Astigmatism
My understanding of the astigmatism was clarified by my optician recently. When I queried the parameters for astigmatism as detailed by the CAA, she advised that having an astigmatism that rendered you unfit for a class 1 medical would also result in you not being able to wear contact lenses. If you can wear lenses that sufficiently correct such a condition, you should be fine, so I'm told.