A person who makes or dispenses lenses, spectacles. / A person who sells lenses, spectacles etc.

An image that is visually deceptive or misleading.

The best, most favourable or desirable, especially under some restriction. / (artificial intelligence) Describing a search algorithm that always returns the best result.

The best of its kind

A person trained and skilled in examining and testing the eyes for defects, in order to prescribe corrective lenses or treatment.

(relational) Of, or relating to the eye or to vision. / (optics, relational) Of, or relating to optics or optical instruments.

(archaic, humorous) An eye. / (optics) A lens or other part of an optical instrument that interacts with light.

a person who expects a favourable outcome / a believer in optimism

a tendency to expect the best, or at least, a favourable outcome / the doctrine that this world is the best of all possible worlds / the belief that good will eventually triumph over evil

Not compulsory; left to personal choice; elective.