Tear biomarkers for keratoconus

Abstract

Keratoconus is a progressive corneal thinning, ectatic condition, which affects vision. Recent advances in corneal topography measurements has helped advance proper diagnosis of this condition and increased research and clinical interests in the disease etiopathogenesis. Considerable progress has been achieved in understanding the progression of the disease and tear fluid has played a major role in the progress. This review discusses the importance of tear fluid as a source of biomarker for keratoconus and how advances in technology have helped map the complexity of tears and thereby molecular readouts of the disease. Expanding knowledge of the tear proteome, lipidome and metabolome opened up new avenues to study keratoconus and to identify probable prognostic or diagnostic biomarkers for the disease. A multidimensional approach of analyzing tear fluid of patients layering on proteomics, lipidomics and metabolomics is necessary in effectively decoding keratoconus and thereby identifying targets for its treatment.

Tear Mediators NGF along with IL-13 Predict Keratoconus Progression

“…10,28,29 Tear mediator profile as a noninvasive biomarker of keratoconus can act as a prognostic biomarker and may aid in the timely treatment of this heterogeneous disease. 6,32,34,46 To the best of our knowledge, there is no longitudinal study evaluating mediators in order to predict the true progression of keratoconus.…”

“…[4][5][6][7][8][10][11][12] Disease specific changes in these molecular markers can be of diagnostic value in keratoconus. 32 To the best of our knowledge, there are no studies examining these mediators in the tear fluid to predict the progression of the disease. However, early detection of progression in keratoconus is of high importance because early identification of the progressive nature of the disease allows early treatment to reduce the risk of visual impairment.…”

Pathogenesis of Keratoconus: The intriguing therapeutic potential of Prolactin-inducible protein

“…Protein levels of PIP and AZGP1 have been found to be down-regulated in tears of KC patients by proteomic analysis, suggesting their application as prognostic markers for KC (Nishtala et al, 2016; Priyadarsini et al, 2014). Our proteomics data also showed that regulation of PIP is closely related to AZGPI glycoprotein of 35–44 kDa (Hassan et al, 2008).…”

“…The human cornea plays an important role in maintaining the balance of ocular surface microenvironment (Nishtala et al, 2016). Complex array of biomolecules are secreted within the tear fluid, which are potential targets of prognostic value in ocular diseases.…”

“…Tear fluid can be collected in a painless, non-invasive fashion, making it an optimal biological fluid to analyse with minimal discomfort to the patient. Studies have been performed and several biomarkers have been suggested including PIP, zinc-alpha-2-glycoprotein (AZGP1) and lipocalin (LCN) (Lema et al, 2010; Nishtala et al, 2016). …”