (multicolored flecks), and Lowe syndrome (thin disciform cataracts)
• Drug reactions: Steroids, miotics, chlorpromazine, amiodarone

Pediatric cataracts exhibit a wide range of etiologies and clinical manifestations. A thorough etiologic evaluation is critical since the specific cause dictates clinical management and long-term treatment planning. Recognizing laterality and identifying potential systemic associations are critical for delivering comprehensive care and optimizing visual outcomes.

Epidemiology

Various epidemiological studies have been conducted to evaluate the causes of childhood blindness. Untreated pediatric cataracts account for approximately 7.4% to 15.3% of cases. The incidence and prevalence of pediatric cataracts vary by region, with lower rates in high-income countries and higher rates in low-income settings. Incidence ranges from 1.8 to 3.6 per 10,000 children annually, while prevalence ranges from 0.63 to 13.6 per 10,000 in low-income countries such as Bangladesh, Pakistan, and India, compared to 0.42 to 2.05 per 10,000 in high-income countries such as the United States and the United Kingdom.[17] No significant differences in prevalence have been observed based on sex or laterality.[18]

Pediatric cataracts are a chief cause of treatable childhood blindness globally, with higher incidence rates reported in developing countries. If not promptly treated, the condition can result in severe visual impairment, affecting the child's quality of life and placing socioeconomic strain on the family and broader community. Pediatric cataracts account for an estimated 5% to 20% of childhood blindness and severe visual impairment worldwide. The global incidence ranges from 1.8 to 3.6 per 10,000 children annually, and prevalence is estimated at 1 to 15 per 10,000. Country-specific studies show varied prevalence rates. In the United States, the prevalence is estimated at 3 to 4 visually significant cataracts per 10,000 live births.[19]

The prevalence of pediatric cataracts in the United Kingdom is approximately 3.18 per 10,000 live births. In China, the incidence is around 5 per 10,000 births. Although geographic variations in prevalence exist, significant differences in laterality (ie, whether 1 or both eyes are affected) or sex are not commonly reported.

Hereditary cataracts account for approximately 30% of all pediatric cases, with about 75% following an autosomal dominant inheritance pattern and the remainder inherited in an autosomal recessive or X-linked fashion. Specific genetic conditions associated with pediatric cataracts include Down and Turner syndromes, as well as myotonic dystrophy. Several metabolic disorders also contribute to cataract development, including diabetes mellitus, hypoglycemia, hypocalcemia, galactosemia, Fabry disease, Zellweger syndrome, hypoparathyroidism, and Lowe syndrome.[20]

Certain medications, such as steroids, miotics, chlorpromazine, and amiodarone, can induce cataracts in children. Trauma is another major cause, accounting for 12% to 46% of pediatric cases. Maternal and congenital infections, particularly those from the TORCHES group, are also notable contributors. A study conducted in the Indian subcontinent reported a high incidence of TORCH infections, with 20% of cases testing seropositive.

Pediatric cataracts represent a critical public health concern that requires timely diagnosis and intervention to prevent long-term visual impairment. A thorough understanding of the epidemiology, including genetic, metabolic, drug-induced, traumatic, and infectious cases, is essential for effective management and treatment planning.[21]

Pathophysiology

Pediatric cataracts have diverse causes, including heritable genetic defects, fetal or childhood developmental insults, and associated systemic syndromes. Autosomal dominant inheritance is the most common pattern seen in hereditary cataracts. A genetic screening study conducted in Australia identified as many as 51 genes and loci associated with the condition.[22] Mutations in genes encoding transcription factors, such as PAX6, FOXE3, MAF (C-MAF), PITX3, MIP, and CRYAA, are frequently observed. Mutations in genes encoding crystallin and connexin are also common.[23][24]

Pediatric cataracts cloud the eye's natural lens and impair vision. The multifactorial pathophysiology involves genetic, metabolic, infectious, and environmental factors that disrupt the normal transparency and function of the lens.

Genetic mutations contribute not only to the presence of pediatric cataracts but also to their phenotypic variability and severity. The affected genes encode proteins essential for lens structure, development, and transparency. Crystallins, for instance, are the primary structural proteins of the lens, maintaining its optical clarity and refractive index. Alterations in crystallin genes lead to protein misfolding or aggregation, resulting in distinct cataract morphologies such as nuclear, lamellar, zonular, and posterior polar types. Connexins form gap junctions that facilitate intercellular communication and metabolic balance within the lens. The disruption of these structures impairs homeostasis and contributes to lens opacification.

Transcription factors such as PITX3 and PAX6 orchestrate lens morphogenesis and differentiation. Mutations in PITX3 have been linked to posterior polar cataracts, while PAX6 alterations are more commonly associated with anterior polar variants. These gene-specific effects highlight the complex molecular basis of pediatric cataracts and underscore the need for genotype-phenotype correlation in guiding diagnosis and management.

