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New Options in Punctal Occlusion

An array of punctal plugs is available for the treatment of dry eye.

Michael Beirne
Associate Editor

Figure 1. The Odyssey Medical Parasol Punctal Occluder automatically collapses like an umbrella, reducing its size by more than 50 percent. Its action can easily be reversed.

Clinicians agree that dry eye is on the rise and will only increase as the population ages. LASIK patients appear to be driving the increase, also. Punctal occlusion is the next best option when artificial tears aren't enough to control the symptoms of dry eye. Punctal plugs permit natural tears to immerse the eye and lessen or eliminate the necessity for eye drops. This treatment may be done on a temporary basis with a dissolvable collagen plug or permanently with a silicone plug. Here's a look at what's available and what may be on the horizon.

Getting Started

John Jarstad, MD, of Auburn, Wash., believes it's good to try all the various plugs and use what works best, depending on your coordination and skill with the product. “The sizes are variable and you need to become familiar with a few different types and stick with them,” he says. He stresses that newcomers to punctal occlusion should always start with punctal sizing devices until they become very familiar with the procedure and can accurately estimate the various punctal diameters behind a slit lamp. A plug that is too large for the punctum will be difficult to insert, while a plug that's too small may automatically extrude.

Plugging Away

Manufacturers are focusing on design innovations that address both safety and comfort. According to Donald MacKeen, MS, PhD, of Bethesda, Md., original silicone plugs provided the benefit of reversibility not available from cautery but posed difficulties in insertion, loss and patient discomfort. Dr. MacKeen, the founder of the Dry Eye Institute, is a former pharmacology and biomedical engineering professor at Northeastern University in Boston.

Companies have also stepped up their focus on sterile delivery systems and extended-duration collagen plugs. A new twist is also in the works: a heat-responsive polymer material that is inserted into the tear duct opening as a liquid and solidifies within seconds to conform to the shape of each individual's tear duct.

Dr. Jarstad has been using Odyssey Medical's Parasol Punctal Occluder small-size, soft, silicone plugs for three years. The plugs are available in three sizes, with the small and medium's fitting 95 percent of patients. Upon contact with the punctal ring, the Parasol automatically collapses like an umbrella, reducing its size by more than 50 percent (See Figure 1). Dilation of the punctum is often unnecessary. Dr. Jarstad feels the Parasol's sharper tip and push-button inserter make it the easiest plug to insert. Once inserted, the plug opens like an umbrella to conform to the size of the canaliculus. The company says the near-customized fit resists accidental removal.

Dr. Jarstad places several drops of proparacaine near the punctum before dilating it slightly with the inserter's punctal dilating end. “I have the patient look up slightly, and I put the lower lid on a slight horizontal stretch before inserting,” he says. If the Parasol needs to be removed, its action is reversed, and it slides out smoothly. He feels that some of the stiffer plugs are very difficult to insert and have an uncomfortable top. A very good pair of fine jeweler's forceps is essential to making an easy insertion of the temporary collagen plugs, he adds.

Lacrimedics designed its original non-dissolvable Herrick Lacrimal Plugs to be inserted in one step through the vertical canaliculus and into the horizontal canaliculus. Robert Herrick Jr., company president, says proper placement all but eliminated the chance of “pop-out” and the chance of a corneal abrasion from the cap. That deep placement, however, meant that, once they were in place, they were not readily visible at follow-up visits. In response, Lacrimedics recently introduced its intracanalicular non-dissolving plug, the Opaque Herrick Lacrimal Plug. The opaque feature allows for simple transillumination of the eyelid to confirm the presence and location of plugs after insertion. Transillumination can also help during plug removal to help visualize the movement of the instrument and the plug, or to confirm the plug's absence months after the procedure.

Lacrimedics offers the Lacrimal Occlusion Starter Kit. You'll be able to test up to 12 patients with dissolvable collagen plugs, and treat up to three patients with the original, non-dissolvable Herrick Lacrimal Plugs.

Alcon says its Tears Naturale Silicone Plugs feature a clear, soft silicone with a low-profile silicone cap also designed for decreased lid awareness. The preloaded inserter, with a built-in dilator, provides for a controlled release.

The silicone Soft Plug from Oasis has a pointed nose for ease of insertion and a wide anchor to fit more securely. The plugs are designed with a soft silicone that easily and readily conforms to the punctum, and is more comfortable for the patient. The company advocates its 0.4-mm Micro Soft Plug in the superior puncta when minimal tear flow reduction is needed.

FCI Ophthalmics says its Ready-Set Punctum Plugs feature a slanted collarette, which allows the plugs to respond to the natural anatomy of the eye and hug the eyelid. They come pre-loaded on a disposable inserter/dilator. The bigger bulbs prevent extrusion. FCI's Slim Line plugs feature non-slanted collarettes that the company recommends for superior and small posterior puncta from 0.5 and 0.6 mm. Atlanta's Stephen Hamilton, MD, has tried two brands of plugs in his own eyes and prefers the Slim Line plug. He says they require little or no punctal dilation and offer a slightly smaller bulb for easier insertion.

