Research in the field of dry eye

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1Optometry and Vision Research Weinheim, Weinheim, Germany

Professor Jennifer P. Craig is a therapeutically qualified academic optometrist. Her main research interest is ocular surface disease, including dry eye and tear film dysfunction. She is professor in the Department of Ophthalmology at the University of Auckland in Australia. She currently heads a team of doctoral, postdoctoral, and undergraduate researchers and leads international multicentre clinical trials, within the Ocular Surface Laboratory at the University of Auckland. Prof. Craig has an H-index of 35, with over 135 peer-reviewed publications and over 70 articles in the professional press. OCL Editorial Board member Dr. Heiko Pult spoke with Professor Craig about her professional career as well as the entire complex of dry eye.

Prof. Dr. Jennifer P. Craig

Prof. Dr. Craig, like so many others, you studied optometry and qualified as an optometrist in Scotland after the so-called pre-registration year. After that, you did a PhD at your initial University and started a unique career. How did this happen? What was your motivation?  

A unique opportunity to undertake a summer elective project in a hospital ophthalmology department between my final two years as an Optometry student opened my eyes to hospital optometry and exciting possibilities, including research, that existed beyond conventional optometry private practice. This led to my seeking pre-registration training at Glasgow Eye Infirmary. I’d say this early experience that highlighted some of the exciting options of where my Optometry degree could take me, was instrumental in my decision to accept the offer to undertake a PhD under the supervision of Professor Alan Tomlinson at Glasgow Caledonian University.

What are your main your areas of research expertise? 

Ever since my PhD which looked at tear film in the normal and dry eye, I’ve retained an interest in ocular surface disease and a primary focus on dry eye disease.  Although I’ve spent time working in other areas such as the cornea and refractive surgery, it seems to be the tear film and dry eye disease that continues to capture my attention. Over many years, I’ve had a particular interest in the role of the tear lipid layer and in meibomian gland dysfunction that leads to evaporative dry eye disease.

What made you decide to concentrate on research in dry eye? 

I think it’s the unexplored nature of this field and the potential to make a difference for patients affected by this disease, that has fuelled my passion for this area.  Although dry eye disease is so common, the way in which it has been managed in clinical practice in the last 20-30 years has been suboptimal.  With research leading to new knowledge in this area, it has allowed clinical practice to change for the better in the last decade and we’re seeing increased success in managing this debilitating condition. Basing clinical decisions on high quality evidence remains paramount, though, therefore I find it important to continue the research in this area to make sure that clinicians can be provided with the best information to facilitate their decision-making when helping patients with dry eye.

What is your estimate of the development of dry eye world-wide 

The prevalence rate according to epidemiological research acknowledges that somewhere between 5 and 50% of the population is affected, depending on how you define the presence of dry eye, but according to current consensus diagnostic criteria, we might typically expect to see dry eye disease affect around one quarter to one third of our patients.  As for the apparent increasing rate of dry eye disease, I think there are several reasons. It’s likely partly a function of the closer attention we’re paying to the disease, so that we’re recognising and acknowledging it more readily. There’s growing awareness amongst the public, too, encouraging patients to seek advice from eye care professionals.  Mainly, though, I believe that lifestyle choices we make are influencing dry eye disease prevalence – everyday lifestyle challenges to which we expose our eyes are exacerbating the condition so that it’s becoming a growing concern, especially as we see it affecting younger individuals than ever before.

Given its impact on quality of life and work performance for example, one may feel dry eye is underrated as a disease, where its status tends to be ranked relatively low in normal daily practice and patients get assigned fairly non-specific treatment recommendations. Do you think eyecare practitioners should put stronger emphasis on this topic?  

Absolutely! If, as clinicians, we can identify those affected and offer solutions at an early stage in the disease process, there is the possibility of minimising the ongoing impact of the disease and promoting a better quality of life for our patients. Dry eye disease can be highly debilitating, not only in terms of causing ocular discomfort but also reducing visual quality. Optimising quality of vision is a key part of our role as optometrists, so I would argue that we have a duty of care to offer (or refer for) comprehensive dry eye assessment and management. It can often be very straightforward to manage and doesn’t need to depend on expensive equipment.

You are a founding Member of the Tear film & Ocular Surface Society. Can you give us more details about aims and what TFOS is doing?

The mission of the Tear Film and Ocular Surface Society (TFOS) is to advance the research, literacy and educational aspects of the scientific field of the tear film and ocular surface. TFOS was incorporated as a not-for-profit organisation in 2000, and has a growing network of over 5000 scientific, clinical and industry-based members in over 80 countries. TFOS endeavours to bring these individuals together, in person or virtually, to drive advances in the field to benefit patients. The organisation has been doing this over the last 20 years through conferences and networking events, and through its international Workshops which are some of its most celebrated initiatives. 

