Dry eyes are a source of common ocular complaints. Symptoms of dry eyes include a foreign body sensation, grittiness, burning, photophobia (light sensitivity), and blurred vision. Severely dried eyes can even lead to eye infections. Dry eye patients will frequently exhibit tearing, making them question the diagnosis of dry eyes: “how can my eyes be dry when they tear so much?” In fact, this tearing response is paradoxical. Tears are composed of three basic layers. In many dry eye patients the watery component is normally produced, but the other layers are insufficient. In an effort to produce the deficient components, the watery part is over produced, leading to the tearing response: quantity is produced rather than quality. (excessive tearing, known as ephiphora, can, however, be due to other eye or lid disorders.)
One method of diagnosis is the use of a Schirmer’s test. This test, usually done under topical anesthesia, measures the degree of wetting of a strip of filter paper over a certain period of time. Other observations that assist in the diagnosis are the lacrimal lake (the amount of tears present and how fast the tears break up or begin to bead on the ocular surface (tear break up time).
Causes of dry eyes include weather, aging changes, contact lenses, medications (such as antihistamines and various cold remedies), hormonal changes, and autoimmune diseases such as Sjogren’s syndrome. Recent research indicates that lacrimal gland and ocular surface inflammation may also play a role in dry eyes. Such inflammation can decrease tear production and release various inflammatory factors. (This knowledge suggests that the anti-inflammatory medications may benefit some dry eye patients.)
Treatment for dry eyes is typically palliative using supplemental artificial tears and lubricating ointments. There are many such over-the-counter (OTC: not requiring a prescription) eye drops. When eye drops are used, patients are best treated with non preserved agents, since preservatives may take the dry eye symptoms worse, leading to other problems.
In addition to eye drops, patients can also have symptomatic improvement with plugging of the drainage system of the eye using canalicular plugs made of silicon. These plugs behave as little corks, stopping the flow of tears away from the ocular surface. The plugs must be sized for best fit. Tears drain through both lower and upper puncta present at the inner corners of our eye lids. Most tears are drained via lower puncta. Accordingly, most dry eye patients only need the lower puncta plugged. One advantage of using silicon plugs is that they are reversible. Other less frequently used methods of plugging the tear drainage system are thermal cautery, laser cautery (as expensive source of thermal cautery), and sutures.
