Understanding what we measure—and why it matters
Do your eyes regularly feel dry, gritty, burning, tired or irritated? Perhaps your vision fluctuates throughout the day, contact lenses have become less comfortable, or your eyes water unexpectedly, especially when you are outdoors, using screens or sitting in air conditioning.
These can all be signs of dry eye disease or another ocular surface condition.
"Dry eye" is not simply a lack of tears. It is a complex, often multifactorial condition involving the tear film, eyelids, oil glands, inflammation, blinking and the surface of the eye. This is why choosing eye drops through trial and error does not always provide enough relief. A product may temporarily soothe your symptoms without addressing the main factors causing them.
At Illume Eye Care in Ponsonby, Auckland, our dry eye and ocular surface assessments are designed to answer three important questions:
- What is contributing to your symptoms?
- How is it affecting the surface of your eyes?
- Which treatments are most appropriate for your individual eyes?
Here is what happens during a comprehensive dry eye assessment and why each part matters.
What is a dry eye and ocular surface assessment?
A dry eye assessment is a detailed evaluation of your tear film, eyelids, meibomian glands and ocular surface.
It goes beyond simply asking whether your eyes feel dry. We combine your symptoms and clinical history with advanced diagnostic imaging, objective tear measurements and a careful microscope examination.
This helps us distinguish between different forms of dry eye, including:
- Evaporative dry eye
- Aqueous-deficient dry eye
- Meibomian gland dysfunction
- Blepharitis and Demodex
- Ocular rosacea
- Inflammatory ocular surface disease
- Contact lens-related discomfort
- Mixed dry eye, where several factors occur together
Dry eye can also cause watery eyes. When the tear film becomes unstable or the eye surface is irritated, the eyes may respond by producing a sudden overflow of reflex tears. These tears are often watery and may not remain on the eye long enough to restore comfort.
We start by listening to your symptoms
Before beginning the clinical testing, we talk with you about how your eyes feel and how your symptoms affect daily life.
This may include questions about:
- Burning, grittiness, itching or irritation
- Watery or fluctuating eyes
- Blurred or variable vision
- Screen use and working environment
- Contact lens comfort
- Previous eye drops and treatments
- Eyelid problems, styes or chalazia
- General health, medications and hormonal changes
- Sleep, hydration, nutrition and lifestyle
- Skincare, makeup and products used around the eyes
Dry eye symptoms can vary significantly between people. Understanding when your symptoms occur, what makes them worse and what you have already tried helps us interpret the clinical findings in the context of your everyday life.
Advanced tear film imaging with the Oculus Keratograph 5M
At Illume Eye Care, we use the Oculus Keratograph 5M to take detailed, non-invasive measurements of the tear film and meibomian glands.
Most of these measurements are completed without touching the surface of your eye. The results also provide useful images that we can show you during your appointment, helping you better understand what is happening.
1. Blink Pattern
A complete blink spreads fresh tears across the eye and helps release oil from the meibomian glands along the eyelids.
During concentrated activities such as computer work, people often blink less frequently or do not close their eyelids completely. This can leave part of the eye surface exposed and allow tears to evaporate more quickly.
Video analysis allows us to observe your natural blinking pattern and identify incomplete or inefficient blinking.
2. Tear Meniscus Height
The tear meniscus is the small reservoir of tears that sits along the lower eyelid.
Measuring its height helps us estimate the volume of tears available on the eye. A low tear meniscus may suggest reduced tear production, although we interpret this alongside your other clinical measurements rather than relying on one test alone.
3. Non-invasive keratograph break-up time
Non-invasive keratograph break-up time, often shortened to NIKBUT, measures how long the tear film remains smooth and stable after a blink.
The instrument projects a pattern of rings onto the surface of the tears and records when the pattern first begins to distort. A tear film that breaks up quickly may contribute to burning, grittiness, visual fluctuation and discomfort during screen use.
This test is performed without applying fluorescein dye, allowing us to observe the tear film in a relatively natural state.
