Trabeculectomy is a drainage surgery used in the management of glaucoma. The term trabeculectomy refers to the making of a hole in the trabecular meshwork, i.e., the drainage area of the eye, allowing fluid to be released thereby lowering the pressure inside the eye.
Most glaucoma is treated by medical therapy in the form of eye drops or laser such as SLT. In most cases the eye pressure is sufficiently lowered by the treatment to reduce the risk of vision loss from glaucoma. In cases where the pressure lowering is not sufficient, further treatment is required. Further options currently include Diamox tablets, microinvasive glaucoma surgery (MIGS), trabeculectomy or glaucoma drainage implant surgery.
Trabeculectomy is performed as day surgery and does not require overnight admission. It is usually required to stop aspirin, warfarin, anti-inflammatories, fish oil or any other blood thinning medications prior to surgery, in consultation with your physician. Local anaesthesia with sedation is preferred as it is safer for the patient and provides more rapid recovery. General anaesthesia can be performed in certain patient indications. The procedure takes one to one and a half hours, depending on the complexity of the glaucoma.
The aim of the surgery is to create a one-way flap valve from the inside of the eye to under the conjunctiva of the eye. The fluid subsequently passes from this small reservoir (bleb) back into the blood vessels of the conjunctiva. It does not result in more tearing from the eye as there is no external drainage of the fluid. During the operation, anti-scarring agents such as Mitomycin C are used to optimize the long-term drainage of the fluid from the eye.
A pad/shield is worn on the first night. As the eye can be uncomfortable due to the nature of the surgery, it is advised to take plenty of rest and oral analgesia if required. It is also advised to sleep slightly elevated on two to three pillows during the first night to prevent over-drainage of fluid. No eye drops need to be administered on the first night.
It is expected that vision will fluctuate in the first few weeks following surgery due to the variable drainage of fluid but this will eventually stabilize. The first 3-4 weeks are critical in establishing the flow through the trabeculectomy site. Several post-operative appointments are required during this period in order regulate the flow and this may be done by massaging the eye and possibly removing the sutures.
Patients generally have 2-3 weeks off work depending on how the eye is healing and the nature of their work. Strenuous physical tasks such as heavy lifting or prolonged bending over, especially in dusty or dirty conditions should be avoided in the first three weeks. It is advised to wear sunglasses during the day and a shield at night.
With any eye surgery there are risks of infection, bleeding, development of retinal problems, loss of vision and sympathetic uveitis. Trabeculectomy surgery in particular, is associated with problems of under- or over-drainage following the surgery either due to loosening of the sutures or wound leak. Occasionally, if the drainage is not controlled, then trabeculectomy may need to be revised. While every step is taken to ensure optimal results, there may be cases that do not improve as expected.
The ultimate goal of trabeculectomy surgery is to reduce the pressure in the eye to a level that will slow down the rate of vision loss. Achieving lower, stable eye pressures is essential for the optimal long-term maintenance of functional vision in glaucoma.