Pediatric cataracts may also arise from underlying metabolic disorders. Diabetes mellitus causes elevated blood glucose levels, leading to osmotic imbalances in the lens that result in swelling and vacuole formation, ultimately contributing to cataractogenesis. In galactosemia, the accumulation of galactitol from impaired galactose metabolism induces osmotic stress and leads to the formation of oil droplet cataracts. Hypocalcemia, characterized by low calcium levels, disrupts lens cell function and protein stability, promoting cataract formation. Fabry disease, a lysosomal storage disorder, results in glycosphingolipid accumulation and is associated with spoke-like lens opacities.[25]

Maternal and congenital infections, particularly TORCH infections, can lead to congenital cataracts in newborns. These infections induce intrauterine inflammation and damage the developing lens, resulting in opacification.[26]

Drug-induced cataracts may occur following prolonged exposure to specific medications. Corticosteroids, for instance, alter lens metabolism and protein structure, contributing to posterior subcapsular cataracts. Other drugs, such as miotics, chlorpromazine, and amiodarone, can induce lens opacities through oxidative stress or disruption of lens cell function. Trauma to the eye, whether accidental or intentional, can also result in cataract formation. Mechanical injury may disrupt the lens capsule, allowing fluid ingress and protein denaturation that ultimately leads to lens opacification.[27]

Environmental and nutritional factors play significant roles in the development of pediatric cataracts. Prolonged exposure to ultraviolet radiation and other environmental stressors can heighten oxidative stress within the lens. This increased oxidative burden damages lens proteins and lipids, ultimately leading to cataract formation. Additionally, deficiencies in essential nutrients, particularly antioxidants such as vitamins C and E, can compromise lens health. Such deficiencies impair the lens’s ability to counteract oxidative damage and contribute to cataract progression.[28]

The mechanisms underlying lens opacification are multifaceted and involve several biological processes. Protein aggregation, often resulting from genetic mutations or metabolic imbalances, leads to the unfolding and clumping of crystallin proteins, which scatter light and impair lens transparency. Osmotic imbalances, as seen in conditions such as diabetes and galactosemia, cause the accumulation of osmotic agents within the lens, triggering cellular swelling, membrane rupture, and protein leakage. Disruption of calcium homeostasis further contributes to lens opacity by altering cell signaling and destabilizing lens proteins.[29]

Inflammatory responses induced by infections or trauma can damage lens cells and proteins, further promoting cataract formation. Given the complex pathophysiology of pediatric cataracts, which encompasses genetic mutations, metabolic disturbances, infections, drug toxicity, trauma, and environmental influences, a comprehensive understanding of these mechanisms is essential for developing effective preventive and therapeutic strategies to preserve vision in affected children.[30]

Histopathology

The histopathology of pediatric cataracts involves the microscopic examination of lens tissue to characterize the structural changes that lead to opacification. Different cataract types exhibit distinct histopathological features, offering insight into their underlying mechanisms and informing potential treatment approaches.

Pediatric cataracts commonly display disorganized and fragmented lens fibers. In healthy lenses, fibers are tightly packed and transparent. However, in cataractous lenses, the fibers may appear swollen, misaligned, or vacuolated. Aggregates of denatured or misfolded proteins, particularly crystallins, are often observed within lens fibers. These aggregates scatter light and contribute to lens opacity. Fluid-filled vacuoles are frequently seen in pediatric cataracts, especially those associated with metabolic disorders. These vacuoles arise from osmotic imbalance and lens cell damage.[31]

Genetic cataracts manifest in various forms, each with characteristic histological features. Nuclear cataracts exhibit central lens opacity with dense protein aggregation and increased compaction of lens fibers in the nucleus. Lamellar cataracts present as disk-shaped opacities involving specific layers of the lens. Histologically, these layers contain swollen and disrupted fibers with embedded protein aggregates. Posterior polar cataracts are localized to the posterior aspect of the lens and involve abnormalities of the posterior capsule and adjacent lens fibers. Histologic findings include capsular fibrosis and aberrant cellular proliferation, both of which contribute to the observed opacification.

Metabolic cataracts encompass a spectrum of conditions associated with metabolic disturbances, each exhibiting distinctive pathological features. Cataracts related to galactosemia are characterized by oil droplet formations within the lens, accompanied by vacuolization, osmotic swelling of lens fibers, and deposits of galactitol. Diabetic cataracts display hallmark features such as vacuolar changes, fiber swelling, and sorbitol accumulation. The osmotic effect induced by intracellular sorbitol promotes water influx into the lens, leading to opacification. Cataracts associated with Fabry disease often present with spoke-like opacities, lipid accumulation, and abnormal glycosphingolipid deposits within lens fibers. These distinct histological findings underscore the complex relationship between metabolic abnormalities and lens pathology in metabolic cataracts.[32]

Congenital infections, particularly those caused by TORCH pathogens, leave characteristic histopathological imprints on the lens. Microscopic examination typically reveals inflammation, fibrosis, and cellular infiltration within lens tissue. Thickening of the lens capsule may also be observed, along with viral or parasitic inclusion bodies, further highlighting the detrimental effects of congenital infections on lens development and integrity.

Traumatic cataracts arise from physical injury to the eye and elicit various pathological changes within the lens. Capsule rupture, subsequent fibrosis, and abnormal cell proliferation are common posttraumatic findings. Disruption of the lens capsule’s integrity often results in disorganized lens fibers and the development of opacities. In some cases, calcium deposition within the lens further contributes to opacity and increases lens rigidity. These pathological alterations underscore the diverse structural and functional consequences of trauma in the development of traumatic cataracts.[33]

Certain medications can also induce cataract formation. Steroid-induced cataracts typically manifest as posterior subcapsular opacities, with histopathological findings of swollen and vacuolated lens epithelial cells. These changes result primarily from altered cellular metabolism and protein aggregation. Other drugs associated with cataract formation include miotics, chlorpromazine, and amiodarone, which produce similar histopathological features, including lens fiber swelling, vacuole formation, and protein aggregation.[34]

Key histopathological techniques include light microscopy, electron microscopy, and immunohistochemistry. Light microscopy examines stained lens tissue sections, revealing structural changes in lens fibers, protein aggregates, and cellular abnormalities. Electron microscopy offers detailed views of subcellular structures, enabling the observation of crystallin protein aggregates, membrane disruptions, and intracellular vacuoles. Immunohistochemistry detects specific proteins and cellular markers, aiding in the identification of genetic mutations and metabolic disturbances contributing to cataract formation.[35]

The histopathology of pediatric cataracts reveals a range of structural and cellular abnormalities that contribute to lens opacification. Understanding these changes at the microscopic level is essential for diagnosing underlying causes and developing targeted treatments to restore vision in children with cataracts.