4. Lipid layer assessment
The outermost layer of the tear film is made up of oil produced by the meibomian glands.
This oil helps slow tear evaporation and keeps the tear film stable between blinks. We assess the appearance and distribution of the lipid layer to look for signs that the oil component of the tears may be inadequate or uneven.
This is particularly important when symptoms are caused by evaporative dry eye or meibomian gland dysfunction.
5. Conjunctival redness measurement
The Keratograph can provide an objective assessment of redness affecting the white part of the eye.
Rather than relying only on a subjective description, this gives us a repeatable measurement that can help document inflammation and monitor changes over time.
6. High-definition meibography
Meibography uses infrared imaging to map the meibomian glands inside the upper and lower eyelids.
These glands produce the protective oil layer of the tear film. Meibography can show whether the glands appear healthy or whether there are signs of shortening, distortion or gland loss.
The images can be particularly helpful for understanding why symptoms have developed and why early management of meibomian gland dysfunction may be beneficial.
Why are the meibomian glands so important?
A large proportion of people with dry eye have an evaporative component, often associated with meibomian gland dysfunction.
When the glands become blocked or inflamed, the oil they produce may become thick, cloudy or difficult to express. Without an effective oil layer, tears can evaporate too quickly—even when the eyes are producing a reasonable volume of watery tears.
This helps explain why standard watery eye drops may not provide enough relief for everyone. The most appropriate treatment depends on which parts of the tear film are not functioning well.
Did You Know? Up to 86% of dry eye sufferers don't actually lack water—they lack oil.1 Your tear film relies on a critical lipid (oil) layer produced by tiny glands in your eyelids called Meibomian glands. If these glands are blocked or inflamed, your tears will evaporate much faster than normal, leaving your eyes feeling gritty and dry no matter how many standard drops you use.
Measuring tear osmolarity with ScoutPro
We may also use ScoutPro tear osmolarity testing as part of your ocular surface assessment.
Osmolarity measures the concentration of dissolved particles within the tears. When the tear film is unstable and excessive evaporation occurs, the tears may become more concentrated.
This can place stress on the cells of the ocular surface and contribute to inflammation and discomfort.
Osmolarity is interpreted alongside your symptoms, imaging and microscope findings. No single measurement diagnoses dry eye on its own, but combining multiple results helps create a clearer clinical picture.
Examining the eyes with the slit-lamp microscope
Advanced imaging provides valuable measurements, but it does not replace a careful examination by an optometrist.
The slit lamp is a specialised microscope that allows us to examine the eyelids, lashes, tear film, cornea and conjunctiva at high magnification.
During this examination, we look for signs such as:
- Eyelid inflammation
- Blocked meibomian gland openings
- Thickened or abnormal gland secretions
- Blepharitis or Demodex
- Ocular allergy
- Conjunctival inflammation
- Corneal dryness or epithelial damage
- Signs of infection or another eye condition
Digital images may also be taken to document important findings and help you see what we can see.
Ocular surface staining
To understand how dryness is affecting the eye tissue, we use small amounts of diagnostic dyes such as fluorescein and lissamine green.
These dyes are widely used in eye care and usually cause little or no discomfort. They temporarily highlight areas where the surface cells are dry, irritated or damaged.
What does fluorescein show?
Fluorescein helps us examine the cornea, assess tear break-up and identify areas where the epithelial surface has been disrupted. Under blue light, dry or damaged areas become easier to see.
What does lissamine green show?
Lissamine green highlights stressed or damaged cells on the conjunctiva and around the eyelid margins. It can provide additional information about ocular surface inflammation and the pattern of dryness.
The location and pattern of staining can help us understand the severity of the condition and may provide clues about contributing factors such as tear exposure, friction, inflammation or incomplete blinking.
Testing how well the meibomian glands work
Meibography shows us the structure of the meibomian glands, but we also need to assess their function.
Using gentle, controlled pressure on the eyelid, we observe whether oil can be expressed from the glands and what the secretion looks like.
