Quantitative evaluation of anterior chamber angle after laser peripheral iridotomy by spectral-domain anterior segment optical coherence tomography (AS-OCT) / 眼科新进展

ABSTRACT

Objective To quantitatively assess anterior chamber angle of primary angle-closure glaucoma (PACG) and primary angle-closure (PAC) patients after laser pheripheral iridotomy (LPI) by spectral-domain anterior segment optical coherence tomography (SD-AS-OCT),and investigate which parameters should be used in these patients and the clinical significance of these parameters in screening and follow-ups of glaucoma.Methods Fifty-five eyes of 40 patients diagnosed with PACG remission (11 eyes,8 patients),PAC (20 eyes,20 patients) or PAC suspect (24 eyes,12 patients) were examined.Each eye was examined by SD-AS-OCT at upper,lower,nasal,and temporal sides.Anterior chamber angle (ACA),trabecular iris angle (TIA),and trabecular iris space area (TISA500/750) were measured or calculated.All results were analyzed.Results The points from the inside to the corneal scleral spur 500 μm and 750 pm were selected,AOD,TIA,ACA,TISA at upper,lower,nasal,and temporal sides were measured,which were included into 500 series and 750 series.The mean values of TIA,ACA and AOD in the 500 series and 750 series were the largest in the temporal side and the lowest in the nasal side.The mean values of TISA measurement was the largest in the lower side and the smallest at the upper side.Pearson correlation analysis showed that TIA500 and ACA500 (r =0.799,P =0.00),TIA750 and ACA750 (r =0.799,P =0.00),TIA500 and TISA500 (r=0.919,P =0.00),TIA750 and TISA750 (r =0.920,P =0.00) had positive correlation.With TIA500 as independent variable x and TISA500 as dependent variable y,the regression equation was obtainedy =-0.300 + 0.005x (F =1195,P =0.00),which showed TISA500 and TIA500 were linearly positive correlated.With TIA750 as independent variable x,and TISA750 as dependent variable y,the regression equation was obtainedy =-0.440 + 0.009x (F =854,P =0.00),which showed TISA750 and TIA750 were linearly positive correlated.The coefficient of variation of the 750 series parameters were less than the 500 Series in the four directions.Conclusion SD-AS-OCT is an efficient tool for efficiency evaluation and follow-up during the course of PACG and PAC after LPI.For narrow angles,as the parameters of 750 series parameters have less variability,so 750 series are more recommended in clinical application.