Importance of inflammation in dry eye

According to Prof. Stefano Barabino (Clinica Oculistica, University of Genoa, Italy) our approach to dry eye must take into account the fact that it is an inflammatory disorder. In his presentation at the World Ophthalmology Congress in Abu Dhabi, United Arab Emirates, Prof. Barabino discussed the importance of inflammation in the treatment of dry eye.

"First of all," Prof. Barabino said, "when we are talking about dry eye we should keep in mind that we are dealing with the ocular surface." He went on to explain that the ocular surface comprises the tear film, lacrimal glands, corneal and conjunctival epithelia and the meibomian glands, which all work together to protect the ocular surface.

"However, is it dry eye if there is inflammation on the ocular surface," he questioned. "The majority of you will think the answer is yes... so why would you be correct?"

In 2005, Prof. Barabino and the team of Prof. Reza Dana conducted an investigation at the Schepens Eye Research Institute, Harvard University, Boston, USA, on mice in a controlled-environment chamber to determine what effect low-humidity and air flow would have on ocular surface signs.¹ These mice developed dry eye to a statistically significant level when compared with a control group of mice. In particular, they demonstrated that fluorescein corneal staining was increased, and that surprisingly tear secretion was decreased after 7 days of exposure to the controlled environment. Also, based on the technique previously developed by the group, the cornea of mice was studied for immunological cells.

Prof. Barabino said, "We used specific markers for macrophages and dendritic cells in these mice corneas and we found that in the periphery and also the centre of the cornea, there is an increased number of these cells, which indicated the presence of an activation of immunological cells in the cornea in mice with dry eye disease."