pressure delivery of fluids. In some cases, a mechanical trauma is added to the corrosive delivery, especially in cases of exploding accumulators or exploding tubings or connectors of concrete pumps. We and many others have observed that, beside a severe trauma of the anterior segment, an additional chemical [10] and blunt trauma [11] to the retina and elevated intraocular pressure directly after the initial trauma [12] can be decisive for the visual outcome.

5.2.2.2  Thermal Contact

Particles

Steam

In case of a steam delivery, the initial reaction and interaction with the ocular tissue result in a strong heat transfer by means of transfer of the condensation energy into the tissue. To get an idea of the amount of energy delivered to the tissue by this, we have to face that condensation gives the same amount of energy needed to boil up water from 20°C to 100°C. Most of the times the reflexive lid closure prevents the inner eye with conjunctiva and cornea from severe damage, and the type of burn that occurs most often is a lid angle surface coagulation with full recovery.

The well-known mechanism of surface contact of hot devices like curling iron [13] and particles relates to heat, thermal conductivity, and time of contact. It is a common fact that the higher the temperature difference and the higher the thermal conductivity, the more the tissue damage. Typically, thermal eye burns, such as those caused by a single touch with a curling iron, are not too harmful, as described below [13]. But, like it happens in about 20% of all cases, if hot chemicals touch the eye, damage is more severe. Damage from small iron particles from iron cutting or welding occur frequently and give rust scars in the cornea which might impair vision when centrally located [14]. Most chemicals are delivered to the eye at temperatures of the surroundings. Cold and frozen particles transfer heat from the body to the particle and lead to freezing damage limited by water thermal conductivity, freezing point, and vascular reserve of the damaged tissue [15].

Hot Fluids

Hot fluids follow the mechanism of the thermodynamic speeding up of any reaction due to faster diffusion and higher reactivity in water-containing surrounding. The limits of water-containing fluids and their chemical interaction are relative to the freezing and the boiling points of the resulting mixtures of corrosive and tissue fluids. Therefore, in highly dissociated corrosives, the freezing point depression acts to temperatures up to – 40° C. In any case of chemical fluid contact, we state that the higher the temperature of immediate contact is, the bigger the expected damage is.

Liquid Metals

Liquid metal burns are known as projections from blast furnace tap or the situation of loading with delivery of bulk into liquid metal. Metal is normally of low viscosity like water and spreads on skin and eye. Thus projections of liquid metal do not behave like viscous materials but like water and spread their enormous heat onto wide areas. When eventually cooling down, liquid metal is trapped in the conjunctival sac. When this happens, there is a maximum heat transfer with high thermoconductivity from metallic surfaces to the conjunctiva with immediate water evaporation and consecutive heat transfer from the metal to the eye up to carbonization of the tissues [16, 17].

Cold Gazes

Further, heat transfers like cold delivery of liquid gazes mostly do not harm too much because of the Leyden frost phenomenon of limited heat transfer in any region of immediate low heat conductivity with evaporation of liquid gazes. Cold metals transfer heat from the conjunctival surfaces within seconds and cold burns are a very uncommon accidental mechanism, but often found in case of medical treatments of the eye [18].

5.2.2.3  Eye Burns with Chemically Active Foreign Bodies

Different foreign body burns may act and develop differently. First are insoluble but chemically reactive