Study	Reason for exclusion
Bisler 1986	Used non‐clinical outcome measures.
Boehm 1989	HCSE applied as part of a combination preparation.
Coninx 1974	HCSE applied as part of a combination preparation.
Dols 1987	HCSE applied as part of a combination preparation.
Dustmann 1984	HCSE applied as part of a combination preparation.
Hirsch 1982	HCSE applied as part of a combination preparation.
Krc¡lek 1973	HCSE applied as part of a combination preparation.
Lochs 1974	Trial performed on healthy volunteers, not people with CVI.
Marhic 1986	Used cream, not oral preparation.
Neumann‐Mangoldt	HCSE applied as part of a combination preparation.
Nill 1970	Used non‐clinical outcome measures.
Paciaroni 1982	Used cream, not oral preparation.
Pauschinger 1987	Used non‐clinical outcome measures.
Zuccarelli 1986	HCSE applied as part of a combination preparation.