Abstract
Purpose: :
To determine the preoperative corneal topography in cataract surgery candidates to select the optimal new technology intraocular lenses (IOLs) such as aspherical IOLs, toric IOLs, and bifocal IOLs.
Methods: :
One hundred forty-nine eyes of 124 consecutive cases which were scheduled for cataract surgery at the Osaka University Hospital were studied. Corneal topographic analysis was performed using the KR-9000PW (Topcon Co., Tokyo, Japan). The corneal total higher-order aberrations (THOA) for 4 mm diameter, differences between central corneal power and simulated K readings (ΔK), corneal spherical aberration for 6 mm diameter (C40), and the corneal cylinder were determined to evaluate the indications for new technology IOLs.
Results: :
Reliable topographic measurements for 6 mm diameter could be made in 77.9% of the eyes. For reliable measurements, the mean ± SD of the THOA was 0.162 ± 0.067 µm. Five percent of the eyes had a THOA > 0.3 µm due to LASIK, pterygium, and so on. In 3.4% of the eyes, ΔK (0.16 ± 0.17 D) was > 0.5 D requiring IOL power calculation with the corneal topographer to reduce post-operative refractive errors. In 12.1% of the eyes, C40 was < 0.1 µm (0.247 ± 0.135 µm) due to keratoconus or an extreme prolate shape, and spherical IOLs would be better to correct the spherical aberration than aspherical IOLs. Nineteen percent of the eyes had > 1.5 D of cylinder (1.04 ± 0.8 D), and a toric IOL or astigmatism surgery would be considered to correct the post-operative astigmatism.
Conclusions: :
Pre-operative assessment of corneal topography before cataract suregery may be valuable for the selection of new technology intraocular lenses in order to avoid the potential problems in eyes with suboptimal optics.
Keywords: topography • intraocular lens • cataract