Allergens in ophthalmic medicaments in New Zealand

Eyelid allergic contact dermatitis (ACD) attributed to ophthalmic medications is often underreported, which can result in poor outcomes. Patch testing for eyelid ACD requires up-to-date knowledge of potential allergens. The aim of this study was to investigate allergens in ophthalmic medicaments in New Zealand.

We conducted a cross-sectional review of ophthalmic medicaments available in New Zealand in October 2023. Prescription and over-the-counter products were catalogued with their respective ingredient lists according to product data sheets. Products unapproved for use as per Section 29 of the Medicines Act 1981, or that were unavailable for purchase were excluded. Ingredients were classified according to their function. Allergens in the New Zealand Baseline Series Extended (NZBSE) were recorded.

Seventy-three topical ophthalmic medicaments were identified with a total of 143 formulations (brands). Twenty-eight formulations were excluded, leaving a total of 67 topical medicaments (115 formulations) for analysis. Fifty-eight per cent of formulations contained at least one NZBSE allergen. The most frequently identified NZBSE allergen was benzalkonium chloride (contained in 48% of formulations), followed by propylene glycol (6%), lanolin (4%), parabens (4%), caine anaesthetics (2%), neomycin sulphate (2%), and cetearyl alcohol (1%).

The majority of ophthalmic preparations contain known allergens. Patch test series must be based on local data and revised regularly to ensure the diagnostic accuracy of patch testing. Patch testing patient's own products is imperative.