Congenital Cataracts: Clinical Case Discussion & Key Points
Model Case Presentation
Patient Demographics
Name: Baby Arya, Age: 6 weeks, Gender: Female, Informant: Mother (Reliable)
Chief Complaints
- White reflex noticed in the left eye since birth – 6 weeks
- Child not fixing and following with the left eye – noticed 2 weeks ago
- Left eye turning inward – noticed 1 week ago
History Summary
Mother noticed a white glow (leukocoria) in the left eye of the child in photographs since birth. The child does not follow faces or objects with the left eye when the right eye is covered. Inward deviation of the left eye (esotropia) noted over the past week. No shaking of eyes (nystagmus) yet. The right eye appears normal.
Born at term via LSCS, cried immediately, birth weight 3.1 kg. Antenatal period unremarkable — no fever with rash, no TORCH infections documented, no medications during pregnancy. No family history of childhood cataracts or eye diseases. Non-consanguineous marriage. Developmental milestones appropriate for age.
Examination Summary
| Parameter | Finding | Significance |
|---|---|---|
| Red Reflex (Left eye) | Absent / White reflex | Leukocoria — cataract |
| Red Reflex (Right eye) | Normal (orange-red, bright) | Normal |
| Fixation (Left) | Poor / absent | Visual deprivation |
| Ocular alignment | Left esotropia | Sensory strabismus due to poor vision |
| Nystagmus | Absent (so far) | Favourable — early presentation |
| Anterior segment (Right) | Normal | Unilateral cataract confirmed |
Slit-lamp / Pen-torch examination (Left eye): Dense, central white lens opacity occupying the entire visual axis. Posterior segment not visualised due to dense cataract.
B-scan ultrasound (Left eye): No evidence of persistent fetal vasculature (PFV), retinal detachment, or retinoblastoma. Axial length normal for age.
✅ Complete Diagnosis
Unilateral Dense Congenital Cataract (Left eye) — Idiopathic — with Early Sensory Esotropia and Deprivation Amblyopia Risk. Urgent surgery indicated.
📝 History — Exam Q&A
Congenital cataract is any opacification of the crystalline lens present at birth or developing within the first year of life. Incidence: approximately 3–6 per 10,000 live births. It is one of the leading causes of treatable childhood blindness, accounting for ~10% of childhood blindness worldwide.
- Leukocoria (white reflex / white pupil) — most common presenting sign; often noticed by parents in photographs
- Strabismus — usually esotropia, due to loss of fixation (sensory squint)
- Nystagmus — pendular nystagmus; indicates severe visual deprivation; ominous sign suggesting delayed presentation
- Poor visual behaviour — not fixing or following with the affected eye
- Abnormal red reflex on routine newborn screening
- Rarely, photophobia (in posterior subcapsular cataract)
| Category | Examples |
|---|---|
| Idiopathic | Most common overall; majority of unilateral cases |
| Hereditary / Genetic | Autosomal dominant (most common hereditary pattern ~44%); also AR and X-linked. Mutations in crystallins (CRYAA, CRYAB, CRYGC, CRYGD), connexins (GJA3, GJA8) |
| Intrauterine infections (TORCH) | Rubella (classic), CMV, Toxoplasmosis, Herpes simplex, Syphilis, Varicella |
| Chromosomal anomalies | Trisomy 21 (Down), Trisomy 13 (Patau), Trisomy 18 (Edward), Turner syndrome |
| Metabolic disorders | Galactosemia, Galactokinase deficiency, Hypocalcemia, Hypoglycemia, Diabetes mellitus (maternal), Lowe syndrome, Wilson disease, Fabry disease |
| Ocular anomalies | Persistent Fetal Vasculature (PFV/PHPV), Posterior lenticonus, Anterior segment dysgenesis |
| Drugs / Radiation | Maternal steroids, chlorpromazine; radiation exposure |
| Trauma | 12–46% of pediatric cataracts (acquired) |
💡 Memory Aid
Unilateral cataract → usually idiopathic / sporadic, associated with local ocular anomalies (PFV, posterior lenticonus). Bilateral cataract → think metabolic, hereditary, TORCH, chromosomal.
