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.

Contents

• WORKING GROUP ON CONTACT LENS USE UNDER ADVERSE CONDITIONS
• COMMITTEE ON VISION
• CONTRIBUTORS
• Foreword
• Preface
• Contact Lenses and the Eye: Basic Considerations
  • 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
    • RESULTS
    • DISCUSSION
    • REFERENCES
  • Environmental Conditions and Tear Chemistry
    • TEAR pH
    • TEAR BUFFERING
    • ACID-BASE INFLUENCES ON CONTACT LENSES
    • TEAR ENZYMES
    • CONCLUSION
  • Tear Evaporation Considerations and Contact Lens Wear
    • WATER EVAPORATION FROM HYDROGEL 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
• Contact Lenses and the Eye: Complications
  • 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
    • MILITARY APPLICATIONS
    • REFERENCES
  • Corneal Topography and Contact Lenses
    • CHRONIC EFFECTS
    • LSU STUDIES
    • CASE REPORTS
    • SUMMARY
    • REFERENCES
  • Treatment of Giant Papillary Conjunctivitis
    • DESCRIPTION OF GPC
    • DIAGNOSIS OF GPC
    • TREATMENT OF GPC
    • REFERENCES
  • Endothelial Effects From Contact Lens Wear
    • TRANSIENT ENDOTHELIAL CHANGES FROM CONTACT LENSES
    • LONG-TERM ENDOTHELIAL CHANGES FROM CONTACT LENSES
    • DISCUSSION
    • REFERENCES
• Contact Lenses and the Eye: Practical Considerations in Everyday and Military Life
  • Corneal Effects of Extreme Environments: Considerations for Pilots Wearing Contact Lenses
    • WIND FORCE
    • ULTRAVIOLET RADIATION AT HIGH ALTITUDES
    • CLIMATE EXTREMES
    • 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
    • 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
    • ATMOSPHERIC IRRITANTS/POLLUTANTS
    • SUMMARY
    • REFERENCES
  • Lens Performance Considerations
    • RIGID LENSES
    • HYDROGEL LENSES
    • 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

This work relates to Department of the Navy contract N0014-80-C-0159 issued by the Office of Naval Research under Contract Authority NR 201-204. However, the content does not necessarily reflect the position or the policy of the government, and no official endorsement should be inferred.

NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competences and with regard for appropriate balance.

This report has been reviewed by a group other than the authors according to procedures approved by a Report Review Committee consisting of members of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine.

The National Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. Upon the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Frank Press is president of the National Academy of Sciences.

The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding engineers. It is autonomous in its administration and in the selection of its members, sharing with the National Academy of Sciences the responsibility for advising the federal government. The National Academy of Engineering also sponsors engineering programs aimed at meeting national needs, encourages education and research, and recognizes the superior achievements of engineers. Dr. Robert M. White is president of the National Academy of Engineering.

The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appropriate professions in the examination of policy matters pertaining to the health of the public. The Institute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal government and, upon its own initiative, to identify issues of medical care, research, and education. Dr. Samuel O. Thier is president of the Institute of Medicine

The National Research Council was organized by the National Academy of Sciences in 1916 to associate the broad community of science and technology with the Academy's purposes of furthering knowledge and advising the federal government. Functioning in accordance with general policies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the government, the public, and the scientific and engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. Dr. Frank Press and Dr. Robert M. White are chairman and vice chairman, respectively, of the National Research Council.