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s Recommendations The working group has formulated a set of 13 recommendations for appropriate contact lens use in military aviation. These recommendations have been formulated to minimize risks associated with contact lens use while exploiting their military benefits. The recommendations fall into five groups: restrictions on contact lens use; spectacle use as backup for contact lens use; lens fitting by qualified specialists; regular follow-up care; and optimal lens type. RESTRICTIONS ON CONTACT LENS USE 1. To minimize the risk of complications, contact lens use should be held to a minimum but, when necessary, should be restricted to immediate mission wear; contact lenses should be regarded as combat gear; not cosmetic gear. The ocular health of military air personnel represents an essential resource that must be protected from unnecessary harm. Practices that represent known risks to this resource such as the wearing of contact lenses in stressful environments should be avoided unless these practices are essential to discharging the aviator's military role. This means mini- mizing contact lens wear as much as possible and not allowing them for everyday cosmetic use. In other words, contact lenses should be treated as a piece of military equipment issued for a specified use, not as personal equipment to be worn at the aviator's discretion. This recommendation is aimed not only at protecting aviators' prime asset their sight—but at preserving their ability to use contact lenses as necessary combat gear in the future. In our experience, the length of time an individual can be expected to enjoy problem-free contact lens use in a 36
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RECOMMENDATIONS 37 lifetime is not unlimited. For most people, it will total a number of years, after which the risk of discomfort and more serious complications increases. The ability to tolerate contact lenses can perhaps be regarded as a nonrenewable resource—once it is used up, it is gone. If it is used for nonmilitary purposes such as cosmetic wear, less will remain for legitimate military uses later on. Ideally, the ability to wear contact lenses to accom- plish military objectives should span the aviator's entire career, which can be 20 years or longer. Therefore, judicious use of this resource is essential. 2. Contact lenses should be worn in a flexible e~ctended-wear mode that allows emended wear of lenses as necessary but mandates spectacle use whenever possible to allow the eye to recover: It is clear that the terms dad) wear and extended wear lose their relevance for military aviation settings. The working group advocates a policy of reducing wear time to the minimum required to accomplish a given mission. This will mean extended wear in many cases and shorter- term wear in other cases. It does not imply using extended-wear lenses in an extended-wear mode all the time, even though this may be the accepted practice in a civilian setting. The term peucible eucten~led wear describes this policy of accommodating the needs of the mission with minimum wear time. The practice of flexible emended wear should not be allowed to de- generate into continuous extended wear without relief. There should be an attempt to maintain some minimum balance between time in lenses and time out of lenses. For example, if three weeks of extended wear are required during a mission, then perhaps three weeks out of lenses should be required later to compensate. Under optimal conditions, much more time will be spent without contact lenses Man with them. The attempt here is both to avoid the greater incidence of acute, mission-threatening effects associated with extended wear of lenses, as well as to manage the longer-term toll of lens wear in general. SPECTACLE USE AS BACKUP FOR CONTACT LENS USE 3. The use of spectacles should be mandated for standard wear; that is, for all activities except authorued aviation missions. This is simply the corollary to recommendation 1, and it is only slightly more restrictive than current military policies governing use of contact lenses and spectacles. Spectacles have a proven record of safety and successful use in a variety of tasks. More importantly, they offer equal or superior visual acuity compared with contact lenses with less risk to the eye
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38 CONTACT LENS USE UNDER ADVERSE CON Z)mONS and are therefore the favored prosthesis when contact lenses do not offer a specific advantage. 4. Spectacles should be required as a backup for ad contact lens-wearing aviators and should be kept on their persons during missions, except when equipment incompatibilities preclude their use. Spectacles should be available as a backup to contact lenses in case lens wear must be terminated mid-mission due to lens loss, discomfort, irritation, foreign body involvement, or other complications. This is standard practice in the Air Force and should be adopted by all the services. 5. Spectacle acuity should be checked when contact lenses are fitted and occasional) thereafter so that contact lenses and spectacles match. Checking spectacle acuity against contact lens acuity will ensure that aviators can easily move from using one to using the other without untoward visual effects. LENS FITTING BY QUALIFIED SPECIALISTS 6. The determination of who should wear contact lenses should be made by qualified ophthalmic specialists. 