Vitreous haemorrhage
Bleeding into the vitreous humour, the gel-like substance that fills the main cavities of the eye. A widespread cause of vitreous haemorrhage is diabetic retinopathy, in which new, fragile, blood capillaries form on the retina.
Vitreous haemorrhage usually affects vision; a major haemorrhage causes poor vision until the blood is reabsorbed, which may not be for a number of months, and may not even occur at all.