Dry eye syndrome (DES) is a complex, multifactorial, immune-associated disorder 
of the tear and ocular surface. DES with a high prevalence world over needs 
identification of potential biomarkers so as to understand not only the disease 
mechanism but also to identify drug targets. In this study we looked for 
differentially expressed proteins in tear samples of DES to arrive at 
characteristic biomarkers. As part of a prospective case-control study, tear 
specimen were collected using Schirmer strips from 129 dry eye cases and 73 age 
matched controls. 2D electrophoresis (2DE) and Differential gel electrophoresis 
(DIGE) was done to identify differentially expressed proteins. One of the 
differentially expressed protein in DES is lacrimal proline rich 4 protein 
(LPRR4). LPRR4 protein expression was quantified by enzyme immune sorbent assay 
(ELISA). LPRR4 was down regulated significantly in all types of dry eye cases, 
correlating with the disease severity as measured by clinical investigations. 
Further characterization of the protein is required to assess its therapeutic 
potential in DES.