Surgery is usually considered when drops or laser cannot bring the pressure down far enough, when several drops are already in use, when very low pressure is needed to protect a badly damaged nerve, or when using drops every day is not possible. Like all glaucoma treatment, surgery protects the sight you have; it does not restore what is lost.
Trabeculectomy
This is the most widely used glaucoma operation. The surgeon makes a small, protected opening in the wall of the eye, so fluid can drain out to a space under the thin clear skin over the white of the eye (the conjunctiva). A small flap acts as a valve, so fluid does not drain too fast. The fluid collects in a small blister, called a bleb, usually hidden under the upper eyelid, and is absorbed from there.
Keeping the new drain open
The body tends to treat the new drainage path as a wound and tries to heal it shut with scar tissue. Scarring is the most common reason the operation stops working over time. To prevent it:
- medicines that slow healing may be used during surgery
- steroid drops are used for several weeks afterwards to calm inflammation
- antibiotic drops are used for a short time
- your doctor may ask you to massage the eye gently in a particular way
Aftercare is intensive in the first weeks, with frequent visits. Keep every one.
Drainage implants (tube shunts)
In eyes with complicated glaucoma, or where a trabeculectomy has failed, a drainage implant may be more likely to succeed. A fine tube carries fluid from inside the eye to a small plate stitched onto the white of the eye, under the conjunctiva. Scarring matters less, so the drain usually stays open long term, and many people no longer need glaucoma drops.
In the early weeks the pressure can drop too low before it settles. Rarely, the tube needs adjusting, or the tissue over it needs repair.
Treatments for a painful eye with little sight
When the pressure is very high and uncontrolled in an eye that has lost most of its sight, the aim shifts to comfort. Treatment of the part of the eye that makes the fluid, by freezing (cyclocryotherapy) or laser, lowers how much fluid is made. No opening is made in the eye, so aftercare is simple, although the eye may ache for a few days.
Risks of glaucoma surgery
Any operation that enters the eye carries risks. Your surgeon will discuss these with you:
- Infection. This is rare, but because a drainage path stays open after a successful trabeculectomy, a small risk remains for life. A red, painful, sticky eye after glaucoma surgery needs to be seen the same day.
- Pressure too low or too high, especially in the first weeks.
- Bleeding inside the eye.
- Cataract. A cataract may form, or an existing one may progress faster.
- The drain closing over time, so further treatment is needed.
Newer procedures such as minimally invasive glaucoma surgery (MIGS) exist too. Whether they are suitable depends on your eye; ask your surgeon.
This guide explains; it does not diagnose. Your doctor’s advice about your own eyes comes first.