Punctal Plugs: A Solution for Lens-related Dry Eye?
BY JASON J. NICHOLS, OD, MPH, PHD
Practitioners have used punctal occlusion therapy for many years to treat dry eye disease, especially of aqueous tear deficiency. The punctal openings of the lid margins are located in the medial canthi-thi at the apex of the lacrimal papillae. The punctal openings lead to the canaliculi, lacrimal tear sac and finally, into the nasal meatus.
Experts believe that tear film drainage is driven by the partial vacuum created as the lid margins begin opening after the blink, and up to two microliters of fluid can be lost through the puncta per blink. Other mechanisms of tear film loss include evaporation and conjunctival absorption.
Types of Therapy
Occluding the puncta is associated with an increased residence time of the "normal" tear film, which may reduce ocular surface desiccation and improve dry eye symptoms. Although punctal occlusion was probably used for years before, it was first described in the literature in the 1970s. Techniques include permanent occlusion (diathermy or cautery), and more temporary occlusions (punctal plugs.) Typically, a semi-permanent (up to 12 months) silicone plug or a temporary (up to three months) dissolvable collagen plug is inserted into the lower and/or upper puncta of the lids depending on disease severity.
Studies demonstrate not only improved dry eye symptoms associated with punctal occlusion, but improved tear film stability, ocular surface staining, conjunctival squamous metaplasia, osmolarity and goblet cell density.
One chart review study of patients with punctal occlusion for dry eye showed that within six months after initial plug insertion, 86 percent of patients were symptom free and 76 percent of patients stopped using daily lubricants.
Spontaneous plug loss was the most common problem; probability of plug retention was 63 percent after six months, puncta refit after loss were twice as likely to lose the replacement plug and upper punctal plugs were lost more than lower punctal plugs. Epiphora is also fairly common with punctal occlusion. As with most ophthalmic devices, there are more serious risks including ocular surface infections, dacryocystitis and canaliculitis.
Lens Wear and Dry Eye
What isn't well understood is the impact of punctal occlusion therapy on contact lens-related dry eye, which is one of the most common clinical entities of dry eye that practitioners face daily, with as many as 50 percent of lens wearers experiencing significant problems. Studies continue to show that after only a few years of lens wear, many patients drop out permanently because of dryness and discomfort problems. Many existing contact lens wearers experience these common and intense dry eye symptoms, which result in a decrease in comfortable wear time each day.
Contact lenses compromise the lipid layer of the tears, leading to increased tear evaporation. Induced aberrations, or visual distortions, which manifest as blurry or fluctuating vision, may also occur because of the changes in tear film properties.
A Promising Study
One initial study on the impact of punctal occlusion therapy in lens wearers showed a fairly significant (35 percent) increase in comfortable contact lens wearing time in the occluded eye (one eye was left unoccluded, but done so in a patient-masked fashion).
This result is promising, and should encourage practitioners to consider this therapy more often for patients who are interested in maintaining longevity of lens wear, although relatively few data exist on the use of punctal occlusion therapy in lens wearers.
Dr. Nichols is assistant professor of optometry and vision science at The Ohio State University College of Optometry.