This paper introduces new methods in RELION-3.1 to detect and correct for symmetrical and antisymmetrical optical aberrations and anisotropic magnification in cryo-EM data. Applying these corrections to several publicly available datasets improved the resolution of the 3D reconstructions, especially when these optical effects were prominent.

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This paper presents valuable new methods for improving the resolution of cryo-EM reconstructions by estimating and correcting for high-order aberrations and anisotropic magnification. The methods are implemented in a widely-used software package, making them accessible to the research community. While the specific impact of these corrections varies depending on the dataset and microscope, the improvements demonstrated are significant, particularly for higher resolution reconstructions. The clarity of explanation and validation on multiple datasets strengthen the paper.