Dry eye syndrome is currently a very prominent topic in optometry.
Increased awareness has caused a surge in articles written on the topic and research performed in the field. However, there are still patients slipping through the cracks that are even more at risk for dry eye syndrome or dry eye disease (DED) than the general population.
Most optometrists are aware of the most common systemic conditions and other causes of dry eyes including, Sjogren’s syndrome, Rheumatoid arthritis, lupus, and thyroid-related conditions.
Diabetes and glaucoma are two conditions that should be at the top of that list and every optometrists’ mind considering the increased risk for dry eye syndrome.
Dry Eye Syndrome and Diabetes
According to the American Diabetic Association, 29.1 million Americans, or 9.3% of the population, had diabetes in the last year reported (2012) and that number is on the rise.1
Diabetes is also one of the leading causes of blindness in persons aged 20-74. Cataracts and diabetic retinopathy are the most thought of cause of blindness; however, ocular surface complications such as superficial punctate keratopathy, trophic ulceration, and persistent and recurrent epithelial erosions need to be realized as a common reason for decreased vision and blindness.2
Secondary complications from diabetes-induced dry eye syndrome include corneal scarring and bacterial infections.
There are three proposed mechanisms of DED complications related to systemic diabetes:3
- Metabolic dysfunction
- Abnormal lacrimal secretions
1) Neuropathy and Dry Eye Syndrome
Decreased corneal sensitivity through neuropathy of the ophthalmic branch of the Trigeminal nerve (CNV) and the long ciliary nerves leads to decrease feedback, decreased healing and basement membrane abnormalities.
This can lead to such things as neurotrophic ulcers, SPK, RCE, and non-healing corneal abrasions. This is of utmost concern for optometrists because a patient may not be complaining of symptoms, but signs of ocular surface disease may be present. It is important for optometrists to astutely assess the corneal structures looking for the aforementioned signs.
2) Metabolic dysfunction
It has been postulated that aldose reductase, which is the first enzyme in the sorbital pathway, may be involved in the process. Decreasing aldose reductase increased healthy tear dynamics in patients.
3) Lacrimal Gland Secretions
Studies using the Schirmer test to measure tear secretion values have shown a reduction in lacrimal secretions in diabetic patients compared to controls, possible due to dysfunction of the autonomic nervous system or due to damage to the microvasculature of the lacrimal glands. Furthermore, there was a decreased TBUT in diabetic patients.2 It has also been shown that diabetics’ tear protein composition differs from that of healthy individuals.3
The prevalence of dry eye disease in patients with concomitant diabetes ranges widely from high teens to over 50%. One study examined 199 diabetic patients for signs of dryness using a diagnosis criteria of decreased TBUT less than 15 seconds or Schirmer test value less than 15mm after five minutes.
The examiner also confirmed the diagnosis with ocular surface dye staining with fluorescein. They found the prevalence of dry eye syndrome in diabetic patients to be 54.3%.2 The study also found a clinically significant association between duration of diabetes and dry eye disease (p = 0.01).
Dry eye disease was also more frequent in patients with diabetic retinopathy (p = 0.02).2
Another study used a 308 mOsm/L cutoff to diagnose dry eye disease using an osmolarmeter. They found the prevalence of dry eye disease in diabetic patients to be 27.7% and also confirmed a correlation between dry eye disease and retinopathy ( p = 0.01).3 The study also showed a significant odds ratio for dry eye disease with increased HbA1C levels (p = 0.04).3
Including TearLab® Osmolarity testing and a dry eye questionnaire, such as the OSDI or SPEED, as part of your diabetic examination can not only help your patients but can be a source of new revenue.
Treatment should be initiated based on exam findings with special attention given to those patients with high HbA1C levels, long duration of diabetes, or with diabetic retinopathy, all of whom may need a higher level of dry eye disease treatment.
- Statistics About Diabetes. American Diabetes Association. http://www.diabetes.org/diabetes-basics/statistics/. Accessed November 1, 2016.
- Manaviat, M., Rashidi, M., Afkhami-Ardekani, M., & Shoja, M. (2008). Prevalence of dry eye syndrome and diabetic retinopathy in type 2 diabetic patients. BMC Ophthalmology, 8, 10.
- Najafi, Malek, Valojerdi, Aghili, Khamseh, Fallah, . . . Behrouz. (2013). Dry eye and its correlation to diabetes microvascular complications in people with type 2 diabetes mellitus. Journal of Diabetes and Its Complications, 27(5), 459-462