A 60-year-old patient with a history of zonular weakness (pseudoexfoliation) is assessed for cataract surgery. The surgeon plans to use a capsular tension ring (CTR). What is the primary function of a CTR in this context?
- A To prevent posterior capsule opacification by blocking lens epithelial cell migration
- B To anchor the IOL to the sclera in aphakic eyes
- C To enlarge the capsulorhexis to allow easier nucleus removal
- D To redistribute circumferential stress across the equatorial capsule, supporting the weakened zonules and maintaining a circular capsular bag shape for stable in-the-bag IOL placement ✓
Explanation
A capsular tension ring (CTR) is a PMMA or silicone open ring placed within the capsular bag in eyes with zonular weakness (pseudoexfoliation, trauma, Marfan syndrome). By expanding to the equatorial diameter of the bag, it distributes the circumferential tension evenly across all remaining zonules, preventing asymmetric bag collapse or decentration during and after surgery. This facilitates safe phacoemulsification and achieves stable, centred in-the-bag IOL implantation. Modified CTRs with eyelet (Ahmed or Cionni rings) can be sutured to the sclera for severe zonular dialysis.
Reference: Khurana Comprehensive Ophthalmology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.