Free previewYou're reading the free part of this topic. The rest is included with Clinical.See what's included
IOL power calculation
Cataract & Refractive Surgery
Key Points
- •Axial length is the single most important variable - a 1 mm error causes approximately 2.5–3.0 D refractive error.
- •Barrett Universal II is currently the most widely recommended formula, performing well across all axial lengths.
- •Optical biometry (IOLMaster, Lenstar, ARGOS) is the gold standard for axial length measurement - use immersion A-scan only when optical biometry fails.
- •Post-refractive surgery eyes require special formulas (Barrett True-K, ASCRS calculator) - standard formulas cause systematic hyperopic surprise.
- •A-constant optimisation using surgeon-specific outcomes data significantly improves refractive accuracy and should be standard practice.
Free preview ends here
Keep reading IOL power calculation
17 more sections are included with the Clinical plan.
- Definition
- Epidemiology
- Aetiology and causes
- Pathogenesis
- Classification
- Risk factors and associations