| Objective1.The aim of this study is to explore the difference and agreement in the measurement of anterior chamber depth (ACD) between Pentacam and ultra-sonographic biomicroscope (UBM) of primary angle-closure glaucoma (PACG) patients.2. To study changes in anterior segment morphology after laser peripheral iridotomy (LPI) in Chinese primary angle closure (PAC) patients using Pentacam.Methods1.Seventy-seven eyes of 77 PACG patients aged (69.96±7.87) were divided into two groups. Thirty-seven eyes with acute primary angle-closure glaucoma (APACG) were assigned to group 1, and forty eyes with chronic primary angle-closure glaucoma (CPACG) were assigned to group 2. Central ACD was measured with Pentacam and UBM, respectively. The Bland-Altman method was used to evaluate the agreement of the two methods.2.In this prospective study, Pentacam was used to record the pre-LPI, 1day,1 week, 1 month and 3 month post-LPI morphology of the anterior segment. LPI was performed on 39 eyes of 29 Chinese PAC patients. The parameters included the horizontal and vertical curvature, the corneal thickness, the Ecc, the central ACD, anterior chamber volume (ACV), anterior chamber angle (ACA), the intraocular pressure (IOP) and the peripheral ACD. All the data were analysed by the SPSS 11.5 statistical software package.Results1. The central ACD value measured by Pentacam and UBM were (1.65±0.27) mm and (1.56±0.27) mm respectively in APACG, indicating a significant difference (t=-7.259, P<0.01) and a positive linear correlation between the results of these two methods (r=0.939, P<0.01). The central ACD value measured by Pentacam and UBM were (2.06±0.23) mm and (1.96±0.22) mm respectively in CPACG eyes with a significant difference between them(t=-10.433, P<0.01) and a significant linear correlation between these two outcomes (r=0.967, P<0.01). The Bland-Altman method showed that the two modalities had comparable results for central ACD.2. The differences between Pachy Pupil and Pachy T values taken before LPI and those taken at 1day,1 week,1 month and 3 month after LPI were not statistically significant. 3. The differences between the horizontal and vertical curvature, the astigmatism, the Ecc values taken before LPI and those taken at 1day,1 week,1 month and 3 month after LPI were not statistically significant.4. The differences between Central ACD values taken before LPI and those taken at 1day,1 week,1 month and 3 month after LPI were not statistically significant. The ACV, ACA and IOP changed significantly after LPI at 1 day,1 week,1 month and 3 month respectively.5. LPI changed the iris contour from convex to flat by Scheimpflug images. The peripheral ACD from 4mm of optical axis in the superior, temporal, inferior and nasal meridians all increased significantly after LPI at 1day,1 week,1 month and 3 month respectively. The peripheral ACD from 2mm of optical axis all increased significantly after LPI at 1day,1 week,1 month and 3 month, respectively.6. Both the central ACD and the peripheral ACD was correlated significantly with the ACV before LPI. The average increase in peripheral ACD(ΔPACD) from 4mm of optical axis was correlated significantly with the average increase ACV (AACV) at 1day,1 week,1 month and 3month, respectively.Conclutions1.Pentacam, as a new 3-dimensional mathematical model of the anterior segment, presents some different results from UBM in the measurement of central ACD, but it is not clinically significant. Combination of Pentacam and UBM may be available for the clinical measurement of central ACD.2. To PAC patietns, the horizontal and vertical curvature, the astigmatism and the Ecc values didn't change after LPI. LPI does not affect the corneal morphology.3. LPI leads the increase of ACV, the peripheral ACD from 4mm of optical axis and the peripheral ACD from 2mm of optical axis. The great change of ACV after LPI was mostly because of the flattening of the iris shape. LPI could prevented development of PAC into PACG in a short period.
|
PDF Full Text Request