Being told that you need surgery for glaucoma can feel like a significant step. For many people, the diagnosis has been managed with drops for years, so the suggestion of an operation raises plenty of questions. The good news is that glaucoma surgery is one of the most common and well-understood procedures in eye care, and knowing what happens beforehand can remove much of the anxiety. This guide walks you through the practicalities of preparing, from the first pre-operative appointment to the morning of your procedure.

Why Your Specialist Has Suggested Surgery

Glaucoma damages the optic nerve, usually because the pressure inside the eye is higher than the nerve can comfortably tolerate. Drops and laser treatment work well for many people, but sometimes they are not enough, are difficult to tolerate, or become less effective over time. Surgery aims to lower the pressure by creating a new drainage route or by inserting a tiny tube or stent.

Your ophthalmologist will explain which type of operation is being proposed for you. The most familiar is a trabeculectomy, which creates a small channel under the upper eyelid. Other options include drainage tube surgery and minimally invasive glaucoma surgery, often combined with cataract removal. Each has its own recovery pattern, so it is worth asking which one you are having and why it suits your eyes.

Your Pre-Operative Assessment

Before a date is set, you will usually attend a pre-operative assessment. This may happen in the eye clinic, on a day surgery unit, or by telephone, depending on your hospital. The appointment has two purposes: to confirm the surgery is right for you, and to make sure you are well enough to have it safely.

You can expect several measurements and checks, including:

• Eye pressure readings, sometimes taken at different times of day to see how it fluctuates.
• Visual field testing, where you look straight ahead and click when you see lights in your side vision.
• Optic nerve imaging, such as a scan or photograph, to record a baseline for future comparison.
• Corneal thickness measurement, as a thin cornea can affect pressure readings.
• Blood tests, blood pressure and sometimes an ECG, particularly if you have heart, kidney or lung conditions.
• A swab for certain bacteria, which some units take routinely before eye surgery.

Bring a list of everything you take, including prescriptions, over-the-counter remedies and supplements. Your team also needs to know about allergies, previous operations, and any history of bleeding problems.

Adjusting Your Medications

One of the most important preparation steps is reviewing your medicines. Drugs that thin the blood, such as warfarin, clopidogrel, apixaban, rivaroxaban or even regular aspirin, can increase the risk of bleeding during and after surgery. Never stop or change these yourself. Your ophthalmology team will liaise with your GP, anticoagulant clinic or cardiologist to decide what is safe.

Similar conversations apply to some diabetes medications and to certain prostate treatments. Your usual glaucoma drops are often continued right up to the day of surgery, and you may be given additional drops to reduce inflammation beforehand. If you are unsure about any instruction, ring the unit rather than guessing.

Understanding Your Anaesthesia Options

Most glaucoma surgery in the UK is performed under local anaesthesia, which means you stay awake but feel nothing. There are several approaches:

• Topical drops numb the surface of the eye, sometimes with a small injection beside the eye for deeper comfort.
• Sub-Tenon's anaesthesia uses a fine cannula to place anaesthetic behind the eye, giving good numbness without a needle into the socket.
• Peribulbar or retrobulbar blocks use an injection around the eye and are very effective at stopping movement.
• General anaesthesia may be recommended if the surgery is complex, if you cannot lie still, or if you would prefer to be asleep.

With local anaesthesia you may see lights, movement or swirling shapes, and feel a sensation of pressure rather than pain. If a general anaesthetic or heavy sedation is planned, you will be asked to fast, typically no food for six hours and no clear fluids for two, although your unit's instructions always take priority.

The Final 24 Hours Before Surgery

The day before, keep things simple. Eat normally unless told otherwise, take your usual medicines with a sip of water, and avoid alcohol. Shower and wash your hair, as you will not be able to get water in the eye for a while afterwards. Skip eye makeup, face cream, perfume and aftershave, as these can irritate the eye and are not permitted in theatre.

On the day, wear loose, comfortable clothing with a front-opening top so you do not have to pull anything over your head. Arrive with time to spare, bring your glasses case, any eye drops you use, a list of medications and a pair of sunglasses for the journey home. Do not drive yourself, and do not use public transport alone if you feel wobbly afterwards.

Arranging Support for the First Few Days

Plan for someone to be with you for the first night and, ideally, the first few days. You will need help with shopping, cooking and any heavy lifting, because bending, straining and lifting raise the pressure inside the eye and can affect how well the surgery works. Stock up on easy meals, keep a phone nearby, and put your drops in a place where you can reach them comfortably.

You will be given a protective shield to wear, usually at night, and a schedule of post-operative drops. Keep your follow-up appointment, and contact the eye unit straight away if you notice severe pain, increasing redness, a sudden change in vision or a discharge from the eye. Most people are surprised by how manageable the whole process is, and a little preparation beforehand makes it smoother still.