Your eyes are protected by a thin layer of tears called the tear film. It is constantly being renewed every time you blink and plays an important role in keeping the surface of your eye healthy and your vision clear.

The tear film contains water, oils and mucins, which work together to keep the surface of the eye comfortable and prevent tears from evaporating too quickly.

Dry eye can occur when the tear film is not working properly. This might be because:

• Your eyes are not producing enough tears

• Your tears are evaporating too quickly

• Your meibomian glands are not producing enough oil

• Your eyelids or eyelashes are affecting the tear film

• The surface of the eye has become irritated or damaged

• Inflammation is present

• Previous eye surgery or certain medications or health conditions are contributing to the problem

This is why there isn't a single treatment that works for everyone.

Dry eye doesn't always feel like "dry" eyes.

You may experience:

• Gritty or sandy eyes

• Burning or stinging

• Red or irritated eyes

• Excessive watering

• Tired or heavy eyes

• Sensitivity to light

• Fluctuating or blurred vision

• Discomfort when using a computer or phone

• Symptoms that are worse in heated or air-conditioned environments

• Difficulty wearing contact lenses

• Eyes that feel worse towards the end of the day

Interestingly, watery eyes can be a symptom of dry eye too.

When the surface of the eye becomes irritated, your eyes can produce a sudden rush of watery tears. These tears may not contain the right balance of oils and other components to remain on the eye effectively, so you can experience watering while still having an unstable tear film.

At our Dry Eye Clinic, we don't simply look at whether your eyes appear dry.

We carry out a detailed assessment of your symptoms, eyelids, tear film, corneal surface, meibomian glands and, where appropriate, ocular surface inflammation.

Your assessment is tailored to you, so you will not necessarily require every test.

Your symptoms and medical history

Your assessment starts with a conversation.

We'll ask about how long you've had your symptoms, what they feel like and when they are worse.

We'll also discuss:

• Previous and current dry eye treatments

• Eye drops, gels and ointments

• Previous eye surgery, including laser/refractive, cataract or eyelid surgery

• Your general health and relevant medications

• Your vision and whether it fluctuates

• Your spectacles or contact lenses

• How your symptoms affect your everyday activities

• We may ask you to complete a Ocular Surface Questionaire

This information can provide important clues about what is causing or contributing to your dry eye.

We use a digital slit lamp with a inbuilt camera to examine the front of your eye in detail.

We assess your:

• Eyelids

• Eyelashes

• Meibomian gland openings

• Conjunctiva

• Tear drainage openings

• Cornea

• Tear film

We're looking for signs of eyelid inflammation, blocked or unhealthy meibomian glands, redness, ocular surface damage and other factors that could be contributing to your symptoms. We can take images so you can see what your optician can see. 

We may use fluorescein, a yellow-orange diagnostic dye, to examine your tear film and the surface of your cornea.

Under a blue light, fluorescein appears bright green and allows us to see areas of disruption on the surface of the eye.

It can help us assess:

Tear film stability

We can see how evenly the tear film spreads over the eye and whether it breaks up prematurely.

Tear Break-Up Time (TBUT)

We measure how long the tear film remains stable after you blink.

If it breaks up quickly, this can indicate an unstable tear film and may be associated with evaporative dry eye.

Corneal health

Fluorescein can highlight very small areas of disruption or damage to the surface of the cornea that might otherwise be difficult to see.

The Schirmer test measures the amount of tears your eyes produce.

A small strip of specialist filter paper is gently placed inside the lower eyelid for a few minutes. The amount of moisture absorbed by the strip is then measured.

This gives us information about your tear production.

A low result may indicate that your eyes are not producing enough tears and can help us identify patients who may have an aqueous-deficient component to their dry eye.

For some patients, we can carry out additional testing using our Medmont Meridia topographer.

This sophisticated technology allows us to assess the tear film and corneal surface without needing to put dye into the eye.

Non-invasive Tear Break-Up Time

The instrument can measure how long the tear film remains stable following a blink.

This provides additional information about tear film instability and evaporation.

Meibography

One of the particularly useful features is meibography.

Your meibomian glands are located within your eyelids and produce the oily component of your tears. This oil helps slow the evaporation of tears.

When these glands become blocked, damaged or lost, it can contribute to meibomian gland dysfunction (MGD) and evaporative dry eye.

Meibography allows us to produce detailed images of the glands so that we can assess their structure and identify changes such as gland shortening or loss.

Assessing tear film quality

The topographer can also analyse reflections from the surface of your eye.

Changes or break-up in these reflections can provide information about how stable your tear film is.

Together, these measurements give us a much more detailed picture of your tear film and meibomian gland health.