Pars Plana Vitrectomy (PPV)
Pars Plana Vitrectomy surgery (PPV) or vitrectomy surgery is a form of surgery that treat disorders of the retina and vitreous. During this procedure, the vitreous is removed and usually replaced with a balance salt solution. Depending on the need for the surgery, the vitreous may also be replaced by either Gas, Silicone oil or a high density Silicone oil. The whole procedure may take between 30 to 90 minutes.
The term pars plana, implies that the surgery is performed in the deeper parts of the eyeball i.e behind the crystalline lens.
Together with PPV, other procedures may be performed as the need arises. Such procedures are:
- Membranectomy (peeling) - removal of layers of unhealthy tissue from the retina with minute instruments such as forceps (tiny grasping tools), picks (miniature hooks), and visco-discection (separating layers or tissue with jets of fluid.)
- Fluid-gas exchange - injection of gas into the eye such as sulphur hexafluoride or perfluoropropane to hold the retina in place or temporarily seal off holes in the retina. These gases disappear spontaneously once they have accomplished their purpose.
- Silicone oil injection - filling of the eye with liquid silicone to hold the retina in place in a number of cases.
- Endophotocoagulation - laser treatment to seal off holes in the retina or to shrink unhealthy, damaging blood vessels which grow in some diseases such as diabetes.
- Scleral buckling - placement of a support positioned like a belt around the walls of the eyeball to maintain the retina in a proper, attached position.
- Lensectomy - removal of the lens in the eye when it is cloudy (cataract) or if it is attached to scar tissue.
When is Vitrectomy surgery indicated?
PPV is indicated in the following cases:
- Removal of scar tissue that may be growing on the vitreous or the surface of the retina. It can pull on the retina and cause a retina detachment.
- Haemorrhage (blood) that prevents the passage of light through the eye to the retina:
- Diabetic traction retinopathy – bleeding and scar tissue forming in the eye of a diabetic patient:
- Rhegmatogenous Retinal Detachments:
- Proliferative vitreoretinopathy – formation of scar tissue following severe retina detachment:
- Infection inside the eye (endophthalmitis):
- Epiretinal Membranes:
- Macular Hole surgery:
- Intraocular foreign body:
- Complications following cataract surgery:
- Trauma related.
How is PPV performed?
Pars Plana Vitrectomy is a surgical procedure that is usually performed under local anaesthesia. In some severe cases, general anaesthesia may also be needed.
During the procedure, microsurgical instruments will be inserted into the eyeball via 3 small incisions (measuring about 2-3mm) that is made through the sclera (white of the eye). A number of instruments may be used during the procedure to removed the vitreous gel and any scar tissues that may have formed on the retinal surfaces. A laser probe can also be inserted during the procedure.
Depending on the complexity of the cases, other procedures may be combined with the PPV. Theses includes scleral buckling, cryopexy, and endotamponades (eg Silicone oil or gases).The entire surgery may take up between 45 minutes to 2 hours to complete.
The visual outcomes following a PPV is largely depended on the severity and complexity of the case. If your eye problem caused permanent damage to your retina before the vitrectomy, then the improvement following surgery may not be great. Surgery is sometimes performed to save the eye only, rather than to achieve an improvement in vision.