Each year at the annual meeting of the Association for Research in Vision and Ophthalmology (ARVO), renowned scientists share their valuable research on a range of topics. This year’s meeting in Denver was especially full of clinically relevant studies that can be applied to practice today, and I’m pleased to be able to share some of the most interesting abstracts from the cornea and contact lens areas in this issue (see pg. 12). In addition, however, I’d also like to take a closer look at two problems that plague the dry eye patient.

Under the heading of dry eye disease, the papers and posters that garnered the most attention were those about neuropathic pain and clinical depression in dry eye sufferers. Much has been written about the relationship between pain and depression in various diseases—for example, neurosensory dysfunction has been shown to be a component of dry eye and its symptoms.¹ 

Neuropathic pain is often described as a burning, tingling or electric type of pain.¹ In addition, spontaneous pain, pain as a response to normally non-noxious stimuli and exaggerated pain are hallmarks of neuropathic pain.^1,2 Dry eye patients with neuropathic pain are more likely recalcitrant to conventional therapies directed at treating the ocular surface.¹ Thus, in order to effectively treat these patients, this subset with neuropathic pain must first be identified and then educated on the chronic nature of their disease.² One way to do this is through the use of questionnaires.¹ 

Several risk factors for dry eye signal an underlying etiology that involves chronic pain or somatization and may account for why tear parameters seldom predict symptoms in dry eye patients.² Essentially, looking at systemic connections is key. Depression is likely a problematic response to the disease process in many patients who suffer with this disease.

ARVO Abstracts
Program 4445, “Incomplete Response to Artificial Tears in Associated with Self-Reported Features of Neuropathic Ocular Pain,” reported that an incomplete response to artificial tears more frequently endorsed symptoms of neuropathic pain and more severe ocular and non-ocular pain compared to those who reported complete response to therapy.³ This may help explain many of the responses we see clinically with a step-up approach to the necessary echelon therapy in treating dry eye patients.

Program 352, “Human Serotonin Levels and Neuropathic Ocular Pain in Dry Eye,” examined serotonin levels as a potential clinical descriptor for neuropathic pain. The researchers found patients with dry eye symptoms and reduced tear production may have higher tear serotonin levels than those with dry eye symptoms and normal tear production, as patients with dry eye symptoms and normal tear production more frequently describe features of neuropathic pain. The results of their study suggest that this group may have central abnormalities in their ocular sensory apparatus driving their symptoms. 

Program 312, “Depressive Symptoms in Dry Eye Patients: A Case-Control Study Using the Beck Depression Inventory,” looked at depressive symptoms in dry eye patients using the well-established Beck Depression Inventory. The researchers found that, overall, patients with dry eye exhibit more symptoms of depression compared to controls without dry eye. An important part of their conclusion section states that with the presence of depression in dry eye, patients may perceive their symptoms in an anomalous fashion that ultimately will likely affect their treatment decisions.

While just a snippet of the complete lineup, the above abstracts from ARVO 2015 highlight the value of the data presented at this fabulous meeting every year. They also show us that we have to be aware of the comorbidities in dry eye patients that are a direct or indirect result of their condition. As such, we must continue to develop clinical interventions to provide the best treatment possible for those afflicted with dry eye disease.  

1. Galor A, Levitt RC, Levitt ER, et al. Neuropathic Ocular Pain. Eye 2015;29(3):301-12.
2. Medscape. Depression, Pain More Common in Dry Eye Than Tear Film Flaw. Available at: www.medscape.com/viewarticle/835592. Accessed May 14, 2015.