Sky News commentator and former Liberal politician Ross Cameron has pointed to Hillary Clinton's "apparent inability to have her two eyes moving in the same direction" as evidence that the US presidential hopeful is suffering from dementia.

Earlier this month he offered via Twitter his theory that Mrs Clinton uses a colostomy bag.

In a live Sky News broadcast before the start of US presidential debate on Tuesday, Cameron reiterated his controversial views that the Democratic presidential candidate's suffered from dementia and that her health was deteriorating rapidly, a fact she was attempting to hide it from the public.

There is no publicly available evidence to support any of these assertions and earlier this month the Clinton campaign released detailed medical records saying she was in good health.