TFOS has initiated many different Workshops that have resulted in publication of the TFOS DEWS Report (2007), the TFOS MGD Report (2011), the TFOS Contact Lens Discomfort Report (2013), and the updated TFOS DEWS II report (2017), and it has recently commenced the TFOS Lifestyle Workshop. What was and is your role in those? 

I first became involved as a member of the TFOS Meibomian Gland Dysfunction Workshop, working with Dr Dan Nelson who was chair of the Definition and Classification Subcommittee.  Subsequently I was appointed as a steering committee member and subcommittee chair on the Contact Lens Discomfort Workshop, where I was responsible for leading the subcommittee that explored the impact of contact lenses on the tear film as a driver of contact lens discomfort.  I was then most fortunate to be invited to serve as Vice Chair of the second Dry Eye Workshop, TFOS DEWS II, where I also co-chaired the Definition and Classification Subcommittee and served on the harmonisation committee.  I am now extremely honoured to serve as Chair of the latest TFOS Workshop; A Lifestyle Epidemic: Ocular Surface Disease, which is exploring the impact of the wide range of lifestyle challenges we expose our eyes to, on ocular surface health.

What do you think is the benefit of those reports to practitioners versus scientists? 

There’s potential benefit to both groups in my opinion.  For the scientists, the reports are a fantastic resource, collating and synthesising the highest quality evidence that exists in the scientific literature – some of the individual subcommittee reports have over 1000 references. It summarises the existing knowledge in the field and identifies gaps and this helps drive relevant research in the future.  Ultimately, however, the mission of TFOS is to improve quality of life for patients affected by ocular surface disease, so the key outcomes of these Workshop reports are critical for practitioners who provide care for these patients. By basing their recommendations on the report outcomes, clinicians can be confident that they are providing their patients with up-to-date, non-biased, evidence-based knowledge, and helping them to achieve the best possible outcomes.

 The TFOS DEWS II report suggests a master algorithm in the diagnosis of dry eye. This one includes non-invasive observation techniques, requiring expensive instruments like a Tearscope-like instrument, an osmolarity system or meibographer. What do you think should be the minimum technical equipment required when a clinician starts to build up a dry eye clinic? 

Certainty in diagnosis increases with the use of a defined battery of non-invasive tests, but it is actually possible to make a dry eye diagnosis with the minimum of a positive symptom score on a validated questionnaire (either OSDI or DEQ-5), and evidence of reduced tear film stability or ocular surface staining (cornea, conjunctiva and/or lid wiper), both of which can be performed in routine eye clinic settings after instilling a tiny amount of sodium fluorescein. Using a yellow barrier filter in addition to the blue excitation filter on the slit lamp further enhances visualisation of the fluorescence, minimising the volume of fluorescein needed.  
For practitioners keen on building up a dry eye clinic, I would say that establishing a means of assessing the tear film stability non-invasively is next most important.  Non-invasive measures are preferable as the very action of instilling fluorescein is disruptive to the tear film. A non-invasive tear film breakup time can be performed with any ophthalmic instrument that reflects mires from the surface of the eye, and a stopwatch. Any topographer or keratometer, or a Tearscope-like device with a grid or placido ring pattern will suffice.  The time taken for distortions or disruptions in the reflected pattern to become visible after a blink, is recorded the ‘breakup time’.  Practitioners investing more heavily in dry eye may choose to use a dedicated instrument such as the Oculus Keratograph to provide an automated measure, but the stopwatch method can work perfectly well in clinical practice.  Tear hyperosmolarity is a key feature in dry eye disease but the equipment needed to measure this in practice is more costly and so its use tends to be limited to more specialist practices.


Professor Craig at a clinical teaching session

Would you envisage that this algorithm can be shortened and/or optimized and do you already have some evidence how to do it? 

Diagnosis via the full TFOS DEWS II criteria remains optimal, as this promotes consistency in the diagnoses provided to patients and allows comparison of dry eye prevalence rates most reliably across different sites and different countries. However, where the full complement of equipment isn’t available, our research has shown that, with a brief non-invasive screening algorithm comprising the SANDE questionnaire (which records frequency and severity of dry eye symptoms on a visual analogue scale) and non-invasive tear film stability, dry eye disease can be diagnosed with a sensitivity of 86% and a specificity of 94%. Adding an assessment of tear meniscus height and lipid layer grade offers further insight into the dry eye subtype – aqueous deficient, evaporative or mixed.

