Blood, retinal pigment epithelial cells (that have passed through a retinal break into the vitreous cavity), or condensed vitreous fibres (from collapse of the vitreous) can all occur in retinal detachment and all can cause vitreous floaters. These move around inside the eye as the patient shifts their gaze. A few longstanding floaters are less worrying, but a large number of floaters, occurring with photopsia, is a serious symptom that requires referral regardless of the examination findings.