occlusion
Occlusion: ASSESS YOUR OPTIONS
A careful approach to treatment of severe dry eye syndrome will lead to better results.
BY C. STEVEN LANCASTER, O.D., Jacksonville Beach, Fla.

Treatment of dry eye syndrome (DES) continues to be a significant clinical challenge to most of us on a daily basis. While punctal and intracanalicular occlusion can be excellent treatments for DES, we must resort to them only after completing the following critical steps.

Proper diagnostic testing is essential to the success of any mode of treatment. This should also include a thorough case history with an in-depth interview of the patient. Understanding the patients' medical history, home and work environments, prior treatment methods, and realistic goals are paramount in helping our patients with this chronic condition; I've found the Ocular Surface Disease Index questionnaire to be an excellent tool in subjectively measuring dry eye severity.

Contact lens and refractive surgical patients must be evaluated on a case-by-case basis. Make the decision to utilize punctal or intracanalicular occlusion only after other treatment modalities have failed to successfully provide subjective and objective relief for the patient.

Getting started

First of all, it's very important for the clinician to have a working knowledge of options for punctal and intracanalicular occlusion. These include collagen, synthetic collagen, thermodynamic acrylic, hydrogel and silicone plugs, as well as surgical closure of the puncta by thermal punctal cautery or argon laser punctal ablation. These methods are primarily used for the treatment of aqueous-deficient dry eye syndrome.

I always review prior and optional treatment modalities with the patient before proceeding with punctal or intracanalicular occlusion. It's important to explain the risks and benefits of any procedure thoroughly to the patient, and be sure to get a signed and witnessed informed consent. Place it in the patient's record once you've done so.

The informed consent should include potential complications including ocular irritation, inflammation and infection. Other well-known potential complications include epiphora, extrusion, migration, granulomas, canaliculitis, nasolacrimal obstruction and dacryocystitis.

Be sure to document all diagnostic testing results in the patient's chart. This may include Schirmer testing, tear break-up times, phenol red thread test, Lissamine green staining, fluorescein staining, rose bengal staining and lactoferrin microassay testing. Note any and all continued subjective complaints in order to substantiate your decision to proceed with punctal or intracanalicular occlusion.

I recommend that you have a Lacrimal kit including forceps (multiple sizes), punctal sizers, punctal dilators (pediatric and adult), Lacrimal cannula, and Bowman probes. Most eyecare practitioners choose to temporarily occlude all four puncta and permanently occlude the lower puncta first. This decision may vary depending upon the individual practitioner's treatment objectives.

The collagen option

Both natural collagen and synthetic collagen plugs are used for temporary punctal occlusion and last from two weeks up to approximately six months (according to manufacturers' claims). Life expectancy may vary with respect to plug type, material and manufacturer. You'll need to use a topical anesthetic prior to insertion. Jeweler's forceps are used to insert the collagen plug into the canaliculus distal to the punctal opening.

It's important to place them far enough into the canal that they don't migrate back to the punctal opening and cause ocular discomfort and/or irritation. Repeat this procedure for the other puncta as required.

Hydrogel intracanalicular plug

Oasis Medical recently announced FDA approval of its Form Fit long-term intracanalicular plug. Made of a hydrogel material that conforms to all patients with a convenient single size, it expands into a soft, pliable, gelatinous plug upon contact with the tear film. It fills the vertical canalicular cavity and is completely hydrated in approximately ten minutes. If necessary, you can accomplish removal by irrigating saline via a Lacrimal cannula through the punctal opening.

In its dry state, the Form Fit plug measures 3mm in length by 0.3mm in diameter. It expands to 20 times the volume of its original size when completely hydrated. Again, use a topical anesthetic prior to insertion.

Thermodynamic acrylic plug

Medennium Inc. makes the SmartPLUG, which is available through many of your local distributors. It's made of a thermodynamic, hydrophobic acrylic polymer that transforms into a soft, gel-like plug seconds after insertion into the canaliculus. It shortens and widens itself as it reaches body temperature, adjusting to fit the puncta. The plug measures 9.0mm in length by 0.4mm in diameter in its dry state and shrinks to approximately 2.0mm by 0.1mm respectively after insertion.

Administer a topical anesthetic prior to insertion. A special forceps, made by the manufacturer, is recommended to ensure proper insertion. Insert the plug carefully to prevent against plug fracture or severance, leaving approximately 1 to 2mm outside the puncta. The remaining exposed plug will shrink into position as it reaches body temperature.

Silicone punctal plugs

There are many manufacturers of silicone punctal plugs. They offer a myriad of design variations with emphasis on comfort, safety, stability and durability. Again, use a topical anesthetic prior to insertion.

It is important to accurately determine the size of the punctal opening prior to selecting and inserting any punctal or intracanalicular plug. Punctal sizers are available for exact determination of the punctal opening. There are many design variations with regard to inserters, size, shape, profile and color. Become familiar with these designs and choose the plug design, type and size based upon proper measurement and ease of insertion.

A silicone punctal plug should be easy to insert and remain in its proper position without causing ocular irritation or inflammation. In most cases, silicone punctal plugs can be removed by careful use of jeweler's forceps. Watch out, though: You can sever the plug by excessive pressure or stretching. Granulomas can form around the plug, restricting removal or causing the plug to partially dislodge. Surgical excision of the plug may become necessary in extreme cases. Document any procedures and inform the patient of all potential complications.

Intracanalicular silicone plug

Lacrimedics designed the intracanalicular silicone plug to be placed through the vertical canaliculus into the horizontal canaliculus. Proper placement is important to prevent ocular irritation from the cap, as well as external dislodgement of the plug. Use a special inserter with the plug to ease implantation. As always, administer a topical anesthetic prior to insertion.

Recently, Lacrimedics developed a newer opaque plug to help doctors visualize the location of the plug. A transilluminator is used to confirm its presence and location in the canaliculus. It's possible for some plugs to migrate throughout the lacrimal system over time. Should epiphora or other complications occur, these plugs can be pushed through the naso-lacrimal system with careful saline irrigation using a lacrimal cannula.

Thermal punctal cautery

Thermal punctal cautery utilizes a cautery stick to permanently close the punctal opening. A topical as well as local anesthetic is given prior to the procedure. The tip of the cautery is inserted slightly into punctal opening. Careful observation and positioning is critical. Over treatment may cause excessive scarring and irregularity of the lid margin.

Be aware that thermal punctal occlusion may re-canalize over time. It can also be reversed in most cases through surgical intervention.

Argon laser punctal ablation

An argon laser is focused on the punctal opening after giving the patient topical and local anesthesia. Ablation of the punctal opening is accomplished within seconds. Use caution in order to prevent over treatment of the punctum. The punctum rarely opens after complete ablation. This treatment can be reversed in most cases through surgical intervention.

Let's review

Use your best professional judgment before performing punctal or intracanalicular occlusion on your dry-eye patients. Perform all necessary diagnostic tests and utilize other treatment methods that you feel are beneficial for the patient's welfare prior to occlusion. Carefully document all pertinent information, and be sure to obtain a witnessed informed consent and place it in the patient's file. Communicate with your patient and make yourself available immediately if complications arise. Punctal or intracanalicular occlusion, performed with care, may provide a world of comfort to your chronic dry eye patients.

Dr. Lancaster practices at the Atlantic Eye Institute. Contact him at (904) 247-1743.