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Acquired Cataract

ROUTINE — Lens

Symptoms

Visual decline

  • Slowly progressive, painless blurring or vision loss over months to years.
  • May be unilateral or bilateral.

Glare & photophobia

  • Significant in bright sunlight or from oncoming headlights at night.

Color & contrast

  • Reduced contrast sensitivity and altered color perception (yellowing).
  • No true dyschromatopsia (unlike optic neuropathies).

Morphology-specific

  • Nuclear: Blurs distance > near.
  • PSC: Profound glare and difficulty reading (near vision worse).
  • Cortical: Glare is the dominant complaint.

Clinical Findings

Core findings

  • Any opacification/discoloration of the crystalline lens; diagnosed on slit-lamp.
  • Screening finding: Dimming or disruption of the red reflex on retinoscopy.

The RAPD rule

  • Cataract alone does not cause an RAPD.
  • If RAPD is present: Search for optic nerve or extensive retinal pathology before surgery.

Morphology types

  • Nuclear sclerotic (NS): Yellow-to-brown central lens discoloration. Causes "second sight" (myopic shift allowing patients to read without glasses).
  • Posterior subcapsular (PSC): Plaque-like granular opacity on the posterior capsule; "snowflake" shadow on retroillumination. Symptoms may paradoxically improve with dilation.
  • Cortical: Radial/spoke-like wedge opacities; vacuoles and water clefts on slit-lamp.

Diagnostic subtypes

  • Sunflower: Copper deposition; pathognomonic for Wilson disease.
  • Christmas-tree: Iridescent multicolored opacities; classic for Myotonic Dystrophy.
  • Oil-droplet: Central opacity on retroillumination; classic for Galactosemia.
  • Snowflake: White AS/PSC opacities; associated with acute juvenile diabetes.
  • Glaukomflecken: Gray-white anterior subcapsular opacities from prior acute angle-closure.
  • Rosette / Vossius ring: Trauma-induced opacities and pigment imprints.

Advanced stages

  • Mature: Totally white lens.
  • Hypermature / Morgagnian: Liquefied cortex; nucleus may sink in the capsular bag.
  • Intumescent: Swollen lens; high risk for phacomorphic angle-closure.

Pre-surgical evaluation

  • Slit-lamp grading (LOCS III) and endothelial health (guttata).
  • Assessment of zonular status (pseudoexfoliation, phacodonesis) and pupil size.
  • Macular OCT to exclude comorbidities (AMD, ERM, DME).
  • Biometry: IOL Master/Lenstar for axial length, K, and ACD.

Etiology

Primary cause

  • Age-related degeneration (most common).

Trauma

  • Penetrating or blunt injury (rosette cataract), electric/lightning injury, or copper IOFB.

Toxic / drug-induced

  • Steroids: Any route (topical, oral, inhaled, IVT); dose-dependent.
  • Long-term miotics or phenothiazines.

Ocular co-morbidities

  • Chronic anterior uveitis, prior vitrectomy, radiation, or retinitis pigmentosa.

Metabolic & systemic

  • Diabetes: Early onset or acute snowflake cataracts.
  • Wilson disease (sunflower) or myotonic dystrophy (christmas-tree).
  • Hypocalcemia (iridescent cortical changes) or galactosemia (oil-droplet).
  • Syndromic: Down syndrome, NF2 (PSC), atopic dermatitis (anterior shield).

Red Flags

Rapid or unilateral progression

  • In young patients: Rule out diabetes, steroid use, trauma, or uveitis.
  • Unilateral: Rule out intraocular tumor or occult hemorrhage; obtain B-scan if view is obscured.

Pediatric PSC

  • Promptly rule out steroid exposure, NF2, or chronic uveitis.

Secondary glaucoma

  • Mature/intumescent lens leading to phacomorphic angle-closure or phacolytic glaucoma.

Fuchs heterochromic iridocyclitis

  • Triad: Stellate KPs, iris heterochromia/atrophy, and rapid PSC; no posterior synechiae.

Steroid risks

  • Fluocinolone implants: ~43% cataract and ~75% IOP-elevation rate at 2 years.

Investigations

Clinical exam

  • BCVA (distance/near), manifest refraction, and pupillary exam.
  • Glare testing: Essential when BCVA is ≥20/30 but patient reports functional decline.

Dilated exam

  • Slit-lamp for LOCS III grading, zonular health, and dilation quality.
  • Fundus exam: Exclude macular/optic nerve disease limiting visual potential.

Imaging & biometry

  • B-scan ultrasonography: Required if fundus view is obscured.
  • Macular OCT: To exclude AMD, ERM, or DME.
  • IOL Master/Lenstar: For IOL power calculation.
  • Endothelial cell count: If corneal guttata are present.

Treatment

Surgical indications

  • Symptomatic visual disability affecting daily activities.
  • Lens-induced disease (phacolytic/phacomorphic glaucoma, uveitis).
  • Requirement for fundus view to treat other pathologies (e.g., diabetic retinopathy).

Procedure

  • Modern small-incision phacoemulsification with foldable IOL insertion.
  • Usually outpatient, ~15 mins, >95% success rate in suitable eyes.

IOL options

  • Monofocal: Fixed for distance or near.
  • Toric: Corrects regular astigmatism.
  • Multifocal / EDOF: Provides extended range; requires counseling on dysphotopsia.

Clinical Pearl

Cataract surgery is refractive surgery — biometry, IOL selection, and patient expectations are as critical as surgical technique. Dissatisfaction usually stems from unmet refractive goals rather than complications.

Differential Diagnosis

  • Posterior capsular opacification (PCO)
  • Corneal pathology (scarring, edema)
  • Age-related macular degeneration (AMD)
  • Vitreous hemorrhage or opacities
  • Uncorrected refractive error

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