BS EN ISO 16672:2015 pdf download – Ophthalmic implants — Ocular endotamponades (ISO 16672:2015).
5.4 Concentration of the components The concentration of each component material in the finished product shall be stated. Since the testing methodology can affect the actual concentration reported, the physical or chemical techniques utilized shall be described and validated. 5.5 Density The density of liquid forms of OE shall be specified in kilograms per cubic metre (kg/m 3 ). 5.6 Gaseous expansion For gaseous forms of OE the intraocular gaseous expansion at (35 ± 2) °C and its dependence on atmospheric pressure shall be expressed. 5.7 Interfacial tension Where applicable, the interfacial tension against water shall be expressed in newton per metre (N/m) at (35 ± 2) °C. 5.8 Kinematic viscosity Where applicable, the kinematic viscosity at (35 ± 2) °C shall be expressed in millimetres squared per second (mm 2 /s). 5.9 Dynamic viscosity For viscous or viscoelastic OE, the dynamic viscosity shall be determined at (35 ± 2) °C in the range between 0,01 and 100 s −1 and expressed in mPa⋅s. 5.10 Molecular mass distribution If the OE is a polymer, the average molecular mass, the range of molecular mass distribution and the polydispersity shall be reported. The manufacturer shall conduct and report such additional tests as necessary to provide an adequate description of the molecular mass distribution of the components in the finished product. Whenever possible, standard methods shall be used and specified.
5.13 Spectral transmittance The spectral transmittance of the OE shall be measured by transmission spectrophotometry over the range 300 nm to 1 100 nm. Results shall be presented graphically, plotting percentage transmission against wavelength. 5.14 Surface tension Where applicable, the surface tension shall be expressed in newton per metre (N/m) at (35 ± 2) °C. 5.15 Vapour pressure Where applicable, the vapour pressure shall be expressed in Pascal (Pa) at (35 ± 2) °C. 6 Design evaluation 6.1 General The OE shall be evaluated for safety by performing a risk assessment in accordance with ISO 14971. The results of the risk assessment shall determine the tests required to evaluate the safety of the OE. The risk assessment shall take into consideration the following: a) the type of product and the duration of intraocular contact; b) potential interactions of the OE with other materials likely to be used in ophthalmic surgery; c) for intraocular gases, any impurity profile changes as the gas is depleted from the tank. NOTE Impurity profile changes can occur as the concentration of the chemical species changes due to the differences in vapour pressure as the tank is depleted. The OE shall be evaluated to demonstrate that the intended performance is achieved. The requirements for evaluation of non-active implants specified in ISO 14630 shall apply.