The structure of your eye could be imagined as that of a camera and the retina is the light sensitive layer at the back of the eye similar to the film of the camera. Just in front of the retina, there is a jelly like structure called the vitreous, which normally supports the retina and transmits light focused by the lens to the retina.
Flashes of lights and floaters are seen because of changes occurring in the jelly part of the eye (vitreous), usually in the form of separation or detachment of the vitreous jelly from the retina. This clinical situation, posterior vitreous detachment, is common in people over the age of 60 but could be seen earlier in short sighted persons and following trauma to the eye. In the majority of patients, vitreous separation from the retina occurs uneventfully but sometimes can be complicated by a bleed inside the eye (vitreous haemorrhage) or by the development of a retinal tear. The development of a retinal tear increases the risk of retinal detachment, and therefore should be managed promptly. A retinal detachment however is a serious eye problem that requires surgical treatment (see guide to retinal detachments).
If you were told that you have a posterior vitreous detachment with no signs of any damage to the retina or the eye, then you do not need to worry. Patients with posterior vitreous detachments can usually be discharged safely from the clinic. Floaters usually remain but become less noticeable with time. Only a small percentage (less than 4 %) of patients with initial uncomplicated vitreous detachment may develop subsequent retinal complications. Should you experience a significant increase of the flashes or floaters or should you see a black curtain coming into your field of vision, you have attend the Eye Clinic urgently, or any Ophthalmic A&E department as soon as possible.
Prepared by Mr. H.J. Zambarakji FRCOphth, D.M
Consultant Ophthalmic surgeon