About those eye drops at the clinic

The drops are the part of the appointment nobody warns you about. You arrive expecting a quick look at your two year old's eyes, and instead a nurse tips his head back, puts something in both eyes, hands you back a furious child and tells you to come back in half an hour. That half hour, in the corridor, with a toddler who has just decided you are the enemy, is where most of the questions in this article get asked.

So here is the whole thing in advance, which is where it belongs.

Why do they have to put drops in? Can't they just look at her eyes?

Not properly, no, and the reason is your child's own pupil. The moment a bright light is shone at an eye, the pupil shrinks. That is the eye doing exactly what it should, and it is also a door closing on the very thing I am trying to look through. Without drops, I am attempting to inspect the whole back of the eye through an opening the size of a pinhead, from across a moving toddler.

The drops open that door. A large pupil lets me see the inside of the eye, the parts sitting behind the coloured iris, which is where a great many childhood eye conditions either show themselves or rule themselves out. There is no clever way around it. If the appointment is about anything more than measuring how well your child sees, the drops are the appointment.

Is it one drop or two, and do they do different things?

Two different jobs, often given as two drops, sometimes as a single combination drop, sometimes as a spray. One type makes the pupil bigger. That is dilation, and it is the one that opens the view. The other relaxes the eye's ability to focus, which is called cycloplegia, and it is the one that matters for glasses.

Both together are the standard for examining a child. It is not two attempts at the same thing, and it is not the nurse being thorough for the sake of it.

Why do drops matter just for checking glasses?

Because a child's focusing muscle is strong enough to hide the truth. Children can focus far harder than adults can, and they do it without noticing. A long-sighted child will strain that muscle all day long and measure as perfectly normal on a test, while quietly working much harder than any child should have to just to see the page.

Relaxing the focusing muscle with drops is the best way to check whether a child actually needs glasses. Switch the muscle off and the eye can no longer compensate, so what I measure is the eye's real focusing power rather than the version your child is propping up. That hidden long-sightedness is a common cause of both a turning eye and a lazy eye, so this is not a technicality. It is the number that decides whether your child is prescribed glasses and how strong they are. A reading taken without drops on a four year old can look reassuringly normal and be wrong.

Do they hurt?

They sting for a few seconds. I am not going to tell you otherwise, because your child will find out in about ten minutes and then neither of us will be believed again. Like most eye drops, there is stinging right after the drop goes in, and it usually lasts only moments. Then it is over, and the crying that follows is mostly about having been held still.

A numbing drop can be given first to reduce that sting, but it is not automatically an improvement, because the numbing drop can sting on its own. That decision belongs to the clinic on the day, not to a plan you make in advance. What genuinely helps is telling your child, plainly and briefly, that it will sting a little and then stop. A child who has been promised nothing will happen and then feels a sting stops trusting everything else you say that morning. If getting a drop into your child is itself the battle, the method that actually works is worth practising at home before the appointment rather than learning in a clinic corridor.

How long will his eyes stay blurry?

Longer than most parents expect, and this is the single most useful thing to know before you plan the day. Near vision goes blurry, and that usually lasts anywhere from four to twenty four hours. Light sensitivity and that close-up blur are the common side effects, and they typically ease over four to six hours.

The pupil itself can stay large longer than the blur lasts, and in a child with lighter coloured eyes it can stay dilated for one to three days. Children also get stronger drops than adults for the glasses measurement, precisely because their focusing muscles are so strong, so everything above tends to run longer in a child than in an adult. Bring a hat or sunglasses for the trip home. Sunlight in a hospital car park at noon, through a pupil that cannot close, is genuinely uncomfortable.

Can she go back to school that afternoon?

Usually yes, with one message to the teacher: she will not be able to read properly for the rest of the day. That is the part schools do not expect, and a child who suddenly cannot see her worksheet can look like a child who is being difficult. A quick note in the communication book solves it.

At home, plan the afternoon around near work being impossible rather than around a child who is unwell, because she is not unwell. Homework is a bad idea. Running around outside is fine, though brighter than she would like. Reading, colouring and small print on a screen will all be frustrating. Most children are back to normal by the next morning, and occasionally the blur carries into the following day. If your appointment is at a government hospital eye clinic, factor the drops into the timing as well: they need time to work before the doctor can start, which is a large part of why that visit takes as long as it does.

Why are his pupils different sizes, and why did his face go red?

Both of these look alarming in the car park and both are known effects of the drops. Unequal pupils after dilation are common, simply because one eye takes the drop better than the other. It is not a sign that something has gone wrong, and it evens out as the drops wear off. What would be different is a pupil difference that appears out of nowhere on an ordinary day, with no drops involved, which is worth a proper look.

The flush is the other one. The stronger, longer acting dilating drop can cause a red face, a dry mouth, a fever and a fast heartbeat. That is a recognised effect of that particular drop rather than a mystery illness, and it is still worth telling the clinic about, both so they can reassure you and so it goes in your child's notes for next time. Rare allergic reactions to dilating drops do happen, and they show as swollen eyelids and red eyes. Also worth knowing: weaker drops are used for premature babies and for children with a history of seizures, so those wear off faster.

I will not tell you which drug or which strength your clinic uses, because that varies and it is theirs to decide. What I will say is that the question is a fair one. Ask what was given, ask how long they expect it to last in your child, and write the answer somewhere, because next year you will want it. The rest of the examination is gentler than the drops, and by then the hardest part of the morning is already behind you both.

Common questions

References

1. AAPOS · Dilating eye drops · aapos.org
2. American Academy of Ophthalmology · Procedures for the evaluation of the visual system by pediatricians · www.aao.org
3. American Academy of Ophthalmology · Vision screening for infants and children, clinical statement 2022 · www.aao.org
4. American Academy of Ophthalmology · Eye screening for children · www.aao.org
5. Medicines for Children (RCPCH) · How to give medicines: eye drops and eye ointment · www.medicinesforchildren.org.uk

By Dr Chan Li Yen. General information only. It does not replace a consultation. If you are worried about your child's eyes or vision, please see an eye doctor.