An Overview of Dry Eye Syndrome
What is Dry Eye Syndrome?
Dry eye related discomfort is one of the most frequent complaints heard by eye doctors. The symptoms of dry eyes are varied and the list below is by no means all inclusive, however patients that suffer from dry eyes usually experience a number of the following symptoms.
- burning sensation
- excess watering/tearing
- stinging sensation
- A foreign body sensation
- light sensitivity
- sandy/gritty sensation
- blurred vision
- excess mucous
- contact Lens intolerance
There are three main components to human tears. The bulk of human tears are produced by the lacrimal gland. The oily component of tears is produced by the meibomian glands and the third component, the goblet cells, keeps all of the components mixed up. When one of the parts of this mixture becomes unbalanced, patients become symptomatic. There are numerous reasons as to why these glands may not be doing their part.
Insufficient tear production and/or poor tear quality are the most common causes of dry eye syndrome. Inflammation of the lacrimal gland is the most common cause of insufficient tear volume. Meibomian gland dysfunction, inflammation of the glands at the eyelid margin, contributes to poor tear quality. Medications frequently cause ocular dryness. The medications most commonly causing dry eyes are antihistamines, oral contraceptives and decongestants. Hormonal changes also contribute to insufficient and poor quality tears.
Who is at Risk for Dry Eye Syndrome?
Dry eye syndrome is very common. It is estimated that between 10% and 30% of the general population experiences dry eyes, resulting in up to 90 million affected individuals in the United States. The incidence of dry eye syndrome is higher, however in those over age 40 and in women.
Some systemic disorders such as Sjögren syndrome, rheumatoid arthritis and acne rosacea make a person more likely to experience ocular dryness.
Refractive surgery procedures such as PRK, LASIK and LASEK disrupt the neural feedback loop and are common causes of dry eyes. Poor tears can cause both decreased visual acuity and discomfort for refractive surgery patients and needs to be addressed during all phases of their care.
Patients often report that their eyes do not seem to be dry until they wear contact lenses. Contact lenses don't cause the dryness, however a patient with dry eyes will experience discomfort because their eyes can not support the presence of the contact lens. Typically, soft contact lenses are 30 to 70% water. Contact lenses essentially work like a sponge in the eye. A patient with borderline dry eye symptoms is often contact lens intolerant. Contact lenses rely on our eyes to produce enough tears to Hydrate the contact lenses and allow them to float on a cushion of tears. If there are not enough tears to both hydrate the lens and lubricate the eye then the patient experiences contact lens intolerance. Often a contact lens intolerant patient can wear contact lenses for a few hours but their wearing time decreases when in the presence of smoke, air conditioning, wind low humidity, etc.
How is Dry Eye Syndrome Diagnosed?
Dry eye syndrome is diagnosed in the office by considering the clinical presentation, patient's complaints and diagnostic testing. Determining the cause of the dryness whether it is insufficient tear production, poor tear quality or a systemic disease is critical in improving your comfort.
How is Dry Eye Syndrome Treated?
Treatment is often accomplished through numerous different courses of action. Artificial tears containing active ingredients such as carboxymethylcellulose and polyvinyl alcohol are helpful in mild cases of dry eye syndrome. Moderate to severe cases are often treated with a combination of artificial tears, punctal occlusion and Restasis®. punctal plug graphic. There are numerous treatments available to patients with dry eyes. The treatment, of course depends on the cause of the dryness. Systemic causes of ocular dryness, such as acne rosacea, medications, endocrine imbalance must be addressed first. If symptoms persist then other treatments are initiated such as artificial tears, the use of medications that promote tearing such as Restasis®, punctal plugs to prevent the tears that are produced from being drained into the nose. Increasing the omega-3 fatty acids in one's diet can also reduce dry eye symptoms.
Address Underlying Conditions
The first course of action is to address any underlying factors that are contributing to the symptoms such as the systemic causes mentioned earlier. Infections of the eyelids such as blepharitis and meibomitis must also be treated before any other treatment is initiated. Often treatment of the underlying conditions still leaves patients symptomatic and additional treatment is required to provide relief.
Artificial tears containing active ingredients such as carboxymethylcellulose, hydroxypropyl methylcellulose, glycerin, castor oil, polyethyline glycol or polyvinyl alcohol are used in mild cases of dry eyes. Not all artificial tear brands work the same or work in all patients. More severe case require additional treatment. If you find yourself using your artificial tears three or more times a day you should use a preservative free tear. Most patients find that artificial tears do help, however the affect is only temporary, lasting only 10-15 minutes. Most of these patients will experience significant relief with punctal occlusion.
In our experience, significant dry eye relief is achieved with punctal occlusion. The puncta is the small opening found on the edge of the upper and lower eyelids next to the nose. Tears drain out of the eye through the puncta into the nose, this is why your nose runs when you cry. If you aren't producing enough tears then you don't want the tears that you are producing to be drained away. Punctal occlusion is painless and performed in the office, taking only a couple of minutes.
Numerous studies have shown that increasing our dietary intake of Omega-3 fatty acids, such as those found in oily fish, such as salmon are very beneficial. Western diets almost never provide enough omega-3 fatty acids to provide a therapeutic benefit, therefore dietary supplementation is almost always required. There is also some degree of controversy over what source of omega 3 fatty acids is most effective.
Pharmaceutical manufacturers have focused a significant portion of their considerable resources into dry eye medications. Restasis® is the first of many medications being developed for dry eye patients. We have found Restasis® to be helpful in patients when the underlying cause of their symptoms is insufficient tear volume due to inflammation of the lacrimal gland. Restasis® does not provide immediate relief, a therapeutic benefit is usually noted in 2-4 months.
Contact Lenses Changes
Merely changing the type of contact lens is very rarely enough to provide sufficient, consistent relief. Careful selection of the contact lens material can often be beneficial and is one of the many treatment options available to us.
There is no silver bullet to dry eye treatment, however, management almost always results in significant improvement in comfort. Symptomatic relief usually involves a multifaceted, systematic approach depending on the severity of your symptoms.