Rubella virus infects the lens during organogenesis (first trimester), causing direct viral damage to lens fibers, halting normal development and producing nuclear cataract. Rubella cataract is typically pearly white, nuclear (central), and may be unilateral or bilateral.
Congenital Rubella Syndrome (Gregg's triad):
- Eye: Cataract, pigmentary retinopathy ("salt and pepper"), glaucoma, microphthalmia
- Ear: Sensorineural deafness (most common feature overall)
- Heart: PDA, pulmonary artery stenosis, VSD
- Other: Microcephaly, intellectual disability, thrombocytopenic purpura ("blueberry muffin" rash), hepatosplenomegaly
Galactosemia is an autosomal recessive deficiency of galactose-1-phosphate uridyltransferase (GALT). Galactose accumulates → converted to galactitol by aldose reductase → galactitol deposits in the lens → osmotic swelling → cataract.
Classic morphology: "Oil droplet" cataract — a central, lamellar/nuclear opacity that appears as an oil droplet on retroillumination. Seen early in infancy and may be reversible if galactose-free diet is instituted early.
Other features: Jaundice, liver disease, hypoglycemia, intellectual disability, E. coli sepsis in neonates.
Lowe syndrome is an X-linked recessive disorder caused by mutation in the OCRL gene (phosphatidylinositol 4,5-bisphosphate 5-phosphatase). It is characterised by the triad:
- Ocular: Dense bilateral cataracts (present at birth), glaucoma, nystagmus
- Cerebral: Intellectual disability, hypotonia
- Renal: Fanconi syndrome (aminoaciduria, phosphaturia, renal tubular acidosis)
Cataract type: Dense nuclear/posterior subcapsular cataract, present at birth. Affects males predominantly (X-linked); female carriers may show lens opacities.
- When was the white reflex / squint first noticed? — Timing affects visual prognosis
- Laterality: Unilateral or bilateral? — Guides etiology and workup
- Visual behaviour: Fixing and following? Tracking? — Severity of visual loss
- Antenatal history: Maternal fever with rash (rubella), TORCH infections, medications (steroids, chlorpromazine), diabetes, radiation
- Birth history: Prematurity, birth weight
- Family history: Childhood cataracts in parents, siblings, other relatives (hereditary cataract)
- Consanguinity: AR conditions (Lowe syndrome, galactosemia)
- Systemic symptoms: Jaundice (galactosemia), hearing loss (rubella), renal disease (Lowe), intellectual disability, seizures
- Developmental milestones: Delayed? May indicate syndromic cause
- Trauma history: Rule out non-accidental injury in unilateral cataract
| Type | Features / Associations |
|---|---|
| Nuclear (central) | Congenital, often hereditary; rubella (pearly white nuclear); visually significant if dense |
| Lamellar (Zonular) | Most common type to present in clinical practice; affects a specific zone; often bilateral and hereditary; usually visually significant |
| Polar — Anterior | Small, axial opacity at anterior pole; often stationary and not visually significant; associated with Alport syndrome (anterior lenticonus) |
| Polar — Posterior | Associated with PFV/PHPV; posterior lenticonus; often visually significant |
| Posterior subcapsular | Associated with Lowe syndrome, steroid use, radiation, Fabry disease |
| Total / Complete | Entire lens opaque; most visually significant; seen in rubella, Down syndrome; early surgery mandatory |
| Membranous | After resorption of lens material; Hallermann-Streiff syndrome, rubella, Lowe, PFV |
| Oil-drop | Galactosemia / galactokinase deficiency; may be reversible |
| Cerulean (Blue-dot) | Peripheral blue opacities; usually not visually significant |
| Sutural | Along the Y-sutures; usually hereditary, often mild |
| Sunflower | Anterior subcapsular, petal-shaped green-brown opacity — pathognomonic of Wilson disease |
PFV (formerly PHPV — Persistent Hyperplastic Primary Vitreous) is failure of regression of the hyaloid vascular system after birth. It is the most common cause of unilateral congenital cataract in full-term neonates after idiopathic cases.
