If you look someone in the eye, you look at them directly to try to convince them that you are telling the truth, even though you may be lying.
John looked me in the eye and told me that he loved me.
I looked at my boss in the eye and told him exactly what I thought.
If there is more to something than meets the eye, then there may be a hidden meaning or quality to it.
I don't like Jane's new husband. He seems kind and gentle but I think there's more to him than meets the eye.
The cornea is the transparent front part of the eye. Corneas can be transplanted by an operation where a damaged or diseased cornea is replaced with one from someone who has just died. The first corneal transplant was in 1905 by Eduard Zirm. It was one of the first successful transplant operations.