contact lens care
Beware of Side Effects from Generic Artificial Tears
BY MICHAEL WARD, MMSC, FAAO
In May, I discussed commercially available contact lens rewetting drops and suggested that certain preservatives may create complications. I've recently seen more patients suffering from contact lens-associated keratitis after using generic brands of artificial tears. The following case report is typical of this artificial tear-related complication.
A 24-year-old female presents complaining of dryness and reports "a scratchy irritation along with a mild redness," which has worsened over the last two months. Her contact lens-wearing time has decreased from all day to between five and six hours each day. She is experiencing mild photophobia and denies sleeping in her lenses.
This patient has been a successful soft contact lens wearer for the past five years. She changes her lenses quarterly; the current pair is two months old. Her lens care system is UltraCare (Advance Medical Optics), which hasn't changed in five years.
When asked about eye drops, she admits to using artificial tears occasionally, but with increasing frequency since the irritation began. She reports that she's now using over-the-counter artificial tears four to five times each day, OU. She buys the least expensive brand of artificial tears to use with her lenses "because they are all alike." Her current bottle is the Publix store brand. The following ingredients are listed on her Publix brand artificial tears bottle: Dextran-70 0.1%, hydroxypropyl methylcellulose 0.3% and the preservative benzalkonium chloride 0.01%.
Slit Lamp Evaluation reveals mild guarding ptosis, well-fitted soft lenses along with a mild ciliary injection. Fluorescein dye staining reveals diffuse corneal punctate epitheliopathy with some grey epithelial roughening.
I made a presumptive diagnosis of toxic keratitis and instructed the patient to stop all contact lens wear, and told her specifically to use nonpreserved artificial tears only. She was to use nothing else, including eye area make-up.
At the patient's follow-up visit one week later, all corneal staining had resolved and only a mild grey epitheliopathy remained. The patient returned to successful contact lens wear two weeks later with new lenses and her original lens care regimen.
Publix and other brands' preserved artificial tears aren't labeled for use as contact lens rewetting drops. But who reads labels? Your patients may not realize that there's a difference between artificial tears and contact lens rewetting drops.
Some artificial tear brands are preserved with benzalkonium chloride (BAK), which is contra-indicated for use with contact lenses. BAK binds to and is concentrated in soft lens polymers. Its later release onto the ocular surface causes a toxic event. BAK interferes with cellular mitosis, slows epithelial healing and can cause a toxic keratitis when used over soft lenses and GP lenses.
Emphasize Your Instructions
Eyecare practitioners should regularly question patients regarding their lens care practices. You should caution your patients not to alter your instructions or to change brands without first checking with your office.
Mr. Ward is an instructor in ophthalmology at Emory University School of Medicine and Director, Emory Contact Lens Service.