oculist vs specialiser

oculist and specialiser both are nouns.

Word	Noun	Adjective	Verb	Adverb
oculist	Yes	No	No	No
specialiser	Yes	No	No	No

As nouns, specialiser is a hypernym of oculist; that is, specialiser is a word with a broader meaning than oculist:

oculist: a person skilled in testing for defects of vision in order to prescribe corrective glasses
specialiser: an expert who is devoted to one occupation or branch of learning

Other hypernyms of oculist include specialist, specializer.

oculist (noun)	specialiser (noun)
a medical doctor specializing in the diagnosis and treatment of diseases of the eye	an expert who is devoted to one occupation or branch of learning
a person skilled in testing for defects of vision in order to prescribe corrective glasses