Punctal Occlusion Improves the Symptoms Caused by Dry Eye Syndrome
What is Punctal Occlusion?
Punctal Occlusion (tear drainage duct occlusion) is a procedure that eye doctors use to improve the symptoms of dry eye syndrome. Punctal occlusion consists of inserting punctal plugs (silicone or collagen) into the tear drainage area of the eye to keep the tears in the eyes longer.
Punctal Occlusion Treats Dry Eyes
Dry Eye Syndrome is a chronic condition that causes problems ranging from mild discomfort to corneal infection and scarring. Dry eyes must be treated because the symptoms do not go away on their own. There are numerous causes of dry eye and many different treatments. Punctal occlusion is one possible treatment that often must be combined with other treatments to solve the complex problem of dry eyes.
How Punctal Occlusion Works
The human tear film consists of 3 layers, lipid, aqueous, and mucous, that are produced from different parts of the eye. The aqueous layer is produced by the glands of Krause and Wolfring and by the lacrimal gland, all located in the superior eyelids. The lipid layer located is located farthest from the eye and is produced by the meibomian glands. It functions to slow the evaporation of the underlying tear layers. The mucin layer of the tears located directly on the cornea is produced by the goblet cells of the conjunctiva. The tears coat and lubricate the eyes and then exit through the eye’s drainage system. The tears flow into the drainage holes, called lacrimal punctum, which are located in the inner corners of both the superior and inferior eyelids. From the punctum the tears flow through to the drainage tubes, called the canalicula and then to the lacrimal sac and then the nasolacrimal duct, and finally exit into the nose and to the back of the throat. (That is why your nose runs when you cry!)
The goal of punctal occlusion is to slow the drainage of the tears to keep the tears on the eye longer for added lubrication. Punctal plugs are very small biocompatible devices that are inserted into the lacrimal punctum. Punctal plugs are very small usually ranging from 0.3 mm to 0.7 mm in diameter. They are made up of two types of materials, collagen and silicone. The collagen plugs are dissolvable so they are temporary, lasting from a few days to a few months. These are usually used first to determine if punctal occlusion would be beneficial for the patient or for temporary dry eye problems such as that caused by LASIK surgery. Silicone punctal plugs are used for more permanent, longer lasting occlusion. It is important to note that prior to punctal occlusion every patient with ocular surface inflammation must first be treated with some type of anti-inflammatory therapy. One of the best anti-inflammatory treatments for dry eye patients is Lotemax.
Punctal Plugs are Inserted Using a Microscope
Insertion of the plugs is painless and only takes a few minutes. The plugs can be inserted in both the superior and the inferior punctum, but is usually done with just the inferior. Topical anesthetic is usually used but can be done without since the discomfort is very minimal. The punctum may be dilated with an instrument for easier insertion. The plugs can then be inserted with forceps or with a syringe-style inserter. Again, both are painless. The plugs come in a variety of designs. Some are inserted just into the punctum so the top of the plug is visible with the microscope. Other type punctal plugs are inserted deeper into the canalicula and are not visible by microscopic inspection. Both provide equal comfort, and both can be removed if needed. Most patients report immediate relief of the dry eye symptoms following punctal occlusion and can resume normal every day activities afterwards!
Two Types of Permanent Punctal Occlusion Plugs
The two types of permanent punctal occlusion therapy include a surface level plug and an intracanalicular plug. The traditional surface punctal plug has a flange that stops it from going completely into the canaliculus (tear duct). It is visible by microscopic evaluation and can be removed by forceps if needed. The intracanalicular plug (Oasis Form Fit) is placed completely into the canaliculus tube and is not visible even with a microscope.
Oasis Form Fit HYDROGEL Punctal PLUG
The Oasis Form Fit™ plug is designed for long-term closure of the punctum similar to other forms of punctal occlusion. It is made of a proprietary patented material that no other plug uses. The difference between the Form Fit and other types of punctal plugs is that it is inserted completely into the lacrimal canal with no flange on the surface that is visible and it is a hydrogel material that absorbs the tears after insertion and swells to block the drainage canal.
After the dry intracanalicular Oasis Form Fit plug is inserted into the lacrimal punctum it will absorb tear fluids and swell (approximately 20 times in volume) to fill and conform to the vertical canaliculus. Full hydration of the intracanalicular plug takes about 10 minutes.
The plug can be removed by a doctor by flushing saline solution through the lacrimal system.
Does the Oasis Form Fit plug ABSORB BACTERIA, Drugs or Protein?
According to the manufacturer, bacteria will not absorb into the hydrated canalicular plug. The hydrogel material forming the hydrated canalicular plug is a homogenous material that is not micro-porous. The pores of the material are too small to allow bacterial penetration. There have been some reports of infections using intracanalicular plugs. It should be noted that Form Fit plugs are FDA approved devices.
Most drugs placed on the eye will dissolve in the tear fluid. They may ultimately diffuse into the hydrated hydrogel plug. The diffusion of the drug components from the tear fluid into the hydrated plug will be very slow and will ultimately depend on the length of time the drug is in contact with the hydrated plug. The effects are not clinically significant.
Proteins will deposit on the surface of hydrated hydrogel plugs. This also occurs for other punctal and canalicular plugs. However, this will not affect either the performance or the safety of this or other competitive plugs.
Possible Complications of Punctal Occlusion Therapy
A few problems can occur with punctal occlusion but the complications are rare. One such problem is epiphora. That is when the plugs work a little too well and cause excessive tearing. This can be relieved by simply removing the plugs. Another problem that can occur is an infection. This can be treated with antibiotics and/or removal of the plug. The plug can also become dislodged and create a blockage causing pain and swelling but the plug can be flushed out if this were to occur. Another possible problem is that the surface plugs can actually pop out. Although there is no harm to the eye if that occurs, the benefits of the therapy are obviously lost. It is important to let your doctor know if you have any discomfort or symptoms of an infection or any other problems that may need to be treated.