Soft contact lens is used -
High myopia
Astigmatism
Presbyopia
Keratoconus
Soft contact lenses are made up of HEMA (hydroxyethylmethacrylate) which is hydrophilic. These are very good for delivering higher concentrations of drugs in emergency treatment. Reference : A K KHURANA OPHTALMOLOGY,E4,Page-417,564
Optics and refraction