Anaesthetic Options for Cataract Surgery: Drops, Injection, Sedation or Being Put to Sleep

Cataract surgery is almost always done under local anaesthetic with you awake: anaesthetic drops numb the eye, sometimes helped by a small injection around it, light sedation is available for people who are anxious, and general anaesthetic is reserved for the small minority who cannot lie still or cooperate for the 15 to 30 minutes the operation takes¹. The choice is made with you at the cataract assessment, and it depends far more on your neck, your breathing, your tremor and your nerves than on the cataract itself².

I wrote the article on what cataract surgery feels like from the inside of the experience. This one is about the decision made before it: which kind of anaesthetic, why, and what each one means for the day.

The ladder of options, from lightest to heaviest

There are four rungs: drops alone, drops plus a local anaesthetic block, either of those with sedation, and general anaesthetic, and most people stop on the first rung². Each step up buys more control over pain, eye movement or anxiety at the cost of more preparation, more recovery and, at the top, more medical risk.

Topical anaesthesia means anaesthetic drops on the surface of the eye, often topped up by the surgeon putting a little anaesthetic inside the eye during the operation. The eye is numb, you are fully awake, and you can go home almost as soon as the eye has been checked. This is the default in most modern cataract units and the one most people reading this will have.

A local anaesthetic block is an injection of anaesthetic around the eye rather than just onto its surface. It numbs the eye more deeply and, depending on the type, stops it moving. It suits longer or more complex operations, eyes that are hard to work in, and people who cannot reliably hold their gaze steady.

Sedation is an add-on to either of those, not a replacement. It settles you; it does not send you to sleep.

General anaesthetic puts you fully asleep with an anaesthetist in charge of your breathing. The operation is the same phacoemulsification through the same 2 to 3 mm incision; only your experience of it changes³.

Drops alone: what “awake” actually means

With anaesthetic drops the eye is numb to pain but not to sensation, so you feel pressure and cool fluid, see bright light and moving colour, and hear the team, without seeing the operation itself¹. That last point is the one people find hardest to believe beforehand.

The lens of the eye sits behind the pupil, and the microscope light shining through that pupil during surgery is so bright that the view dissolves into a wash of white and colour. You are not watching an instrument come towards you. Several people describe it as like looking into a kaleidoscope, or at the sun through closed eyelids.

The eyelids are held gently open by a small spring clip, which people worry about and then barely notice, because it takes away the urge to blink rather than fighting it. You are asked to look towards the light and keep your head still on the padded rest, and a nurse often holds your hand so you can squeeze it if you need to say something without moving. The operation itself takes about 15 to 30 minutes, often quoted as around 20⁴.

The advantages of drops alone are practical. No needle near the eye, no bruising, no fasting in most units, no cannula unless sedation is planned, and the eye starts working again within hours rather than sitting numb and immobile for the rest of the day. The trade-off is that it relies on you: you have to be able to lie flat, keep reasonably still, and follow simple instructions for the duration.

The injection: sub-Tenon’s and other blocks

A sub-Tenon’s block, the most widely used injection in many centres, delivers anaesthetic under the outer membrane of the eye through a blunt cannula after the surface has already been numbed with drops, so there is no sharp needle and no pain from the injection itself². You feel pressure and a spreading fullness, and within a few minutes the eye is numb and, usually, still.

The older sharp-needle blocks, peribulbar and retrobulbar, put anaesthetic deeper behind or beside the eye. They are used less often now because a needle placed blind carries a very small risk of touching the eye or a blood vessel, and the blunt sub-Tenon’s approach avoids most of that. Either type of block leaves the eye more thoroughly numb than drops and stops it darting about, which is why a surgeon may prefer one for a difficult eye, a long operation, a very anxious patient, or someone who genuinely cannot hold still.

Two things follow a block that nobody warns you about. First, a red, bruised looking eye, often a bright patch of blood under the clear membrane, is common and harmless and fades over one to two weeks. Second, the eye can stay numb, blurred and half closed for several hours, sometimes into the evening, so the “seeing straight away” that drops patients describe does not apply until the block wears off. The next day usually looks the same either way.

If you take blood thinners, this is one of the reasons the team asks about them: they are usually continued for routine cataract surgery, but the type of anaesthetic may be chosen with them in mind, which is covered in medicines to tell your surgeon about.

