Trabeculectomy is well described here, here , and here.  This page just has a few notes, with an animation here.

The pages here, here , and here,  describe the operation, but there are important details to remember

• the operation creates a valve that leads fluid out of your eye. If this valve blocks as part of the healling process, anti-healing treatment to open the valve up is often needed. This will help to stop closing again. The anti-healing treatment often has to be repeated.
• nearly all patients need antihealing treatment.
• after the operation your sight may not be quite as clear, and there are risks as described on the pages with links above;
• the operation is just the first stage; for instance
  1. the first day after your operation, if the pressure is very low, the steroid drops are stopped for a few days. For instance, if the 'AC' is deep, and the pressure 0, stop drops for 2 days (as an example).
  2. 1-2 weeks after the operation, if the pressure is >14mmHg, you usually need the releasable suture releasing
  3. a pressure of 10-14 is ideal at this stage (severe glaucoma needs a lower pressure)
  4. patients are often seen every week for a while to ensure the presure stays at this required level
  5. in the days after the operation patients with too much leak and a shallow anterior chamber may need further surgery to seal the leak.
• after the operation, steroid drops, antibiotic drops, and drops to dilate the pupil are often needed.
• always bring the drops with you to the clinic, as the dose will be adjusted etc
• in the weeks after the operation, if the wound becomes very red extra steroid drops may be needed (the redness is a sign of an over-active healing process)
• if the pressure rises, anti-healing injections will be offered
• you should not go on holiday abroad for 3 months after your operation (advice changes depending on how severe the glaucoma is, etc)
• some ophthalmologists recommend no swimming after the operation in the years after surgery, but others feel swimming is safe once the eye has recovered after the operation (accepting there is a very small risk of problems, but that the benefits outweigh the risks)