In treating advanced retinopathy, doctors may use laser surgery to shrink abnormal blood vessels at the back of the eye. This treatment results in a loss of some peripheral (side) vision, a sacrifice that preserves the remaining field of vision. Laser surgery for retinopathy may also reduce color and night vision. A surgical alternative to laser surgery, called vitrectomy, is sometimes used if the eye has become cloudy due to hemorrhage (bleeding). Vitrectomy replaces the vitreous humor (transparent fluid in the interior of the eyeball behind the lens) with a salt solution.