Features: Unilateral (95%), microphthalmic eye, retrolental fibrovascular plaque, leukocoria, elongated ciliary processes, secondary cataract.
Important: PFV must be excluded by B-scan ultrasound before cataract surgery, as surgical approach differs and prognosis is guarded due to the small eye and associated posterior segment anomalies.
🩺 Examination — Exam Q&A
The Red Reflex Test (Brückner test) is the standard newborn screening tool for congenital cataract and other ocular pathology. It should be performed in every neonate before discharge and at every well-child visit up to 6 years of age (AAP / AAPOS guidelines).
Technique: Darken the room. Hold a direct ophthalmoscope ~50 cm (arm's length) from the child's face. Set the ophthalmoscope to 0 dioptre. Shine the light into both eyes simultaneously. Observe the reflex.
Normal: Bright, orange-red, symmetric reflex in both eyes.
Abnormal findings:
- White / absent reflex (leukocoria) → Cataract, retinoblastoma, PFV, retinal detachment, corneal opacity
- Asymmetric reflex → Significant anisometropia, unilateral cataract
- Dark spots in the reflex → Cataract, vitreous opacity
- Dull / dim reflex → Media opacity
🚨 Key Point
An abnormal or absent red reflex in a neonate requires urgent ophthalmology referral — it may indicate not only cataract but also life-threatening retinoblastoma.
Leukocoria = white pupillary reflex (from Greek: leuko = white, kore = pupil). It is the most common presenting sign of congenital cataract.
Differential diagnosis of leukocoria (CREAM mnemonic):
- Cataract (congenital / traumatic)
- Retinoblastoma — must always be excluded first; life-threatening
- Endophthalmitis / ocular toxocariasis
- Anorexia bulbi / retinal detachment
- Media opacities (corneal leucoma), PFV / PHPV
- Coloboma, Coats disease, ROP (stage 5)
- Fix and follow: Does the child fix on a face/light and follow it with each eye separately?
- Ocular preference: Covering the good eye — does the child object? (Objection = good vision in covered eye; no objection = poor vision in uncovered eye)
- Central, Steady, Maintained (CSM): Standard documentation for fixation behaviour
- Visually Evoked Potential (VEP): Objective electrophysiological test of visual pathway function
- Preferential looking (Teller Acuity Cards): Grating-based acuity in pre-verbal children
- Nystagmus / strabismus: Presence implies significant visual deprivation
A cataract is considered visually significant (and requires surgery) if:
- The opacity is ≥3 mm in diameter on retinoscopy (central opacity)
- The opacity lies in the visual axis
- Dense enough to block the red reflex
- Associated with strabismus, nystagmus, or poor fixation
- Dense enough to prevent adequate fundal view
Small peripheral or anterior polar cataracts (<3 mm, stable, not axial) may be monitored conservatively.
Nystagmus in a child with cataract indicates severe and prolonged visual deprivation during the critical period of visual development. It is a poor prognostic sign — it suggests the cataract was present for a significant duration before surgery and that permanent damage to the visual system has likely already occurred. The visual cortex fails to develop normal connections, resulting in irreversible sensory nystagmus. Surgical success in achieving good visual acuity is significantly reduced once nystagmus has developed — hence the urgency of early intervention.
| System | Look for | Suggests |
|---|---|---|
| General | Dysmorphic features, short stature | Chromosomal syndrome |
| Head | Microcephaly | Rubella, chromosomal |
| Ears | Hearing loss (DPOAE/ABR testing) | Rubella, Alport syndrome |
| Heart | Murmur (PDA, VSD) | Rubella, Down syndrome |
| Abdomen | Hepatosplenomegaly | Galactosemia, TORCH |
| Neurological | Hypotonia, intellectual disability, seizures | Lowe syndrome, Down, metabolic |
| Skin | Purpuric rash (blueberry muffin) | Rubella |
| Joints/Bones | Renal rickets | Lowe syndrome (Fanconi) |
| Eyes (other) | Iris coloboma, microphthalmia, glaucoma | Chromosomal, TORCH |
Amblyopia is a reduction in best-corrected visual acuity in an eye without structural cause, resulting from abnormal visual experience during the critical period of visual development (birth to approximately 8 years, most sensitive in first 3 years).
