Purpose Evaluate the influence of a posterior pole variable, macular thickness, in the calculation of the intraocular lens to be implanted in cataract patients since optical biometry has been used. Therefore, the aim of this work is to determine the importance of different biometric, topographic and retinal variables in the calculation of the intraocular lens to be implanted and to propose a new biometric formula that includes these new variables. Methods A retrospective cross-sectional observational study was carried out using a database of 230 patients who underwent cataract surgery at the Oftalvist centre in Almeria between January 2021-December 2021. Correlations between implanted IOL power and biometric, topography and retina variables were explored. A linear model was proposed with IOL power as dependent variable. The method was forward-backward steps. Results The model achieves an adjusted R-squared of 0.96 indicating that the power of the implanted lens is 96% dependent on the value of the axial length, the mean of the preoperative Ks (the mean has been performed because of the excessive collinearity between the two Ks) and the preoperative macular thickness. The introduction of the preoperative macular thickness improves the R-squared of the model and is significant in the calculation of the coefficients. Conclusions Macular thickness is a variable to take into account as it improves our prediction model of the IOL to be implanted. Keywords: Biometry, macular thickness, cataract surgery, intraocular lens power, calculation formula, precision, refractive accuracy.

Background To evaluate the efficacy and safety of Femto-LASIK, PRK, and Artiflex/Artisan phakic lens implantation in the surgical correction of myopia at three months, one, two, and five years of follow-up. Methods A retrospective study was proposed in patients who underwent Femto-LASIK technique (287 eyes of 171 patients), PRK (245 eyes of 191 patients), and phakic lens implantation (147 patient eyes) between 2010-2011 with a preoperative spheric equivalent greater than -6 diopters. The effectiveness and safety indexes were calculated during follow-up, comparing Femto-LASIK, PRK, and Artiflex/Artisan phakic lens implantation. In addition, a multivariate linear regression model was estimated. Results There were statistically significant differences in effectiveness and safety until five years when comparing Artiflex/Artisan versus PRK and Femto-LASIK (p<0.01). A linear regression model has established whose dependent variable was the UCVA at five years and independent variables were spherical equivalent preop, phakic lens implantation, and PRK. The model explained 30.32% of the patients' visual acuity variability at five years. Conclusions Artiflex/Artisan type phakic lens implantation is an effective, safe, and predictable technique at three months, 1, 2, and 5 years with stable refractive results throughout the follow-up periods compared with PRK surgery and Femto-Lasik. The model presented shows phakic lens surgery increases the UCVA result at five years and surgery with PRK decreases this final result.

Background. This study aimed to compare the efficacy and safety of Femto-LASIK, PRK, and Artiflex/Artisan phakic lens implantation in the surgical correction of myopia at different moments of postoperative follow-up; to propose a linear predictive model of visual acuity without correction at five years of refractive procedures; and to evaluate its validity. Methods. A retrospective observational analysis was performed. Patients were clinically reviewed after three months, one year, two years, and five years. Univariate and bivariate analyses and a multivariate linear regression model were performed. Results. Six hundred seventy-nine eyes were analyzed: 18.9% Artiflex, 2.8% Artisan, 42.3% Femto-LASIK, and 36.1% PRK. There were significant differences in effectiveness and safety after five years when comparing Artiflex/Artisan versus PRK and Femto-LASIK (p < 0.01). The linear regression model explained 30.32% of the patients’ visual acuity variability after five years. Conclusions. PRK surgery, Femto-Lasik, and Artiflex/Artisan type phakic lens implantation are effective, safe, and predictable techniques with stable refractive results. Phakic lenses magnify myopic patients who improve their UCVA and BCVA. Concerning phakic lens implantation, corneal endothelial cells remain stable. The predictive model calculated that surgery with a phakic lens increased the UCVA result at five years, and surgery with PRK slightly decreased the long-term results.