Advances in the clinical diagnosis and management of dry eye disease

Abstract

ABSTRACT Aim: Dry eye is a multifactorial disease of the ocular surface, with numerous causes and influences having an impact on each case of dry eye disease (DED). Therefore, the diagnosis and management of DED is a challenge for eye care practitioners. This thesis describes studies on the performance of new clinically applicable diagnostic devices recently developed for the diagnosis and classification of DED. These devices were then utilised to compare the therapeutic efficacy of a number of frequently used ocular lubricants in the management of DED. Methods: New clinically applicable devices to assess tear evaporation rate (TER) and tear osmolarity were investigated and compared to established techniques. These new devices were then used along with a battery of other techniques to investigate the therapeutic efficacy of tear supplements that contain different viscosity-enhancing or osmoprotective agents in the management of DED. Results: It was found that the new devices were comparable to the established techniques currently used to assess TER and osmolarity. A significant correlation was found between the TER measured with the new VapoMeter and the lab-based ServoMed, giving a sensitivity of 80.0%, and a specificity of 86.7% to diagnose DED. Tear osmolarity measurements with a new osmometer (the I-PEN) were found to be significantly correlated with the established TearLab osmometer. The diagnostic cut-off value for the I-PEN was 306 mOsm/L, with a sensitivity of 63.6%, and a specificity of 81.0% to diagnose DED. Therapeutic studies on various ocular lubricants found that those containing carboxymethyl cellulose (CMC), sodium hyaluronate (SH), or combining trehalose with SH showed comparable improvements in a range of signs and symptoms of DED. Conclusion: The results of the new clinically applicable devices indicate their diagnostic efficacy in the assessment of TER and osmolarity. This will aid practitioners in the diagnosis of DED, as they provide reliable, fast, commercially available options for measuring TER and osmolarity in the clinic. Viscosity-enhancing and osmoprotective agents used in artificial tears to enhance the lubrication and protection of the ocular surface were found to be effective and showed comparable therapeutic efficacy in improving the signs and symptoms of DED.