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Background It is essential to measure and assess the parameters of ocular anterior segment for refractive surgery in myopic eyes.Some different imaging devices can be used for biometric measurement of ocular anterior segment,but which is more accurate and convenient is still under investigation.Objective This study was to compare the anterior segment parameters in myopic eyes measured by anterior segment optical coherence tomography (AS-OCT),Orbscan topography and ultrasonic pachymetry (US).Methods One hundred and forty eyes of 70 myopic subjects with the diopter of-0.75 to-10.25 D,who intended to receive corneal refractive surgery in the Second Affiliated Hospital of Zhejiang University School of Medicine from November 2011 to May 2012,were retrospectively analyzed.Central corneal thickness (CCT) was measured using AS-OCT,Orbscan Ⅱ and US,respectively,and anterior chamber depth (ACD) was measured by AS-OCT and Orbscan Ⅱ,and the angle to angle (ATA) distance and corneal white-to-white corneal distance (WTW) were measured by AS-OCT and Orbscan Ⅱ,respectively.The parameters from different apparatuses were statistically compared.Results The mean CCT were (516.57±30.25) μm in AS-OCT,(523.68±31.87) μm in US and (514.69±38.40) μm in Orbscan Ⅱ,without significant difference among them (F =2.775,P =0.063).Then the patients were divided into three groups based on the US measurement of CCT (＜500 μm group,500-569 μm group,and ≥ 570 μm group).In the ＜500 μm group,there was a significant difference in the CCT among the three methods (F =22.236,P =0.000),significant differences were found between AS-OCT and Orbscan Ⅱ,or Orbscan Ⅱ and US(both at P＜0.05).In the 500-569 μm group,there was no significant difference in the CCT among the three methods (F =3.011,P =0.051).In the ≥ 570 μm group,there was a significant difference in the CCT among the three methods (F =4.133,P =0.021),a significant difference was found between AS-OCT and US(P＜0.05),but there was no significant difference between AS-OCT and Orbscan Ⅱ (P＞0.05).The ACD values measured by AS-OCT was (3.83±0.21) mm,which was higher than (3.75 ± 0.21) mm by Orbscan Ⅱ,with a significant difference between them (t =-8.520,P =0.000).In addition,the ATA value by AS-OCT (12.43 mm±0.74 mm) was higher than the WTW value (11.42 mm±0.33 mm) by OrbscanⅡ,with a significant difference between them(t=-18.088,P=0.000).Conclusions AS-OCT,US and Orbscan Ⅱ can offer accurate CCT value,and they can provide references to one another before refractive surgery.However,the ACD,ATA and WTW values by AS-OCT and Orbscan]Ⅱ have large differences.
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<p><b>OBJECTIVE</b>To investigate the role of caspase-3 and its inhibitor Ac-DEVD-CHO in rat lens epithelial cell apoptosis induced by hydrogen peroxide (H(2)O(2)) in vitro.</p><p><b>METHODS</b>Rat lenses were incubated in modified Eagle's medium containing 2 mmol/L H(2)O(2) to induce apoptosis in vitro. Apoptosis in lens epithelial cells was assessed by transmission electron microscopy and annexin V-propidium iodide (PI) double staining flow cytometry after 12, 24 and 48 h of incubation. The activity of caspase-3 was analyzed by western blotting.</p><p><b>RESULTS</b>Observations under transmission electron microscopy revealed that 2 mmol/L H(2)O(2) could effectively induce lens epithelial cell apoptosis in vitro. Caspase-3 activity increased during cell apoptosis and the peak measurement occurred at 24 h after treatment with H(2)O(2). Cell apoptosis was blocked by caspase-3 inhibitor Ac-DEVD-CHO.</p><p><b>CONCLUSIONS</b>The activation of caspase-3 plays an important role in executing apoptosis in H(2)O(2)-treated lens epithelial cells and in the formation of cataract. The caspase-3 inhibitor Ac-DEVD-CHO may effectively prevent lens epithelial cell apoptosis caused by oxidative injury.</p>