We must think outside of the box when it comes to dry eye treatment
When it comes to managing dry eye, let’s start thinking of something better than artificial tear replacement.
At Clinica London, we have the Tears Clinic which is for patients who have dry eyes and watering eyes. We now regard dye eye disease as a virtual epidemic which is likely to expand. Soon, the type of patient with dry eyes that ophthalmologists typically see will expand beyond the classical elderly female. We now see many younger men and women of all ages wanting to know why they have dry eyes and what the treatment options are available.
When I was a medical student, I remember my mother saying she had dry eyes. Her doctor gave her a bottle of hypromellose drops to use. That was the be-all and end-all of treatment. She sometimes used the hypromellose drops, but it seemed to be pretty ineffective. I do not think she liked having dry eyes.
Fortunately 20-30 years later patients presenting with dry eyes have many more treatment options. Perhaps there is a verifiable increase in the number of patients with dry eyes, i.e. an increased prevalence, or perhaps we have become more sensitive to the diagnosis. Personally, I think there has been a real increase. We live longer, and our lives are “more developed”. We have more air conditioning. We have central heating. We have more screen use, and we work harder with longer hours in those environments. Also, we have significantly changed our diet.
Our longer living population means that more patients have refractive treatments including contact lens wear, laser refractive surgery and cataract surgery all of which play a role in the development of dry eyes. Even the increased treatment of glaucoma with glaucoma drops has some contributory role in drying eyes.
Increased awareness of systemic diseases, such as autoimmune Sjogren’s disease, rheumatoid arthritis, thyroid disease are all contributing their link to the development of dry eye disease and helping us to detect it and treat it earlier. I recently learned that even men who are on anti-androgen treatment because of prostatic hypertrophy or for prostatic cancer are more at risk of dry eye disease. Meibomian gland dysfunction increases with those drugs.
Just because we name this condition dry eye disease, that implies that the eyes are not wet and that they are dry, does not mean that just adding tear volume in the form of lubricant drops should solve the problem. We must think outside of the box when it comes to dry eye treatment.
If the eye is dry, then you should wet it. Therefore, artificial tears have been the mainstay of dry eye disease treatment for decades. For example, my mother had hypromellose. However, a new understanding of inflammatory cytokines and tear films and imbalance of the ocular surface tear film has led us to better understand the treatment of dry eye disease over the last 20 years.
We can now much better recognise tear film inflammation. We now know that tear quality is more important than just quantity. We now recognise whether a patient has a primary deficiency of aqueous tears called primary aqueous deficient dry eye, or whether they have evaporative dry eye associated with meibomian gland dysfunction or a combination of the two. Both of those produce inflammation of the ocular surface which triggers a continued inflammatory cycle which causes stress on the eye surface and leads to responses which cause dry eyes from an imbalanced and unstable tear film.
It is estimated that about 85% of dry eye disease is associated to some degree or other with a lipid layer imbalance from the lid margin disease and meibomian gland dysfunction. Because a normal lipid layer is required to maintain a smooth protective barrier at the front of the ocular surface, any disruption of this layer also has a disruption on the patient’s vision. So, the refraction of the patient, in other words, how well they see, can be disrupted where there is a regular breakup of the tear film and ocular surface stress.
The many causes of dry eye disease – or risk factors – include age, being female, having a systemic autoimmune disease and lifestyle environmental factors with hormonal fluctuations. Ageing, meibomian gland atrophy and immunological disease identify as key factors in this multifactorial disease of dry eyes.
We must assess each patient as to how the variable degree of these factors contributes to his or her specific dry eye disease. By making an effective diagnosis, we can offer a more effective treatment that consists not merely of lubricant drops.
To diagnose dry eye disease, we now measure tear film osmolarity and look at inflammatory markers and structural imaging of the meibomian glands to help more accurately diagnose and improve targeted guided treatment for dry eye disease. We now have scientific evidence for the pathophysiology of the disease and can measure and monitor a treatment’s effectiveness. Anti-inflammatory treatment, with Cyclosporine drops, is not necessarily the first line. Instead, it can be a part of the ocular surface inflammation treatment in some patients who have not responded to more conventional treatments.
All ophthalmologists now encounter dry eye disease in patients:
- the anterior segment refractive surgeon,
- the glaucoma surgeon,
- the retinal surgeon and
- the oculoplastic surgeon.
One of the main reasons that oculoplastic surgeons now get so closely involved in the treatment of meibomian gland dysfunction and dry eyes is that we are looking after the eyelids and the surface of the eye every day. Many patients with dry eyes have symptoms and a feeling of wetness. Therefore, with our new understanding of this disease, innovation and new products will arise to help tackle the symptoms and signs.
With anti-inflammatories, specific lid margin treatments, even nerve stimulation within the nose, future biogenic modification and possible stem cell therapies, the next five years look to be very interesting for patients with dry eye disease. We as ophthalmologists will offer more symptomatic relief and even reversal of some of the changes that have caused dry eye disease.