Proliferative vitreoretinopathy (PVR) is a fibrotic disease caused by a complex cellular reaction representing a vitreo-retinal wound healing response that results from a retinal injury. It is the leading cause of failure of retinal detachment surgery. It occurs in approximately 10% of all retinal detachments.  Appropriate management of a retinal detachment at the first operation is crucial, as the risk of proliferation and re-detachment increases with each subsequent surgery. Studies on risk factors for PVR are difficult to interpret and have often yielded contradictory results. In general, PVR risk increases with:[1,2,3]
Pastor, J.C., et al., Proliferative vitreoretinopathy: risk factors and pathobiology. 2002. 21(1): p. 127-144.
Cowley, M., et al., Clinical risk factors for proliferative vitreoretinopathy. 1989. 107(8): p. 1147-1151.
Girard, P., et al., Clinical risk factors for proliferative vitreoretinopathy after retinal detachment surgery. 1994. 14(5): p. 417-424.
Paediatric patients are known to be at high risk of PVR, but age in adults has not been shown to correlate with risk of developing PVR. Patients with retinal detachment following trauma and in pigmented races are also likely to be at higher risk for PVR.
Patients with PVR retinal detachments require vitrectomy with epiretinal/subretinal membrane peeling ± relaxing retinectomy. In addition, lensectomy and scleral buckling should be considered. Factors that may influence this decision include:
Lensectomy should be especially considered in patients who are older or who have cataract. Removing the lens allows for better visualization and removal of the peripheral vitreous including anterior loop traction. Since an endotamponade will be used, insertion of an intraocular lens may be delayed as a secondary procedure. Aphakia allows for the most complete vitreous removal but invites the complications associated with aphakic oil if oil is the required tamponade. A peripheral iridectomy is required in aphakic eyes. It is often preferable to leave the capsule behind for future sulcus lens implantation, however remaining capsule can be a scaffold for anterior loop proliferation and for posterior synechiae. If the PVR is mainly posterior, implantation of a lens can be considered. Placement of a 3-piece lens may decrease the rate of capsular phimosis.
If the breaks/PVR are anterior, the addition of an encircling scleral buckle provides extra support for these areas and the vitreous base.
If all three procedures are to be undertaken in the same operation, the usual sequence is:
Retinectomy in the setting of PVR should be considered when one or more of following are present:
Some important points to remember:
The usual endotamponade is silicone oil or C3F8 gas. In the Silicone Study, C3F8 gas and silicone oil (1000 centistoke) were shown to be equivalent in terms of visual outcomes and re-attachment rates in patients with severe (at least grade C) PVR. Long-term endotamponade may require a higher density of silicone oil (5000 centistoke) to prevent emulsification and glaucoma (Figure 8.3.2). “Heavy” silicone oils (e.g. Densiron® 68 and Densiron® Xtra) may be used for inferior PVR but should be removed within 3 months to avoid retinotoxicity. In severe cases of PVR, perfluoro-n-octane (PFO or “heavy liquid”) can be injected temporarily (1 - 2 weeks) to reattach the retina before being exchanged for silicone oil or C3F8 gas. It is important not to leave it longer than this since it is retinotoxic. Some surgeons will inject subtenon’s triamcinolone at the same time to mitigate the pro-inflammatory effects of PFO.
Vitrectomy With Silicone Oil or Sulfur Hexafluoride Gas in Eyes With Severe Proliferative Vitreoretinopathy: Results of a Randomized Clinical Trial: Silicone Study Report 1. JAMA Ophthalmology, 1992. 110(6): p. 770-779.
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