We study linear ordinary differential equations with ramified irregular singularies with the help of the theory of singularities of plane curve germs.

Especially we shall see analogies between

- Komatsu-Malgrange irregularities of ODEs and intersection numbers and Milnor numbers of curves,

- Local Fourier transform of ODEs and blow up of curves,

- Stokes structures of ODEs and iterated torus knots of curves.