Glaucoma is a condition where high pressure builds up inside the eye and can damage the optic nerve. This nerve carries important signals for vision from the eye to the brain. Eye drops can help control the pressure to prevent visual damage. In children and young people, surgery is often a better option because it can lower the pressure more effectively to protect their vision.
The surgery is done under general anaesthesia, which means the child is asleep during the surgery and does not feel anything. The surgery involves making a small incision on the surface of the eye in order to get access to the microdrainage canal, which lies behind the filter drainage channels (trabecular meshwork) that are not fully opened and do not let fluid drain out properly and hence causes an increase in eye pressure.
The surgeon opens up the eye’s blocked natural drainage canal and channels, if possible, over a full 360 degrees. This is done by inserting a microcatheter into the canal which is pulled through, opening up the canal and the overlying blocked filter channels (trabecular meshwork). This improves the fluid outflow and helps lower the pressure inside the eye. This is sometimes combined with allowing some fluid to flow out of the eye under the covering skin, called conjunctiva.
An intraoperative local anaesthetic is also given to ensure child remains comfortable postoperatively as well.
The surgery improves the fluid outflow and helps lower the eye pressure preventing glaucoma progression. In the majority of patients it reduces the drop burden.
The main risks are infection, inflammation, bleeding and loss of vision. The risk of infection is very small (< 1/1000) and the risk is reduced by the use of antibiotic eye drops for a few weeks. A limited superficial bleeding is common, but has no clinical significance. There may be a possibility of intraocular bleeding, which tends to clear within a few weeks. If it does not clear by itself, we may have to take the child back to theatre to wash it out. Rarely the bleeding at the back of the eye may cause a pull on the retina, causing a retinal detachment, which may need further surgery. Loss of vision is very rare (<1/1000) if any of the above complications are severe.
If there are significant blockages in the circular channel that are being opened during surgery, the surgeon may not be able to open it completely.
The initial success rate can be very high (up to > 90% for year one), but effectiveness of surgery depends on the type of glaucoma and may decline with time.
If the drop in intraocular pressure is not adequate, further options would include eye drops, laser or other surgical options.
Your child will have a preoperative assessment by our nursing team, either over the phone or face-to-face. You will be given instructions about fasting before surgery. You need to continue the eye pressure lowering medication until surgery. Please see our general anaesthetic fact sheet.
The child will wake up with a patch over the eye which will be removed as soon as they fully recover from anaesthesia. The nurses will give you some eye drops to take home and administer to your child several times a day for a few weeks. The drops are important as they prevent potential inflammation and infection.
The eyes should only have a mild discomfort, but if the child appears to be in pain you may use paracetamol as required.
If your child wears glasses you can put them back on the same day. The first postoperative appointment will be within 2 weeks from surgery.
Your child can resume their regular activities once given the all clear in clinic, provisionally adequate hygiene is maintained. Swimming should be avoided for at least 6 weeks after surgery.