History and Physical

Pediatric cataract evaluation requires a meticulous approach, integrating a comprehensive history, thorough ocular examination, and systemic assessment. This multifaceted process is essential to identify potential underlying causes and associated ocular or systemic conditions.

History taking should elicit key details such as the age of onset, symptom duration, antenatal and perinatal events (including maternal infections, exposures, and birth complications), developmental milestones, and behavioral signs of visual dysfunction (eg, inability to catch objects, frequent falls, photophobia). The evaluation should also include any history suggestive of systemic abnormalities, trauma, prior treatment or surgery, and family history of congenital or developmental cataracts or consanguinity.[36]

A detailed physical examination is equally important. The pediatrician should assess for systemic or genetic associations through careful inspection. For instance, head circumference measurement is particularly relevant in cases of congenital cataracts, as certain syndromes, such as trisomy 21 and Hallermann-Streiff-Francois, Lowe (oculocerebrorenal), Cri-du-chat (5p deletion), Nance-Horan, and Edward syndromes, may present with both cataracts and abnormal head size.[37]

Reviewing family photos can be helpful when the exact onset of cataracts is unclear. Early cataracts that develop during critical periods of ocular and visual system maturation may be associated with a poorer prognosis.[38] Examination of the eyes of family members, particularly parents and siblings, may reveal undiagnosed lenticular changes suggestive of inherited causes. Autosomal dominant inheritance is the most common pattern, although X-linked recessive transmission can also occur, as seen in conditions such as Lowe and Nance-Horan syndromes.[39][40]

A comprehensive ocular examination is essential for pediatric cataract assessment. Visual acuity testing should be tailored to the child's developmental level. In preverbal children, assessment tools may include the Bruckner test, cover test, resistance to occlusion of the better eye, monocular fixation, fixation preference, vertical prism test, forced-choice preferential looking, Teller acuity cards, optokinetic nystagmus, and pattern visual evoked potential.[41][42]

The Bruckner test, performed using a direct ophthalmoscope, enables simultaneous visualization of the red reflex in both eyes. This technique can detect anisometropia or unequal refractive power. In strabismus, the deviated eye typically shows a lighter red reflex than the fixating eye. Similarly, in anisometropia, one eye may display a brighter reflex than the other.

Verbal children undergo a multifaceted visual acuity assessment. Detection acuity testing, using tools such as the Catford drum test and the Standardized Tests for Young Children and Retardates (STYCAR) graded ball test, evaluates the ability to perceive light or motion.[43]

Recognition acuity testing assesses the ability to identify specific visual stimuli. This modality includes direction recognition using the Landolt C or Snellen E tests, letter identification with Snellen charts or high-contrast optotype visual acuity tests, and picture recognition with tools such as Allen picture cards or Domino charts. Behavioral pattern assessment, through methods like the Cardiff acuity test and the optokinetic drum test, determines visual function indirectly by observing the child’s responses to visual stimuli.[44]

The slit-lamp examination evaluates associated anterior segment findings, such as microcornea, anterior segment dysgenesis, iris coloboma, cataract morphology, microspherophakia, ectopia lentis or lens subluxation, and preexisting posterior capsular defects (see Image. Slit-Lamp Examination of Pediatric Zonular Cataract). The morphological classification of pediatric cataracts includes the following types:

• Anterior cataracts: Anterior lenticonus (associated with Alport syndrome), anterior polar, anterior pyramidal, anterior subcapsular
• Cataracts involving the entire lens: Total and membranous cataracts
• Posterior cataracts: Mittendorf dot, posterior lenticonus, posterior subcapsular cataract (see Image. Pediatric Cataract, Posterior Lenticonus)
• Central cataracts: Lamellar (zonular), pulverulent, oil drop, coronary, blue dot cataracts
• Sutural cataract
• Wedge-shaped cataract [45]

Ocular motility evaluation assesses for strabismus and nystagmus, which should be specifically examined in children. These findings may be the initial signs of pediatric cataracts and indicate potential visual impairment. Strabismus commonly occurs in unilateral cataracts and typically develops after significant visual loss has already taken place. Congenital sensory nystagmus is frequently associated with pediatric cataracts. The presence of either strabismus or nystagmus suggests that the cataracts are visually significant.[46][47][48]

Intraocular pressure (IOP) measurement, performed with a tonometer, helps rule out glaucoma associated with congenital rubella syndrome.[49] Pupillary reaction testing provides a rough assessment of optic nerve head function. Direct and indirect ophthalmoscopy are used to evaluate for associated vitreous or posterior segment abnormalities, such as vitreous hemorrhage, persistent fetal vasculature, fundal coloboma, and optic or macular hypoplasia.

