Living Columns & Blogs

Understanding dry eye disease

Dry eye disease is a chronic condition that occurs when the eyes do not produce enough tears, or if the tears produced are of poor quality so they evaporate too quickly. Symptoms can range from having mild eye irritation in some to decreased vision in others. Although this condition is not life-threatening, it can lead to increased risk of eye infections and corneal inflammation if left untreated.

In order to have comfortable vision, the front surface of our eyes needs a constant supply of tears, known as the tear film. There are three components to the tear film:

▪ The lipid layer (the outermost layer) — oily layer that prevents tears from evaporating

▪ The aqueous layer (the middle layer) — water layer that nourishes and lubricates the eye

▪ The mucin layer (the innermost layer) — layer that makes tears adhere to the eye

Your eyes can become dry if any of these layers are not functioning properly.

Aqueous deficient dry eye is caused when the lacrimal glands (located above your eyes) do not produce enough tears. This may be due to trauma, nerve damage or inflammation from underlying diseases (e.g., lupus, rheumatoid arthritis, Sjogren’s syndrome).

Evaporative dry eye can result if your lipid or mucin layers are deficient. Either your glands are not making enough oil to prevent your tears from evaporating or your eye is not making enough mucin to allow the tears to “stick” to your eyes. The lack of sufficient tears and moisture on your eyes can lead to a burning and stinging sensation.

The irony with dry eyes is that sometimes you may experience excessive tearing. You may then wonder, how can I have dry eyes if they are constantly watering? Excessive watering comes from reflex tearing (emotional tears), which are produced in response to irritation or injury. These tears are of poor quality and do not “stick” to your eyes to lubricate them.

What causes dry eye disease?

There are various causes of dry eyes. These include:

▪ A natural aging process, especially common among women older than 40

▪ Environment (wind, smoke, dry weather or use of heaters and air conditioners)

▪ Medications (antihistamines, antidepressants, birth control pills, etc.)

▪ Eyelid problems (such as deficiency of tear producing glands, or incomplete lid closure)

▪ Certain systemic diseases (Rheumatoid arthritis, Lupus, Rosacea, Sjogren’s syndrome)

▪ Long-term contact lens wear

▪ Smoking

How is dry eye disease diagnosed?

Diagnosing dry eyes starts with talking to your doctor about your medical history. It is important that your eye doctor is aware of any medical conditions you may have, the medications you use, your typical environmental conditions and if you are a contact lens wearer. Looking into individual patient histories gives the doctor a good understanding of what may be causing dry eyes and how to treat it.

During the examination, your eye doctor may measure your tear volume, perform a tear analysis to measure your tear osmolarity (the saltiness of your tears) and examine your eyelid glands. Your doctor will also use a dye to determine if any damage has been caused to the eye.

How is dry eye disease treated?

Treatment varies depending on the source and severity of your dry eyes. You may be asked to start using artificial tears to keep your eyes well lubricated. The secret to these eye drops is that they must be used consistently every day for this therapy to actually work. Also, know that these drops are not the same as eye drops that are marketed to relieve eye redness or itching.

If lubricating eye drops do not provide you with relief then your practitioner may suggest prescription eye drops, which help your eyes to produce more tears. In some cases, your doctor may also prescribe a steroid for more immediate short-term relief.

Furthermore, supplementing your diet with fish oil can greatly reduce your symptoms of dryness. The omega-3 fatty acids contained within fish oil have an anti-inflammatory effect, which helps to reduce inflammation within the eyelids and on the surface of the eye. This allows for glands to secrete more oil into the tear film and for the eyes to stay hydrated longer. Our daily intake of omega-3 fatty acids, even with a modified diet, is insufficient to reduce inflammation and additional supplements are required. While looking for fish oil supplements, it is important to pay attention to the DHA/EPA content as these are the ingredients containing fatty acids that target inflammation and their concentration per supplement can vary greatly between brands. Depending on the specifics of your case, your health care provider may recommend fish oils as a stand alone treatment or in conjunction with other treatment methods.

Another treatment is the use of puntal plugs. These are micro-inserts that are used to block the tear ducts at the inner corners of our eyes where fluid drains. This increases the tear reservoir.

However, if your condition is caused by lid disease, then maintaining good lid hygiene becomes very important. You can achieve this by performing lid scrubs, hot compresses and lid massages to soften oils in inflamed oil glands. The softened oil is better able to express out of the glands and reach the tear film.

Visit your eye doctor to get a thorough eye exam and to receive more information on dry eye disease and what treatment options are best for you.

Dr. Jasleen Kaur is an optometrist at Nittany Eye Associates.