Contact Lens Care & Compliance
Climate Changes, Pollen Production, and Contact Lenses
BY MICHAEL A. WARD, MMSC, FAAO
As I write this column, the southern United States is experiencing unseasonably warm temperatures (≥30° above normal) with associated weather events. What does this mean for contact lens wearers? We may be in for an early and elevated allergy season.
A mild winter can signify an early allergy season, with trees pollinating earlier. A late freeze can slow pollen production. Rain temporarily decreases pollen in the air, but a rebounding “bloom” can occur from the moisture, especially in winter. Allergy forecasting is challenging as it considers current and historical local data, weather conditions, freeze dates, and rain conditions (www.pollen.com/allergy-season.asp; Bangor University, 2015).
Pollens from grass species, which are highly allergenic and occur worldwide, elicit allergic responses in ~20% of the general population and 40% of atopic individuals. An increasingly important factor affecting pollen counts is carbon dioxide (CO2) levels in the atmosphere. Studies indicate that elevated levels of CO2 increased the amount of grass pollen produced by ~50% per flower, regardless of ozone levels (Albertine et al, 2014; acaai.org/allergies/types/pollen-allergy).
Pollens affect contact lens wearers in multiple ways. They are both physical (scratchy irritation) and immunologic irritants (hay fever or allergic rhinitis). Allergic rhinitis with associated allergic conjunctivitis is the primary immunologic consequence to seasonal tree pollens (Ward, 2013). For example, pine pollen is a bi-lobed vesiculate pollen grain with a rough-surfaced body measuring 50µm to 75µm. This is particularly irritating to corneal GP lens wearers.
Advice for Allergy Sufferers
To elimate or reduce symptoms, keep room humidity below 50% to inhibit mold growth; keep windows closed (high efficiency air filters and electrostatic air cleaners can remove pollen and dust); replace filters regularly and often; wear a mask, goggles, or close-fitting sunglasses if working outdoors during high-pollen conditions; shower immediately after outdoor exposure to remove pollens from clothes, hair, and skin; and wash face and hands often with cold water (cold compresses can help to relieve ocular itching).
Contact Lens Care
Here are specific recommendations for contact lens patients:
• Consider single-use (daily disposable) lenses, which allow wearers to throw away the lenses—and the allergens—daily, or shorten the replacement interval for reusable soft contact lenses.
• Instruct patients to rub and thoroughly rinse reusable lenses upon removal to reduce debris and contaminants on lens surfaces.
• Change to preservative-free peroxide disinfection systems if multipurpose solution sensitivity is suspected.
• Frequent use of low-viscosity, preservative-free artificial tears helps to dilute and rinse out irritants (Ward, 2011).
• Systemic antihistamines can help alleviate allergic symptoms, but can exacerbate ocular dryness. Topical decongestants should be used sparingly to avoid vascular rebound. Mast cell stabilizers are helpful if used proactively before symptoms occur. Combination drops seem to offer the greatest relief of allergic symptoms by combining the immediate antihistaminic relief with the prolonged effect of mast cell stabilizers. Topical antihistamines do not affect other proinflammatory mediators, such as prostaglandins and leukotrienes, which remain uninhibited (LaRosa et al, 2013).
• Avoid wearing lenses under severe conditions. CLS
For references, please visit www.clspectrum.com/references and click on document #243.
Mr. Ward is an instructor in ophthalmology at Emory University School of Medicine and Director, Emory Contact Lens Service. You can reach him at firstname.lastname@example.org.