Although the patient can see movement in the periphery,the patient can no longer see to read books or do crossword puzzles.Which is the most likely cause of the patient's vision loss?

A) Cataracts
B) Glaucoma
C) Diabetic retinopathy
D) Macular degeneration

Age-related macular degeneration occurs when the macula (specialized portion of the retina responsible for central vision)degenerates as a result of aging and loses its ability to function efficiently.An early sign includes distortion that causes edges or lines to appear wavy.In later stages,patients may see dark or empty spaces that block the center of vision.Cataract is clouding of the lens in the eye that affects vision.Interferes with passage of light through the lens and reduces the light that reaches the retina.Cataracts usually develop gradually and often result in cloudy or blurry vision,glare,double vision,and poor night vision.Glaucoma is a slowly progressive increase in intraocular pressure that causes progressive pressure against the optic nerve.At first,vision stays normal,and there is no pain.If left untreated,there may be a loss of peripheral (side vision).Diabetic retinopathy are pathological changes of the blood vessels of the retina secondary to increased pressure resulting in hemorrhage,macular edema,and reduced vision or vision loss.