Hello It seems from the history that you had a injury to head with a basket ball following which you are having black spot in the eye. This is called as floater and this is because of any opacity in the posterior part of the eye infront of the retina. The commonest cause is problem in the vitreous like vitreous opacity. This might be because of vitreous detachment as a result of trauma. Floaters by themselves does not require treatment but sudden increase in the floaters or association with diminution of vision requires evaluation as this indicates retinal problems like retinal tear. Hence I advice you to consult your eye doctor for further evaluation and treatment accordingly. Thank you