No, a person may have normal of accommodation and yet he may be myopic or hypermetropic. Infact. Myopia may arise when length of eye ball elongated and hypermetropia may arise when length of eye ball gets shortened.

A person who is blind to red-green colour may be deficient in cone shaped cell having red and green pigment in the retina of his eyes. It is a genetic disorder and not a refractive defect of vision. That is why such a person may have normal vision.

(i) The structures of the eye such as cornea, pupil, ciliary muscles, eye lens, aqueous humour and vitreous humour etc.,
(ii) The retina of the eye which converts light signals to electrical impulses and 
(iii) Optic nerve that transmit electrical impulses to brain.

Myopia is a defect in which the image 1S formed in front of retina. We need to use diverging lens so that it can further diverge the light rays before it enters our eye and make it possible to meet on the retina.
In case of hypermetropia, the image is formed beyond retina, we need to use convex lens so as to converge the rays and make it possible for the rays to meets on the retina