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Chie Yukawa, Masaharu Iida, Keita Takada, Ryohei Nejima, Keiichiro Minami, Kazunori Miyata; Factors influencing ametropia following toric intraocular lens implantation in eyes with high corneal astigmatism. Invest. Ophthalmol. Vis. Sci. 2018;59(9):253. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
In the use of toric intraocular lens (IOL), misalignment of the IOL and the corneal astigmatic axes is critical for eyes with high corneal astigmatism. However, postoperative ametropia has not been assessed till date. This retrospective case series evaluated the incidences of ametropic cases following implantation of toric IOLs with cylinders of 2.56, 3.08, 3.60, and 4.11 D, and explored the factors involved.
Clinical records of patients with senile cataract and implantations of SN6AT6, SN6AT7, SN6AT8, and SN6AT9 (Alcon) were reviewed. Inclusion criteria were: postoperative best-corrected distance visual acuity of 0.096 logMAR or better and no history of corneal surgery. Uncorrected distance visual acuity (UDVA), manifest refraction (spherical equivalent and cylinder), and difference of the IOL axial marks from intended positions, were measured 3 months after surgery. An ametropic case was defined by UDVA lower than 0.096 logMAR. The frequency of ametropic cases for the 4 IOL models were calculated, and the factors involved were identified.
Ninety-one eyes from 91 consecutive patients were studied. No difference was found in the UDVA and manifest cylinder among the IOL models (P = 0.71 and 0.54, respectively). There was no ametropic case in the use of SN6AT6, and ametropic cases were found in 2 of 32 eyes, 3 of 15 eyes, and 3 of 11 eyes with the use of SN6AT7, SN6AT8, and SN6AT9, respectively. The frequency of ametropic cases increased with the cylindrical corrections (P = 0.001, Cochran-Armitage trend test). The factors identified were: misalignment of IOL (6 eyes), and refractive errors due to IOL power (3 eyes).
Increase in ametropic cases and the misalignment of IOL demonstrate the importance of axial alignment for eyes with high corneal astigmatism. The IOL power-related factor suggests that preoperative assessment of the patients’ demographics would be beneficial against ametropia.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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