A vitrectomy is an operation to remove the vitreous gel from inside the eye. The vitreous does not grow back after surgery and the eye functions perfectly well without it. This type of surgery is performed for several different eye conditions involving the retina and vitreous. In order to understand the reasons for performing vitrectomy surgery, it is helpful to know a little about the eye and how it works.
The eye can be compared to a camera. The pupil of the eye is like the aperture of a camera, regulating the amount of light entering the eye. Light is focussed by the cornea, the clear window into the eye, and the lens, which lies behind the pupil.
In the healthy eye, light passes through the lens and vitreous to reach the retina. The vitreous is a clear, jelly-like substance which occupies about two thirds of the volume of the eye. It is comprised of over 99% water, but also contains structural elements such as collagen fibres, proteins, and hyaluronan. The vitreous is normally attached to the retina in several areas, and so many disorders of the retina and vitreous are closely related.
The retina is the light-sensitive nerve tissue that lines the inner wall of the eye, like the film in a camera. Rays of light enter the eye, passing through the cornea, pupil and lens before focusing on to the retina. The retina contains photoreceptors which convert light into electrical impulses. In the healthy eye these impulses are sent via the optic nerve to the brain, where sight is interpreted as clear, bright, colourful images.
The retina lies on a layer of supporting tissue known as the retinal pigment epithelium or RPE. The RPE is important as it nourishes the photoreceptors and removes their waste products.
The macula is a small area at the centre of the retina. It is very important as it is responsible for our central vision. It allows us to see fine detail for activities such as reading, recognising faces, watching television and driving. It also enables us to see colour.
The sclera is the white fibrous outer coating of the wall of the eye.
How is a vitrectomy performed?
A vitrectomy is a microsurgical procedure performed in a hospital operating theatre, using general or local anaesthesia. The surgeon uses an operating microscope to view the inside of the eye and its structures. Three tiny incisions are made through the sclera. Saline is infused through one of these incisions to maintain the pressure of the eye during surgery. A fibreoptic light pipe is inserted to illuminate the structures of the eye from within.
A vitreous cutter or other instruments such as microforceps are inserted into the eye through the remaining incision, in order to perform surgery such as removing vitreous or blood, scar tissue, or membranes from the retinal surface. A laser probe may be inserted to perform laser surgery on the retina. A temporary bubble of gas or air may be inserted into the vitreous cavity at the end of the operation.
What should you expect after vitrectomy surgery?
Most vitrectomy procedures are performed using the 25-gauge system, which uses tiny, self-sealing incisions in the sclera. Sutures are usually unnecessary using this system. This makes the procedure relatively pain-free. An eye pad and protective plastic shield are placed over the eye at the end of the operation. Patients usually remain in hospital for 1 night following surgery, although some patients may be discharged on the same day. If a gas bubble is placed inside the eye during surgery then the patient may be required to maintain a particular head position for several hours or days to ensure a successful result.
The eye may be swollen, red, and tender to touch for a week or more following surgery. Eyedrops will be dispensed by the hospital before discharge and are usually needed for 2 – 3 weeks postoperatively. Most patients are prescribed a combination of steroid and antibiotic drops.
Visual recovery after vitrectomy varies greatly depending on the underlying condition for which surgery was performed. If a gas bubble is used then vision will be poor until the gas resorbs. This usually takes between 2 and 3 weeks. Following vitrectomy surgery it may take months or even years for the best vision to be reached. Even with optimal surgical treatment, vision may not fully recover in patients with severe retinal disease.
What are the possible risks and complications of vitrectomy?
Any surgical procedure carries risk. Using modern microsurgical techniques the risks of vitrectomy surgery are low, however occasional complications can occur.
Haemorrhage and infection in the eye are rare but potentially serious complications which may cause permanent loss of vision or even loss of the eye.
Retinal detachment may occur following vitrectomy surgery and may require additional surgery.
Cataract formation may be accelerated by vitrectomy surgery. This means that a cataract often develops within 1 – 2 years in an eye which has undergone a vitrectomy. This may require a further operation, a cataract procedure.
Anaesthetic complications may occur. Local anaesthesia is usually given by a blunt cannula around the eye so direct damage to the eye is very unlikely, however haemorrhage can occur. General anaesthesia always carries a very small but potentially severe risk. These risks will be explained by the anaesthetist prior to surgery.
If you have any questions concerning the procedure or possible complications please do not hesitate to contact Dr Isaacs or the team at Perth Retina.