Visually significant cataracts are typically centrally or posteriorly located and measure more than 3 mm in diameter. These cataracts often result in visual acuity of 20/60 or worse, reduced contrast sensitivity, increased glare, impaired stereoacuity, and associated strabismus or nystagmus.[50][51]

Examination of The Red Reflex

Medical professionals caring for children, especially newborns and neonates, must be proficient in performing the red reflex test. The American Academy of Pediatrics (AAP) recommends that red reflex testing be conducted on all neonates and during all routine well-child visits and healthcare appointments.[52][53][54][55]

The red reflex is commonly observed in photographs taken with a flash and is essentially a reflective phenomenon. Light entering the eye through the pupil is reflected by the retina and exits back through the optical media, producing a reddish glow. A normal red reflex confirms the transparency of the eye’s optical structures, including the tear film, cornea, aqueous humor, lens, vitreous gel, and retina.[56] The test focuses on the reflex’s presence or absence, as well as its color, brightness, and symmetry between the eyes.[57]

Requirements for performing a red reflex test include the following:

• Dimming or turning off the room lights
• Positioning the child on the parent's lap so that the child’s eyes are level with the examiner’s
• Setting the direct ophthalmoscope diopter power to the examiner's refractive correction or to "0"
• Holding the ophthalmoscope close to the examiner’s eye and 12 to 18 inches away from the child’s eyes
• Encouraging the child to look at the light, with help from an assistant or toys if needed
• Directing the light at each eye individually to detect and compare the light reflexes
• Assessing reflex symmetry by shining the light on both eyes simultaneously (Bruckner test) [58]

The red reflex examination’s simplicity, speed, and noninvasiveness make it an essential tool for the early detection of pediatric cataracts.

Evaluation

Laboratory investigations encompass blood and urine tests as well as other targeted studies. Routine blood work should include a complete hemogram, blood glucose, and urine routine microscopy. Additional tests are obtained on a case-by-case basis, guided by the clinical history and examination findings. These assessments may include the following:

• Serum calcium for hyperparathyroidism or hypoparathyroidism [59]
• Venereal Disease Research Laboratory (VDRL) testing for syphilis [60]
• TORCH infection antibody titers [61]
• Red cell galactokinase or uridyl transferase assays for galactosemia [62]
• Urine protein analysis for Alport syndrome [63]
• Urine amino acid screening for Lowe syndrome
• Urine sodium nitroprusside or plasma homocysteine for homocystinuria [64]
• Urine or serum copper levels for Wilson disease [65]
• Karyotyping to detect genetic abnormalities

Ocular investigations for pediatric cataracts involve several key diagnostic tools. Ultrasound B-scan is essential for excluding posterior segment pathologies that may mimic congenital cataracts, such as retinoblastoma, PHPV, Coats disease, retinopathy of prematurity with retrolental fibroplasia, organized vitreous hemorrhage, congenital falciform folds, ocular toxocariasis, and retinal hamartomas.[66][67] Additionally, ultrasound biometry provides essential optical parameters, such as axial length, anterior chamber depth, and lens thickness, that are critical for IOL power calculation.[68][69]

Keratometry, typically performed using handheld keratometers, requires the child’s cooperation for accurate readings. Standard K values of 43.00 D may be used if the child is uncooperative.[70] Optical coherence tomography is employed to assess retinal structure and detect associated pathologies. For systemic imaging, magnetic resonance imaging or computed tomography is recommended when persistent fetal vasculature or retinoblastoma is suspected, as these modalities provide detailed visualization of the brain and orbits.

Additional evaluation considerations include consultations with various specialists. A pediatrician assesses systemic health and coordinates care. A geneticist should be consulted when hereditary conditions are considered, as they can provide genetic analysis and counseling. An endocrinologist may be involved when metabolic disorders affecting ocular health are suspected, ensuring targeted management.[71]

Preoperative assessment for pediatric cataracts requires a comprehensive anesthetic evaluation, particularly for infants and children with comorbidities, to ensure fitness for anesthesia. Managing pediatric cataracts demands an interprofessional approach that integrates clinical, laboratory, and imaging assessments. Adherence to national and international guidelines helps standardize diagnosis and management, improving outcomes. Early detection and thorough evaluation are critical to preventing long-term visual impairment and improving the quality of life for affected children.

Treatment / Management

Managing pediatric cataracts requires a coordinated effort among ophthalmologists, pediatricians, anesthesiologists, counselors, parents, and other family members. Treatment options may be medical or surgical.

Medical Management

Medical management includes amblyopia therapy, such as patching the better-seeing eye to stimulate use of the amblyopic eye or using atropine drops to blur vision in the dominant eye as an alternative.[72] Refractive correction is achieved through glasses or contact lenses to address residual refractive errors after surgery. Bifocals or multifocals may be needed for near-vision tasks.[73](A1)

Low vision aids, including magnifiers and telescopic lenses, can enhance visual function in children with significant visual impairment.[74] In cases of partial or nonamblyogenic cataracts, 2.5% phenylephrine may be used to achieve mydriasis and permit vision through the nonopacified area. Optical iridectomy, though now obsolete, served a similar purpose by allowing light to pass through a clear zone of the lens.[75]

Surgery

Surgical indications include any visually significant lens opacity, cataracts associated with visual acuity of 20/60 or worse, cases where the optic disc is not visible on indirect ophthalmoscopy, and central cataracts measuring at least 3 mm in size. Other indications include posterior subcapsular and nuclear cataracts, bilateral involvement, and cataracts accompanied by strabismus or nystagmus.[76][77](B3)

Before surgery, family members must be counseled about the expected visual prognosis, the available treatment options, and the importance of regular follow-up. Postoperative visual rehabilitation and adherence to amblyopia therapy, when indicated, are essential components of care.

