Ocular Surface Morbidities in Glaucoma

Introduction: Ocular surface disease (OSD) is a major cause of ophthalmological consultation. Within this group, glaucoma patients constitute an important percentage due to the nature of their chronic topical treatment. Advances in the understanding of ocular surface pathology on both a cellular and molecular level, and the interaction to the toxic nature of some topical medication solution compounds, are stimulating the development of better alternatives in topical treatment. Materials and Methods: Extensive review of available literature and current research on topical ophthalmological treatments in both OSD and glaucoma was performed. Emphasis was made on inflammatory modulators of the ocular surface and pathological changes associated with the use of preservatives in solutions, in particular benzalkonium chloride (BAK). Independent research is been also performed by the authors, using a rubbing-induced reflex tears collecting method with capillary tubes. Cytokines in tear samples were subsequently analysed with the multi-Plex System (Luminex® R-200). The 12 cytokines analysed using this method are the interleukins (IL)-1β, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12, the tumour necrosis factor alpha (TNFα), the vascular endothelial growth factor (VEGF), the granulocyte-macrophage-colony stimulating factor (GM-CSF) and the interferon gamma (IFg). Results: Our unpublished, preliminary results trend to show higher values in IL-5 and IL-6 in glaucoma patients than in normal controls. Also, higher values in IL-2, IL-5 and IL-12 in DES patients were found versus normal controls. Conclusions: Inflammation is an important element in OSD and strong association seems to exist between this and the use of BAK preservative. New kinds of preservative molecules, as well as single-dose eye drops and sophisticated dispensing bottle mechanisms are currently available on the market in order to avoid the secondary effects of this topical treatments, increasing patient compliance and adherence to chronic topical glaucoma treatment.