Researchers find link between pain sensitivity, ocular discomfort

Pain sensitivity plays a role in patients’ perception of ocular discomfort, according to results of a study involving 42 experienced contact lens wearers.

Because discrepancies between signs and symptoms of dry eye are frequently seen, the researchers hypothesized that pain perception may be the cause.

The subjects, whose mean age was 23.2 years, completed the Pain Sensitivity Questionnaire, and researchers assessed exposed interpalpebral area, tear meniscus height, tear-film lipid layer thickness, ocular surface cooling and noninvasive tear break-up time, according to the study.

Subjects were asked to refrain from wearing their contact lenses for at least 24 hours before their visits, which occurred twice a day over the course of 2 days. They were asked to not blink until they felt discomfort – which was referred to as the maximum interblink period (MIBP) – while researchers measured ocular surface cooling rate on the right eye only.

Researchers found in the mostly-female group that a longer MIBP was associated with decreased pain sensitivity (P = .04), lower ocular surface cooling rate (P < .001) and Asian ethnicity (P = .005).

“It is estimated that individuals would be able to refrain from blinking for an additional 4 seconds if they had the lowest (0.6) compared to the highest (6.1) pain sensitivity in the cohort,” the researchers wrote.

The authors stated that these study results point to the importance of understanding how pain sensitivity, ethnicity and sex influence the link between signs and symptoms of dry eye.

They noted that due to the youth and good health of the subjects the results may not necessarily be applied to older people. – by Nancy Hemphill, ELS, FAAO

Disclosures: The authors reported no relevant financial disclosures.

Pain sensitivity plays a role in patients’ perception of ocular discomfort, according to results of a study involving 42 experienced contact lens wearers.

Because discrepancies between signs and symptoms of dry eye are frequently seen, the researchers hypothesized that pain perception may be the cause.

The subjects, whose mean age was 23.2 years, completed the Pain Sensitivity Questionnaire, and researchers assessed exposed interpalpebral area, tear meniscus height, tear-film lipid layer thickness, ocular surface cooling and noninvasive tear break-up time, according to the study.

Subjects were asked to refrain from wearing their contact lenses for at least 24 hours before their visits, which occurred twice a day over the course of 2 days. They were asked to not blink until they felt discomfort – which was referred to as the maximum interblink period (MIBP) – while researchers measured ocular surface cooling rate on the right eye only.

Researchers found in the mostly-female group that a longer MIBP was associated with decreased pain sensitivity (P = .04), lower ocular surface cooling rate (P < .001) and Asian ethnicity (P = .005).

“It is estimated that individuals would be able to refrain from blinking for an additional 4 seconds if they had the lowest (0.6) compared to the highest (6.1) pain sensitivity in the cohort,” the researchers wrote.

The authors stated that these study results point to the importance of understanding how pain sensitivity, ethnicity and sex influence the link between signs and symptoms of dry eye.

They noted that due to the youth and good health of the subjects the results may not necessarily be applied to older people. – by Nancy Hemphill, ELS, FAAO

Disclosures: The authors reported no relevant financial disclosures.