| Visual system is the most fundamental of our senses in receiving external information. Most operations during the flight is under vision control. So the vision plays an important role in aviation safety. To maintain visual function and do medical evaluation is an important part of routine aeromedical health service work. Fundus examination, as an important element of classic physical examination, can not only detect eye diseases, but also show the relationship to the systematic diseases. Vessels in retinal are the only micro vessels which can detected by non-invasive method. Meanwhile, the visibility of retinal vessels provides the possibility for non-invasive examination in vivo. Retinal vessels are regarded as an essential indicator in evaluating cardiovascular and cerebrovascular diseases, as well. At present, the direct ophthalmoscope examination is still widely used method for ocular fundus examination. Nevertheless, the results of this method are depended on the experience of examiner, lacking objectivity and easy to be misdiagnosed or missed diagnosis. Muti-spectual ocular fundus imaging(MSI) is a new inspectingmethod in detecting ocular fundus diseases, which using optical imaging principles, take pictures on different layers of ocular fundus, including retinal and choroid. The improved MSI method overcomes the inadequacies of ordinary with the progress which is rapid and noninvasive. In order to establish new method to ocular fundus examination and to detect system diseases early signs in airmen and to improve the level of aviation medical evaluation, we explored the application of MSI in the aviation medical evaluation.Materials and Methods Subjects in this project included 213 military aircraft pilots, 465 civil aircrew and 506 non-aircrew wrinkly or elderly people, who took the annual physical examination during 2014 and 2015. The examinations were investigated and documented according to the routine procedure. The direct ophthalmoscope examination was operated by ophthalmologist and MSI was conducted by the specialist with independent. Then, the professional ophthalmologist would review the photographs taken by specialist. In order to reduce bias, we made the diagnosis by comprehensive assessment with cooperative. The direct ophthalmoscope was conducted as conventional approach and if it was necessary the mydriatic would be used. MSI examination in both eyes was conducted, each eye was taken 10 photographs, each of which represented to different layers of ocular fundus, including retina and choroid. After all, we took archiving the fundus photographs. With the purpose of discussing the possible risk factors leading to arteriosclerotic retinopathy, we use the method of 1:1 paired design in those military aircraft pilots between hyperlipidemia and normal lipidemia group, and we use the same method in pilots between +Gz payload group(fight plan pilot) and non +Gz payload group. We gathered other biochemical criterions and medical information retrospectively. Methods SPSS17.0 software was used to statistical analysis. We applied chi-square test to compare with fundus abnormalities rate between groups and we used indicator of Kappa value to estimate the consistency test with MSI and direct ophthalmoscope.Results 1. The application of MSI in screening and diagnosing for fundus abnormalities of metabolic syndrome The detection rate of MSI and direct ophthalmoscope were 12.16% and 8.11% in NPDR, 11.73% and 5.56% in grade 1 hypertensive retinopathy(HRP), 11.11% and 6.17% in grade 2 HRP, respectively. Compared with direct ophthalmoscope, MSI had a higher detection rate in diagnosis of NPDR and grade 1 or 2 of HRP. 2. The distribution of the fundus abnormalities in military aircraft pilots 213 military aircraft pilots were examined by MSI. The total prevalence of abnormal ocular fundus was 13.15%. The predominant abnormality was retinal arteriosclerosis, which accounted for 5.16%. And the prevalence of retinal pigmentation disorder and maculopathy was about 3.29% and 2.35%, respectively. Besides, we also deteced some cases like microaneurysm, central serous chorioretinopathy and medullated nerve fibers of retina. 3. The possible risk factors leading to arteriosclerotic retinopathy in military aircraft pilots Our research showed that the prevalence of arteriosclerotic retinopathy in the groups of hyperlipidemia is higher than that in normal lipidemia groups, OR=8. But there is no significant differences in pilots between +Gz payload group(fight plan pilot) and non +Gz payload group. 4. The distribution of the fundus abnormalities in cival aircrew 465 civil aircrew were examined by MSI. The total prevalence of abnormal ocular fundus was 21.51%. The most abnormal was maculopathy which was 9.89%. The predominant abnormality was maculopathy, which accounted for 9.89%. And the prevalence of retinal arteriosclerosis and microaneurysm was about 6.23% and 1.07%, respectively. Besides, we also detected some cases like retinal pigmentation disorder, epiretinal membranes and medullated choroid coloboma, et al. The results showed a slight distinct between different professions. The prevalance ofabnormal fundus in pilots and fight attendants was 23.19% and 9.38%, respectively. The prevalence of abnormal fundus also showed increasing trend with age, in the same way with the flight time. 5. The consistency between MSI and direct ophthalmoscope In our research, 401 civil aviator were taken fundus examination by both MSI and direct ophthalmoscope. The detection rates of direct ophthalmoscope and MSI were 15.71% and 23.19%, respectively. There was statistically significance between two methods. The sensitivity and specificity of MSI was 98.4% and 90.8%, and the Kappa value was 0.75. The Youden index of MSI was 89.4%. Therefore, MSI and direct ophthalmoscope have a good consistency.Conclusion As an ophthalmic examination, fundus examination can detect the fundus abnormalities. Moreover, we can observe the fundus abnormalities of metabolic syndrome to understand the development and progression of systematic diseases in a comprehensive way. Therefore, it is essential to take fundus examination as a common part of physical examination. Compared with direct ophthalmoscope, MSI, according to the characteristics of different wavelengths, could not only present the changes of nerve fiber layer, but also can show the abnormal structures of retinal pigment epithelium and choroid membranes. This MSI method offered an objective way in detecting the fundus abnormalities in detail, which cannot be detected in common way. The total prevalence of abnormal ocular fundus in military aircraft pilots and civil aircrew was 13.15% and 21.51%. High detection rate of arteriosclerotic retinopathy and maculopathy was expressed in both military aircraft pilots and cival aircrew. Hyperlipidemia could be a possible risk factor for arteriosclerotic retinopathy, however, +Gz payload still could not be the possible risk factor for arteriosclerotic retinopathy. It showed increasing trend with age and flight time, especially in fundus microvascular disease. Consequently, MSI can inspect and record the fundus oculi disease of pilot objectively in a sensitive way, besides, it is more effective andapplicable in screening and diagnosing for fundus abnormalities of metabolic syndrome. And it showed superiority in the prediction of cardiovascular and cerebrovascular diseases. MSI possess promising application future in clinical aviation medicine. |
PDF Full Text Request