Considerations in Contact Lens Use Under Adverse Conditions

Proceedings of a Symposium

Autor: Flattau, Pamela Ebert
Editor: National Academies Press
ISBN: 9780309044387
eISBN Pdf: 9780309572217
Lloc de publicació: United States
Any de publicació digital: 1991
Mes: Gener
Pàgines: 178
DDC: 615
Idioma: Anglés

Descripció

This book summarizes current understanding of the scientific, clinical, and technical issues surrounding the use of contact lenses. It discusses the special occupational conditions experienced by military personnel, particularly in extreme environments, that give rise to the question of whether or not to use contact lenses.

Experts in optometry, ophthalmology, visual psychophysics, and engineering describe recent developments in design and use; and representatives of the military services provide examples of actual situations in aerospace settings. Considerations in Contact Lens Use Under Adverse Conditions will be of particular interest to those involved in the design of contact lenses and those responsible for occupational safety and health matters in the private sector.

Considerations in Contact Lens Use under Adverse Conditions
COPYRIGHT
CONTRIBUTORS
FOREWORD
PREFACE
CONTENTS
Environmental Gases and Contact Lens Wear
- OXYGEN
- CARBON DIOXIDE
- CORNEAL STROMAL PH
- BUBBLE FORMATION UNDER LENSES WITH PRESSURE CHANGES
- NOXIOUS GASES
- REFERENCES
Hypoxia
- INTRODUCTION
- HYPOXIA AND CORNEAL PHYSIOLOGY
- CORNEAL EDEMA
- THE CLOSED EYE ENVIRONMENT
- HYPOXIA AND ITS CLINICAL SEQUELAE
- REFERENCES
Contact Lenses and Corneal Energy Metabolites in the Rabbit
- PERTINENT ISSUES
- METHODOLOGY
  - Experimental Animals
  - Processing Procedure
  - Underlying Principles
- RESULTS
- DISCUSSION
- REFERENCES
Environmental Conditions and Tear Chemistry
- TEAR PH
- TEAR BUFFERING
- ACID-BASE INFLUENCES ON CONTACT LENSES
- TEAR ENZYMES
- CONCLUSION
- ACKNOWLEDGEMENT
Tear Evaporation Considerations and Contact Lens Wear
- WATER EVAPORATION FROM HYDROGEL LENSES
  - Effects of Lens Hydration
  - Effect of Lens Thickness
  - Effect of Abnormally Fast Lens Drying
  - Pervaporation of Tear Water Through Silicone Elastomeric Lenses
- EFFECT OF TEAR WATER EVAPORATION ON EYES WITH RIGID CONTACT LENSES
- HYDROGEL CONTACT LENS WEAR IN AIRCRAFTS
- REFERENCES
Mechanical Aspects of Soft Contact Lenses
- ELASTOHYDRODYNAMICS
- AN ILLUSTRATION
- REFERENCES
Medical Problems Associated with Contact Lens Use
- RATES OF COMPLICATIONS
- CONTRAINDICATIONS
- NONMEDICAL CONSIDERATIONS
- MEDICAL COMPLICATIONS
- CONCLUSION
- REFERENCES
Adverse Reactions Associated with Contact Lens Use
- MICROBIAL KERATITIS
- DIAGNOSIS AND THERAPY
- MILITARY APPLICATIONS
- REFERENCES
Corneal Topography and Contact Lenses
- CHRONIC EFFECTS
- LSU STUDIES
- CASE REPORTS
  - Case 1
  - Case 2
- SUMMARY
- ACKNOWLEDGMENT
- REFERENCES
Treatment of Giant Papillary Conjunctivitis
- DESCRIPTION OF GPC
- DIAGNOSIS OF GPC
- TREATMENT OF GPC
