Glaucoma. Close-up of the eye of a patient suffering from glaucoma, where the lens of the eye is peeling away from the iris. The lens peeling away" or pseudo-exfoliation is seen as grey within the pupil of the eye. Glaucoma is caused by a structural abnormality in the drainage angles of the eyes. Normal fluid drainage is impaired and pressure builds up, damaging the eye's internal structures, such as the lens here. Reddening of the eye can be caused by blood vessels becoming permeable and leaking blood. The eyeball can become hard and painful when this condition develops acutely. Treatments include diuretic drugs or drainage surgery to reduce pressure."