Myopia Profile


Atropine eye drops and ocular allergy - what's the cause?

Posted on June 25th 2020 by Connie Gan

Sponsored by


In this article:

A child has an allergic reaction to low dose atropine - or does he? Here practitioners consider the possible causes, with advice for management.

When ocular allergy occurs with low-dose atropine use, how should it be managed? Curious as to whether other clinicians have experienced a similar case, PC posted a photo of a child with red eyes after 2 weeks use of low-dose atropine on our Facebook discussion group.

PC Has anyone come across this level of allergic conjunctivitis with low-dose atropine? Onset about 2 weeks after starting treatment. Cleared up well with FML over the weekend. Child not usually atopic and no history of red eyes like this. Could be a coincidence though, of course.eyes.jpg

What are the considerations?

Patient history and use of other medications

LM More like related to adenovirus than allergy for me. Any history of cold or other respiratory infections?YC … Some eyedrop can cause this special redness pattern. Could ask your patient whether he was using Gentamicin eye drop?

The key message here is to check for history of recent health issues or other eyedrops used to rule out other possible causes of the red eyes.

Potential causes of allergic reaction

YC More like drug allergy for me because the redness is in the lower part of conjunctiva where the drop can pool around. Allergy to atropine is possible but more often allergy to preservative should be consider. Could try switching to non-preserved atropine eyedrop to distinguish the allergy source.MP Did you see the diffuse staining associated with medicamentosa? The dose is so small including the preservative but it could happen I suppose…SD Yes I have seen this type of reaction to the BAK in low dose atropine in a few patients. It happens pretty quickly, usually within the first month or so, and all of them did have other seasonal type allergies. But as soon as we went to non-preserved, it went away.
  1. Allergic reaction to preservative
    Many suggested the allergic reaction is due to preservative toxicity. The type of preservative and its concentration can affect the extent of allergic reaction. Some suggested to contact the compounding chemist to confirm the concentration of atropine and any preservatives used in the drops that were dispensed to the patient. Benzalkonium chloride (BAK), thimerosal and chlorobutanol are the common preservatives1 in multidose topical eye drops which can be associated with ocular hypersensitive reaction manifested in the forms of ocular dryness, ocular surface damage, blepharitis and contact dermatitis.2 The next logical step is then to ensure that non-preservative atropine is dispensed to the patient.
  2. Allergic reaction to atropine
    Whilst uncommon, this is still possible. Kothari et al3 describes the common signs and symptoms of allergy to atropine to be itching, burning, periocular redness and eyelid swelling. However, these reactions were not limited to those on preservative-free formulations. They found that the severity of this response was correlated with concentration of atropine echoing the findings in the ATOM2 study4 whereby allergic conjunctivitis and dermatitis was noted in the 0.1% and 0.5% group, and none in the 0.01% group. The LAMP study reported 'occurrence of allergic conjunctivitis being similar among all groups' indicating no difference in rates between the placebo, 0.01%, 0.025% or 0.05% formulations.5

Communicating with compounding pharmacies

KG … If it’s a potential preservative allergy it’s worth at least a discussion with the pharmacy.SD … It does not surprise me to see reactions to BAK. I wish there were an alternative preservative but that is the only one that I have found that compounding pharmacies use for low dose atropine. But how much they put in is up to their own formulation, so perhaps you can call and see what % BAK they used.MP Call up the chemist and see if it’s already non preserved. I know some will dilute down from the 1% which is already preserved and then it too will dilute down, while others make it from scratch and still stored in a dropper bottle but non preserved…

Some have suggested calling compounding pharmacies to understand their formulation of these drops. The aqueous base, amount and type of preservatives (if any) may vary between pharmacies, so it is useful to understand which other non-active ingredients are going into the drops that are ultimately dispensed to the patient.

Take home messages

  1. Consider other differential diagnoses - in this case viral conjunctivitis or another medication toxicity was suggested.
  2. It is more likely for a patient to be allergic to preservatives than atropine. As atropine is prescribed in such low concentrations for myopia control, this makes the case for a reaction to atropine quite unlikely.
  3. Ensure that the patient is dispensed a preservative-free formulation to avoid potential long-term effects of preservative toxicity.
  4. Get familiar with the ingredients (and any preservatives) used in formulations at your local compounding pharmacies.
  5. Communicate the symptoms to watch for with potential allergic reactions to the patient and parents, to avoid any nasty surprises down the road.

Read our six-part blog series on atropine

When to prescribe Atropine for myopia control
Complex Atropine Cases
Complications in atropine compounding

Systemic Side Effects Of Atropine Eye Drops

The Latest And Greatest Research On Atropine

Check out this additional clinical case

Which atropine dosage should I prescribe for myopia control?

You can also listen to our three podcasts on atropine with world-leading researchers

  1. Atropine, engaging with science and responsible practice with Professor Karla Zadnik from Ohio State University, USA. (link)

  2. More on atropine 0.01% treatment for myopia management with Professor Mark Bullimore from the University of Houston, Texas USA. (link)

  3. Atropine 0.01% for myopia management with Professor James Loughman from Technological University Dublin, and the Centre for Eye Research Ireland. (link)

Meet the Authors:

About Connie Gan

Connie is a clinical optometrist from Kedah, Malaysia, who provides comprehensive vision care for children and runs the myopia management service in her clinical practice.

Read Connie's work in many of the case studies published on Connie also manages our Myopia Profile and My Kids Vision Instagram and My Kids Vision Facebook platforms.

About Kimberley Ngu

Kimberley is a clinical optometrist from Perth, Australia, with experience in patient education programs, having practiced in both Australia and Singapore.

Read Kimberley's work in many of the case studies published on Kimberley also manages our Myopia Profile and My Kids Vision Instagram and My Kids Vision Facebook platforms.

This content is brought to you thanks to unrestricted educational grant from

Back to all articles

Enormous thanks to our visionary sponsors

Myopia Profile’s growth into a world leading platform has been made possible through the support of our visionary sponsors, who share our mission to improve children’s vision care worldwide. Click on their logos to learn about how these companies are innovating and developing resources with us to support you in managing your patients with myopia.