| Type | Cause | Example |
|---|---|---|
| Deprivation amblyopia | Physical obstruction of visual axis | Congenital cataract, ptosis, corneal opacity |
| Strabismic amblyopia | Cortical suppression of deviated eye | Constant esotropia |
| Anisometropic amblyopia | Different refractive errors causing image blur | One eye high myopia |
Deprivation amblyopia is the most severe and difficult to treat form. Even after removal of the obstruction, intensive amblyopia therapy (occlusion/patching of the fellow eye) is mandatory, especially for unilateral cases.
🔬 Investigations — Exam Q&A
Red Reflex Test (Brückner test) using a direct ophthalmoscope — the primary screening tool, performed by the pediatrician in the newborn period.
Slit-lamp examination (or handheld slit-lamp in infants, or examination under anesthesia/EUA) — to characterise the morphology, density, size, and location of the cataract.
B-scan ultrasonography — mandatory when the posterior segment is not visible (dense cataract). Rules out retinoblastoma, PFV, retinal detachment, and posterior coloboma.
For unilateral cataract: Systemic workup usually not needed (most are idiopathic/sporadic).
For bilateral cataract without obvious family history: Metabolic and infectious workup required.
| Investigation | Detects |
|---|---|
| Urine for reducing substances | Galactosemia (Clinitest positive; glucose oxidase negative) |
| Galactose-1-phosphate uridyltransferase (GALT) enzyme assay | Classic galactosemia |
| Galactokinase assay (RBC) | Galactokinase deficiency |
| Urine amino acids | Lowe syndrome, other metabolic disorders |
| Serum calcium, phosphorus | Hypocalcemia (hypoparathyroidism) |
| Blood glucose | Hypoglycemia, diabetes |
| TORCH titres (IgM/IgG) | Rubella, CMV, Toxoplasma, Herpes, Syphilis (VDRL) |
| VDRL / TPHA | Congenital syphilis |
| Serum copper, ceruloplasmin | Wilson disease (sunflower cataract) |
| Karyotype / chromosomal microarray | Trisomy 21, 13, 18; Turner syndrome |
| Genetic testing (Next-Generation Sequencing) | Hereditary cataract genes |
💡 Note
If a positive family history of childhood cataracts is present (autosomal dominant) with no systemic features and parents have lens opacities on examination, systemic/metabolic workup is NOT required.
B-scan ultrasound is essential when the cataract is dense and the posterior segment cannot be visualised. It provides:
- Exclusion of retinoblastoma (calcified mass) — critical before any intervention
- Diagnosis of PFV/PHPV (retrolental fibrovascular stalk, small axial length)
- Detection of retinal detachment
- Assessment of posterior coloboma
- Axial length measurement (A-scan) — needed for IOL power calculation
ERG (Electroretinogram): Records the electrical response of the retina to a light stimulus. Used to assess retinal function when the posterior segment cannot be visualised. Helps determine if the retina is functioning before committing to cataract surgery (especially in dense unilateral cataracts with PFV).
VEP (Visually Evoked Potential): Records electrical response of the visual cortex to a visual stimulus. Used to objectively assess visual acuity in pre-verbal children and to monitor visual development after surgery. Absent or delayed VEP indicates significant visual pathway damage.
EUA is performed in infants who cannot cooperate with a clinical slit-lamp examination. It provides:
- Full characterisation of cataract morphology and size
- Assessment of corneal clarity (rule out corneal cause of leukocoria)
- Measurement of intraocular pressure (IOP) — to rule out associated glaucoma
- Measurement of corneal diameter and axial length (for IOL planning)
- Dilated fundus examination to rule out posterior segment pathology
EUA is typically combined with the surgical procedure itself to avoid multiple episodes of anesthesia.
