VISION DISORDERS

Normal vision depends on normal ocular media, visual axis, image formation over retina, reception over retina, afferent optic nerve and central processing.

Consequently, disorders of vision may be divided into—(a) amaurosis (blindness), (b) amblyopia, i.e. defective central processing, (c) abnormal image formation, i.e. refraction, and (d) abnormal visual axis, i.e. strabismus or other ocular movement disorders. Visual assessment in children needs age-appro­priate modifications in vision tests. Table 26.14 lists common tests, used to assess vision at different ages in childhood.

26.3.1