Correlation Between Measured ELP and Crystalline Lens Position as Tool for Customized IOL Calculation
Narrative Responses:
Purpose
Effective lens position (ELP) is a mathematical abstraction of the anticipated intraocular lens (IOL) position after cataract extraction. Its precision determines postoperative refraction accuracy. We investigate the correlations between measured ELP and the preoperative crystalline lens position in order to detect anatomical landmarks that may predict ELP.
Methods
We evaluated prospectively 14 eyes of 7 patients scheduled for rotine cataract surgery. Optical biometry was obtained by the Lenstar LS 900 optical biometer (Haag-Streit AG) and used for IOL calculation. Anatomical crystalline landmarks were: Anterior Capsule, Central Position, and Posterior Capsule. All patients were examined between 30 and 60 postoperative days. The central position of the IOL (measured as the average of anterior and posterior surfaces) was determined by the optical biometry in pseudophakic mode.
Results
Mean age: 73±8 (61-83); mean cataract grade: 2±1 (2-3); mean AL: 22.91±1.05 (21.22-24.92); mean K: 44.09±1.30 (41.46-45.77); and mean IOL spherical power: 22.17±2.56 (18.50-26.00). Mean crystalline landmarks were: Central: 5.29±0.35 (4.80–5.91); Anterior: 2.89±0.46 (2.12-3.71); and Posterior: 7.69±0.32 (7.00-8.34). All IOLs detected by optical biometry. Moderate correlations were found between Central IOL Position and: Central Lens Position (r=0.65), Anterior Lens Capsule (r=0.55), and Posterior Lens Capsule (r=0.53).
Conclusion
There is a correlation between crystalline lens landmarks and measured IOL ELP. New approaches for IOL calculation may use these landmarks for further precision improvement.