| Objective: Hit by external force, eye ball would be injured not only structurally, but also functionally, most of which was refractive myopia. This kind of myopia was transient and the pathogenesis was unknown. Ultrasound Biomicroscope (UBM ) had advantages in high resolution and could measure the eye structure quantitatively, which performed in vivo without the limitation . In this study , we used UBM to measure the thickness of cornea, anterior chamber depth, trabecular ciliary process distance (TCPD), A-angle and the height of the ciliary process (T values), in order to investigate the pathogenesis of myopia after blunt eye trauma.Methods: A total of 31 patients, including 36 eyes, were diagnosed clinically as blunt eye trauma. The average interval was 12.47±3.65 days between the acute and convalescent stages. Refraction was measured with an autorefractometer in the acute and convalescent stages after a blunt eye injury. The lens thickness were also measured by A-scan ultrasoundgraphy in the acute and convalescent stages. The cornea thickness,anterior chamber depth,TCPD,A-angle and the T values were examined by UBM in the acute and convalescent stages. At the same time, 36 normal eyes were measured twice as the control group. The average interval was 15 days. Topical mydrin P was applied to eyes 30 minutes before examination. All parameter were performed by paired T-test. We studied the correlationship among the difference of parameters. The significant lever was 0.05.Results1 Autorefractometer were used to measure refractive shift. All 36 eyes were diagnosed as traumatic myopia .The average myopia shift was –2.34±2.63D in the acute stage and –0.20 ±2.48D in the convalescent stage. The difference of the two group was significant (t=8.184, p<0.05). 2 The results were measured by A-scan ultrasonography.The average lens thickness was 4.02±0.41mm in the acute stage and 3.79±0.39mm in the convalescent stage. The difference of the two group was significant (p<0.05), which showed that the lens thickened in the acute stage. 3 The results were measured by UBM.3.1The average cornea thickness of traumatic eyes in the acute stages was 0.57±0.21 mm, while that was 0.56±025mm in the convalescent stages ,and the difference of the two groups was not significant (t=1.88, p>0.05) .3.2. The central anterior chamber depth was shallow after the injury in the acute stage. The average central anterior chamber depth was 3.27±0.51mm in the acute stage and 3.40± 0.39mm in the convalescent stage. The difference of the two group was significant (t=-2.468, p<0.05). 3.3 The average TCPD was 0.94±0.10mm in the acute stage and 0.99±0.11mm in the convalescent stage. The difference of the two group was significant ( p<0.05). 3.4 A-angle in traumatic eyes were smaller in the acute stage than that in the convalescent stage. The average A-angle was 87.56±4.33D in the acute stage and 91.28±3.70D in the convalescent stage. The difference of the two group was significant (t=-7.680, p<0.05).3.5 T value in traumatic eyes was larger in the acute stages than that in the convalescent stages. The T value was 1.37± 0.33mm in the acute stage and 1.34±0.22mm ±in the convalescent stage. The difference of the two group was significant (p<0.05). The control group was measure twice in the same way. When parameters were compared, the difference was not significant (p>0.05).4 The correlations among the parameter The differences between lens thickness and refraction were positive correlation, the linear regression equation was y=1.5413+2.4128x and correlation coefficient was 0.3473 (p<0.05). The differences between anterior chamber depth and refraction were positive correlation, the linear regression equation was y=1.7727+2.7462x and correlation coefficient was 0.4375 (p<0.05). The differences between TCPD and refraction were positive correlation, the linear regression equation was y=0.7209+29.6038x and correlation coefficient was 0.6230 (p<0.05). The differences betwe... |
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