Contact Lens Use Under Adverse Conditions Applications in Military Aviation (1990) / Chapter Skim
Currently Skimming:
1. Introduction
1. Introduction
Pages 1-9
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 1... ...
But contact lenses can also offer functional advantages over spectacles in many areas, such as in sports, work in humid environments, and in occupations in which spectacles are inconvenient or incompatible with required equipment, like special headgear. The military services the United States Army, Navy, Air Force, and Marines draw their personnel from this general population; it therefore follows that many military personnel have imperfect vision.
|
From page 2... ...
aircraft; · defines the advantages offered by contact lenses in each of these settings and determines their relative importance; · details the likely complications or adverse effects for the aviation use of contact lenses in general and for each of these settings in particular; determines the risk factors responsible for likely complications, ranks these risks as to severity, and detail possible strategies to ameliorate them; and · makes recommendations regarding contact lens use in each of the pertinent settings. In addition to examining lens types, care procedures, and wear strategies for specific settings of interest to the military, our broader aim is to point up those factors critical to the success of a comprehensive contact lens policy for military aviation, as well as to outline the risks inherent in such a policy.
|
From page 3... ...
, ——~ —— —cat ., ~ , ,, with a typical wear tune or one weed Nonetheless, all contact lenses, either daily wear or extended wear, must be removed at regular intervals to prevent complications from oxygen deprivation, bacterial infection, and mechanical irntation. CONTACT LENS USE IN MILITARY AVIATION Military Ophthalmic Policies Despite increasing electronic sophistication in the cockpit, an aviator's eyesight remains a critical asset.
|
From page 4... ...
Currently, there is no uniform policy across the military services regarding the aviation use of contact lenses, but no service allows their unrestricted use aboard military aircraft. In general, spectacle use is mandated for correcting refractive error unless a waiver is obtained for the medical use of contact lenses or for their use under special circumstances.
|
From page 5... ...
Spectacles Versus Contact Lenses Traditionally, spectacles have been used to accommodate vision defects among aviators and to control glare. The well-known military style of "aviator glasses" has a substantial history of development and successful use, not to mention significant popularity today, even among civilians (~edici, 1976~.
|
From page 6... ...
As stated before, there are also disadvantages to contact lens use that have kept them from being universally adopted across the military services Predict and Flynn, 1986; Brennan and Girvin, 1985~: limited allowable wear time; · variable visual acuity or acuity sometimes poorer than that attainable with spectacles; · difficulty in correcting some types of refractive error, most notably, moderate to severe astigmatism; · not well tolerated by some; · present increased risk of serious ocular complications; · may be dislodged (hard lenses) or torn (soft lenses)
|
From page 7... ...
Air Force studies of soft contact lens wear at high altitude have shown that a combination of low atmospheric pressure and low humidity, as commonly experienced on many military aircraft, results in no degradation of visual performance after 4 hours. However, these conditions do produce a significant increase in physiological stress as indicated by increased tear debris, conjunctival injection, and uptake of stain by the corneal epithelium.
|
From page 8... ...
has allowed the use of contact lenses in civil aviation both among commercial and private pilotsfor well over 20 years. Prior to December 1976, however, civil pilots wishing to wear contact lenses could do so only after obtaining a special medical waiver a time-consuming process.
|
From page 9... ...
The FAA does not routinely collect data on dropout rates, complication rates, lens types in use, or mode of wear among contact lens-wearing pilots. Nonetheless, the FAA has not become aware of any adverse trends associated with contact lens wear from the medical examiners who work with and evaluate civil pilots.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.