FCI's Ready-Set PVP Perforated punctum plugs were developed to keep a stenosed punctum open when simple probing is not enough to allow proper tear drainage. These plugs come in one size, 0.9 mm in diameter, with a 0.6-mm perforation to ensure fluid flow. PVP (polyvinalpyrrolidone) is a thin coating on the medical silicone that prevents debris from collecting on its surface.

CIBA Vision's TearSaver Plug incorporates tapered-shaft technology that creates a downward vector force in the canaliculus while securing it within the punctal opening. The company says this reduces the rub-out risk sometimes found with the straight shaft design of other plugs.

Figure 2. CIBA Vision’s Bio-Insulated Punctum Plug after insertion. The cap portion resting on the lid was designed with rounded contours.

CIBA introduced the Bio-Insulated Punctum Plug in March. The plug features a patented Hydrograft surface coating that provides a barrier between the eye tissues and the silicone plug material. CIBA says the plug's smoother surface may have some advantages over the coarser surface of a silicone plug by reducing long-term tissue irritation and providing a surface less prone to capturing bacteria. The cap portion resting on the lid was designed with rounded contours and a very low profile to minimize interference with blinking or contact with the cornea (See Figure 2).

EagleVision's FlexPlug features a ribbed interior and exterior shaft of the plug. EagleVision says this makes it easy to find and manipulate, while providing approximately 30-percent more surface area. You can bend the plug so that the collar is at a 90-degree angle to the point. It can be compressed or stretched to about one-fifth of its resting length.

Each of the firms mentioned in this article offer a set of sizing gauges. For example, FCI's Punctal Gauge/Dilator Set features a gauge tip on one end and a specially calibrated dilator on the other end to fit the corresponding plug. In this case, the properly sized gauge is the largest one that fits through the punctum ring with a minimum of restriction.

According to Odyssey Medical's director of sales, Ray Wallace, the Odyssey Shuttle System has temporarily been put on the shelf while engineers make improvements to enhance the consistency of the insertion instrument. The system, which was introduced last spring, was designed to cut in half the cost of using plugs. It includes a reusable, sterilizable inserter and a disposable sterile capsule containing a punctum plug.

“Maybe one shuttle cartridge out of 20 would not perform the way that it was supposed to,” says Mr. Wallace. “Since it was a new product introduction and because Odyssey has received tremendous response from our sterile preloaded plugs and our bulk, non-sterile plugs, we decided to make the necessary improvements now.” Mr. Wallace says Odyssey will continue to service existing Shuttle System customers and maintain a waiting list for the product while engineers make the necessary adjustments.

Figure 3. Dilation in preparation of punctal occlusion (left). On right, insertion of CIBA Vision’s Bio-Insulated Punctum Plug.

What's Ahead
Dr. Jarstad feels the future of punctal occlusion is a gel-type punctal plug that will conform to the patients lacrimal anatomy and will be in an intermediate range of duration of action. “It may dissolve over three months' time and also provide a time-released lubricant artificial tear,” he says, “kind of a dual-action occluder and moisturizer.”

Along those lines, Edward E. Schmitt, PhD, who has spent years working with polymers for ophthalmic applications, developed the PORT (Punctal Occluder for the Retention of Tears) device for California-based Landec Corp. The company's temperature-activated Intelimer polymers can be customized to change their physical characteristics abruptly when heated or cooled through a pre-set temperature switch. The PORT system involves liquifying a gel with gentle warming and injecting the fluid into the punctal openings where the lower temperature of adjacent tissue causes it to gel. You can remove the plug with gentle warming of the adjacent lid area.
Landec licensed the rights to the PORT device to Alcon, which hopes to market it upon U.S. Food and Drug Administration approval. Landec will be the exclusive supplier of the Intelimer polymer material to Alcon.

Dr. MacKeen says the moldable canalicular occluder will be the optimal method of reversibly blocking tear outflow, giving you the ability to customize the plug to the patient's eyes. He feels that a plug conforming to the shape of the canaliculus could easily stay in place for an indefinite period. “The only problem I can envision is an abnormal canalicular distension resulting from excessive instillation pressure of the liquid phase,” he cautions.

Takashi Hamano, MD, of Japan has also patented a solution formulation for punctal occlusion. Dr. MacKeen says this is a liquid consisting of gelatin, agarose, a mixture of fibrinogen and thrombin, a polysaccharide and a calcium salt, which gels when injected into the punctal opening because of the warmer temperature of the adjacent canalicular tissues. No marketing plans are set for this plug yet.

Although no data has been published on these two new methods of punctal occlusion, Dr. MacKeen says he has been told that both of these new plugs have been found to conform to the canaliculus, they do not migrate distally or proximally, and no material protrudes from the punctal opening.

The newer punctal plugs may also have additional ophthalmic applications beyond dry eye. EagleVision says its Eagle Plug Flow Controllers, available from 0.4 mm to 0.8 mm, retain ocular medications and the anti-infective capacity of natural tears' enzymes for pre- and post-surgical indications. Punctal occlusion can increase drug contact time and decrease systemic absorption, making topical treatment more effective. EagleVision says its flow controllers slow the flow of lacrimal fluid through the punctum and canaliculus. Many of these firms are targeting contact lens wearers having trouble with limited tear fluid retention.