Surgery should be performed promptly for visually significant cataracts, ideally within a few weeks after birth, to prevent amblyopia. Surgical planning is more favorable for children older than 4 years, as ocular development is largely complete and the risk of postoperative complications is lower.

Unilateral cataracts are typically operated on between 4 to 6 weeks of age. For bilateral cases, the recommended window is between 6 to 8 weeks, with the second eye ideally treated within 2 weeks of the first. In bilateral cataract surgery performed within the first year of life, long-term visual acuity at 5 years is not significantly affected by the exact timing of surgery. However, earlier intervention, preferably before 2 months, correlates with better visual outcomes in unilateral cases.[78]

Despite these benefits, early cataract surgery is associated with a higher risk of glaucoma, particularly in unilateral cases. Thus, some surgeons may opt to delay the procedure slightly to balance visual and safety outcomes, accepting a modest reduction in visual acuity.

General anesthesia with continuous monitoring of vital parameters is preferred for pediatric cataract surgery. A trained anesthesiology team and interprofessional support are essential, given the unique physiological and surgical needs of children.

The type of surgery and its associated challenges have evolved significantly. Modern techniques such as phacoaspiration with IOL implantation have largely replaced older methods like discission. In 1959, Choyce and Binkhorst were the first to implant a monocular IOL in a child.

Pediatric cataract surgery differs considerably from adult surgery and presents distinct intraoperative challenges. Low scleral rigidity complicates incision construction and wound closure. A smaller globe size, shallow anterior chamber, and small pupil reduce surgical maneuverability. The highly elastic lens capsule, elevated positive intravitreal pressure, and risk of vitreous loss or expulsion of intraocular contents further increase procedural complexity.

Primary IOL implantation offers several advantages, including immediate refractive correction, minimal optical aberration, a full visual field, and a reduced likelihood of amblyopia, strabismus, and nystagmus. The procedure also reduces the dependence on patient compliance for corrective devices. However, IOL implantation in children younger than 2 years remains controversial. Limited long-term data, frequent coexisting ocular abnormalities, high rates of deprivation amblyopia, and increased postoperative complications have historically discouraged early implantation.

The Infant Aphakia Treatment Study reported a higher incidence of intraoperative and postoperative complications, as well as a greater need for additional surgeries, in children who underwent IOL implantation before 1 year of age.[79] In contrast, recent data from the Swedish Pediatric Cataract Register suggest that primary bag-in-the-lens IOL implantation before 2 years of age is safe and effective. This technique was associated with low rates of VAO, supporting its routine use in Sweden.[80](A1)

A consensus on the timing and technique of surgery with IOL implantation is as follows:

• Younger than 18 months to 2 years: Lens aspiration without IOL implantation, combined with posterior curvilinear capsulorhexis (PCCC) and limited anterior vitrectomy (LAV). The child remains aphakic and is managed with postoperative aphakic correction, followed by secondary IOL implantation at a later age.
• 2 to 5 years: Lens aspiration with IOL implantation, along with PCCC and LAV.
• Older than 8 years: Lens aspiration with IOL implantation and PCCC, without LAV. Alternatively, phacoaspiration with IOL implantation may be performed as in adult cataract surgery.[81][82]
(B3)

To reduce the risk of VAO, PCCC is recommended for children younger than 8 years. LAV is advised for patients younger than 5 years.

Recent studies have shown that posterior optic capture following PCCC without LAV yields comparable outcomes to conventional in-the-bag IOL implantation with PCCC and LAV in terms of posterior capsular opacification, complication rates, and refractive development.[83][84] However, posterior optic capture is technically demanding, with a steep learning curve. The procedure requires precise sizing of both the anterior and posterior capsulorhexis and should be used cautiously in infants or eyes with posterior capsular defects.[85]

Accurate IOL power calculation is crucial for achieving optimal refractive outcomes after surgery in children. However, this process poses significant challenges, particularly in accounting for the child's age and axial length. Biometry and keratometry measurements may vary depending on the instruments and techniques used. Studies have shown that the SRK/T and Holladay 2 formulas yield the lowest predictive error among current IOL power formulas. Ongoing research continues to develop improved formulas to enhance the accuracy of IOL calculations in pediatric patients.

"Emmetropisation" refers to the postnatal adjustment of 3 primary ocular parameters—axial length, corneal curvature, and lenticular power—toward adult values as the child matures. A progressive myopic shift is expected as axial length increases with ocular growth. Therefore, the initial refractive target after IOL implantation is hypermetropia. Undercorrection of IOL power based on age has been shown to improve postoperative refractive outcomes. Dahan and Drusedau recommended undercorrection by 20% in children younger than 2 years and by 10% in those aged 2 to 8 years. The consensus targets for residual refraction are approximately +6 D (1 to 2 years), +5 D (2 to 4 years), +4 D (4 to 5 years), +3 D (5 to 6 years), +2 D (6 to 7 years), and plano in children older than 14 years.[86][87][88][89](B2)

A recent 15-year follow-up study reported that cataract surgery performed at or before 2 years of age resulted in significant refractive shifts. Median myopic or anisometropic changes ranged from -8 to -11 D, regardless of whether the child was aphakic or pseudophakic.[90]

National and International Guidelines

National and international guidelines provide comprehensive recommendations for the detection and management of pediatric cataracts. The American Academy of Pediatrics recommends performing red reflex examinations at every well-child visit beginning at birth, with immediate referral to a pediatric ophthalmologist if an abnormal red reflex is identified. The American Academy of Ophthalmology (AAO) emphasizes early detection and timely treatment, particularly in infants with visually significant cataracts. The American Academy of Ophthalmology also recommends genetic counseling and appropriate genetic testing for families with a history of pediatric cataracts.

