ISO 15798:2022 眼科インプラント—眼科用粘液外科装置 | ページ 5

3.1

absolute complex viscosity

absolute value of complex viscosity (3.2)

Note 1 to entry: Absolute complex viscosity is expressed in pascal seconds (Pa·s).

3.2

complex viscosity

η* = η′− i · η′′

viscosity consisting of a viscous η′ and an elastic η′′ component where i is an imaginary number defined by i = (−1)^0,5

3.3

delivery system

primary container in which the product is supplied and any additional components provided to introduce the product into the eye

3.4

elasticity

G ’= σ₀/ε₀·cosδ

tendency of a body to return to its original shape after having been deformed

Note 1 to entry: Elasticity is quantitatively defined as stress (the force generated within the body) divided by strain (the change in dimensions of the body) multiplied by cosine of the phase lag between stress and strain.

Note 2 to entry: Elasticity is expressed in pascal (Pa).

3.5

lost to follow-up subject

subject for which the final post-operative case report form is overdue and who cannot be contacted despite extensive written and telephone follow-ups to determine the final clinical outcome

Note 1 to entry: This category does not include subjects who have died.

3.6

ophthalmic viscosurgical device

OVD

generic term that includes a variety of materials with viscous and/or viscoelastic properties, which are designed to create and maintain space, to protect intraocular tissues and to manipulate tissues during surgery in the anterior segment of the human eye

3.7

primary container

vial or syringe that contains the OVD

Note 1 to entry: This container forms part of the delivery system.

3.8

rheologically active component

compound or mixture of compounds in the finished OVD giving the product viscous and/or viscoelastic properties

3.9

shear viscosity

tendency of a fluid to resist flow when subjected to stress

Note 1 to entry: Quantitatively, shear viscosity is the quotient of shear stress divided by shear rate in steady shear flow.

Note 2 to entry: Shear viscosity is expressed in pascal seconds (Pa·s), traditionally in millipascal seconds (mPa·s).

Note 3 to entry: Shear rate is the velocity gradient in a flowing fluid, expressed in s⁻¹ (per second).

Note 4 to entry: The shear viscosity divided by the solution density gives the kinematic viscosity, which is a measure of the viscosity of a fluid influenced by inertia (e.g. gravity).

3.10

sterile barrier

sealed packaging, containing the product and delivery system (3.3) , which maintains sterility during transport and storage

3.11

storage container

that part of the packaging intended to protect the device during transport and storage, containing the sterile barrier

3.12

surgical invasive medical device

invasive device which penetrates inside the body through the surface of the body with the aid or in the context of a surgical operation

3.13

viscoelasticity

characteristics of a fluid having both viscous and elastic properties

Note 1 to entry: The viscous modulus, G′′, is frequently called the loss modulus and the elastic modulus, G′, is frequently called the storage modulus, both moduli are expressed in Pascal (Pa). The moduli can be combined to show the elasticity of the OVD (see 5.3.5).

3.14

zero shear viscosity

plateau viscosity at vanishing shear rate in a log-log plot of viscosity versus shear rate

Note 1 to entry: Zero shear viscosity is expressed in pascal seconds (Pa·s), traditionally in millipascal seconds (mPa·s), or as a logarithm of the zero shear viscosity.