Dry eye is a condition in which a person doesn't have enough quality tears to lubricate and nourish the eye. Tears are necessary for maintaining the health of the front surface of the eye and for providing clear vision.
Dry eye is a common and often chronic problem, particularly in older adults. With each blink of the eyelids, tears spread across the front surface of the eye, known as the cornea. Tears provide lubrication, reduce the risk of eye infection, wash away foreign matter in the eye and keep the surface of the eyes smooth and clear. Excess tears in the eyes flow into small drainage ducts in the inner corners of the eyelids, which drain into the back of the nose. Dry eyes can occur when tear production and drainage is not in balance.
Dry eyes can occur when tear production and drainage are not in balance. People with dry eyes either do not produce enough tears or their tears are of a poor quality:
Dry eyes can develop for many reasons, including:
People with dry eyes may experience irritated, gritty, scratchy or burning eyes; a feeling of something in their eyes; excess watering; and blurred vision. Symptoms include:
Dry eyes can be diagnosed through a comprehensive eye examination. Testing with emphasis on the evaluation of the quantity and quality of tears produced by the eyes may include:
What causes Dry Eye? Dry eye can be influenced by a number of factors related to environment and health that determine tear quality.
Tears have 3 layers:
If there’s an imbalance in these layers, your vision and comfort of your eyes may be affected. For example, if not enough lipid layer is being produced, tears may evaporate too quickly and cause symptoms ranging from discomfort to extra tear production and poor quality of vision. Poor tear quality is often caused by Meibomian Gland Dysfunction (MGD), a condition that impacts the production of oils in your tears. The most common form of MGD is obstruction of the oil producing glands in the eyelids. At Eyecare Experts, we will test your tear quality to determine whether MGD is contributing to or causing your dry eye symptoms and create a customized treatment plan to address it.
Craig JP, Nichols KK, Akpek EK, et al. TFOS DEWS II Definition and Classification Report. Ocul Surf. 2017;15(3):276-283. doi:10.1016/j.jtos.2017.05.008
An intact tear film ensures that our eyes do not dry out. It consists of several layers, with an oily lipid layer protecting the watery layer beneath it from evaporating. The watery layer contains oxygen and supplies the cornea with essential nutrients. Beneath this, there is a mucous mucin layer by which the tear film adheres to the cornea. The tear film also protects the eye against foreign bodies and bacteria.
The meibomian glands are located along the inner edge of the eyelids. They produce the lipids of the oily layer. This is distributed across the ocular surface with every blink of the eye, protecting the tear film from evaporating too quickly. If the functions or structure of the tear film are impaired, this leads to sensations of dryness.
There is no single test to reliably diagnose dry eye, as there are always several factors involved, and sufferers may report a variety of symptoms. The key to proper analysis of the various factors involved in eye wetting disorders and determination of their causes lies in a broad-based diagnostic approach. The necessity of this is already evident in view of the variety of risk factors that may trigger dry eye symptoms.
Risk factors for dry eye:
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