Postoperative amblyopia therapy and regular follow-up are advised to monitor visual development and address complications.[91][92] The World Health Organization (WHO) supports the integrated management of childhood illnesses, including screening for congenital conditions such as cataracts. The World Health Organization also advocates for the development of national programs aimed at preventing and managing childhood blindness.[93][94](A1)

Follow-Up Care

Follow-up care for pediatric cataracts involves several key components to ensure optimal outcomes. Regular ophthalmic evaluations are essential, with frequent follow-ups to monitor for complications in the immediate postoperative period. Long-term follow-up tracks visual development and addresses any refractive changes.[95]

Developmental and educational support, including occupational therapy, is important to promote visual skill development and support activities of daily living. Special education services ensure appropriate accommodations for children with visual impairment.[96]

Parental education and support are critical. Caregivers must receive clear instructions on postoperative care, including the administration of eye drops and recognition of potential complications. Emphasis is placed on adherence to amblyopia therapy and scheduled follow-up visits.[97](B3)

Psychosocial support should also be provided, including access to counseling and support groups to help families manage the emotional and psychological challenges associated with pediatric cataracts. This comprehensive and interprofessional approach, aligned with national and international guidelines on early detection, timely surgical intervention, effective postoperative care, and ongoing visual rehabilitation, is essential for optimizing visual outcomes and improving quality of life for affected children.

Differential Diagnosis

Pediatric cataracts typically present as a whitish opacity in the eye, often first noticed by the parents. Other potential etiologies must be ruled out before diagnosing a pediatric cataract as the cause of a white pupillary reflex (leukocoria). These conditions include the following:

• Corneal abnormalities (eg, corneal opacity)
• Lens abnormalities (eg, cataracts)
• Vitreous causes (eg, vitreous hemorrhage, PHPV)
• Retinal disorders (eg, Coats disease, retinoblastoma, familial exudative vitreoretinopathy, retinal detachment, retinopathy of prematurity, and coloboma)
• Tumors such as medulloepithelioma and retinal astrocytoma [98][99]

Cataracts may occur in isolation or association with other causes of leukocoria. The differential diagnosis may be refined based on the clinical history, family history, and comprehensive ophthalmic examination.[100][101] Other potential causes of lens opacity must also be considered, including the following:

• Retinoblastoma
• Persistent fetal vasculature
• Coats disease
• Toxocariasis
• Retinal detachment [102]
• Optic nerve hypoplasia
• Congenital glaucoma [103]
• Retinal dysplasia
• Intraocular inflammation (uveitis) [104]
• Congenital rubella syndrome
• Norrie disease
• Leber congenital amaurosis
• Familial exudative vitreoretinopathy
• Retinitis pigmentosa [105]
• Marfan syndrome [106]
• Lowe syndrome [107]
• Congenital syphilis
• Metabolic disorders (eg, galactosemia and diabetes mellitus)
• Aniridia
• Coloboma [108]
• Stickler syndrome
• Bardet-Biedl syndrome
• Joubert syndrome
• Von Hippel-Lindau disease
• Wolfram syndrome
• Langerhans cell histiocytosis
• Oculocerebrorenal syndrome (Lowe syndrome)
• Alport syndrome
• Usher syndrome
• Wilms tumor, aniridia, genitourinary anomalies, and range of developmental delays (WAGR) syndrome
• Peter anomaly
• Axenfeld-Rieger syndrome
• Sturge-Weber syndrome
• Tuberculosis
• CMV infection
• Toxoplasmosis
• HSV infection [109]
• Congenital varicella syndrome
• Retinal hemorrhages (eg, from shaken baby syndrome)
• Albinism
• Blue cone monochromacy
• Best disease (Best vitelliform macular dystrophy)
• Choroideremia
• Congenital stationary night blindness
• Bietti crystalline dystrophy
• Batten disease (neuronal ceroid lipofuscinosis)
• Usher syndrome
• Hyphema
• Sickle cell retinopathy
• Retinal vein occlusion
• Familial hypercholesterolemia
• Fabry disease
• Niemann-Pick disease
• Smith-Lemli-Opitz syndrome
• Congenital Zika syndrome
• Ehlers-Danlos syndrome
• Ataxia-telangiectasia
• Juvenile idiopathic arthritis
• Neurofibromatosis type 1
• Hypocalcemia

A thorough clinical investigation with the appropriate diagnostic modalities can guide management.

Staging

Pediatric cataracts may be staged according to morphology, location, and their effect on vision. Staging provides a framework for guiding appropriate treatment and management strategies. The criteria commonly used for staging are summarized below.

Morphological Classification

Pediatric cataracts may be categorized based on the location and pattern of lens opacities. Morphological classification aids in assessing severity and predicting the potential impact on visual development.

• Nuclear cataract: Located in the central nucleus of the lens. Often congenital and can significantly impair vision if dense.
• Cortical cataract: Affects the cortex or outer layer of the lens. May progress slowly, with the degree of visual impairment depending on the extent and location of opacities.
• Posterior subcapsular cataract: Positioned at the back of the lens, just anterior to the posterior capsule. This type often causes glare and difficulty with bright light, markedly affecting near vision.
• Lamellar (zonular) cataract: Involves a specific layer or zone of the lens (see Image. Pediatric Cataract, Zonular Type). Dense, centrally located opacities can cause substantial visual impairment.
• Anterior polar cataract: Located on the anterior surface of the lens capsule. Typically small and may not considerably impair vision unless the cataract enlarges.[110]

Each morphological type presents unique clinical considerations. Awareness of these differences ensures more tailored treatment and follow-up strategies.