💊 Management — Exam Q&A
Recommended timing for visually significant cataracts:
- Unilateral dense cataract: Surgery by 4–6 weeks of age
- Bilateral dense cataract: Surgery by 6–8 (up to 10) weeks of age
Why is early surgery critical? The visual system undergoes rapid development in the first months of life (the critical period). An opacity blocking the visual axis prevents adequate visual stimulation of the retina and visual cortex → deprivation amblyopia. If uncorrected, the neural connections in the visual cortex fail to develop properly, leading to permanent, irreversible visual loss. The younger the child, the more urgent the surgery. Onset of nystagmus (usually by 3 months) is a sign that irreversible damage is occurring.
Procedure: Lensectomy + Anterior Vitrectomy (in infants) or Phacoemulsification with aspiration (in older children).
The steps include:
- Continuous curvilinear capsulorhexis (CCC) — anterior capsulotomy
- Aspiration of lens matter (lens is soft in infants; no phaco needed)
- Posterior capsulotomy + anterior vitrectomy — mandatory in children under 6–7 years to prevent posterior capsule opacification (PCO), which occurs rapidly in young eyes
- IOL implantation — if appropriate for age
💡 Key difference from adult cataract surgery
In adults, the posterior capsule is preserved to support the IOL. In infants/young children, primary posterior capsulotomy with vitrectomy is essential to prevent rapid visual axis opacification (PCO), which can cause recurrent amblyopia.
| Age Group | IOL Decision | Rationale |
|---|---|---|
| < 6 months (especially < 2 months) | Usually no IOL (aphakic correction with contact lens or spectacles) | Rapid eye growth → unpredictable refraction; high risk of glaucoma with early IOL |
| 6 months – 2 years | Controversial; IOL may be considered case-by-case | Balance between amblyopia risk and refractive unpredictability |
| ≥ 2 years | IOL implantation recommended | Eye growth more predictable; better refractive outcomes |
Aphakic optical correction (when no IOL):
- Contact lenses (silicone hydrogel) — preferred for infants under 2 years; gives better optical quality than spectacles for unilateral aphakia
- Aphakic spectacles — used for bilateral aphakia; thick, heavy lenses; not ideal for unilateral cases (severe anisometropia)
After optical correction (IOL/contact lens/spectacles), the amblyopic eye must be actively stimulated through occlusion therapy (patching) of the fellow (better) eye.
Unilateral cataract: Patching of the good eye for 50% of waking hours initially (progressive schedule). This forces the amblyopic eye to work, stimulating visual cortex development. Must begin as soon as possible after surgery and continue throughout the sensitive period (up to 7–9 years).
Bilateral cataract: If symmetric surgery and correction, patching may not be needed. If asymmetric, patch the better eye.
Pharmacological penalization: Atropine drops in the good eye (blurs near vision) — used as an alternative to patching in older children.
✅ The 3-step approach
1. Remove the cataract (surgery) → 2. Correct aphakia (contact lens/IOL/spectacles) → 3. Treat amblyopia (patching / penalization). All three steps are essential. Surgery alone is NOT sufficient.
| Complication | Notes |
|---|---|
| Aphakic glaucoma | Most common serious complication; risk is lifelong; higher with surgery < 4 weeks of age; requires IOP monitoring for life |
| Visual axis opacification (PCO) | Rapid in children; prevented by primary posterior capsulotomy + vitrectomy |
| Amblyopia | Despite surgery, if optical correction or patching is inadequate |
| Strabismus | May persist / require surgical correction |
| Nystagmus | May be irreversible if surgery delayed |
| Retinal detachment | Increased lifetime risk; especially with PFV, high myopia, repeated surgeries |
| Endophthalmitis | Rare but devastating; prophylaxis required |
| Corneal edema / decompensation | Intraoperative complication |
| IOL-related | Decentration, uveitis-glaucoma-hyphema (UGH) syndrome |
Visually non-significant cataracts can be managed conservatively with:
- Observation — regular review for progression and amblyopia monitoring
- Optical penalization — cycloplegic drops (cyclopentolate / phenylephrine, NOT atropine as it causes amblyopia) to dilate the pupil and improve vision through a partial opacity
- Refractive correction — glasses/contact lenses for associated refractive error
- Part-time patching — if mild amblyopia is developing
Candidates: Small (<3 mm), peripheral, stationary cataracts (e.g., anterior polar cataract, cerulean cataract) not in the visual axis.