Sedation: taking the edge off without going under

Sedation for cataract surgery is deliberately light, enough to blunt anxiety while leaving you able to lie still and look where you are asked, and it is offered to a minority rather than given to everyone². Heavier sedation is generally avoided, because a patient who drifts into sleep can jerk awake or move their head without warning at exactly the moment stillness matters most.

In practice it is a small dose of a sedative, sometimes as a tablet before you go in and sometimes through a cannula in the back of the hand, given and monitored by an anaesthetist or a trained nurse. You stay conscious, you can talk, and most people remember the operation, just with the fear turned down. It adds fasting instructions in most units, a companion to take you home, and a rule against driving, drinking alcohol or making important decisions for the rest of the day.

Who asks for it? People with a bad experience of medical procedures, people who panic in enclosed spaces (the drape over your face is the part that triggers this, and a cold stream of air under it helps a great deal), and people who simply know themselves well enough to say they will not manage without. There is no prize for refusing it and no penalty for accepting it. What matters is that the team knows before the day.

General anaesthetic: who it is for and what it costs you

General anaesthetic for cataract surgery is used for a small minority, typically people who cannot lie still or cooperate for the operation, and it is chosen because the surgery could not be done safely any other way rather than for comfort alone⁴. The situations that lead to it are specific: some people with dementia or a learning disability, severe tremor or involuntary movement, a persistent cough or breathing difficulty lying flat, profound deafness with no way to follow instructions, children and young people, and occasionally anxiety so overwhelming that sedation is judged unsafe or insufficient.

What it costs is a full anaesthetic day. Fasting, typically no food for around 6 hours and clear fluids only until around 2 hours before, a cannula, an anaesthetist’s assessment of your heart and lungs beforehand, a longer stay in recovery, a sore throat sometimes, and a wobbly afternoon. For an older person with heart or lung disease the extra risk is real, and it is the reason guidelines steer routine cases firmly towards local anaesthetic¹. If both eyes need surgery, needing a general anaesthetic each time is one of the recognised reasons a centre may consider doing both eyes in a single visit.

The operation under general anaesthetic is identical, and the outcome is identical: around 9 in 10 people achieve improved vision, assuming the eye has no other disease³. The eye does not know whether you were awake.

How the choice is actually made

The anaesthetic is decided at the assessment, by the surgeon and sometimes an anaesthetist, from a short list of practical questions: can you lie flat for half an hour, can you keep your head still, can you hear and follow instructions, how anxious are you, and what medicines and conditions do you have⁴. Nobody expects you to know which option you want. They expect you to answer those questions truthfully.

The things worth volunteering, because they change the plan, are: a neck or back that will not tolerate lying flat, a cough that will not settle, breathing trouble when horizontal, a tremor, claustrophobia, hearing loss, a previous bad experience under local anaesthetic, and any degree of fear that you think might make you flinch or grab. A tremor that seems trivial in the waiting room is not trivial with a microscope focused on your eye.

The list of questions in questions to ask before cataract surgery is worth taking in with you. Add this one: “Which anaesthetic are you planning for me, and what happens on the day if I find I cannot cope?” The answer, in most units, is that more anaesthetic can be added, sedation can be given, and in the rare case where none of that works the operation can be stopped and rebooked under a different plan. Knowing that beforehand takes a surprising amount of the fear away.

What I chose, and what I nearly asked for

I went into my first assessment fully intending to ask to be put to sleep. Anyone coming near my eyes had always made me shrink back, and the idea of lying awake while somebody operated on one seemed impossible. The nurse listened, told me that almost everybody says the same thing, and explained that being asleep was not on the table for a routine case like mine but that a sedative was there if I wanted it, and that plenty of people who ask for one in advance do not end up using it.

On the day I had the drops, no injection, and I never asked for the sedative I had rehearsed asking for. What steadied me was not bravery. It was the numbed tooth feeling that spread over the eye within minutes, the surgeon telling me exactly what I would feel before I felt it, the nurse’s hand, and the discovery that the bright light hid everything I had been dreading seeing. Twenty-odd minutes, as I have written elsewhere. The second eye, some weeks later, I walked in for with no plan to ask for anything.

I say this not to talk anyone out of sedation, or out of a block, or out of a general anaesthetic if that is what their surgeon judges they need. Those exist because some people genuinely need them, and there is no virtue in white knuckling through an operation you could have had calmly. I say it because the version of me sitting up at midnight would have wanted to know that the question I was most afraid to ask had an ordinary, kind answer, and that most people who ask it end up, as I did, needing rather less than they thought. The rest of the day is walked through in what happens on the day of cataract surgery.