Severity Based on Density and Extent

Pediatric cataracts may also be staged based on severity, which helps guide clinical decisions. Classification into mild, moderate, or severe reflects the degree of visual impact and informs the timing of treatment. 

• Mild cataract: Small lens opacities that do not substantially interfere with vision. Managed conservatively with regular monitoring.
• Moderate cataract: More extensive opacities that cause noticeable visual impairment. May require surgical intervention if vision is functionally compromised.
• Severe cataract: Dense opacities that markedly impair vision or cause blindness. Prompt surgical management is typically necessary to restore vision and reduce the risk of amblyopia.[111]

Effective management of pediatric cataracts depends on accurate severity assessment. Early intervention in moderate-to-severe cases is critical for optimal visual outcomes.

Impact on Vision

Assessing the functional impact of a cataract on a child’s vision is crucial. This classification supports early identification of cases requiring surgical management versus observation.

• Visually insignificant cataract: Lens opacity that does not strikingly impair vision or causes only minor visual disturbances. Regular follow-up is necessary to monitor for progression.
• Visually significant cataract: Leads to marked visual impairment that affects daily function and visual development. Requires timely surgical intervention to prevent amblyopia and optimize visual outcomes.[112]

Timely identification of visually significant cataracts ensures appropriate surgical planning and supports better developmental outcomes. Nonsignificant cataracts should still be monitored for possible progression.

Location Relative to the Visual Axis

The location of a pediatric cataract within the lens influences its effect on vision. Cataracts are commonly described as either central or peripheral based on their position.

• Central cataract: Situated along the central visual axis. More likely to interfere with vision and visual development, often necessitating early intervention.
• Peripheral cataract: Located outside the central visual axis. May not significantly impair vision unless the cataract progresses centrally.

This classification assists clinicians in prioritizing cases for surgical referral. Central cataracts pose a higher risk and should be addressed more urgently.

Laterality

The distinction between unilateral and bilateral cataracts guides prognosis and therapeutic approach. Early identification is essential to minimize the risk of long-term visual impairment. 

• Unilateral cataract: Involves only one eye. Carries a higher risk of amblyopia due to unequal visual input, necessitating early diagnosis and prompt intervention.
• Bilateral cataracts: Involve both eyes. Can cause symmetrical visual impairment and typically require coordinated surgical and rehabilitative management for both eyes.[113]

Laterality not only affects the severity of visual loss but also determines surgical timing and rehabilitation. Tailored strategies are essential for optimal outcomes in each type.

Staging pediatric cataracts involves evaluating their morphology, severity, location, and impact on vision. This comprehensive assessment informs treatment planning and supports optimal visual outcomes and development. Regular monitoring and timely intervention are essential for effective management.

Prognosis

Numerous factors influence the final visual outcome in children with pediatric cataracts. Visually significant cataracts produce blurred retinal images, which disrupt the development of visual pathways and cortical connections in the occipital lobe. With improved understanding and surgical techniques, early removal of visually significant cataracts is now recommended to prevent sensory deprivation amblyopia. Unilateral cataracts are more amblyogenic than bilateral cases, underscoring the importance of early surgery within the first few weeks to months of life.

The timing of diagnosis plays a critical role in determining visual prognosis—the earlier the diagnosis and treatment, the better the outcome. Associated ocular conditions such as microcornea, corneal opacities, glaucoma, intraocular inflammation, posterior segment abnormalities, and ocular motility disorders (eg, unsteady fixation, strabismus, or nystagmus) are associated with poorer postsurgical outcomes.[114]

The prognosis of pediatric cataracts depends largely on the timing of diagnosis and intervention, the presence of systemic or genetic conditions, and the effective management of complications. Early detection and prompt treatment are essential for optimizing long-term visual outcomes.

Children diagnosed and treated within the first few weeks to months of life generally have a better prognosis. Early intervention prevents amblyopia and supports normal visual development. In contrast, delays in diagnosis and treatment can result in permanent visual impairment, including amblyopia and associated developmental deficits, highlighting the importance of timely detection.[115]

Patients with isolated cataracts, ie, those not associated with ocular or systemic abnormalities, tend to have a more favorable prognosis when treated early. Cataracts linked to genetic syndromes or metabolic disorders present additional management challenges and often carry a more guarded prognosis due to the presence of concurrent health issues.

Modern surgical techniques, including IOL implantation, have markedly improved outcomes in pediatric cataract management. Successful cataract extraction, followed by effective visual rehabilitation, frequently results in favorable visual outcomes. Postoperative care plays a crucial role. Proper management of complications such as PCO and secondary glaucoma, along with regular follow-up and adherence to treatment, considerably enhances long-term prognosis.[116]

Corrective lenses, whether glasses or contact lenses, along with amblyopia therapy such as occlusion of the better-seeing eye, are essential components of visual rehabilitation. Consistent use of these interventions is critical for optimal visual development. Ongoing support through occupational therapy and visual skills training can further improve outcomes, particularly in children with developmental delays secondary to visual impairment.

Continued surveillance is required to detect and manage late-onset complications such as glaucoma or retinal detachment, which may adversely affect long-term prognosis. Regular ophthalmic evaluations throughout childhood and adolescence enable timely identification and management of these conditions.[117]

Visual outcomes vary widely across patients. Prognosis depends on the type and severity of the cataract, the child's general health, the presence of coexisting ocular or systemic abnormalities, and the family’s adherence to postoperative care and rehabilitation strategies.