  - Cleaning the Lens
    - Lens Care
    - Deposits
  - Type of Contact Lens
    - Lens of the Same Design
    - Lens of a Different Design
    - Lenses of Different Design for Each Eye
    - Rigid Gas-Permeable Lens
  - The Conjunctiva
    - Irrigation
    - Withdrawal of Lenses
    - Cromolyn Sodium
- REFERENCES
Endothelial Effects from Contact Lens Wear
- TRANSIENT ENDOTHELIAL CHANGES FROM CONTACT LENSES
- LONG-TERM ENDOTHELIAL CHANGES FROM CONTACT LENSES
  - Endothelial Cell Density
  - Endothelial Polymegethism
  - Cell Pleomorphism
- DISCUSSION
- REFERENCES
Corneal Effects of Extreme Environments: Considerations for Pilots Wearing Contact Lenses
- WIND FORCE
- ULTRAVIOLET RADIATION AT HIGH ALTITUDES
- CLIMATE EXTREMES
  - Heat
  - Cold
  - Increased Humidity
  - Decreased Humidity
- EFFECTS OF ALTITUDE ON THE CORNEA
- IMPRESSIONS OF PREVIOUS RESEARCH AND RECOMMENDATIONS
- REFERENCES
- ADDITIONAL READINGS
Effect of Aircraft Cabin Altitude and Humidity on Oxygen Tension under Soft and Hard Gas-Permeable Contact Lenses
- MILITARY AIRCRAFT CABIN PRESSURIZATION
- CABIN ENVIRONMENT AND CONTACT LENSES
- PROPOSED ''ACCEPTABLE" CORNEAL SWELLING/MINIMUM OXYGEN LEVEL
- APPROACH
- CALCULATION OF OXYGEN TENSION UNDER CONTACT LENSES
  - General Equation
  - Effect of Humidity on Soft Lens Oxygen Transmission
  - Effect of Humidity/Altitude on Oxygen Tension under Soft Lenses
  - Effect of Altitude on Oxygen Tension under HGP Lenses
- DISCUSSION AND RECOMMENDATIONS
- REFERENCES
Ocular Occupational Health Concerns: Considerations for Pilots Wearing Contact Lenses
- THE BAILOUT AND WIND BLAST
- FACIAL PERSPIRATION
- OCULAR RISKS OF PROLONGED EXTENDED WEAR: NEOVASCULARIZATION
  - Ocular Risks of Extended Wear: Infection
- ATMOSPHERIC IRRITANTS/POLLUTANTS
  - Particulate Matter (Dust), Microparticles, and Smoke
  - Environmental Chemicals
  - Gravitational Effects
  - Vibration
  - Hypoxia
  - Dry Environments
- SUMMARY
- REFERENCES
Lens Performance Considerations
- RIGID LENSES
  - Advantages of Rigid Lenses
  - Disadvantages of Rigid Lenses
- HYDROGEL LENSES
  - Advantages
  - Disadvantages
- SOFT SILICONE LENSES
- REFERENCES
Vision Performance with Contact Lenses
- VISUAL ACUITY MEASURES
- ACUITY CHANGES
- SPHERICAL ABERRATION
- RESIDUAL ASTIGMATISM
- REFERENCES
An Overview of U.S. Army Aviation and Contact Lens Issues
- PRELIMINARY STUDY
- DRIVING FORCE
- REFERENCES
Contact Lens Wear in the Aerospace Environment
- INCIDENCE OF SPECTACLE WEAR IN THE U.S. AIR FORCE
- CONTACT LENS PERFORMANCE
- USAF CONCERNS
Use of Soft Contact Lenses by Tactical Aircrews
- METHOD
- THE TEST PLAN
- TEST PROTOCOL
- PRELIMINARY RESULTS
Job Demands in Naval Aviation
- CARRIER OPERATIONS
- HELICOPTER OPERATIONS
- VISUAL ACUITY
Extended-Wear Lenses: The U.S. Navy's Experience
- COMPRESSION AND DECOMPRESSION
- EXTREME ENVIRONMENTS
- CURRENT MILITARY EXPERIENCE WITH EXTENDED-WEAR LENSES
- CONCLUSION
- REFERENCES