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Most Common Complication of Post-Cataract Surgery
Posterior Capsule Opacification (PCO) - "After Cataract"
PCO is the most common late complication of uncomplicated cataract surgery, occurring in 20-25% of patients.
Mechanism: After cataract extraction, lens epithelial cells that remain within the capsular bag proliferate onto the posterior capsule. There are two main patterns:
- Pearl-type (vacuolated) PCO - proliferating swollen lens epithelial cells forming "Elschnig pearls," similar to bladder (Wedl) cells seen in posterior subcapsular cataract
- Fibrotic-type PCO - fibroblastic metaplasia of epithelial cells that develop contractile qualities; also associated with a Soemmering ring (equatorial proliferation of lens epithelial cells)
Risk factors:
- PMMA and hydrogel IOLs are more prone to PCO than acrylic
- IOL design matters more than material - a square optic edge inhibits PCO (though it may increase dysphotopsia)
- PCO incidence is reduced when the capsulorhexis opening is in complete contact with the anterior IOL surface
Symptoms: Slowly worsening blurring, glare, and sometimes monocular diplopia
Treatment: Nd:YAG laser posterior capsulotomy - creating a 4-5 mm opening in the posterior capsule. This is safe, effective, and easily performed. Complications of the laser itself include: IOP spike (usually transient), IOL pitting (visually inconsequential), rare retinal tear/detachment, and CMO (less common if delayed at least 6 months post-surgery).
Kanski's Clinical Ophthalmology, 10th ed., p. 347-348
Irvine-Gass Syndrome
Irvine-Gass syndrome is Cystoid Macular Edema (CME) occurring as a complication of cataract surgery (post-cataract extraction CME).
Where it's seen:
- After any intraocular surgery, but classically after cataract extraction (extracapsular or phacoemulsification)
- Peak incidence: 6 to 10 weeks postoperatively
- Also described after laser photocoagulation and cryotherapy
Incidence increases with cataract surgical complications including:
- Vitreous loss
- Vitreous to the corneoscleral wound
- Iris prolapse
- Uveal incarceration
Mechanism: Disruption of the blood-retinal barrier leads to fluid leakage from perifoveal capillaries into the outer plexiform and inner nuclear layers of the macula, forming cystic spaces.
Diagnosis:
- Symptoms: Blurred central vision, decreased VA
- Slit-lamp: Irregular/blunted foveal light reflex, macular thickening with/without intraretinal cysts
- IVFA (gold standard): Early perifoveal capillary leakage, late macular staining in a classic "petaloid" or "spoke-wheel" pattern. Optic nerve head leakage is sometimes also observed.
- OCT: Documents loss of foveal contour, enlarged cystic spaces, macular thickening
Note: Subclinical CME (angiographic only on IVFA, no OCT findings) commonly develops after cataract surgery but does NOT require treatment.
Treatment:
- Topical NSAIDs (ketorolac 0.5% QID, bromfenac 0.09%, or nepafenac 0.3% daily) - first-line, often combined with topical steroids (prednisolone acetate 1% QID)
- Discontinue prostaglandin analogs, epinephrine drops if applicable
- Sub-Tenon steroid injection (triamcinolone 40 mg/mL)
- Intravitreal steroid or anti-VEGF (bevacizumab 1.25 mg) for refractory cases
- Systemic NSAIDs or steroids
- Vitrectomy if vitreous is incarcerated in the wound
Follow-up: Every 4-6 weeks to monitor response to treatment.
The Wills Eye Manual, p. 824-826; Kanski's Clinical Ophthalmology, 10th ed.
Quick Summary Table:
| Feature | PCO | Irvine-Gass Syndrome |
|---|
| What it is | Posterior capsule clouding | Cystoid macular edema (CME) |
| Timing | Months to years post-op | Peak at 6-10 weeks post-op |
| Mechanism | Lens epithelial cell proliferation | Blood-retinal barrier breakdown |
| Key investigation | Slit-lamp exam | IVFA (petaloid pattern), OCT |
| Treatment | Nd:YAG laser capsulotomy | Topical NSAIDs + steroids |
| Incidence | 20-25% of cataract surgeries | Varies; higher with complications |