Ivy wrote:

both of BCs eyes seem to change the colour. That's actually a specific kind of heterochromia where both eyes seem to change depending on the light.

I have the same kind of heterochromia and my eye colour, ranging from sapphire blue to steel grey and even green in the right circumstances, varies based on not only the light, but also what I'm wearing near my face.

I think that the episode that most dramatically demonstrates this type of heterochromia for Benedict is TSOT. Sherlock is usually lit with shadows. He's almost a vampire in that we rarely see a closeup of his face in bright natural light. During The Speech, he is flooded with sunlight and his eyes are super, super light green, almost unnatural! We flashback to scenes that aren't as well lit, for example the eyeball tea scene, and his eyes appear much darker.

What he wears also affects his eyes; they appear darker when he has a scarf on than when he's wearing the white buttoned up shirt and light tie in TSOT.

Mary
 

One of my close friends also has Heterochromia and doctor said that it’s a hereditary disorder; the color of his eyes is quite similar to Josh Henderson’s green eyes. Well I really love her eyes, but she is afraid about her children.