In the daily routine of standard eye exams, time is valuable. However, one risks overlooking dry eye in some patients if not specifically addressed in this eye exam. What would be a good starting point to detect dry eye patients who can then be invited to an extra dry eye consultation?  

I think having the result of a validated questionnaire and a tear film stability measure is a really good starting point in any dry eye consultation.  An OSDI score of ≥13 or a DEQ-5 score of ≥6 plus a tear breakup time of < 10 seconds is indicative of dry eye disease and of the need for further assessment. At a subsequent consultation, the patient should be evaluated more comprehensively using a larger battery of tests to establish the severity and subtype from which the most appropriate management strategy can then be selected.

How has the perspective changed in treating dry eye today compared to 10 years ago? Are there new approaches on the horizon? 

We’re moving away from the concept of a ‘one size fits all’ management approach.  It’s more widely recognised that lubricants alone are not going to address the issues faced by most patients with dry eye.  There’s a definite move to address the root causes of dry eye rather than taking a palliative approach of simply managing the symptoms.  Reassuringly for patients, there’s a far wider range of treatments available today than a decade ago, particularly for the treatment of evaporative dry eye disease caused by meibomian gland dysfunction (MGD).  There’s been significant investment in research and development in dry eye, which means there are always new products and innovative solutions on the horizon. Currently these include pharmacological approaches for treating MGD and in-office thermal pulsation therapies which have the potential to offer benefits beyond those achievable with the current standard of care offered by warm compresses and lid hygiene. 

Your family cultivates many Scottish traditions like playing the bagpipes and dancing, yet you’re living on the other side of the world. What brought you to New Zealand and how have you upheld these Scottish traditions? 

I was a professional ceilidh dancer who had been playing amateur ‘fiddle’ (violin) in trad music sessions in Scotland when my career took me to New Zealand to take up an academic post in the Department of Ophthalmology at the University of Auckland. Before long, I discovered the passion of Scottish ex-pats and descendants of Scots to maintain and promote Scottish traditions. Even though I didn’t actively encourage my children to take up bagpipes and drums, their regular exposure to the traditional music scene through my involvement in ceilidh dancing, and as a dance caller, seem to have inspired them to celebrate their Scottish roots through music.  My ophthalmologist husband, who has Scottish heritage, and my younger son both play the snare drum, while my older son plays the bagpipes. 

The majority of international, scientific conferences covering your research topics are in the USA and UK, however there is a nest of researchers in Australia, Asia and New Zealand, how does this fit together? How do you deal with travelling? 

I used to spend a good many days each year dealing with jet lag, but not in the last two years.  International travelling has sadly become extremely limited due to the global pandemic, and the inability to attend conferences in person and to network effectively is being felt by researchers not only in the Asia Pacific region, but around the world. Fortunately, a major benefit of living in this digital age is the ability to maintain international collaborations and continue to pursue research goals remotely. Until such time as we can safely travel to meet in-person, scientific conferences have continued to be held virtually using innovative platforms to allow the latest research findings to be shared across the world. While it’s not the preferred format for many of us, in some cases, this modality has demonstrated benefits, as it has facilitated attendance for those who might otherwise be unable to travel long distances due to the time and costs involved.

What is your next phase of your research in this area? 

I’m extremely lucky to work with an enthusiastic team of researchers who are currently involved in a number of projects that aim to help us better understand the epidemiology and pathophysiology of dry eye disease. In addition, we have several diagnostic accuracy studies underway, as well as a number of projects evaluating the effectiveness of various strategies for managing dry eye disease. We’re currently investigating blinking exercises as a treatment modality for some forms of dry eye disease, and evaluating the efficacy of dry eye therapies such as quantum molecular resonanace, thermal pulsation, and novel pharmaceutics.

How do you see a practising optometrist benefitting from your research in their daily routine?  

We try to ensure the key messages from our research are relevant for practising optometrists in their everyday clinical interactions with patients. Much of our research seeks to answer questions clinicians want to know the answer to, in order to feel confident that they’re providing their patients with the best possible care. Robust scientifically designed studies are challenging to perform in commercial practice.  The academic setting allows us to conduct randomised controlled trials that can prove, with more certainty, how effective different therapeutic strategies are, and identify specific patient groups that respond most favourably.  Our double-masked studies can also reveal important risks associated with common practices, such as the observation that ocular surface damage can occur with the use of dilute baby shampoo for lid hygiene in patients with blepharitis.