Healthy meibomian oil is generally clear and flows relatively easily. In meibomian gland dysfunction, the secretion may be cloudy, thickened or toothpaste-like. In some areas, little or no oil may be released.
This distinction matters because glands can still be visible on imaging but may not be working effectively.
Why does such detailed testing matter?
Dry eye disease rarely has one simple cause.
One person may have reduced tear production. Another may produce enough tears but lose them too quickly because the oil layer is inadequate. Someone else may have inflammation, eyelid disease, incomplete blinking, ocular allergy or several factors occurring at the same time.
A detailed assessment allows us to move beyond a one-size-fits-all recommendation.
Depending on your results, your management plan may include:
- Advice on the most suitable lubricating eye drops
- Warm compresses or eyelid care
- Blink exercises and screen-use strategies
- Management of blepharitis, Demodex or ocular allergy
- Prescription anti-inflammatory or antimicrobial treatment
- Nutritional and lifestyle recommendations
- Contact lens changes
- In-clinic treatments for meibomian gland dysfunction and blepharitis
- Thermal treatment and meibomian gland expression
- IPL, low-level light therapy, LipiFlow or Tixel-i when appropriate
Not every patient needs advanced treatment. Our role is to identify which options are likely to be useful for your eyes and avoid treatments that are unlikely to address your particular condition.
What happens after the assessment?
We explain your results using the images and measurements collected during the appointment.
You will receive an individualised management plan based on your symptoms, clinical findings, lifestyle and treatment priorities. We can also provide a written report outlining the assessment findings and recommendations.
Dry eye management is often a process rather than a single treatment. Follow-up appointments allow us to monitor objective changes, review your symptoms and adjust the plan when needed.
Frequently asked questions
How long does a dry eye assessment take?
A comprehensive dry eye and ocular surface assessment generally requires a dedicated appointment so there is enough time to discuss your symptoms, complete the diagnostic testing, examine the eyes and explain the results. Allow 45minutes.
Does a dry eye assessment hurt?
Most testing is non-invasive and does not touch the eye. Diagnostic dyes and gentle gland assessment may be used during the microscope examination, but these are usually well tolerated.
Can watery eyes be caused by dry eye?
Yes. An unstable or irritated eye surface can trigger reflex tearing. The eyes may water excessively even though the underlying tear film is not providing effective, lasting lubrication.
Will I need dry eye treatment forever?
This depends on the cause and severity of your condition. Some contributing factors can be improved, while others require ongoing management. The aim is to create a practical plan that controls symptoms, protects the ocular surface and supports long-term eye comfort.
Can I have an assessment if I have already tried eye drops?
Yes. Many patients come to us after trying several products without enough improvement. Please bring a list—or photographs—of the eye drops, supplements and eyelid products you currently use.
Book a dry eye assessment in Auckland
At Illume Eye Care, our optometrists provide comprehensive dry eye and ocular surface assessments using advanced diagnostic technology, including the Oculus Keratograph 5M, ScoutPro tear osmolarity, digital imaging, vital dyes and slit-lamp examination.
Our clinic is located in Ponsonby, Auckland. We see patients from across Auckland and also welcome people travelling from other parts of New Zealand who are seeking a more detailed dry eye evaluation or additional support with a complex ocular surface condition.
If dry, gritty, burning, watery or uncomfortable eyes are affecting your day, a comprehensive assessment can help identify the main contributors and guide a more personalised approach to treatment.
Book a dedicated Dry Eye and Ocular Surface Assessment with the clinical team at Illume Eye Care.
References
- Lemp MA, Crews LA, Bron AJ, Foulks GN, Sullivan BD. Distribution of aqueous-deficient and evaporative dry eye in a clinic-based patient cohort: a retrospective study. Cornea. 2012;31(5):472–478. doi:10.1097/ICO.0b013e318225415a.
- Komai S, Yokoi N, Kato H, et al. Clinical implication of patchy pattern corneal staining in dry eye disease. Diagnostics. 2021;11(2):232. doi:10.3390/diagnostics11020232.