John Lee, MD
Orbital decompression is a surgical procedure which has been in existence for well over 100 years to treat a variety of eye related diseases. The orbit (eye socket) is a space within your skull that has four bony walls (roof, floor, and two side walls) and contains all the contents of the eye (including the eyeball, the muscles of the eye, the nerve of vision (optic nerve) and fat). The goal of orbital decompression is to remove some of the bony walls of the eye socket so that there is more room and space for the entire eye as well as decreasing pressure within the eye socket. Endoscopic orbital decompression was introduced in the early 1990s and has become an effective means of decompressing the eye without any cuts to the outside of the face. This minimally invasive procedure is accomplished with the use of endoscopes (small rigid telescopes), allowing your surgeon to go through the nose and sinuses to delicately remove some of the bony walls of the orbit. In the following sections, we will review the indications, risks and benefits of this procedure.
The indications for orbital decompression usually involve any condition which is causing an increase in the overall volume or size of the eye and directly affecting a patient’s vision or appearance. One of the most common indications is Graves’ disease, an autoimmune disorder that primarily affects the thyroid gland and the eye. If the eye is affected (Grave’s orbitopathy), there is an enlargement of the orbital fat and the muscles of the eye (See Figure: arrows pointing to enlarged muscles). This can then cause the eye to bulge outwards, preventing the eyelids from closing completely which may cause eye dryness, excess tearing, and abrasions of the surface of the eye. Furthermore, while the eye contents have enlarged, the bony eye socket has not changed so there may be a restriction in the movement of the eye (causing double vision). This lack of space may also increase intraorbital (eye socket) pressure, which can cause compression on the optic nerve (causing a deterioration or loss of vision). Mild cases of Graves’ orbitopathy may be treated with medications. However, in patients with significant problems of eye irritation, double vision or reduced vision, endoscopic orbital decompression may be a good form of treatment.
Endoscopic orbital decompression may also be indicated for any other condition which is causing either significant pressure or compression within the eye socket. This may be caused by trauma, an infection of the eye (abscess), a collection of blood (hematoma), or even a tumor within the contents of the eye.
Endoscopic orbital decompression is a surgical procedure which is usually performed under a general anesthetic. Going through your nose, your surgeon will first perform endoscopic sinus surgery and open the sinuses directly beside the eye (frontal, maxillary, ethmoid, and sphenoid sinuses). Once this is complete, the bone along one side of the eye (closest to the nose) and also part of the floor of the eye is carefully removed. This exposes the thin lining (periorbita) which covers the entire contents of the eye. Your surgeon will then make cuts along the periorbita, allowing the fat (See Figure: asterisk indicates fat) and muscles of the eye to bulge into the sinuses. This procedure has then effectively enlarged the space of the orbit which in turn “decompresses” the entire eye. At the end of the surgery, there is usually no packing in the nose. You will likely be admitted to hospital overnight for observation.
Endoscopic orbital decompression involves operating both within the eye and in the sinuses. Consequently, there are known risks of this surgery. This includes but is not limited to the following: loss of vision, double vision, inadequate decompression of the eye, bleeding around the eye, cheek numbness, nasal bleeding, leakage of brain fluid (CSF), meningitis, infection of the eye, injury of the tear duct (which can cause excess tearing), and sinusitis.
By removing part of the walls of the orbit, endoscopic orbital decompression may allow the eye to move back into a better position within the eye socket. This may help with eye dryness, tearing, abrasions of the eye, and even the appearance of the eye. It may also decrease the pressure within the eye socket, which can prevent/improve the problems of double vision or loss of vision.
Endoscopic orbital decompression is a well-established, minimally invasive procedure that can increase the bony space which contains the eye. In conditions such as Graves’s disease affecting the eye, this surgery may be particularly helpful. Speak with your surgeon to see if you are a candidate for this surgery.