The primary treatment is galactose-free diet (elimination of milk and dairy products). If instituted early (neonatal screening), the oil-drop lens opacity may be reversible and surgery can be avoided. However, in established dense cataracts, surgical removal is required. The diet must be maintained lifelong to prevent progression of systemic complications (liver disease, intellectual disability).
Similarly, in Wilson disease, sunflower cataracts may regress with copper chelation therapy (penicillamine).
🔭 Recent Advances — Exam Q&A
Next-Generation Sequencing (NGS) / whole exome sequencing has revolutionised the genetic diagnosis of congenital cataract. Over 100 causative genes have been identified. NGS allows identification of causative mutations in up to 90% of bilateral hereditary cataracts. This enables:
- Precise genetic counselling and recurrence risk assessment
- Identification of associated systemic conditions before clinical manifestation
- Cascade testing of family members
- Potential future gene therapy targets (lens crystallin genes)
Genetic testing is particularly valuable in bilateral cataracts without clear systemic cause or positive family history.
- Sharp-edged (square-edged) IOLs: Significantly reduce posterior capsule opacification (PCO) / visual axis opacification — now the preferred IOL design in children
- Hydrophobic acrylic IOLs: Associated with lower PCO rates; preferred material in most centers
- Bag-in-the-lens (BIL) IOL: A novel design that captures both the anterior and posterior capsulorhexis edges within the IOL optic, eliminating the space for lens epithelial cell migration → near-zero PCO rate
- Accommodative IOLs: Under study in pediatric age group; not currently recommended
- Target refraction strategy: IOL power is chosen to leave the eye mildly hypermetropic at surgery to account for future myopic shift as the eye grows
The IOLunder2 was a prospective multicentre UK cohort study examining outcomes of cataract surgery in infants under 2 years of age with and without IOL implantation. Key findings:
- No significant difference in visual acuity outcomes between IOL and aphakic groups at 5 years for unilateral cataracts
- IOL group had higher rates of adverse events (glaucoma, strabismus surgery, additional procedures)
- Supported a conservative approach of delaying IOL implantation until ≥2 years of age in most infants
- Highlighted the challenges of optimal refractive correction in young infants
The IATS was a randomised controlled trial (USA) comparing IOL implantation vs. contact lens (aphakic) management in infants with unilateral congenital cataract, operated between 1–6 months of age. Key findings:
- No significant difference in visual acuity at 4.5 years between IOL and contact lens groups
- IOL group had significantly higher adverse event rates — especially glaucoma (17% vs 12%) and additional surgeries
- Conclusion: Contact lens correction should be the primary optical rehabilitation for infants operated below 6 months; IOL implantation offers no visual acuity advantage and carries more risks in this age group
- Lanosterol eye drops: Lanosterol (an endogenous steroid) was shown in animal models (dogs, rabbits) to dissolve protein aggregates in cataracts and restore lens clarity. Human clinical trials are ongoing but results have been inconsistent.
- Oxysterols (25-hydroxycholesterol): Another pharmacological approach under investigation for lens protein disaggregation.
- Gene therapy: Theoretically possible for hereditary cataracts caused by single-gene mutations; preclinical research ongoing.
- Stem cell-based lens regeneration: Research in China demonstrated that after removing the lens epithelial cells via a minimally invasive approach, endogenous stem cells could regenerate a functional lens in young rabbits and non-human primates — very early stage, not yet in clinical practice.
Currently, surgical removal remains the only proven treatment for visually significant congenital cataract.
