has part has part has_part characteristic of has modifier retinal cone cell abnormal retina cone cell morphology retina cone cell degeneration retinal cone cell degeneration a retrogressive impairment of function or destruction of one of the photoreceptor cell types in the retina, in which the photopigment is in invaginations of the cell membrane of the outer segment MP:0008444 MPheno.ontology retina photoreceptor degeneration abnormal degenerate