Measurement of anterior scleral thickness and its correlation with central corneal thickness and axial length in different types of glaucoma patients / 中华实验眼科杂志

ABSTRACT

Background A close relation between sclera thickness and glaucoma has been determined.Clinical features vary in different types of glaucoma patients,which hints that the scleral thickness might be distinct among these patients.Objective The aim of this study was to investigate the differences of central corneal thickness(CCT),anterior scleral thickness(AST) and axial length in glaucomatous patients.Methods This study was approved by the Ethic Commission of First Hospital of Peking University.Written informed consent was obtained from each individual prior to the examination.A retrospective descriptive study was designed.One hundred and sixty consecutive patients were recruited from March,2009 to November,2010 in First Hospital of Peking University,including 35 eyes with primary angle closure glaucoma(PACG) (35 cases),34 eyes with primary open-angle glaucoma POAG) (34 cases),37 eyes with normal tension glaucoma(NTG) (37 cases)and 17 eyes of ocular hypertension OHT) (17 cases).Thirty-seven eyes of 37 subjects with incipient cataract served as the control group.CCT and ocular axial length were measured with ultrasonic pachymeter and A-scan unit,respectively,and AST at the temporal quadrant 2 mm posterior to the scleral spur was measured by ultrasonic biomicroscopy (UBM).The measuring parameters among different groups were compared by analysis of covariance,and the correlations of AST,CCT with ocular axial length were analyzed using Pearson linear correlation and linear regression.The differences and correlation of CCT,AST and AL among five groups were analyzed.Results The CCT values in PACG group,POAG group,NTG group,OHT group and control group were (535.54 ± 5.20),(550.47 ± 5.28),(521.61 ± 5.07),(575.75 ± 7.76) and (535.06± 5.06) μm,respectively,showing a significant difference among them (F =9.560,P =0.000),and the CCT value of OHT group was increased in comparison with POAG group,PACG group,NTG group and control group(all P =0.000).The CCT of the POAG group was thicker than that in the PACG group,NTG group and control group(P=0.046,0.000,0.040).No significant difference was found in CCT among NTG group,PACG group and control group(P=0.950,0.060).The AST values of PACG group,POAG group,NTG group,OHT group and control group were(0.593±0.050),(0.600±0.050),(0.592-±0.060),(0.610-±0.060) and(0.604±0.060) mm,respectively,showing a insignificant difference among them (F =0.700,P =0.590).The axial length in the patients with PACG was shorter than that of the POAG group,NTG group,OHT group and control group (all P =0.000).The Pearson correlation analysis showed significantly positive correlation between CCT and AST in POAG group and NTG group(r=0.445,P=0.008;r=0.400,P=0.014).Conclusions This study confirms that there is dissimilarity in CCT but not in AST among different types of glaucomatous patients.The changes of CCT and AST are consistent in POAG and NTG patients.