7. The fitting of contact lenses should be performed on) by qualified specialists tie., optometrists or-ophthalmologists). The fit of a contact lens can make the lens comfortable or unbearable, prone to complications or relatively benign. Lens fitting is an exacting skill. Without a professional determination of who should wear contact lenses, followed by a professional fitting, the chances of complications or less-than-perfect vision resulting from the lenses are greatly increased. REGULAR FOLLOW-UP CARE BY QUALIFIED SPECIALISTS 8. After initial fitting, follow-up exams should be conducted quarter) or as shorts,' thereafter as possible. Without at least an annual exam, the contact lens wearer should be grounded. 9. Follow-up should be conducted by qualified ophthalmic personnel only. 10. Follow-up exams must be fully documented, including lens choice, complications, and reasons for discontinuing contact lens use, and the data collected at a central location. Competent follow-up care is as essential to the success of contact lens wear and the avoidance of complications as is proper fit, especially in the
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RECOMMENDATIONS 39 frequent and regular basis if possible complications are to be detected before they become debilitating. Penalties should apply to those unable to meet the necessary care schedule. Information gathered from these exams should form part of a centrally located data base that can be used to assess the performance of various lens models or lens care schemes, as well as to critically evaluate the contact lens program in terms of actual complication rates experienced in the various aviation settings. OPIIMAL LENS lYPE 11. Unless medical indicated, rigid lenses (both PMMA and REP lensesJ should not be used in any of the aviation environments considered due to their sensitivity to particulate contamination. While it may be true that military aviators have successfully employed PMMA and RGP lenses in many cases, we have concluded that, over the longer term, the use of these lenses in high-particulate environments such as aircraft cabins poses a higher risk than the use of hydrogel lenses. ~ 12. Hydrogel lenses of as low a water content as feasible (60 percent or less) should be worn in F-A-R and helicopter units. Hydrogel lenses of as low a water content as possible offer the least risk in terms of particulate sensitivity, while minimizing the desiccating effects of low humidity. In a low water content lens, the lens reaches a steady state more quickly, water loss slows, and the properties of the lens stabilize. Hydrogel lenses are also most amenable to the concept of flexible wear, because, with proper fitting, intermittent wear is possible without adaptation problems. It should be noted that the working group views the prognosis for the benign use of contact lenses in helicopter units as poor. Unsanitary field conditions, possible lens wear beyond safe limits, and a high particulate level will probably lead to high dropout rates and disability for more than a few aviators. However, given the stated need for contact lenses on these missions, extended wear hydrogel lenses are certainly the most appropriate choice. 13. Contact lenses should not be used aboard T-T-B airport because they offer no clear advantage over spectacles in this environment, except in certain special cases (e.g. operator of filet loading boom). The working group sees no overriding advantage to using contact lenses in anything other than high-performance aircraft and helicopters, except in special cases. This is not to say that contact lenses cannot be used
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40 CONTACT ~ INS USE UNDER ADVERSE CONDITIONS successfully in the T-T-B environment if a definite advantage to their use emerges in the future. Contact lens use should be disallowed, however, in all but essential situations. CONCLUSION As a final comment, the working group notes with dismay that aircraft systems are not generally designed with ophthalmic considerations in mind. This is true for everything from heating and air conditioning systems to chemical protective hoods to sophisticated optical steering and targeting devices. Retrofitting to accommodate the belated input of the ophthalmic community seems to be common, but it is rarely satisfactory. The result is a foreclosing of options, as in the Army's chemical protective hood, for which spectacle use is impossible and contact lenses are the only remaining possibility for those needing vision correction. With the level of refractive errors common today among military aviators, this approach is clearly counterproductive. Consultation with the military ophthalmic community in the early phases of hardware design could reduce incompatibility with ophthalmic needs and increase the range of options available to cope with vision defects. Although such an approach might well reduce the military advantages of contact lenses in aviation by reducing spectacle-incompatible designs, it might also reduce the risks currently associated with aviation use of contact lenses.
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