A 72-year-old woman with pseudoexfoliation syndrome undergoes cataract extraction with IOL implantation. Which is the most common postoperative complication following cataract surgery?

Explanation

## Most Common Postoperative Complication After Cataract Surgery **Key Point:** Posterior capsular opacification (PCO) is the most common postoperative complication of cataract surgery, occurring in 20–50% of eyes within 5 years, depending on IOL material and design. ### Postoperative Complication Frequency | Complication | Incidence | Timing | Etiology | |---|---|---|---| | Posterior capsular opacification | 20–50% (5 years) | Months to years | Lens epithelial cell proliferation and migration | | Cystoid macular edema | 1–2% (clinical), 10–20% (subclinical) | 4–12 weeks | Prostaglandin release, blood–aqueous barrier breakdown | | Endophthalmitis | 0.04–0.1% | Days to weeks | Bacterial or fungal infection | | Retrobulbar hemorrhage | < 0.1% | Immediate/intraoperative | Needle trauma to orbital vessels | **High-Yield:** PCO is so common that it is considered an expected long-term sequela rather than a true "complication." It is managed by Nd:YAG laser capsulotomy, which is a routine outpatient procedure. ### Pathophysiology of PCO 1. Residual lens epithelial cells remain in the capsular bag after phacoemulsification 2. Cells proliferate and migrate onto the posterior capsule 3. Fibrosis and lens fiber differentiation cause capsular opacification 4. Anterior migration of cells can also occur (anterior capsular opacification, less common) ### Risk Factors for PCO - **IOL material:** Silicone and PMMA lenses have higher PCO rates; acrylic lenses (especially hydrophobic acrylic) have lower rates - **IOL design:** Square-edge optics reduce PCO by creating a barrier to cell migration - **Surgical technique:** Complete cortical cleanup reduces residual cells - **Age:** Younger patients have higher PCO rates due to greater epithelial cell activity **Clinical Pearl:** Modern hydrophobic acrylic IOLs with sharp optic edges have reduced PCO rates to < 10% at 5 years, making it less of a clinical burden than in the era of older lens materials. **Warning:** Do not confuse PCO with other causes of reduced vision after cataract surgery (refractive error, macular pathology, dry eye). PCO presents as progressive dimming and glare, and is confirmed by slit-lamp examination showing a hazy posterior capsule.