Dry Eye Treatment

Dry eye is ultimately the dysfunction of the tear film. The tear film is a complex system that is comprised of the:

1. Mucin layer: this mucous layer provides a “sticky” foundation and acts as a barrier to the eye surface

2. Aqueous layer: this “watery” layer is produced by the lacrimal glands and provides moisture to the eye

3. Lipid layer: this “oily” layer is produced by the meibomian glands and prevents the tears from evaporating

Each component needs to work in balance and harmony to keep the tear film stable. When you have an imbalance in these layers, the vision and comfort of your eyes are affected. Our doctor will evaluate what is causing the disruption in your tear film that makes you suffer from dry eye.

If you imagine the tear film like you would building a house:

• the mucin layer is the foundation

• the aqueous layer is the beams

• the lipid layer is the roof

When you have dry eye caused by meibomian gland dysfunction (MGD), your glands are clogged and are not producing enough lipid layer, meaning your roof has been compromised. With holes in your roof, you can’t maintain stable temperature in your house. Cool or hot air would escape out.

As such, when your lipid layer is compromised, your tears evaporate too quickly. You have to fix the roof (the lipid layer) for the house (the tear film) to be structurally sound and for you to live comfortably.

Blepharitis is an inflammation of the eyelids in which they become red, irritated and itchy and dandruff-like scales form on the eyelashes. It is a common eye disorder caused by either bacteria, a skin condition (such as dandruff of the scalp or rosacea) or demodex (eyelashes mites). It can affect people of all ages. Although uncomfortable, blepharitis is usually not contagious and generally does not cause any permanent damage to eyesight.

Blepharitis is classified into two types:

• Anterior blepharitis occurs at the outside front edge of the eyelid where the eyelashes attach.

• Posterior blepharitis affects the inner edge of the eyelid that touches the eyeball.

It is currently unclear whether blepharitis causes dry eye or dry eye causes blepharitis.

Blepharitis is often associated with either or both:

• Demodex mites: when bacteria multiply and overgrow at the margins of the eyelids and at the base of the eyelashes, a biofilm is formed. Biofilm is a toxic environment similar to plaque that forms on your teeth, from which parasitic eyelash mites called demodex can feed on. When untreated, demodex create a vicious cycle that worsens the eyelid inflammation and causes more dry eye symptoms.

• Meibomian gland dysfunction: bacteria in the eyelid biofilm produce substances called exotoxins that cause inflammation of the meibomian glands. Over time, inflamed meibomian glands become obstructed, which causes (and worsens) dry eye discomfort.

Demodex refers to 2 types of microscopic eyelash mites that live on humans:

• Demodex folliculorum, which live within hair follicles on eyelashes

• Demodex brevis, which live in sebaceous glands (oil glands) in the skin around the eyes

Most of the time, these mites are harmless and will go unnoticed. However, when they multiply and their population get out of control, Demodex can cause many ocular diseases like conjunctivitis, chalazia, blepharitis and contribute to dry eye symptoms, including eyelid itchiness and falling eyelashes.

These mites can also cause unwanted symptoms and skin problems like rosacea, androgenetic alopecia, non-specific facial dermatitis (acne-like blemishes). Demodex is transferred between hosts through contact with hair, eyebrows, and the oil glands of the face.

Meibomian gland dysfunction (MGD) is a common eye condition when the meibomian glands in your lids are clogged or have been compromised by chronic inflammation, demodex infestation, long-term use of contact lenses or failure to blink regularly when using digital device use without breaks.

When blocked, the meibomian glands secrete too little or no oil (meibum), which is needed to stabilize your tear film and help avoid your tears from evaporating too quickly.

Meibomian gland dysfunction is considered to be the primary cause of dry eye and is estimated to affect 86% of dry eye patients.

When available, an optometrist can check the structural quality of your meibomian glands by taking pictures of the inside of your lids with a meibographer as shown below.

1. When the meibomian glands function properly, they will secrete clear oil naturally every time you blink to create a stable tear film.

2. When blocked or clogged, the meibomian glands secrete little to no oil. Instead, they will secrete unhealthy crusty, pus or toothpaste-like oil when expressed with forceps.

3. When left inflamed or clogged for too long, the meibomian glands may atrophy and die off. At that stage, you will suffer irreversible and permanent dry eye symptoms.