Understanding Dry Eye

Dry Eye Overview

Dry eye syndrome is a condition caused by a lack of moisture or improper tear consistency on the eye. It typically affects adults, with its incidence increasing with age and can progress in severity if not treated. It is important to understand the most common causes and symptoms of the condition, and to seek assessment routinely from an eye care provider.

The Tear Layers

For the eyes to be healthy and to function properly, they require an adequate and consistent layer of tears on the surface. A healthy tear film is made up of 3 components. Each of these components are produced from different sources in the eye.  Disruption or deficiency in any of these tear layers can result in one to experience the symptoms of dry eyes. Dry eye or in its more severe form, keratoconjuctivitis sicca, the symptoms can include any of the following:

dryness, burning, a sandy-gritty eye irritation, often gets worse as the day goes on or with prolonged reading or screen viewing, may also be described as itchy, scratchy, stinging or tired eyes, pain, redness, a pulling sensation, fluctuating vision and watering. Watering occurs as a result of reflex tearing that is brought on by the irritation associated with dry eyes.  These reflex tears are more watery than normal tears.

Lipid Layer

An oily component that prevents tears from evaporating and rolling over on to the cheek.

Aqueous Layer

A watery or aqueous component that makes up the bulk and middle layer of the tear film.

Mucin Layer

A mucus-like component that helps spreads the tears across the surface of they eye.

MGD: The Leading Cause of Dry Eye

The meibomian glands are responsible for producing an oil called meibum, which makes up the lipid, or oily and superficial layer of the eye.  There are about 30 to 40 meibomian glands located within each eye lid, and their pores open and release on to the lid margin of the eyelid.

Meibomian Gland Dysfunction (MGD for short), occurs when there is compromise to the function and/or structure of the Meibomian glands. MGD is the leading cause of dry eye and there are a number of ways to affect their production. These can include: heat application through daily warm compresses, Omega-3 supplementation, lid debridement with metal debridors or systems such as Blephex, and medical light or heat treatment such as the IPRL or I-LUX. More on this later.

The Risk Factors For Dry Eye

Below are some of the leading risk factors or associations with dry eye symptoms and disease.  Dry eye was defined by the TEAR FILM AND OCULAR SURFACE SOCIETY as  “…a multi­-factorial disease of the ocular surface, characterized by a loss of homeostasis of the tear film, and accompanied by ocular symptoms, in which tear film instability and hyper-osmolarity, ocular surface in­flammation and damage and neuro-sen­sory abnormalities play etiological roles.”

Device Usage

When looking at electronic screens or reading, we tend to blink less. This will lead to greater tear film evaporation as the act of blinking is what produces our tear film. The average person blinks 12 times a minute. In cases of healthy tear film composition, the time it should take for tears to begin evaporating is greater than 10 seconds, known as the tear break-up time (TBUT).

Age

Dry eye syndrome occurs much more commonly with advancing age, especially after 50. It is thougth this is mostly due to hormonal changes, but loss of meibomian oil glands over time is also a likely contributing factor.

This is particularly true for women in menopause, who experience a higher incidence of dry eye than that of men of the same age.

External Environment

The conditions of the environment that you are in can increase the risk of experiencing dry eye symptoms.

The conditions that have the greatest impact on perpetuating dry eye symptoms include being around air conditioning, fans or heating; environments with dry climates or windy conditions/dusty environments.

Medications

Many prescription and nonprescription medicines can increase the risk of dry eye symptoms — including antihistamines, anti-depressants, decongestants, beta-blockers, some blood pressure medications (diuretics), tranquilizers and birth control.

General Health

The medical conditions that have the greatest impact on perpetuating dry eye symptoms include diabetes, blepharitis, Sjogren’s Syndrome, Lupus, neurotrophic corneas and arthritis. Many of these conditions are considered auto-immune in nature, which should highlight the fact that dry eye often has an inflammatory component in the makeup of the disease.

Contact Lenses and Eye Surgery

Soft contact lenses especially, require moisture from the eye’s tear film to sustain their comfort and clarity. Individuals with borderline dry eye may become symptomatic when wearing contact lenses. Previous eye surgery, such as LASIK and cataract surgery, can affect the corneal nerves, thereafter blink regulation and tear film production.

Dry Eye Therapies

Dry Eye Intensity Survey

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