BAK-free glaucoma medications may reduce toxicity-related ocular surface disease
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Glaucoma medications free of preservatives, such as benzalkonium chloride, may significantly reduce toxicity-related ocular surface disease, according to findings published in The Clinical Ophthalmologist Journal.
Aristeidis Chandrinos, PhD, and Dorotheos-Dimitrios Tzamouranis, MSc, observed the hidden links between glaucoma, contact lenses and ocular surface disease.
“The use of preservatives extends the shelf life of medications by far,” Chandrinos, of the department of biomedical sciences at the University of West Attica in Greece, and Tzamouranis, of the Investigative Techniques in Optometry Research Group in Greece, wrote. “Therefore, preservatives continue to be in widespread use in ophthalmic medications due to the convenience they provide, regulatory requirements and the higher cost of alternatives.”
The researchers determined that 70% of glaucoma medications contain the preservative benzalkonium chloride (BAK). BAK-related toxicity resulted in loss of tear film stability, direct damage to the cornea and conjunctival epithelium as well as the possibility for immune allergic reactions.
Chandrinos and Tzamouranis wrote that other types of preservatives may have reduced toxicity but are still irritating agents. The degree of side effects was based on the preservative concentration and duration of treatment.
The researchers stated that glaucoma patients experience a reduced quality of life in addition to decreased compliance in the use of anti-glaucoma medications.
As the elderly comprise the majority of patients with glaucoma, aging also increases the risks for dry eye disease, Chandrinos and Tzamouranis wrote. The use of the medication, plus the effects of aging and contact lens use, leads to serious multifactorial dry eye condition.
The researchers said that advice from the FDA suggested that patients who wear contact lenses wait at least 15 minutes following application of medicine before inserting the lenses. – by Earl Holland Jr.
Disclosures: The authors report no relevant financial disclosures.
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Andrew D. Pucker, OD, PhD, FAAO, FSLS
This review from Chandrinos and Tzamouranis described the interactions among dry eye, contact lenses and glaucoma medications. Glaucoma affects millions of patients around the world, and it is expected that this condition’s prevalence will increase with the rapid increase in the number of patients with conditions like myopia. While many patients can successfully manage their glaucoma with IOP-lowering drops, most glaucoma medications contain preservatives that have the potential to cause corneal toxicity and ocular irritation.
These signs and symptoms are especially common in patients who use drops containing harsh preservatives such as BAK. These negative issues can likewise result in decreased compliance. Preservative-free glaucoma medications do exist, although they typically cost more, which may be a barrier to patient acquisition. Nevertheless, this added cost may be warranted in contact lens wearers who tend to have more symptoms than nonwearers; the contact lenses themselves may also keep the preservatives on the eye longer and amplify the drop’s negative effects. Preservative-free drops may further benefit patients with ocular surface disease such as dry eye because research suggests that preservative-containing drops may amplify the dry eye-related issues such as destabilizing the tears.
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