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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, METHODS, RESULTS. Meshes: Adult, Aged, Cornea, Diagnostic Imaging, Diagnostic Techniques, Ophthalmological, Female, Humans, Keratomileusis, Laser In Situ, Lasers, Excimer, Lens Implantation, Intraocular, Male, Middle Aged, Myopia, Optics and Photonics, Preoperative Period, Prospective Studies, Refraction, Ocular, Young Adult.
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Do estimating the Preoperative Corneal Power With Scheimpflug Imaging in Eyes That Have Undergone Myopic LASIK? Context: To investigate whether the Estimated Pre-Refractive SimK accurately predicts the preoperative corneal power (K) in eyes with previous myopic femtosecond laser-assisted LASIK (FS-LASIK) and whether a better prediction can be developed. Preoperatively and 3 months after FS-LASIK, patients underwent anterior segment imaging with the Pentacam HR rotating Scheimpflug camera (Oculus Optikgeräte, Wetzlar, Germany). Posterior and anterior corneal curvature and power and asphericity (Q-value at 8 mm) were recorded. Multiple linear regression was used to assess the relationship among variables. One hundred four eyes of 104 patients were enrolled. The Estimated Pre-Refractive SimK (43.19 ± 1.63 diopters [D]) was lower (P = .0014) than the mean preoperative K (43.44 ± 1.49 D). The difference was within ±0.50 and ±1.00 D in 53.8% and 86.5% of eyes, respectively. Multiple linear regression detected a statistically significant relationship (r(2) = 0.8497, P < .0001) among the investigated parameters: preoperative anterior corneal radius = 1.156 + 1.012 * postoperative posterior corneal radius - 0.3800 * postoperative Q-value. When this equation was used to predict the preoperative K, the difference between the actual preoperative K and the predicted value (43.41 ± 1.38 D) was not statistically significant. The rate of eyes with a difference between the predicted and actual preoperative K within ±0.50 and ±1.00 D increased to 61.5% and 93.3%, respectively.
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The corneal power before FS-LASIK can be accurately predicted from the postoperative corneal measurements of a rotating Scheimpflug camera. The multiple regression formula described may be more accurate than the Estimated Pre-Refractive SimK available on the Pentacam. [J Refract Surg. 2016;32(5):332-336.]. Final Decision: yes