Ceramides in the pathophysiology of the anterior segment of the eye

Purpose: Sphingolipid (SL) research reached a peak in the past years. Yet this positive trend was not evident for eye research as the relative number of studies centered on SLs is decreasing. Our aim is to encourage the inclusion of SL metabolites in studies of ocular pathophysiology by summarizing recent findings and current awareness concerning ceramides in the anterior segment of the eye. Methods: Review of literature relating to ceramides as bioactive lipids and the extent to which their particular nature was investigated in ocular pathophysiology. Results: Ceramides are rare but indispensable lipids that influence cellular responses through their effects on membrane biophysical properties or direct interaction with target proteins. Their biological significance is increased by variability and adaptability as there are tens of enzymes designed to modulate their function. The eye offers a set of unique environments where ceramides or other SLs have not been extensively studied. Not surprisingly, ceramides were associated with apoptosis in the metabolically active tissues, while little is known about its effects on the biophysical properties of the tears or lens lipids. More so, there are still aspects of the ocular homeostasis control where SLs contribution has not been investigated to date (e.g. pathogen aggression). Conclusions: Ceramides and SL metabolism still receive increasing attention and have proven to be a significant metabolite in many research fields (e.g. cancer, stress response and inflammation) and there are yet many questions that they will aid answer. With the present work, we seek to increase awareness of these lipids also in eye research and to highlight their importance as common regulators of various diseases.