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Oxygen permeability of hydrogel contact lenses with organosilicon moieties

Paper ID Volume ID Publish Year Pages File Format Full-Text
13752 897 2002 6 PDF Available
Title
Oxygen permeability of hydrogel contact lenses with organosilicon moieties
Abstract

Oxygen transport through two extended wear (day and night) hydrogel contact lenses that contain organosilicon moieties (balafilcon A and lotrafilcon A) was studied in the hydrate (hydrogel) and dry (xerogel) states. The water uptake increased the oxygen permeability [(Dk)app] and transmissibility [Dk/Lav] coefficients of the dry materials by about 70%. The (Dk)app for the hydrated lenses was determined following the so-called stack procedure. The values obtained were 107±4 barrer for balafilcon A and 141±5 barrer for lotrafilcon A, about 5–10 times larger than those previously reported for conventional (without organosilicon moieties) extended wear hydrogels contact lenses. The Dk/Lav for −3.00 diopter lenses (harmonic average thickness, Lav=75±2 μm for lotrafilcon, and 85±2 μm for balafilcon) was 123±6 barrer/cm for balafilcon A and 183±8 barrer/cm for lotrafilcon A. The minimum oxygen transmissibility 87 barrer/cm stipulated by Holden and Mertz to avoid corneal edema with extended wear contact can be easily achieved with lotrafilcon and balafilcon lenses of diverse dioptric powers if the central and peripheral thickness of the lenses are kept below the critical level of oxygen transmissibility.

Keywords
Oxygen permeability; Oxygen transmissibility; Cornea; Contact lenses; Siloxane hydrogels
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Oxygen permeability of hydrogel contact lenses with organosilicon moieties
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Publisher
Database: Elsevier - ScienceDirect
Journal: Biomaterials - Volume 23, Issue 13, July 2002, Pages 2767–2772
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us