lens practice pearls
Uncovering Causes of Contact Lens Associated "Dryness"
BY THOMAS G. QUINN, OD, MS, FAAO
The symptom of dryness during lens wear is perhaps the most common patient complaint. But are they suffering from true dryness? Here are a few great pretenders and how to identify them.
Lenses that move a bit too much or have a less than ideal edge may irritate the eye so subtly that we often see few signs to tip us off. In some cases the superior tarsal plate may develop papillary changes in response to excessive rubbing during the blink. These changes will be more localized than what you'll observe in response to allergy (Figure 1). Be particularly suspicious of mechanical issues if the patient is wearing a higher-modulus lens material.
Consider hypoxia-induced "dryness" if the patient is wearing a low-Dk/t lens. Besides looking for the obvious corneal signs of neovascularization, striae and microcysts, also look for a steady increase in myopia over time (myopic creep). Refitting these patients into a higher-oxygen material lens will provide relief.
Poor Surface Condition
When assessing lens fit, note the lens surface condition. An oily surface may result from use of lotions or handsoaps containing moisturizers or perfumes. Often reviewing proper hygiene habits can resolve this dryness complaint. We recommend that all patients rub, particularly those wearing silicone hydrogels, regardless of which system they use.
Figure 1. Mechanical papillary changes.
If lens fit looks good, the surface is clean and the patient is already wearing a lens of high oxygen transmissibility, consider the possibility of dryness symptoms induced by solution sensitivity. This irritation may result from solution incompatibility with the patient or with the lens material. The interesting paradox about this condition is that some patients will be symptomatic but show no slit lamp signs while others may show diffuse staining without comfort complaints. The key point here is to recognize that even though no physical changes may be observed, switching patients complaining of dryness into a hydrogen peroxide-based care system or a daily disposable lens will often resolve the problem.
Of course, some complaining of contact lens-associated dryness will have a true dry eye. Signs to tip you off include a thin tear prism, lissamine green staining, a rapid tear break-up time and low tear production measurements.
Explore systemic medications as a possible cause for low tear production. Ophthalmic medications such as Restasis (Allergan) may help. Another approach is to refit the patient into a "moisture retaining" material.
In the presence of poor tear quality, warm compresses and lid scrubs can help relieve symptoms. Oral agents such as doxycycline or minocycline may help emulsify the lipid contents of the lid glands. Tablets high in omega-3 oils may also provide relief.
Be a Detective
Discomfort, often in the form of dryness, is the leading cause of lens dropout. When managing a patient with this complaint, ask questions and perform a detailed slit lamp examination of the lens, eye and eyelid. This will reveal the true cause of irritation.
Dr. Quinn is in group practice in Athens, Ohio, is a diplomate of the Cornea and Contact Lens Section of the American Academy of Optometry and advisor to the GP Lens Institute.