The Dry Eye Zone

Rebecca's Blog


Journal roundup: Environment, electronics and the office

Sick building syndrome and “2EH”

Journal of Occupational Health published a literature review recently about something called 2EH:

  • It’s responsible for “Sick Building Syndrome”

  • There is increasing evidence of it in indoor air in buildings

  • It’s from things like floor adhesives rather than construction materials, and especially things used to apply flooring to moisture-containing concrete

  • Concentrations are higher in the summer


Unlike other volatile organic compounds that cause SBS, 2EH can be retained in indoor air for long durations, increasing the likelihood of causing undesirable health effects in building occupants exposed to it. As a precautionary measure, it is important to use flooring materials that do not emit 2EH by hydrolysis, or to dry concrete before covering with flooring materials.

More: Comprehensive review of 2-ethyl-1-hexanol as an indoor air pollutant. (Wakayama et al, Jan 2019)

Smartphones, tablets and computers

See separate blog post here.

Pollution and tear film lipids

Environmental Science and Pollution Research International studied people in urban and in industrial zones in Argentina to learn the effects of different levels of particulate matter on dry eye.

The incidence of dry eye was greater in the industrial zone (p < 0.001), showing in both populations for this pathology higher FA ω-6 levels, which are responsible for the inflammation process. The lipid profile in populations exposed to higher levels of PM10, like the industrial zone, shows a differentiated profile of FA and more incidence of dry eye with higher FA ω-6 levels, which are responsible for the inflammation process.

More: Comparative study of tear lipid composition in two human populations with different exposure to particulate matter in La Plata, Argentina. (Gutierrez et al, Jan 2019)

Computers, blink interval and TBUT

International Journal of Ophthalmology published a study recently where 930 Visual Display Terminal users were tested to see if their tear film break-up time was shorter than their blink interval - in other words, if their tears were evaporating faster than they were blinking (blinking secretes more tears).

If their TBUT was shorter than their blink interval, they were considered to have an unstable tear film. So a whopping 80% had an unstable tear film by this standard, and being over 40 years old made you more likely to fall into that category, while wearing contact lenses would actually work in your favor. Interestingly, though, apparently the people with an unstable tear film didn’t actually feel worse.

Almost 80% of the subjects were categorized into the unstable tear group. Unstable tear group has significantly lower Schirmer values and TBUT (17.5±11.6 vs 21.1±11.5 mm, 3.7±2.6 vs5.7±2.7s, both P<0.001). There were no significant differences in epithelial staining or severity of symptoms….

More: Association between tear film break up time and blink interval in visual display terminal users. (Uchino et al, Oct 2018)