Two women were talking. One of them was worried about her son's (Sydney) health. However Miss Mayfield noticed that the worried woman had strange eyes.

Miss Mayfield noticed her eyes. They were at odds with the rest of her. They were large and rather beautiful, like Sydney’s, and the same colour, but their expression was – Miss Mayfield sought for the right word – wild, distraught?No, those were temporary states, easily attributable to concern for Sydney’s health; it went deeper– unstable, that was the word. Across a wilderness of thirty-five years’ remembering, Miss Mayfield heard her father’s voice, speaking of a horse he had been offered.‘It’s got an unreliable eye.’

1, I understand she's thinking that the states of her eyes were just temporary, but I don't understand the part "it went deeper"? What went deeper? And then she thinks to herself that her eyes were "unstable"?

2. Does it mean that across the wilderness a voice of her father (who died 35 years ago) came to her ears?
1. It went deeper: It isn't just the concern that caused the expression, there's more to it.

2. Not necessarily dead, but the conversation happened 35 years ago.
It's clearer. Thanks.