Posterior vitreous detachment (PVD)
Posterior vitreous detachment is a common occurrence. By the age of 65 around 65% of people will have had a posterior vitreous detachment. The occurrence of posterior vitreous detachment is earlier in more short sighted people, and earlier than usual after cataract surgery..
The floaters that come on after posterior vitreous detachment are caused by the mobility of the posterior face of the vitreous body. The opacities or irregularities have always been present, but when they are stuck firmly to the retina the brain can ignore them. Once they are moving around inside the eye it is impossible to ignore them and they become much more noticeable. However, the process that causes the posterior vitreous detachment, that is the shrinkage of the vitreous gel, continues and the vitreous opacities tend to move further away from the retina in time. If this occurs the shadow they cast on the retina becomes less stark and the symptoms become more bearable. However, the floaters will never go away completely. Particularly in bright areas or against brightly lit pale backgrounds or against the blue sky they are more easy to see. Floaters after a posterior vitreous detachment do not normally get worse; the first day you have them is usually the worst they will ever be.
The importance of the new onset symptoms of floaters or flashing light is that is means a vitreous detachment has probably happened. It is the start of symptoms that is important, not that they continue. This is because during a posterior vitreous detachment a retinal tear can happen. By three months after the vitreous detachment has happened retinal tears are less likely than before the vitreous detachment occurred. It is important to keep in mind the symptoms of retinal detachment for the first three months after the symptoms start. These symptoms are of a progressive shadow, which starts in the outer part of the vision and creeps towards the centre. If this occurs this is an emergency situation and usually requires surgery within one or two days.
So far as treatment for the vitreous detachment itself usually nothing is done.
It is possible to use a YAG laser to fragment the floaters. There are mixed reports of outcomes. One of the problems is that as no good clinical trials have been done that I am aware of it is difficult to know whether peoples’ symptoms are improved because of the natural history of posterior vitreous detachment symptoms (slow reduction in symptoms) or because the laser has improved the symptoms. I have looked after people who have had this treatment done and have suffered severe complications as a result. Although I have equipment for it it’s not something I do or recommend.
We can go inside the eye and remove the floaters. This is with an operation called a vitrectomy. A vitrectomy usually causes cataract and we expect that within six month to two years a cataract operation would need to be done as well. There is also a risk of between 1/20 and 1/40 of causing a retinal tear and lower risk of a subsequent retinal detachment which could lead to loss of sight. Because of these risks I do not recommend vitrectomy for mild or early symptoms, but if the floaters are stopping you enjoying life or doing your job then it is reasonable to consider.
The floaters that come on after posterior vitreous detachment are caused by the mobility of the posterior face of the vitreous body. The opacities or irregularities have always been present, but when they are stuck firmly to the retina the brain can ignore them. Once they are moving around inside the eye it is impossible to ignore them and they become much more noticeable. However, the process that causes the posterior vitreous detachment, that is the shrinkage of the vitreous gel, continues and the vitreous opacities tend to move further away from the retina in time. If this occurs the shadow they cast on the retina becomes less stark and the symptoms become more bearable. However, the floaters will never go away completely. Particularly in bright areas or against brightly lit pale backgrounds or against the blue sky they are more easy to see. Floaters after a posterior vitreous detachment do not normally get worse; the first day you have them is usually the worst they will ever be.
The importance of the new onset symptoms of floaters or flashing light is that is means a vitreous detachment has probably happened. It is the start of symptoms that is important, not that they continue. This is because during a posterior vitreous detachment a retinal tear can happen. By three months after the vitreous detachment has happened retinal tears are less likely than before the vitreous detachment occurred. It is important to keep in mind the symptoms of retinal detachment for the first three months after the symptoms start. These symptoms are of a progressive shadow, which starts in the outer part of the vision and creeps towards the centre. If this occurs this is an emergency situation and usually requires surgery within one or two days.
So far as treatment for the vitreous detachment itself usually nothing is done.
It is possible to use a YAG laser to fragment the floaters. There are mixed reports of outcomes. One of the problems is that as no good clinical trials have been done that I am aware of it is difficult to know whether peoples’ symptoms are improved because of the natural history of posterior vitreous detachment symptoms (slow reduction in symptoms) or because the laser has improved the symptoms. I have looked after people who have had this treatment done and have suffered severe complications as a result. Although I have equipment for it it’s not something I do or recommend.
We can go inside the eye and remove the floaters. This is with an operation called a vitrectomy. A vitrectomy usually causes cataract and we expect that within six month to two years a cataract operation would need to be done as well. There is also a risk of between 1/20 and 1/40 of causing a retinal tear and lower risk of a subsequent retinal detachment which could lead to loss of sight. Because of these risks I do not recommend vitrectomy for mild or early symptoms, but if the floaters are stopping you enjoying life or doing your job then it is reasonable to consider.