1. American Optometric Association. http://www.aoa.org/patients-and-public/eye-and-vision-problems/glossary-of-eye-and-vision-conditions/dry-eye?sso=y Accessed April 16, 2017.
  2. National Eye Institute. https://nei.nih.gov/health/dryeye/dryeye Accessed April 16, 2017.
  3. Mayo Foundation for Medical Education and Research. http://www.mayoclinic.org/diseases-conditions/dry-eyes/basics/definition/con-20024129 Accessed April 16, 2017.
  4. The International Dry-Eye Workshop (DEWS Report). The Definition and Classification of Dry Eye Disease: Report of the Definition and Classification Subcommittee of the International Dry Eye Workshop. Ocul Surf. 2007; 5:75-92.