photophobia vs simple phobia

photophobia and simple phobia both are nouns.

Word	Noun	Adjective	Verb	Adverb
photophobia	Yes	No	No	No
simple phobia	Yes	No	No	No

As nouns, simple phobia is a hypernym of photophobia; that is, simple phobia is a word with a broader meaning than photophobia:

photophobia: a morbid fear of light
simple phobia: any phobia (other than agoraphobia) associated with relatively simple well-defined stimuli

photophobia (noun)	simple phobia (noun)
pain in the eye resulting from exposure to bright light (often associated with albinism)	any phobia (other than agoraphobia) associated with relatively simple well-defined stimuli
a morbid fear of light