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M. Tang, Y. Li, D. Huang; An Optical Coherence Tomography-Based Intraocular Lens Formula. Invest. Ophthalmol. Vis. Sci. 2007;48(13):5435.
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© ARVO (1962-2015); The Authors (2016-present)
To develop an intraocular lens (IOL) formula that is not biased by prior laser vision correction (LVC).
Twenty-seven eyes from 27 patients who underwent uneventful cataract surgery from 4/27/2005 to 5/10/2006 at Doheny Eye Institute were enrolled in the prospective observational study. Patients received Alcon AcrysofTM SN60AT (24 eyes) or SA60AT lenses (3 eyes). IOL-Master (Zeiss) was used to measure anterior corneal curvature and axial length of the eye. A high-speed (2000 Hz) anterior chamber optical coherence tomography (OCT) system was used to measure central corneal thickness, posterior corneal curvature, anterior chamber depth and crystalline lens thickness preoperatively. We developed an IOL formula that uses the OCT and IOL-Master measurements to predict refractive outcome.
The prediction error for postoperative manifest refraction spherical equivalent was 0.04 ± 0.44 D for the OCT-based IOL formula and -0.35 ± 0.42D for the SRK/T formula. Twenty-one eyes (78%) were within 0.5D for OCT formula compared to 18 eyes (67%) for SRK/T. Hoffer Q and Holladay formulae provided similar results and the differences between formulae were not statistically significant.
For normal cataract patients, the OCT-based IOL formula was equivalent to the current theoretic formulae in accuracy. Because OCT directly measures posterior corneal power, it may be more accurate post-LVC. Clinical trial on post-LVC cataract patients is to be performed.
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