Understanding ocular surface disease requires a robust ability to observe changes in cellular activity and responses to disease therapies. Clinicians have traditionally depended upon methods such as slit lamp microscopy, tear film break-up tests, or corneal and conjunctival staining. In conditions such as dry eye and late phase allergy, a big part of the story is the infiltration of immune cells and inflammatory mediators to the ocular surface. Methods that provide greater quantitative and temporal information on the cellular status of the cornea and conjunctival epithelium are now being implemented. Confocal video microscopy, for example, allows the ophthalmologist to monitor cell dynamics in real time, and to follow responses to treatments at a cellular level. Recent studies have looked at immune cell populations over the course of a dry eye treatment and found that changes in cell population correlated better with other signs and symptoms (such as OSDI scores) that traditional measures of surface health such as Schirmer’s or tear osmolarity. Confocal techniques can also be used for meibomian gland assessments, and have the potential to define new metrics for future clinical trials. While this method is yet to gain a position as part of the typical practitioner’s clinic, it is becoming a key part of research efforts in ocular surface disease and therapeutics.
The research and development group at Ora has optimized the use of confocal video microscopy to track the dynamics of allergic responses in the conjunctiva as part of our Conjunctival Allergen Challenge model. The method shares may traits of impression cytology, but rather than providing a single time point measure, it’s possible to follow the infiltration of immune cells into the conjunctiva over time. An example of confocal video following CAC
