Visual acuity ( VA ) is acuteness or clearness of vision , which is dependent on optical and neural factors , i.e. , ( i ) the sharpness of the retinal focus within the eye , ( ii ) the intactness and functioning of the retina , and ( iii ) the sensitivity of the interpretative faculty of the brain .
Visual acuity ( VA ) is acuteness or clearness of vision , especially form vision , which depends on the sharpness of the retinal focus within the eye , the sensitivity of the nervous elements , and the interpretative faculty of the brain .