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Shavini Athukorala, Neal Kansara, Tara O'Rourke, Ingrid U Scott, Seth Pantanelli; Comparison of Pre-operative Measured to Post-operative Refractive Astigmatism in Pseudophakes. Invest. Ophthalmol. Vis. Sci. 2021;62(8):954.
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To evaluate the relationship between various measures of pre-operative keratometric astigmatism and post-operative refractive astigmatism (RA).
Consecutive eyes evaluated between 11/2018 and 07/2020 underwent pre-operative biometry (IOLMaster 700), tomography/topography (Galilei G4), cataract surgery with implantation of a monofocal intraocular lens, and manifest refraction between 21 and 90 days after surgery. Eyes excluded from the analysis included those with biometry or topography of poor quality (as defined by the device’s respective image quality metrics), history of ocular surgery other than laser, corneal disease of any kind, cataract surgery combined with another procedure, intraoperative complications, implantation of a toric or multifocal IOL, missing post-operative manifest refraction, or a best-corrected distance visual acuity worse than 20/40. Post-operative RA was compared to pre-operative astigmatism measured using the following methods: Keratometry (K; IOLMaster), Simulated Keratometry (SimK; Galilei G4), Total Keratometry (TK; IOLMaster), and Total Corneal Power (TCP2; Galilei G4). Difference vectors (DV) were calculated between RA and each of the four pre-operative measures.
One-hundred eighteen eyes met criteria for inclusion in the analysis. The centroid of the DVs for the four measurement methods were 0.26 ± 0.75 D @ 173, 0.52 ± 0.75 D @ 177, 0.08 ± 0.77 @ 151, and 0.30 ± 0.81 D @ 174, respectively. K and TCP2 DVs were not significantly different from one another (p = 0.58); all other differences were significant (p < 0.0001). The proportion of eyes with DV magnitudes < 0.5 were 36.4%, 23.7%, 41.5%, and 28.8% (p < 0.0001), respectively. The proportion of eyes with DV magnitudes < 1.0 D were 85.6%, 67.8%, 83.9%, and 75.4%, respectively (p < 0.0001 for all comparisons except K vs. TK [p = 0.48]).
Of the pre-operative measurement methods evaluated, TK most closely approximated post-operative RA. The effect of surgically induced astigmatism (SIA) was not evaluated due to the retrospective nature of the study.
This is a 2021 ARVO Annual Meeting abstract.
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