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Yosai Mori, Ryohei Nejima, Yukiko Terada, Yumi Hasegawa, Nobuyuki Nagai, Miyuki Ogata, Keiichiro Minami, Kazunori Miyata; Femtosecond Laser-Assisted Astigmatic Keratotomy for Astigmatic Correction in Pseudophakic Eyes. Invest. Ophthalmol. Vis. Sci. 2014;55(13):1555.
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© ARVO (1962-2015); The Authors (2016-present)
Astigmatic keratotomy (AK) effectively reduce corneal astigmatism without the need for expensive equipment. The predictability is lower than astigmatic correction using excimer laser. Femtosecond laser-assisted AK (FSL-AK) has been used for correcting high astigmatism after penetrating keratoplasty, and its accurate resections and acceptable astigmatism reductions have been reported. However, there was no assessment in use for eye after cataract surgery. This prospective study was to assess the efficacy of FSL-AK for astigmatic correction in pseudophakic eyes.
Eight eyes of six patients who received an intraocular lens and corneal astigmatism of 2.0 diopters (D) or more underwent FSL-AK. Mean preoperative uncorrected distance visual acuity (UDVA) was 0.52 ± 0.21 logMAR, and the manifest cylindrical refraction (CYL) and corneal astigmatism were 2.88 ± 0.64 D and 2.84 ± 0.83 D, respectively. AK incisions were created using the IntraLase iFS laser (Abbott Medical Optics). Paired symmetrical arcuate incisions with a diameter of 8.5 mm and length of 80 degrees were created with a depth of 350 or 375 µm. Outcome measures included UDVA, CYL, and surgically induced astigmatism (SIA) at 1 week and 1 month postoperatively. Corneal topography (TMS-4 Advance, Tomey) was compared between preoperatively and 1 month postoperatively using Fourier analysis. The incisional depth was measured using anterior-segment optical coherence tomography (SS-1000, Tomey) at 1 month postoperatively. The differences between the measured and intended incisional depths were compared.
UDVA improved significantly to 0.33 ± 0.13 logMAR, 0.21 ± 0.17 logMAR at 1 week and 1 month (P=0.013 and P=0.01, respectively). CYL decreased significantly to 0.97 ± 0.77 D, 0.91 ± 0.64 D at 1 week and 1 month, respectively (P<0.027). SIA at 1 month was 3.22 ± 1.37 D. Fourier analysis at 6 mm diameter zone showed significant decreases in spherical and regular astigmatic components (P<0.05) and significant increases in high-order irregular astigmatism (P=0.05). The mean incision depth was 416.3 ± 38.9 µm, which was 60 µm deeper than the intended depth.
FSL-AK reduced astigmatism in pseudophakic eyes and improved the UDVA, while the SIA and measured incision depth demonstrated a trend of overcorrection. Development of a new nomogram is required to increase the accuracy.
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