Affecting millions of Americans, especially the elderly, dry eye disease is one of the most common reasons for patient visits to an ophthalmologist. And yet, it remains a challenging condition for ophthalmologists to treat, due to the lack of understanding of its root causes.
As a disease with multiple underlying factors, it is challenging to diagnose or treat dry eye disease. On the diagnostic front, there has been a lack of consistency in the clinical work-up with no single test that is both readily available and reproducible. This lack of objective tests has hampered the development of new treatments for the disease.
As a solution to this problem, there has been a growing interest in identifying objective biomarkers that can be used as diagnostic tools for dry eye disease, and for objectively monitoring the progression of the disease and efficacy of treatments. In published studies, USC Roski Eye Institute researchers, Drs. Sarah Hamm-Alvarez and Maria Edman, analyzed tears in Sjögren’s Syndrome patients to identify diagnostic biomarkers for the autoimmune disease, which can cause dry eye that shows a significant change in water and specific protein levels. The result of their study was that the increased activity of the protease, Cathepsin S, was a potential biomarker for Sjögren’s Syndrome. The next step was to find biomarkers for additional subtypes of dry eye disease.
This year, researchers from the USC Dry Eye Center of Excellence (whose members includes Drs. Hamm-Alvarez and Edman) received an IRB approval to create a tear biorepository for identifying biomarkers for subtypes of dry eye. The USC Dry Eye Center of Excellence is comprised of a multidisciplinary team of USC Roski Eye Institute clinicians led by Dr. Annie Nguyen as well as other basic scientists from USC Roski Eye Institute and other USC schools (Keck School of Medicine, School of Pharmacy and Viterbi School of Engineering).
Patients seeking care for dry eye at the USC Roski Eye Institute already receive a thorough work-up according to the recommendations of the DEWS II workshop, which includes dry eye questionnaires, slit lamp examination, Schirmer’s test, tear osmolarity, lipid layer evaluation and MMP-9 testing. Together, these measurements provide an excellent view of each patient’s level of aqueous deficiency, meibomian gland disease and ocular surface inflammation. With the patient’s consent, the USC Dry Eye Center of Excellence researchers will store the tears generated during clinical work-up, as well as the clinical data, in the tear biorepository.
The tear biorepository will create a solid foundation for furthering the development of Cathepsin S as a biomarker for Sjögren’s Syndrome, testing its performance against other subtypes of dry eye and correlation with different clinical parameters. It will also allow researchers to characterize new alterations in tear composition in patients with different underlying conditions, varying degrees of meibomian gland disease, aqueous deficiency and other dry eye parameters. This will not only further the understanding of the different dry eye conditions but may also help identify new biomarkers and therapeutic targets.
The hope is that this will benefit a wide range of subsets of dry eye patients, paving the way for personalized medicine. Finally, the deep characterization of the dry eye disease population at the USC Roski Eye Institute will allow for better design of clinical trials for dry eye treatments performed at the clinic.