Saturday, November 21, 2015

Dry Eye: Proper Administration of Artificial Tears

According to the the Dry Eye Workshop report, prevalence of dry eye ranges from 5–30% in people aged 50 years and older.[1]

The management of dry eye involves various strategies and therapeutic approaches, which include:
  • Find out the underlying cause of the dry eye[10]
  • Select a good and affordable OTC drop[11]
In addition, proper administration of dry eye medications remains vital to a successful treatment.

Preservative-Free Eye Drops


Artificial tear formulations are typically buffered solutions that contain electrolytes, surfactants, and one or more viscosity agents or lubricants, and may or may not also contain a preservative.[1]

However, for long-term usage of eye drops, you may want to avoid artificial tears using preservatives such as benzalkonium chloride (BAK).  Why?  Based on a recent study conducted at the University of Illinois at Chicago, scientists have found that topical application of BAK to the eye may cause:[5-7]
  1. Corneal neurotoxicity[7]
  2. Inflammation 
  3. Reduced aqueous tear production

Recommended Ways of Product Use


In the following discussions, we will focus on two areas:
  1. Different forms of artificial tear preparations — liquids, gels, or ointments
  2. Preservative or preservative-free drops

For optimizing benefit from ophthalmic medications, here are the recommended way of product usage:
  1. General instructions
    • If using two different types of eye drops, instill the first, wait 5 minutes, then instill the second.
    • If using drops and ointment, instill the drop first, wait 5 minutes, then apply ointment.
    • When using products in single-use vials, agitate the container so that the color and/or opaqueness of its contents are uniform. 
  2. Preventing contamination
    • For patients who need to instill artificial tears several times daily, larger containers of medication are desirable
      • British researchers observed that patients who frequently apply eye drops may need to carry multiple single-dose containers, which are cumbersome.[2] They also recognized that purchasing single-dose containers can be more than 1,000 percent as expensive. 
    • If you want to save remaining medication for use beyond the first day, then consider:
      • Dry eye medications have been tested and scientists have found that they remained uncontaminated when exposed to room air for as long as 28 days
      • However, to reduce the risk of infection to a level with which we are relatively comfortable.  Here are what Dr. Perry and Dr. Donnefeld have advise their patients:[3]
        • Preservative-free artificial tears are free of contamination the day they are opened, are probably not contaminated on the second day, but are likely contaminated on the third day and must be discarded
    • Wash hands before opening container
    • Prevent container tip from touching the eye
    • When finished, tighten container cap
    • Single-use vials should be used immediately after opening and discarded after use
  3. Eye Drops
    • Instilling instructions
      • Lean head back. 
      • Instill eye drops by gently sliding skin below eyelid over prominent point of cheekbone to form pocket. 
      • Put one drop into pocket. 
      • Close eye and refrain from blinking for about 1 minute. 
      • Press tightly (but not tightly enough to cause injury) with one finger on inside corner of eye for about 30 seconds after instilling drop. 
      • Use only 1 drop at a time.
        • The eye’s conjunctival fornix can accommodate only 1 drop at a time. Any fluid beyond 1 drop will overflow. 
  4. Ointment
    • Application instructions
      • Start at inside corner of eye
      • Squeeze thin line (about 0.5 cm) of medication along inside of lower lid
      • Blink
    • Artificial tear ointments may offer longer lasting relief but may cause blurred vision and, as such, may work best just before bedtime.

References

  1. An Overview on Dry Eye Treatment: Approaches for Cyclosporin A Delivery
  2. Eye Health: How to Choose an OTC Drop (Travel to Health)
  3. Oldham GB, Andrews V. Control of microbial contamination in unpreserved eyedrops. Br J Ophthalmol. 1996;80:588–591.
  4. Issues in the UseOf Preservative-Free Topicals
  5. OTC Drops: Telling the Tears Apart
  6. Becquet F, Goldschild M, Moldovan MS, et al. Histopathological effects of topical ophthalmic preservatives on rat corneoconjunctival surface. Curr Eye Res. 1998;17:19-25;410–425.
  7. Corneal Neurotoxicity Due to Topical Benzalkonium Chloride
  8. "Help Improve Your Vision with Simple Exercises" (Dr. Mercola)
  9. How to Get Rid of Dry Eyes Naturally
  10. How do I soothe dry eye symptoms?
  11. Eye Health: How to Choose an OTC Drop (Travel to Health)

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