Sunday, November 22, 2015

Eye Health: How to Choose an OTC Drop

The understanding of dry eye disease has advanced recently through increasing recognition that the etiology of the condition involves both tear evaporation[5] and insufficient tear production, and that tear film instability and inflammation play roles in the various stages of the disease.[1]
In this article, we will review over-the-counter (OTC) drops used for dry-eye symptoms from two perspectives:
  • What to consider
  • What to avoid

What to Consider


Artificial tears are eyedrops used to lubricate dry eyes and help maintain moisture on the outer surface of your eyes. They are available without a prescription. When choosing an OTC artificial tear to manage dry-eye symptoms, you need to know the underlying cause of your dry eye first. Based on that finding, you then consider other factors such as:
  1. Ingredients of the tear
    • Common artificial tear ingredients include tonicity, buffering, viscosity, wetting, and lubricating agents; antioxidants; and preservatives[7]
    • Good products should mimic the biphasic nature of tears by providing a lipid and an aqueous component to the tear
    • Consulting with your doctor to find if you have more of an aqueous deficiency, mixed disease or an evaporative form of dry eye, then make the decision
    • Choose products with lower osmolarity
      • May have a better effect on the ocular surface based on some studies
        • Tonicity agents adjust the preparation’s osmolality
    • Choose products with Osmoprotectants
      • Osmoprotectants L-carnitine and erythritol, alone or in combination, protect against stress activation of corneal epithelial cells cultured in hyperosmolar media
        • They are taken up by cells, and they blunt the response of the epithelial cells on the surface of the eye to high osmolarity in the tears.
  2. Severity of symptoms
    • Patients with mild dry eye
      • May prefer a watery drop like Refresh Plus
      • Problem with a watery drop
        • Sometimes they really don’t last much longer than three to four minutes
    • Patients with more severe dry eye
      • May prefer a thicker drop that stays on the cornea longer.
        • A thicker drop may decrease friction in the eye and lubricate the eye better
        • “For more severe dry-eye patients and for patients who have many erosions on their corneal surface, I would prefer a thicker, more viscous drop, such as Refresh Celluvisc or Systane Ultra preservative-free,” Dr. Latkany says.[2]
      • Problems with a thicker drop
        • It tends to blur the vision because they are gooey and sticky
          • Some people use them at night, but you can even have blurred vision for an hour or so after you wake up in the morning
        • It leaves more residual foreign particles in the eye
        • It allows allergens and other chemicals to stick to the tear film
    • High-risk individuals, postmenopausal females, patients requiring 4 or more drops of artificial tears per day, and patients with rheumatologic conditions
      • Should strongly be considered candidates for anti-inflammatory therapy.[6]

What to Avoid


“Self-selection of medications is not a good idea,” says Dr. Sheppard. “Invariably, when patients bring in their drops, they will be the Wal-Mart or Safeway brand of tears, which are by far the most inferior tears on the market.

Based on [2], here are the products to avoid:
  1. Topical vasoconstrictor like Visine
    • Which induces vascular fragility, rebound vasodilation and dependence upon the vasoconstrictor to maintain a quiet, white-looking eye.
  2. Artificial tears using preservatives such as benzalkonium chloride (BAK)
    • A recent study conducted at the University of Illinois at Chicago found that topical application of BAK to the eye causes:[2,9,10]
      • Corneal neurotoxicity[10]
      • Inflammation
      • Reduced aqueous tear production
Finally, heed the following advice:
  • After starting on an artificial tear, you needs frequent follow-up by eye doctors to determine whether the drop is relieving symptoms.
  • Avoid using drops too frequent
    • Patients were quoted to be using drops every 30 minutes or every hour, and this has a deleterious effect on their lifestyle and well-being.
    • Be warned that artificial tears are helpful as adjunctive agents, but that they are not the answer for dry-eye patients.
      • “None of these can come close to the complexity of our natural tears,” Dr. Latkany says.[2,13]

References

  1. Systane® lubricant eye drops in the management of ocular dryness
  2. OTC Drops: Telling the Tears Apart
    • Dr. Sheppard says. “The hydroxypropyl-guar in Systane provides an excellent matrix for the aqueous component of the tear. Refresh Optive Advance as well as Soothe from Bausch + Lomb provide a lipid substitute to better stabilize the tear film. Another valuable additive to over-the-counter tears is hyaluronic acid, which can be found in Blink tears from Abbott,” he explains.
  3. Sarkar J, Chaudhary, Namavari A, et al. Corneal neurotoxicity due to topical benzalkonium chloride. Invest Ophthalmol Vis Sci 2012;53(4):1792-1802.
  4. Corrales RM, Luo L, Chang EY, Pflugfelder SC. Effects of osmoprotectants on hyperosmolar stress in cultured human corneal epithelial cells. Cornea 2008;27:574-579.
  5. Effect of systane and optive on aqueous tear evaporation in patients with dry eye disease.
  6. DRY EYE SYNDROME
  7. Power Graphics. Common ingredients in artificial tears. 1999;3(1):1–2.
  8. I have dry eyes. What should I look for when selecting artificial tears? (Mayo Clinic)
  9. 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.
  10. Corneal Neurotoxicity Due to Topical Benzalkonium Chloride
  11. Dry Eye: Proper Administration of Artificial Tears (Travel to Health)
  12. Oxidative Preservatives and Dry Eye
  13. The Microscopic Structures of Dried Human Tears
    • Both tears of grief and joy are psychic tears, triggered by extreme emotions, whether positive or negative. Would a tear of grief look any different than a tear of joy?

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