DRY EYE DISEASE

Patients with concomitant chronic pain syndromes such as fibromyalgia tend to have more severe symptoms of dry eye disease, reported Jelle Vehof PhD at the World Cornea Congress VII in San Diego, USA. Dr Vehof and colleagues at the University Medical Centre Groningen, the Netherlands, compared dry eye signs and symptoms in two groups of patients in the Netherlands and the UK.

All patients completed the Ocular Surface Disease Index (OSDI) questionnaire. Patients with chronic pain syndromes such as fibromyalgia, irritable bowel syndrome and pelvic pain had higher symptoms scores in every one of the 12 items on the index, with six reaching statistical significance in the UK group and three in the Dutch group. These include light sensitivity, blurred vision and discomfort in windy conditions.

However, a comprehensive evaluation of clinical signs in patients with and without chronic pains syndromes found no significant difference in factors such as tear osmolarity, tear break-up time, or Schirmer’s tests.

“These findings suggest a role for central sensitivity for neuropathic pain in at least part of the dry eye population. This could help explain the poor correlation between symptoms and signs at the ocular surface. This could also help us with management of patients with dry eye disease,” said Dr Vehof.

PAIN SENSITIVITY

In a previous related study (JAMA Ophthalmol. 2013;131(10):1304-1308), Dr Vehof and colleagues looked at the relationship between dry eye disease and pain sensitivity. That study was based on the TwinsUK study, a population-based cross-sectional study of 1,635 female twin volunteers, aged 20 to 83 years.

In that study, 27 per cent of patients met the criteria for dry eye disease. A subset of women completed the OSDI questionnaire. The researchers used quantitative sensory testing using heat stimulus on the patients’ forearms to assess pain sensitivity, expressed in terms of heat pain threshold and pain tolerance .

The testing showed that patients with dry eye disease had a significantly lower heat pain threshold and pain tolerance. This indicates that the patients with dry eye disease had greater sensitivity to pain than those without dry eye symptoms.

These findings add another piece to the puzzle that is dry eye disease. Previous reports show associations of dry eye disease with the severity of tear insufficiency, cell damage, and psychological factors.

“Given the generally poor relationship between symptoms and signs in DED, it would be useful to examine whether any particular clinical findings in DED populations (such as corneal staining, reduced tear break-up time, or reduced Schirmer values) relate to pain sensitivity and pain symptoms,” the researchers note.

Jelle Vehof: j.vehof@umcg.nl