Overall, the prognosis for children with pediatric cataracts is favorable when early detection, timely intervention, and comprehensive postoperative care are provided. Advances in surgical techniques and visual rehabilitation have significantly improved outcomes, enabling many children to attain good vision and normal functional development. Continued vigilance remains essential to manage potential complications and preserve long-term visual health.

Complications

As with other intraocular procedures, pediatric cataract surgery carries inherent risks that may necessitate further treatment. These complications can compromise visual outcomes if not promptly identified and managed.

VAO is a potential cause of amblyopia following cataract surgery.[118] The condition is inevitable if the posterior capsule is left intact. VAO arises from the proliferation, migration, and metaplasia of lens epithelial cells extending from the equator to the posterior capsule. Even after a well-executed posterior capsulotomy, secondary membranes and media opacities may still form. An intact hyaloid face can serve as a scaffold for epithelial cell migration and transformation.

One of the most influential factors in VAO development is the age of the patient at the time of surgery. Other contributing factors include the type of cataract, the presence of associated ocular abnormalities (eg, PHPV, uveitis), aphakic or pseudophakic status, IOL type, the size of the capsular opening, and the completeness of cortical cleanup. Adequate posterior capsulotomy, with or without vitrectomy, is essential to prevent VAO. In-the-bag IOL implantation further reduces the risk. If the child is cooperative, Nd:YAG laser capsulotomy may be used to clear the opacification. Surgical intervention, such as membranectomy, may be necessary to restore visual axis clarity in cases of dense or thick VAO.[119]

Glaucoma develops in 10% to 25% of cases following pediatric cataract surgery.[120] Open-angle glaucoma is more common, although pupillary block glaucoma can also occur. Medical therapy is typically the initial approach. However, surgical management becomes necessary in refractory cases. Surgical options include trabeculectomy, implantation of glaucoma drainage devices, and cyclodestructive procedures.[121]

Postoperative anterior uveitis is more common in children than in adults due to heightened tissue reactivity. No-touch surgical techniques and in-the-bag IOL fixation help reduce the incidence of this condition. Frequent postoperative administration of topical steroids or posterior sub-Tenon injection of triamcinolone acetonide may be necessary. Dense fibrinous exudates and postoperative miosis occur in some cases. Mydriatic agents, such as atropine or subconjunctival injection of mydricaine, may be used to prevent synechiae formation and achieve adequate mydriasis.

Postoperative IOL-related complications may include surface deposits, synechiae, pupillary capture, opacification, and decentration. Additional IOL-related issues may involve incorrect IOL power calculation, dislocation, or intraocular inflammation. These complications highlight the importance of accurate IOL power estimation and meticulous surgical technique. Surgical repositioning or replacement may be required in cases of IOL dislocation or significant malfunction.

Amblyopia is a developmental condition in which an eye fails to achieve normal visual acuity, often due to unequal visual input. This condition frequently arises in children with cataracts, particularly when the cataract is unilateral or dense. Early diagnosis and intervention are essential to prevent long-term visual impairment. Treatment strategies include occlusion therapy (patching of the dominant eye), pharmacologic penalization with atropine, and refractive correction using glasses or contact lenses.[122]

PCO is the most common postoperative complication following pediatric cataract surgery. The lens capsule becomes cloudy, resulting in decreased visual acuity. Nd:YAG laser capsulotomy is typically performed to restore a clear visual axis and improve vision.[123]

Strabismus may develop in children with cataracts due to unequal visual input to the brain, which disrupts binocular vision and leads to ocular misalignment. Management options include corrective glasses, patching, orthoptic exercises, and surgical realignment of the extraocular muscles.[124]

Postoperative inflammation and infection, including endophthalmitis, are serious complications of cataract surgery in children. Prophylactic antibiotics and anti-inflammatory agents are administered postoperatively to minimize risk. Rapid recognition and aggressive treatment of infection are essential to prevent irreversible vision loss.[125]

Retinal detachment, though rare, is a potentially sight-threatening complication characterized by the separation of the neurosensory retina from the underlying retinal pigment epithelium. Immediate surgical repair is necessary to reattach the retina and preserve visual function.[126]

Postoperative refractive errors, such as myopia (nearsightedness) and hyperopia (farsightedness), may occur following pediatric cataract surgery, potentially affecting visual clarity. Corrective lenses, ie, glasses or contact lenses, are prescribed to address these errors and achieve optimal visual outcomes.[127]

Phthisis bulbi is a condition in which the eye becomes shrunken and nonfunctional due to severe intraocular damage or chronic inflammation. Preventive strategies include timely and appropriate management of postoperative complications. Enucleation may be necessary in advanced or painful cases.[128]

Corneal opacification may develop as a result of chronic inflammation or infection, reducing corneal transparency and impairing vision. Continuous monitoring and aggressive management of underlying causes are essential. Corneal transplantation may be required to restore visual function in advanced cases.

Other complications may include cystoid macular edema, retinal detachment, endophthalmitis, heterochromia, corneal decompensation, bullous keratopathy, astigmatism, and unexpected postoperative refractive outcomes.[129] Monitoring and managing morbidities linked to pediatric cataracts are essential for achieving optimal visual outcomes. An interprofessional approach, emphasizing regular follow-up, timely intervention, and comprehensive care, is crucial for effectively addressing these complications and improving the quality of life in children with cataracts.