Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
SHR Neuro Krebs Kardio Lipid Stoffw Microb
Heidinger, A; Schmut, O; Wedrich A.
Synthetische Tränen - Ein Schritt näher der menschlichen Tränenflüssigkeit.
Spektrum der Augenheilkunde. 2015; 29(3): 92-98.
Doi: 10.1007/s00717-015-0262-9
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- Führende Autor*innen der Med Uni Graz
- Heidinger Andrea
- Co-Autor*innen der Med Uni Graz
- Schmut Otto
- Wedrich Andreas
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- Abstract:
- Today it is not possible to synthesize tear substitutes identical to human tears. Beside water and sodium chloride natural tears contain various other components like proteins, lipids, mucins, antioxidants and buffer substances. Tear substitutes which are used for therapy of dry eye syndrome contain little to no of these components. To create tear substitutes identical to human tears an addition of several components of natural tears is necessary. One of these components concerns ingredients with antioxidative potential. Aim of this study is to identify substances with protective function against ultraviolet light and ozone, which could be used in artificial tear substitutes. Furthermore this paper examines physiological components of natural tears for creation of an optimized artificial tear substitute. Viscosity measurements were used to identify substances with protective function against environmental influences. All substances investigated are described in literature as radical scavengers with possible antioxidant function. They were dissolved in accurately defined concentrations in 0.25 % hyaluronic acid solution and irradiated with ultraviolet light or steamed with ozone followed by a viscosity measurement with a KPG-Ubbelohde viscosimeter. Ultraviolet light and ozone lead to a depolymerisation of hyaluronic acid associated with a decrease of viscosity, which can be traced back to the formation of free radicals. A lower decrease of viscosity or no change of viscosity despite irradiation or steaming can be interpreted as protective function of the added substance. Concerning other tear film components a research of actual literature has been summarized. All in all 11 substances with possible protective function against ultraviolet light and ozone were investigated: eyebright and mannitol could significantly protect hyaluronic acid from depolymerisation through influence of ultraviolet light and ozone (p < 0,05). Uric acid and melatonine were able to achieve a significant effect against ultraviolet light (p < 0,05), but not against ozone. Arginine, curcumin, fructose, urea, lysine, spermidine and taurine were not able to protect hyaluronic acid from depolymerisation. Sodium chloride, glucose and bicarbonate are tear ingredients with important function in maintaining homeostasis of ocular surface. For creation of an ideal tear substitute a use of natural tear components like sodium chloride, glucose and bicarbonate should be preferred. For maintaining the antioxidative function of tears eyebright and mannitol, could be added. Both substances are capable of preventing hyaluronic acid in tears from depolymerisation through influence of ultraviolet light and ozone. Also hyaluronic acid in artificial tears may be protected and retention time and lubricating effect on the ocular surface may be extended.
- Find related publications in this database (Keywords)
- Hyaluronic acid
- Artificial tears
- Oxidative stress
- Eyebright
- Mannitol