This standard specifies the terms and definitions, classification, technical requirements, test methods, inspection rules, packaging requirements and recommendatory fitting procedures concerning the rigid gas permeable contact lenses for orthokeratology.
2 Normative References
The following documents contain provisions which, through reference in this text, constitute provisions of this standard. For dated reference, subsequent amendments to (excluding any corrigendum), or revisions of, any of these publications do not apply. However, parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. For any undated references, the latest edition of the document referred to applies.
GB/T 14233.2 Test methods for infusion, transfusion, injection equipment for medical use—Part 2: Biological test methods
GB/T 17341 Optics and optical instruments—Focimeters
GB/T 16886.5 Biological Evaluation of Medical Devices—Part 5: Test for in vitro cytotoxicity
GB/T 16886.10 Biological evaluation of medical devices—Part 10: Tests for irritation and sensitization
GB/T 16886.11 Biological evaluation of medical devices—Part 11: Tests for systemic toxicity
ISO 10334 Ophthalmic optics—Contact lenses—Part 4:Saline solution for contact lens testing
Pharmacopoeia of People's Republic of China, Volume II (Edition 2000)
3 Terms and Definitions
For the purposes of this standard, the following terms and definitions apply.
3.1
Contact lenses
Any lenses that can be designed to be worn at the front surface of cornea.
Note: the definition of contact lenses covers the myopic lenses, hypermetropic lenses and trial (diagnosis) lenses.
3.2
Rigid gas permeable contact lenses
The contact lenses made of rigid oxygen permeable material; generally, the polymeric material used for contact lenses contains organic silicon and organic fluorine.
3.3
Rigid gas permeable contact lenses for orthokeratology
The rigid gas permeable contact lenses (hereafter referred to as orthokeratology lenses) intended to change the corneal shape by orthokeratology, thus to remedy ametropia.
3.4
Oxygen permeability (Dk)
The arithmetic product of gas solubility coefficient and diffusion coefficient.
Note 1: it is one of the most common parameters of contact lens materials.
Note 2: Dk value in mmHg is obtained after multiplying the Dk value in hpa, i.e. (cm2/s)[mL O2/(mL·hPa)] or (cm3O2·cm)/(cm·s·hPa), by 1.333 22.
Note 3: oxygen permeability: the oxygen flux of unit thickness of contact lens material at unit pressure difference under certain conditions.
