After-cataract (Secondary cataract / Posterior capsule opacification)

1. Fibrous type: Capsular wrinkling and fibrosis, common in adults.
2. Elschnig pearl type: Pearly clusters of proliferating lens epithelial cells, commoner in children and young patients.
3. Soemmering ring: Peripheral equatorial collection of retained lens material.

• Gradual, painless reduction of vision after initially successful cataract surgery
• Glare and haloes, especially at night
• Reduced contrast sensitivity
• On slit-lamp examination: opacity, folds, fibrosis, or pearls on the posterior capsule
• Fundus view may become hazy

1. Nuclear cataract
   • Opacity involves the central embryonic or fetal nucleus of the lens.
   • May be total or partial.
2. Lamellar cataract
   • Also called zonular cataract proper.
   • A particular lamella of the lens cortex is opaque, with clear lens matter inside and outside it.
   • Often associated with radial spoke-like opacities called riders.

• Simple lamellar opacity
• Lamellar cataract with riders
• Zonular pulverulent type, with fine dust-like opacities

Delayed postoperative complications of cataract operation

1. After-cataract / posterior capsular opacification
   • Commonest delayed complication
   • Causes gradual painless blurring of vision and glare
   • Treated by Nd:YAG laser capsulotomy.
2. Cystoid macular oedema (Irvine-Gass syndrome)
   • Painless reduction of central vision, usually after 4-12 weeks.
3. Retinal detachment
   • More likely in high myopia, posterior capsular rupture, or vitreous loss.
   • Presents with flashes, floaters, or a curtain-like visual-field defect.
4. Chronic postoperative endophthalmitis
   • Low-grade recurrent anterior uveitis with reduced vision, often due to Cutibacterium acnes.
5. Secondary glaucoma
   • May result from retained lens matter, steroid response, inflammation, pigment dispersion, or IOL-related problems.
6. IOL-related complications
   • Decentration, tilt, subluxation/dislocation, pupillary capture, or opacification of the IOL.
7. Corneal decompensation / pseudophakic bullous keratopathy
   • Due to progressive endothelial cell loss, causing corneal oedema and reduced vision.
8. Chronic uveitis or synechiae formation
   • May lead to persistent discomfort, raised IOP, and poor vision.

Delayed postoperative complications of SICS

1. Posterior capsular opacification (after-cataract)
   • Commonest late complication
   • Causes gradual painless fall in vision and glare
   • Treated by Nd:YAG laser capsulotomy.
2. Cystoid macular oedema (Irvine-Gass syndrome)
   • Reduced central vision, usually weeks after surgery.
3. Chronic postoperative endophthalmitis
   • Recurrent low-grade uveitis, pain, redness, and gradual visual loss.
4. Secondary glaucoma
   • Due to steroid response, chronic inflammation, retained lens matter, pupillary block, or IOL-related causes.
5. IOL-related complications
   • IOL decentration, tilt, pupillary capture, subluxation/dislocation, or IOL opacification.
6. Capsular contraction syndrome
   • Fibrosis and shrinkage of anterior capsule causing IOL decentration.
7. Corneal decompensation / pseudophakic bullous keratopathy
   • Persistent corneal oedema due to endothelial damage.
8. Retinal complications
   • Retinal detachment, especially in high myopes or after posterior capsular rupture with vitreous loss.
   • Late retinal tears may occur.
9. Persistent or induced astigmatism
   • More relevant in SICS because of sclero-corneal tunnel configuration, wound healing, or sutures.
10. Chronic anterior uveitis / posterior synechiae

• May result in poor vision and raised intraocular pressure.

Types of intraocular lenses (IOLs)

1. According to site of implantation

• Anterior chamber IOL (ACIOL): Placed in the anterior chamber, supported in the iridocorneal angle.
• Iris-fixated IOL: Attached to the iris, either clipped to the iris or sutured.
• Posterior chamber IOL (PCIOL): Placed behind iris, ideally in the capsular bag. This is the most commonly used IOL.
• Scleral-fixated IOL (SFIOL): Fixated to sclera when capsular support is absent.

2. According to material

• Rigid IOL: Polymethyl methacrylate (PMMA). Requires a larger incision.
• Foldable IOLs: Can be inserted through a small incision. Types include:
  • Silicone
  • Hydrophobic acrylic
  • Hydrophilic acrylic / hydrogel
  • Collamer

3. According to optical design

• Monofocal IOL: Provides focus at one distance, commonly distance vision.
• Multifocal IOL: Provides distance and near vision.
  • Bifocal
  • Trifocal
• Extended depth-of-focus (EDOF) IOL: Improves distance and intermediate vision over an extended range.
• Toric IOL: Corrects pre-existing corneal astigmatism.
• Accommodative IOL: Designed to provide pseudo-accommodation for near vision.
• Aspheric IOL: Reduces spherical aberration and may improve contrast sensitivity.

4. According to haptic design

• Single-piece IOL
• Three-piece IOL
• Plate-haptic IOL
• Loop-haptic IOL

Clinical manifestations of ocular chalcosis

Chronic chalcosis, usually with copper content <85%

• Kayser-Fleischer ring: Golden-brown or greenish ring at the peripheral cornea, in Descemet membrane.
• Iris changes: Greenish discoloration or heterochromia iridis.
• Sunflower cataract: Central anterior capsular disc with radiating petal-like spokes.
• Vitreous opacities with glistening particles.
• Retinal changes: Golden metallic plaques, pigmentary degeneration, and reduced retinal function.
• Visual impairment: Gradual diminution of vision, depending on cataract and retinal involvement.

Acute severe copper toxicity, usually with copper content >85%

• Pain, redness, photophobia, and marked inflammation
• Sterile endophthalmitis with hypopyon
• Corneal oedema or melting, scleral necrosis/abscess
• Retinal detachment and severe loss of vision.