J Korean Ophthalmol Soc.  1987 Feb;28(1):59-65.

A Clinical Study of Intraocular Lens Power Calculation

• Whang HR
• Jung SK
• Park BI

Abstract

Intraocular lens power was calculated from data of axial length, corneal curvature, and anterior chamber depth in 112 eyes which underwent IOL implant surgery. Postoperative refractions of 112 eyes were analyzed into three groups such as the group of which constant A is 116.2, the group of which constant A is 116.8, and TI-59 system group. The results were as follows; 1. The A constant derived from retrograde analysis in our 112 cases was 116.2. In the cases of the constant A 116.2, error of predicted required spectacle lens power was -0.16D +/- 0.89 in relative average, 0.67D +/- 0.57 in absolute average. Using the standard formula described by Hoffer, the accuracy of IOL power calculation by the constant 116.2 was 76.1% +/- 1.0D / 97.4% +/- 2.0D / +2.42 to -2.11D. 2. The specific constant A of intraocular lenses inserted in our hospital was 116.8. In the cases of the constant A 116.8, error of predicted required spectacle lens power was -0.39D +/- 0.88 in relative average, 0.75D +/- 0.60 in absolute average. Using the standard formula described by Hoffer, the accuracy of IOL power calculated by the constant A 116.8 was 72% +/- 1.0D / 96% +/- 2.0D / +2.34 to -2,50D. 3. In TI-59 system of IOL power calculation, error of predicted required spectacle lens power was -0.12D +/- 1.0D in relative average and 0.75D +/- 0.66 in absolute average. Using the staudard formula described by Hoffer, the accuracy of IOL power calculation in this method was 73% +/- 1.0D / 91.5% +/- 2.0D / +2.77 to -2.31D. 4. There was a significant difference between the error of the A constant 116.2 and that of 116.8(P. 0.05), but wasn't between the error of the A constant 116.2 and that of TI-59 system. 5. In the case of axial length 21mm +/- 0.5, the IOL power calculation by the A constant 116.2 was the most accurate among three groups.

MeSH Terms

Anterior Chamber
Lenses, Intraocular*