How is dry eye diagnosed?

Getting an accurate diagnosis of your dry eye is essential but this complex ocular disease is not always easy to pin down. If you think you might have dry eye the Dry Eye Zone recommends that you pop along to see an independent eye care professional, many of whom take a special interest in the diagnosis and managment of this increasingly common eye condition.

Dry eye is an inflammatory condition caused by poor natural tear quality or quantity, and because your eye care professional understands this more than any other health care professional they know what to look for …

Starting with a few questions

Your eye care professional will most likely start with asking you to describe your symptoms and your life style. This will give important clues as to what they will look for next and could offer some simple solutions to the problem.

The type of questions will certainly include some about the  severity, frequency and type of symptom you are experiencing, your health in general, any medication you are taking and the amount of time you spend concentrating on screens or reading. There are established questionnaires which will provide you with a score to indicate the severity of your symptoms. These have been developed over many years and are available to use online.

Taking a closer look

Eye care professions almost universally use an instrument called a slit-lamp. This is a horizontally mounted bio-microscope that allows then to zoom in to get a better look at the surface of your eye. By adjusting the focus they will be able to actually look your tears, in particular the tear meniscus (a reservoir of tears found along the edge of the eye) a reduced height might mean you are not producing enough of the aqueous (watery) tear layer.

They might also ask you to blink and then stare straight forward without blinking – during this time the eye care professional will be getting an idea of how stable your tears are – if they ‘break-up’ too quickly (typically less than 10 seconds) this is more than likely an indication of compromised tear quality. This is called the tear break up time or TBUT.

Signs of eye surface damage

There might also be signs that your tears are no longer fully protecting your eyes in the form of surface cell damage. A dye called fluorescein is applied which will show up patches of cellular disruption – this is referred to as staining and your eye care professional will examine the extent and patterns on the ocular surface.

Eye lids need to be included

During the initial slit-amp examination the condition of the eyelids will be reviewed. Signs of blocked meibomian glands will be noted, eyelid swelling and any deposits around the base of the eye lashes.

And they might even give your eye lids a little squeeze to access the quality of the meibum oil you are producing. If it is more like toothpaste than olive oil in consistency you could have meibomian gland dysfunction – a leading cause of evaporative dry eye.

Tear concentration

One of the most reliable indicators of dry eye is the concentration or saltiness of your tears (your eye care professional might refer to this as osmolarity). A tiny sample of your tears can be taken and measured using specialist diagnosis equipment. An elevated saltiness (known as hyper-osmolarity)  strongly correlates to the presence of dry eye disease.

Signs of inflammation

At the beginning we said that dry eye is an inflammatory condition. Inflammation is part of your body's natural defence mechanism. In the case of dry eye it is a response to changes in the ocular environment, such as your tear film becoming too salty, which then triggers a process by which the immune system recognizes and attempts to rebalance these potentially harmful changes. Another diagnostic tool available is a lateral-flow test that measures certain inflammatory biomarkers. Once again a tiny tear sample is taken and the level of these inflammation indicators measured – a higher than normal level of the protein MMP-9 suggests that you have active ocular inflammation that might be due to dry eye disease.

Expert analysis

None of these indicators will be taken in isolation, instead your eye care professional will take all this data and use it make a diagnosis. They are likely not to just tell you that you have dry eye but what type of dry eye too. Your dry eye could be due to too few tears or poor quality or a combination of both. Getting this initial diagnosis right means that the management routine suggested will have the best change of slowing or even halting the progression of your dry eye.

Make sure you explore the many links in this blog to bring more depth to the subjects touched on here and to help give you a fuller knowledge of all things dry eye related.

You can learn more about all things dry eye related at the DRY EYE ZONE. Don’t forget to subscribe to the regular free information and research updates.

If you are experiencing dry eye symptoms then you should ask the advice of your eye care professional. Why not book your next eye examination with an independent optician today.

Sources:

L. Jones et al. TFOS DEWS II Management and Therapy Report. The Ocular Surface xxx (2017) 580e634

http://dx.doi.org/10.1016/j.jtos.2017.05.006

Okumura Y, Inomata T, Iwata N, Sung J, Fujimoto K, Fujio K, Midorikawa-Inomata A, Miura M, Akasaki Y, Murakami A. A Review of Dry Eye Questionnaires: Measuring Patient-Reported Outcomes and Health-Related Quality of Life. Diagnostics (Basel). 2020 Aug 5;10(8):559. doi: 10.3390/diagnostics10080559. PMID: 32764273; PMCID: PMC7459853.

Aljarousha M, Alghamdi WM, Attaallah S, Alhoot MA. Ocular Surface Disease Index questionnaire in different languages. Med Hypothesis Discov Innov Ophthalmol. 2025 Feb 1;13(4):190-200. doi: 10.51329/mehdiophthal1510. PMID: 40065803; PMCID: PMC11890261.

Yuan Y, Wang J, Chen Q, Tao A, Shen M, Shousha MA. Reduced tear meniscus dynamics in dry eye patients with aqueous tear deficiency. Am J Ophthalmol. 2010 Jun;149(6):932-938.e1. doi: 10.1016/j.ajo.2010.01.004. Epub 2010 Apr 8. PMID: 20378096; PMCID: PMC2878896.

The Mayo Clinic. Dry Eye Diagnosis. https://www.mayoclinic.org/diseases-conditions/dry-eyes/diagnosis-treatment/drc-20371869#

Kim, W., Woo, I.H., Eom, Y. et al. Short-term changes in tear osmolarity after instillation of different osmolarity eye drops in patients with dry eye. Sci Rep 13, 11012 (2023). https://doi.org/10.1038/s41598-023-35965-0