Traditional patching therapy has poor compliance, especially in older children. Newer approaches being studied include:
- Dichoptic therapy (binocular training): Uses specialised glasses/screens to present different contrast images to each eye, training binocular visual cortex. Shows promising results in older children with strabismic and anisometropic amblyopia.
- Virtual Reality (VR) based amblyopia games: Improve compliance over traditional patching; currently in clinical trials.
- These approaches are most relevant for older children with residual amblyopia after deprivation cataract — not a substitute for early surgical and optical correction.
⚡ Key Points — Quick Revision
One-Liners for Exam
- Congenital cataract incidence: 3–6 per 10,000 live births; leading cause of treatable childhood blindness
- Most common presenting sign: Leukocoria (white reflex)
- Red reflex test: First screening investigation; done by ophthalmoscope at arm's length; abnormal = urgent ophthalmology referral
- Differential of leukocoria: Cataract, Retinoblastoma (must rule out first!), PFV, Retinal detachment, Coats disease, endophthalmitis
- Unilateral cataract: Usually idiopathic/sporadic; associated with PFV, posterior lenticonus; systemic workup not always needed
- Bilateral cataract: Think hereditary (AD most common), metabolic (galactosemia), TORCH infections, chromosomal syndromes
- Galactosemia cataract: Oil-drop morphology; may be reversible with galactose-free diet if detected early
- Rubella cataract: Pearly white nuclear; Gregg's triad = cataract + deafness + cardiac defect
- Lowe syndrome: X-linked; Oculo-Cerebro-Renal; dense nuclear cataract + hypotonia + Fanconi syndrome
- Sunflower cataract: Wilson disease (pathognomonic); reversible with penicillamine
- Most common hereditary type: Autosomal dominant (~44%)
- Visually significant cataract: Opacity ≥3 mm, in visual axis, dense, blocks red reflex
- Surgery timing — Unilateral: By 4–6 weeks of age
- Surgery timing — Bilateral: By 6–8 weeks of age
- Nystagmus: Ominous sign of visual deprivation; poor prognosis for final visual acuity
- Primary posterior capsulotomy + vitrectomy: Mandatory in children < 6–7 years to prevent PCO
- IOL in infants < 6 months: Not recommended (IATS); use contact lens correction
- IOL recommended from: ≥ 2 years of age
- Most serious postoperative complication: Aphakic glaucoma — lifelong IOP monitoring required
- 3-step rule: Surgery → Optical correction (IOL/CL/glasses) → Amblyopia therapy (patching) — all 3 mandatory
- Deprivation amblyopia: Most severe type; requires immediate treatment; patching of fellow eye 50% waking hours
- B-scan ultrasound: Mandatory when posterior segment not visible; rules out retinoblastoma, PFV, RD
- Lamellar cataract: Most common morphology in clinical practice; usually bilateral; visually significant
- Cerulean (blue-dot) cataract: Usually not visually significant; no surgery needed
- Gold standard IOL design in children: Sharp-edged (square-edged) hydrophobic acrylic IOL — lowest PCO rate
💡 Syndromes and Their Cataracts — Quick Table
| Condition | Cataract Type | Other Key Feature |
|---|---|---|
| Galactosemia | Oil-drop (nuclear/lamellar) | Reversible with diet; Clinitest+ |
| Lowe syndrome | Dense nuclear/posterior subcapsular | X-linked; Fanconi syndrome; hypotonia |
| Wilson disease | Sunflower (anterior subcapsular) | Hepatolenticular degeneration; reversible |
| Congenital Rubella | Pearly white nuclear | Deafness + PDA; TORCH infection |
| Down syndrome (Trisomy 21) | Total / Lamellar | Brushfield spots; Mongolian slant |
| Alport syndrome | Anterior lenticonus (anterior polar) | Haematuria; sensorineural deafness; X-linked |
| Fabry disease | Posterior subcapsular; spoke-wheel | X-linked; angiokeratomas; pain crises |
| Nance-Horan syndrome | Dense nuclear (X-linked) | Dental anomalies; X-linked |
| Hallermann-Streiff | Membranous (spontaneous resorption) | Bird-like face; dyscephaly; hypotrichosis |