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Improper Use of Eye Drops May Bring Harm Rather Than Relief - CHOICE # 430

  • 2012.08.15

For some people, getting relief for red and dry eyes can be as simple as putting in a few eye drops, but self medication can be a problem without prior medical consultation or instructions.

It may result in a delay in medical care, which may in turn lead to visual impairment or blindness, as shown by the following cases.

Case 1
A contact lens wearer used an eye drop for red eyes as artificial tears to help relieve eye irritations. Though the eye drop was able to shrink the red vessels in the eyes, but the temporary resolution of eye redness had in turn masked the cause of the problem, the ill-fitting lenses, which finally led to a delay in medical treatment.

Case 2
An elderly lady suffered a ruptured eyeball after using for weeks an eye drop, which she bought over-the-counter with alleged claim to "remove redness" in the eyes. After the diagnosis, it was believed that the ruptured eyeball was associated with the patient's overuse of steroid eye drops, which led to thinning of the cornea and rise of intraocular pressure that eventually led to its rupture.

Case 3
A 5-year old boy was prescribed some eye drops and ointment for itchy eyes after visiting an ophthalmologist. With the marked progress of the boy after taking the drug, his father increased the daily dosage without seeking medical opinion. Later the boy experienced eye discomfort and his father took him to another optometry clinic, where the boy was found to have eye pressure up to 30-40 mmHg, and his cornea was swollen with bumps and dents. The boy was later referred to an ophthalmologist for further check up, and the doctor pointed out that the high intraocular eye pressure was caused by an overdose of steroid eye drops.

According to the Drug Education Resources Centre of the Society of Hospital Pharmacists of Hong Kong, long-term misuse of steroid eye drops can lead to serious effects like cataract, glaucoma, thinning of the cornea and increased risk of eye infection.

Consumers should avoid changing the prescribed frequency of administration or dosage without consulting the doctor. Steroid eye drops should be purchased on prescription and used according to instructions issued by medical doctors.

Meanwhile, the Consumer Council has examined the product information of 16 over-the-counter eye drops available in the market, most of which are products that serve to soothe and moisten the eyes, reduce redness and alleviate allergy symptoms.

Of these, 11 eye drop samples listed the use of preservatives - mostly benzalkonium chloride - while 3 samples indicate that the products are preservative-free.

The remaining 2 samples of eye moisturizers did not indicate whether the products contain preservatives, but in response to the enquiries from Consumer Council, the companies confirmed that the products do contain preservatives (one contained benzalkonium chloride and the other alkyldiaminoethylglycine hydrochloride).

According to Department of Health, the existing guidelines on the labeling of registered pharmaceutical products require sterile pharmaceutical products to label their preservatives, if any.

The two samples concerned did not come with registration number of pharmaceutical products and the Consumer Council had referred the cases to the Department of Health for further study. The Department's initial findings showed that the two products did not contain active pharmaceutical ingredients, so they were likely not classified as pharmaceutical products.

The information on whether the eye drops have contained preservatives is deemed crucial for consumers as preservatives can be potentially toxic to the eyes, causing dryness and irritations to the cornea. The symptoms may be worsened if the cornea had been damaged due to dryness.

For contact lens wearers, preservatives like benzalkonium chloride may cling to the lens surface and become a source of irritant. Some products in the study with the preservative have carried warning labels, advising consumers not to put eye drops in the eyes when wearing the lens.

Consumers are advised of the following when using eye drops:

  • Consult healthcare professionals even if one can buy over-the-counter eye drops or lubricants without a prescription, as it would be the best way to get the right remedy for the problem.
  • Take off the contact lenses when applying eye drops, and wear only the lenses 15 minutes after using an eye drop with the preservatives.
  • Check the expiry date for eye drops. Do not use the eye drop when it has already expired or changed colour, and it must be disposed one month after being opened (or as suggested by product insert).

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