A hydrogel forming composition comprising: a) 5 - 70 wt.-% of at least one water-soluble (meth)acrylic compound, b) At least one free radical initiator, c) At least one catalyst for free radical formation, and d) 20 - 75 wt.-% of water, all proportions being based on the total weight of the hydrogel forming composition, wherein the at least one catalyst for free radical formation is an amine compound of formula wherein R 1 to R 5 represent independently from each other linear or branched alkyl groups having 1 to 6 carbon atoms and optionally having one or more oxygen atoms, and n has a value of 0; or R 1 to R 8 represent independently from each other linear or branched alkyl groups having 1 to 6 carbon atoms and optionally having one or more oxygen atoms, and n has a value of 1; or R 1, R 2, R 7, and R 8 together form a 5- or 6-membered ring structure with the two nitrogen atoms, R 3 to R 6 represent independently from each other linear or branched alkyl groups having 1 to 6 carbon atoms and optionally having one or more oxygen atoms, and n has a value of 1, and wherein the at least one water-soluble (meth)acrylic compound is selected from the group consisting of hydroxyethylmethacrylate (HEMA), hydroxypropylmethacrylate (HPMA), methoxy polyethylene glycol methacrylate (MPEG-MA), polyethylene glycol dimethacrylate (PEG-DMA), maleic acid, itaconic acid, sodium acrylate, sodium methacrylate, potassium acrylate, potassium methacrylate, magnesium acrylate, potassium salt of 3-sulfopropylacrylat, 2-acrylamido-2-methylpropane sulfonic acid, and sodium salt of 2-acrylamido-2-methylpropane sulfonic acid. a) 5 - 70 wt.-% of at least one water-soluble (meth)acrylic compound, b) At least one free radical initiator, c) At least one catalyst for free radical formation, and d) 20 - 75 wt.-% of water, all proportions being based on the total weight of the hydrogel forming composition, wherein the at least one catalyst for free radical formation is an amine compound of formula wherein R 1 to R 5 represent independently from each other linear or branched alkyl groups having 1 to 6 carbon atoms and optionally having one or more oxygen atoms, and n has a value of 0; or R 1 to R 8 represent independently from each other linear or branched alkyl groups having 1 to 6 carbon atoms and optionally having one or more oxygen atoms, and n has a value of 1; or R 1, R 2, R 7, and R 8 together form a 5- or 6-membered ring structure with the two nitrogen atoms, R 3 to R 6 represent independently from each other linear or branched alkyl groups having 1 to 6 carbon atoms and optionally having one or more oxygen atoms, and n has a value of 1, and wherein the at least one water-soluble (meth)acrylic compound is selected from the group consisting of hydroxyethylmethacrylate (HEMA), hydroxypropylmethacrylate (HPMA), methoxy polyethylene glycol methacrylate (MPEG-MA), polyethylene glycol dimethacrylate (PEG-DMA), maleic acid, itaconic acid, sodium acrylate, sodium methacrylate, potassium acrylate, potassium methacrylate, magnesium acrylate, potassium salt of 3-sulfopropylacrylat, 2-acrylamido-2-methylpropane sulfonic acid, and sodium salt of 2-acrylamido-2-methylpropane sulfonic acid.