Limits of the precision in refractive results after cataract surgery

In order to improve refractive results in cataract surgery with an intraocular lens implant, it is important to know the sources of error as well as the limit of this process. Therefore, the objective of the present work is to approximate the theoretical limit in the precision in the refractive result after cataract surgery with the currently available means and to assess the impact of different sources of error in this process. We conducted a search of the literature to determine the variability provided by each component of the process. Based on the Barrett Universal-II formula, we performed an error propagation analysis. The theoretical limit was defined as the situation in which the refractive result is only affected by the variability in the parameters introduced in the formula, the tolerance of the intraocular lens and the subjective refraction. The main contributors to the error were (1) intraoperative and postoperative variability variables not considered by the formulas (49.33%), (2) postoperative subjective refraction (38.29%), (3) mean keratometry (5.98%) and (4) the variability in the labelling of the power of the intraocular lens (5.09%). The theoretical limit obtained for the intraocular lens calculation with the means available today was 91.9% of the eyes between ±0.50D. We found a theoretical limit for the intraocular lens calculation of 91.9% of the eyes between ±0.50D. Approaching the precision limit described in the study requires the use of optical biometrics and state-of-the-art formulas, a reproducible surgical technique, and the compensation of systematic errors by adjusting constants. Para mejorar los resultados refractivos en cirugía de cataratas con implante de lente intraocular es importante conocer las fuentes de error así como el límite de mejora de dicho proceso. Por tanto, el objetivo del presente trabajo es aproximar el límite teórico en la precisión en el resultado refractivo tras cirugía de cataratas con los medios disponibles en la actualidad y valorar el impacto de distintas fuentes de error en dicho proceso. Realizamos una búsqueda de la bibliografía para determinar la variabilidad aportada por cada componente del proceso. Tomando como base la fórmula de Barrett Universal-II realizamos un análisis de propagación de errores. El límite teórico fue definido como la situación en la que el resultado refractivo únicamente está afectado por la variabilidad en los parámetros introducidos en la fórmula, la tolerancia de la lente