Abstract
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 39 eyes of 20 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 :
The mean age was 73 ± 8 (61 - 83) years old. Based on nuclear sclerosis, the mean cataract grade was 2 ± 1 (2 - 3). IOL types: 15 C-Flex 570, Rayner, and 24 Restor, Alcon. For preoperatively IOL calculation, the mean AL was 23.18 ± .69 (22.03 - 24.73), the mean K was 43.60 ± 1.78 (39.34. 39.34 - 47.52), and the mean IOL spherical power was 22.32 ± 2.08 (18.00 - 27.50). Preoperatively, the 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 were detected by optical biometry. For C-Flex, Moderate correlations were found between: Central Lens Position and Central IOL Position (r = .69), Anterior Lens Capsule and Central IOL Position (r = .25), and Posterior Lens Capsule and Central IOL Position (r = .47). For Restor: middle size of the lens: strong correlation (.85), strong correlation to posterior capsule (.84) and moderate to anterior capsule (.74).
Conclusions :
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.
This is a 2020 ARVO Annual Meeting abstract.