| Summary: | 碩士 === 國防醫學院 === 航太醫學研究所 === 97 === Introduction: At least 80% of all information acquired by aircrew in flight is
vision. In order to maintain flight safety and flight performance, aircrew should
have excellent visual function. However, hypoxia is the most aviation hazard to
vision. Recently, the prevalence of refractive error is high in Taiwan, and
wearing soft contact lens might be chosen to correct visual acuity in R.O.C.
military in the future. The stability of visual acuity and flight performance might
be affected when PO2 is lower than basic metabolism of cornea. Some studies
indicate the new material - silicone hydrogel (SH) can provide higher O2
transmissibility and improve the symptoms of dryness and discomfort than that
of the conventional hydrogel contact lens in most environments. The purpose of
this study was to determine the efficacy and safety of SH contact lens wear
under high altitude environment. Methods: Thirteen subjects wearing SH
contact lens were exposed to 35,000 ft in hypobaric chamber (Type I chamber
fly); six subjects were subjected to 18,000 ft in hypobaric chamber (Type VI
chamber fly); and four subjects were tested to 8,000 ft in aircraft
(Beech-1900)(In-flight). Vision performance and physiologic response were
monitored by measurements of visual acuity, contrast sensitivity, visual function
questionnaire(NEI-VFQ) and slit-lamp examinations. Results: All subjects ‘s
questionnaire scores were not statistically different between before and after
exposure(Type I chamber fly: pre-exposure scores is 96.75±0.63, post-exposure
scores is 96.57±0.73; Type VI chamber fly: pre-exposure scores is 95.24±1.26,
post-exposure scores is 95.24±1.26; In-flight: pre-exposure scores is 96.88±1.19,
post-exposure scores is 95.09±1.54) and the slit-lamp examinations were
unremarkable. The performance of night visual acuity and night contrast
sensitivity were worse than day’s but still in the normal range. There were no
statistically significant in visual acuity and contrast sensitivity neither in day nor
night. Conclusions: Wearing SH contact lens in high altitude and hypoxia
environment did not make eyes discomfort, cornea edema and cornea injury.
Visual acuity and contrast sensitivity were normal. Therefore, SH contact lens
may provide another choice of treatment to correct refractive error in military
aircrew.
|
|---|
