Influence of Tear Protein Deposition on the Oxygen Permeability of Soft Contact Lenses

Table 1

Characteristics of contact lenses.

Classification	Hydrogel			Silicone hydrogel
Brand name	Optima FW	Focus dailies	1 day Acuvue	Focus night & day	Purevision
USAN	Polymacon	Nelfilcon A	Etafilcon A	Lotrafilcon A	Balafilcon A
Claimed Dk; (×10^−11)	8.4	26	21.4	140	101
Water content; (%)	38.6	69	58	24	36
Polymer	pHEMA	PVA	pHEMA + MAA	DMA + TRIS + siloxane macromer	NVP + TPVC + NCVE + PBVC
Thickness at; −3.00D (mm)	0.035	0.1	0.084	0.08	0.09
FDA Group	I	II	IV	I	III

PVA: polyvinyl alcohol; pHEMA: poly-2-hydroxyethyl methacrylate; MAA: methacrylic acid; DMA: N,N-dimethylacrylamide; TRIS: trimethylsiloxy silane; NVP: N-vinyl pyrrolidone; TPVC: tris-(trimethylsiloxysilyl)propylvinyl carbamate; NCVE: N-carboxyvinyl ester; PBVC: poly(dimethylsiloxy)di(silybutanol)bis(vinyl carbamate)). United States Adopted Name; Oxygen permeability value claimed by manufacturer; unit, (cm²/s) (mL O₂/mL × mmHg).