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Intraocular lens calculations in patients with keratoectatic disorders
Ryan G Smith1, Alexander Knezevic, Sumit Garg
1Gavin Herbert Eye Institute, University of California, Irvine, California, USA.
Current Opinion in Ophthalmology
|June 4, 2020
Summary
Intraocular lens (IOL) calculations for keratoconus patients remain challenging. The Barrett II Universal formula shows accuracy in mild-to-moderate cases, but no single formula is universally best.
Area of Science:
- Ophthalmology
- Refractive Surgery
- Biomaterials
Background:
- Intraocular lens (IOL) calculations for patients with keratoconus and other keratoectatic disorders present significant challenges for cataract surgeons.
- Accurate preoperative biometry and consensus on reliable IOL calculation formulas are lacking, leading to unpredictable outcomes in these patients.
Purpose of the Study:
- To review recent data (June 2018–January 2020) on intraocular lens (IOL) calculations in patients with keratoconus.
- To identify the most accurate IOL calculation formulas for cataract surgery in eyes with keratoconus.
Main Methods:
- Literature review of studies published between June 2018 and January 2020.
- Analysis of data on the accuracy of various intraocular lens (IOL) calculation formulas in keratoconic eyes.
Main Results:
- Cataract surgery can significantly improve vision in keratoconus patients, but outcomes are often unpredictable.
- Recent studies indicate the Barrett II Universal calculation formula is most accurate for mild-to-moderate keratoconic eyes.
- Predictability decreases with increasing keratometric steepness; the SRK/T formula has historically been reliable.
Conclusions:
- There is no definitive consensus on the optimal IOL calculation formula for keratoconic eyes.
- For mild-to-moderate keratoconus, a combination of the Barrett II Universal and SRK/T formulas is recommended.
- Thorough preoperative patient counseling regarding expectations is crucial to manage potential refractive surprises.
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