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Comparative Study
. 2012 Apr;38(4):589-94.
doi: 10.1016/j.jcrs.2011.11.025.

Intraocular lens power calculation after previous myopic laser vision correction based on corneal power measured by Fourier-domain optical coherence tomography

Maolong Tang  1 , Li Wang, Douglas D Koch, Yan Li, David Huang
Affiliations
Comparative Study

Intraocular lens power calculation after previous myopic laser vision correction based on corneal power measured by Fourier-domain optical coherence tomography

Maolong Tang et al. J Cataract Refract Surg. 2012 Apr.

Abstract

Purpose: To use Fourier-domain optical coherence tomography (OCT) to measure corneal power and calculate intraocular lens (IOL) power in cataract surgeries after laser vision correction.

Setting: Doheny Eye Institute, Los Angeles, California, and Cullen Eye Institute, Houston, Texas, USA.

Design: Prospective comparative case series.

Methods: Patients with previous myopic laser vision correction who had monofocal IOL implantation were enrolled. A Fourier-domain OCT system was used to measure corneal power and pachymetry. Axial length and anterior chamber depth were measured with partial coherence biometry. An OCT-based IOL formula was developed, and the mean absolution error (MAE) of postoperative refraction was compared with that for the Haigis-L formula. At Doheny, corneal power was also measured using the clinical history method, the contact lens overrefraction method, and slit-scanning tomography total optical power.

Results: Sixteen eyes of 16 patients were enrolled at the 2 sites. Previous laser vision correction ranged from -9.81 to -0.88 diopter (D). The MAE was 0.50 D for OCT-based IOL calculation and 0.76 D for the Haigis-L formula (P=.14). In the 6 eyes enrolled at Doheny, the MAE of OCT-based IOL calculation was 0.60 D. In comparison, the contact lens overrefraction (MAE = 1.46 D, P<.05) and clinical history (MAE = 1.78 D, P<.05) methods were worse. Slit-scanning tomography gave an MAE of 1.28 D (P>.05).

Conclusion: The predictive accuracy of OCT-based IOL power calculation was equal to or better than current standards in post-laser vision correction eyes.

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Figures

Figure 1
Figure 1
Effective corneal power for eyes after myopic laser vision. The squares represent data from Doheny Eye Institute. The triangles represent data from Cullen Eye Institute (ECP = back-calculated effective corneal power [the “true corneal power”]; NCP = optical coherence tomography net corneal power; OCT = optical coherence tomography).
Figure 2
Figure 2
Distribution of refraction prediction error for Haigis-L formula and OCT-based formulas (OCT = optical coherence tomography).
Figure 3
Figure 3
Comparison of the refraction prediction error between the Haigis-L formula and OCT-based IOL calculation.
See this image and copyright information in PMC

References

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