| Prediction Error and Accuracy of Intraocular Lens Power Calculation in Cataract Surgery |
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Kyung Euy Hong, Nahyun Kim, Hyung Bin Hwang, Sung Kun Chung |
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Department of Ophthalmology and Visual Science, College of Medicine, Seoul St. Mary’s Hospital, The Catholic University of Korea, Seoul, Korea |
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Received: 23 July 2015 • Revised: 22 August 2015 • Accepted: 24 August 2015 |
| Abstract |
Purpose: To analyze and compare, between preoperative refraction data estimated according to axial length of patient’s eye and actually achieved post operative refraction data in cataract surgery. Preoperative refraction data is calculated by selecting appropriate intraocular lens (IOL) estimation formula according to diverse axial lengths (AXL).
Methods: We retrospectively studied 110 eyes of 78 patients who underwent cataract surgery between March 2012 and December 2012. AXL were measured using A-scan (Ultrasonic biometer, Model UD-6000, Tomey, Los Angeles, CA, USA) and IOL power was calculated using the SRK II, SRK/T and Hoffer Q formula. Patients were divided into four groups based on AXL (A group; less than 22.5 mm , B group; 22.5 to 23.5 mm, C group; 23.5 to 24.5 mm, D group; more than 24.5 mm). Refractive error (RE) of all the postoperative eyes were analyzed by Canon, RF-10 Full Auto Refactor, two months after surgery. Each groups’ preoperative expected refraction and postoperative actual refraction was converted to spherical equivalent, compared by using mean numerical error and mean absolute error data.
Results: Though the RE of each group showed a tendency for hyperopic shifts, none of groups showed statistically significant (p = 0.154, 0.132, 0.084, 0.062). Compared with each groups for mean absolute error (MAE), the Hoffer Q formula was the lowest MAE in Group A (p = 0.002). In the other groups (B, C, D), the SRK/T had the lowest MAE, with statistically significant differences (p = 0.004, 0.034, 0.012). All groups (A, B, C, D) were highest MAE, with statistically significant for SRK II formula (p = 0.001).
Conclusions: As AXL significantly affect RE, it should be considered when investigating postoperative RE tendency and when determining IOL power. Postoperative RE will be greatly affected by whether AXL is short or long, and therefore this factor should be considered in IOL power estimating formula determination.
Ann Optom Contact Lens 2015;14(3):134-139 |
| Key Words:
Eye axial length, Intraocular lens, Refractive error |
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