ABSTRACT
@#AIM: To examine and investigate the contrast visual acuity and eyes care habits in Air Force pilot cadets, and analyze the change of contrast visual acuity and the related influencing factors.<p>METHODS: The contrast visual acuity of the students in Grade One and Grade Two at an aviation university was recorded and analyzed, and the visual habits were recorded and analyzed by questionnaire.<p>RESULTS: A total of 117 students in Grade One and 210 students in Grade Two were enrolled. The contrast visual acuity of both eyes over 1.0 were 83 students(70.9%)in Grade One and 174 students(82.9%)in Grade Two respectively(<i>P</i><0.05). Questionnaire survey on the eye care habits by students, showing the second grade students of daily reading time, outdoor sports, sports category, use at night time, with a focus on electronic product knowledge and the degree of attention and when flying cadets were significantly different(<i>P</i><0.05). There were 87.2% students of Grade One and 93.3% students of Grade Two taking less than or equal to 6h to get daily reading and learning time, 34.2% students of Grade One and 13.8% students of Grade Two taking outdoor sports less than or equal to 2h, 57.3% students of Grade One and 90.0% students of Grade Two taking more than One category of exercise,38.5% students of Grade One and 43.3% students of Grade Two using electronic production less than or equal to 2h, 85.5% students of Grade One and 75.7% students of Grade Two using electronic production at night, and 61.5% students of Grade One and 81.0% students of Grade Two paying high attention to the use of scientific knowledge(<i>P</i><0.05). <p>CONCLUSION: The contrast visual acuity of Air Force pilot cadets keeps improving at theoretical study stage, mainly including the following reasons such as the decreasing of reading time, the increasing of outdoor sports, the improving of exercise methods, the reduce using of electronic production and the enhancing of eyes-using knowledge.
ABSTRACT
Background Rigid gas permeable (RGP) contact lens,as a kind of new correction of refraction error,has been wildly used,but whether it will cause eye optical system of the change and influence on the visual acuity is unclear.Objective Present study was to evaluate and compare the visual quality of low to moderate myopia following wearing of RGP contact lens and spectacles.Methods Sixty-eight eyes of 35 subjects with low or mediate myopia were included in this study.Wave-front aberrations and visual acuities under the different contrasts (10％,30％,40％,52％,76％,92％) in the light or dark environment were examined before and 3 months after wearing of RGP corneal contact lens.These parameters were compared with those after wearing of spectacles with paired t test.Results The best corrected visual acuity (BCVA) was improved significantly from 0.94±0.10 to 1.26±0.03 3 months after wearing of RGP corneal contact lens (t=-9.266,P=0.000).After fitting of RGP corneal contact lens,the total higher order wave-front aberrations,the 3rd and 4th order aberrations were significantly declined in comparison with those of before fitting (total:t=4.683,P=0.000;RMS3:t=4.656,P=0.000;RMS4:t=3.929,P=0.000).However,no significant differences were detected in the 5th and 6th order aberrations between RGP corneal contact lens fitting and spectacles wearing (RMS5:t=1.766,P=0.083 ;RMS6:t=1.150,P=0.256).In both bright and dark environments,BCVA values were much better in the eyes with RGP corneal contact lens wearing than that in the eyes with spectacles wearing (all P＜0.05).The BCVA was always reduced with the decline of contrast level whether bright or dark backgrounds both in RGP corneal contact lens wearing eyes and spectacles wearing eyes.Conclusions Wearing of RGP corneal contact lens provides better visual quality for low to moderate myopia than the spectacles wearing.
ABSTRACT
Purpose: To assess contrast visual acuity (CVA) in patients with retinitis pigmentosa (RP) and compare the result with standard visual acuity (VA), retinal thickness, status of inner segment/outer segment junction, and central visual field. Materials and Methods: Thirty-nine eyes of 39 patients with RP and 39 eyes of 39 healthy individuals were studied. To see the difference in CVA between RP patients and normal controls, only subjects with standard VA of 1.0 (20/20) or better were included. This was a cross-sectional study. CVA in various light conditions was measured with CAT-2000 and was compared between patients and controls. CVA of patients was further analyzed for association with other parameters including foveal retinal thickness, outer nuclear layer thickness, the status of inner segment/outer segment junction measured with optical coherence tomography (OCT), and visual field mean deviation (MD) measured with Humphrey field analyzer 10-2 program. Results: CVA impairment was evident in RP patients compared to controls (P < 0.01, in all measurement conditions). Multivariate analysis showed association of logarithm of the minimum angle of resolution (logMAR) with CVAs in several conditions. None of the OCT measurements was associated with CVA. When patients were divided into three groups based on MD, the most advanced group (MD worse than or equal to –20 dB) showed impairment of mesopic CVA (P < 0.05, under mesopic condition of 100% without glare, with glare, and 25% without glare). Conclusion: CVA impairment was confirmed in RP patients, especially in advanced cases. CVA measured with CAT-2000 may be a useful tool for assessing foveal function in RP patients.