Sara Wester, M.D.
Contributing Editor
Please check out our Dry Eye Treatment section for more information about the products mentioned in this article.
Dry eye syndrome is a common ocular problem that affects 10-15% of all adults. Causes of dry eye syndrome include decreased tear production, poor tear film quality, or excessive tear evaporation. Patients with dry eye syndrome can range from those with mild symptoms and minimal ocular surface disease to patients with severe and disabling irritation and the potential for sight threatening corneal complications. In the advanced stages, corneal calcification and band keratopathy may occur.
Several different treatment strategies are aimed at addressing the wide range of symptoms with dry eyes. While the use of artificial tears is helpful in some, in moderate and severe cases interventional treatment is often needed. Punctal plugs, which can be inserted into the lower or upper punctum, or both, have become a more common office procedure to treat patients with dry eye symptoms which do not respond to topical treatment.
There are several types of punctal plugs, which have different properties and uses depending on the material from which they are composed. They are commonly divided into punctal (or punctum) plugs, which are placed at the top of the puncta, with the tops visible and intracanalicular plugs, which are inserted into the canaliculus, and thus cannot be seen after insertion and need to be flushed out with irrigation for removal. In practice, both types are plugs are commonly referred to as “punctal plugs”.
Collagen implants are dissolvable punctal plugs that may be used as a trial to assess if occlusion will ameliorate the patient’s symptoms and to rule out intolerable epiphora due from occlusion before irreversible punctal occlusion is performed. They dissolve within 4-7 days and do not cause complete canalicular occlusion. They are available in a variety of sizes and from a variety of manufacturers (see below for list of some manufacturers). Collagen implants may be used as a trial of punctal occlusion prior to more permanent treatment, for temporary enhancement of topical medications, for post-operative reduction of dry eyes and in the assessment of the effect of aqueous tear deficiency on ocular surface disease.
Silicone punctal plugs come in a variety of shapes and sizes, and usually remain for several months to years unless they are manually displaced or are too loose at the time of insertion. Most are umbrella shaped with the “umbrella” portion of the plug resting on the eyelid margin at the punctum. The benefit of these plugs is that they are visible at the slit lamp and can be manually displaced. Of note, once a plug has been displaced from a punctum, subsequent plugs are more likely to be displaced from that punctum, and overdilation of the punctum should be avoided. There are several risks to the placement of silicone punctal plugs. The plugs can be advanced too deeply, causing inadvertent insertion into the nasolacrimal system, which necessitates surgical removal. Other risks of plug placement include the development of a pyogenic granuloma, canaliculitis, or dacryocystitis, although these are infrequent side effects. More common risks include spontaneous extrusion of the plug (which occurs in almost 40% of patients within the first six months), local irritation at the site of the plug, or epiphora which is intolerable to the patient. Excessive tearing is more common when both the upper and lower punctal are blocked. In cases of intolerable epiphora, the plug can be removed at the slit lamp.
There are several companies which manufacture both collagen and silicone punctal plugs, including Eaglevision, US-IOL, FCI Ophthalmics, Delta Life Science, Odyssey, Angiotech, Medenium, Lacrimedics, Oasis and others. While collagen and silicone plugs have been available for some time, newer technologies have developed such as the SmartPLUG (by Medennium), which uses a hydrophobic acrylic polymer and the Oasis Hydrogel Intracanalicular Long-term Plug, which uses a hydrogel material. These materials change shape when exposed to body temperature and tears, respectively, allowing them to reshape into soft, gel-like plugs that occlude the punctum. In addition, silicone plugs have been modified to have varying shapes and sizes, with some designed to regulate the lacrimal drainage for cases in which total occlusion may cause epiphora. The Herrick dissolvable plugs (from Lacrimedics) function as medium-term occlusion treatment, lasting approximately 4-6 months. They have the same indications as collagen implants, but a longer duration of action. They are made of polydiaxonone and are placed in the horizontal canthus similarly to intracanalicular collagen implants.
Treatment of dry eye syndrome with punctal plugs has evolved as the variety of plug types has expanded significantly. A decision regarding which plug to use is facilitated by an assessment of the indication, degree of the patient’s symptoms, desired length of effect, ease of placement and cost.
Please check out our Dry Eye Treatment section for more information about the products mentioned in this article.