# General formula to design a freeform singlet free of spherical aberration and astigmatism: comment

@article{ValenciaEstrada2020GeneralFT, title={General formula to design a freeform singlet free of spherical aberration and astigmatism: comment}, author={Juan Camilo Valencia-Estrada and Jorge Garc{\'i}a‐M{\'a}rquez}, journal={arXiv: Optics}, year={2020} }

In their article -Appl. Opt. 58, 1010_1015 (2019)- Gonz\'alez-Acu\~na et al claimed:"an analytical closed-form formula for the design of freeform lenses free of spherical aberration and astigmatism." However, as we show here, their formula can only be applied when the object and image are both real and the image is inversed, additionally, the refractive index in the object and image media is the same. Here, we present the complete solution of this particular formula.

## One Citation

### Calculation of a lens system with one or two aspherical surfaces having corrected spherical aberration.

- PhysicsJournal of the Optical Society of America. A, Optics, image science, and vision
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The paper presents a detailed theoretical analysis of characteristics of a rotationally symmetric lens system with one or two aspherical surfaces having corrected spherical aberration and reduced…

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