ABSTRACT
Background Pentacam anterior segment analysis system (Pentacam) is more accurate in the quantitative evaluation of ocular anterior segment in primary angle-closure glaucoma (PACG) eyes than slit lamp microscope and ultrasound biomicroscope (UBM).However,its accuracy in the earlier stage of PACG before and after YAG laser peripheral iridotomy (LPI) is not fully elucidated.Objective This study was to assess the effect of YAG LPI in PACG patients with Pentacam.Methods A prospective self-controlled study was performed.Thirtyfive fellow eyes (pre-clinical stage of PACG) of acute PACG and 35 fellow eyes of chronic PACG were included in the Second Hospital of Hebei Medical University from July,2012 to December,2013.YAG LPI was performed on the eyes,and the parameters of ocular anterior segment including central anterior chamber depth (ACD),anterior chamber volume (ACV) and peripheral anterior chamber angle (ACA) were measured and compared by Pentacam before and 1 day,7 days,28 days after operation.This study was approved by the Ethic Committee of the Second Hospital of Hebei Medical University and informed consent was obtained from all subjects.Results In pre-clinical stage of PACG eyes,the postoperative ACD and ACV values were increased in comparison with preoperation,showing significant differences among various time points (ACD:F =6.783,P =0.004;ACV:F =19.090,P =0.000),and no significant difference was found in ACA among different time points (F =0.153,P =0.928).In the fellow eyes of chronic PACG,the postoperative ACD and ACV values were larger than those of preoperation,with significant differences among various time points (ACD:F =21.576,P =0.000;ACV:F =47.506,P =0.000),and no significant difference was found in ACA among different time points (F=0.581,P=0.629).The change values of ACD and ACV were (0.064±0.022) mm and (27.840±4.963) mm3 in the eyes of pre-clinical stage of PACG,and those in the fellow eyes of chronic PACG were (0.047-± 0.020) mm and (21.000 ± 3.278) mm3,showing significant differences between the two groups (ACD:t=2.783,P=0.008;ACV:t=5.749,P=0.000).Conclusions Pentacam allows easy,fast,automatic and non-contact quantification and three-dimension image of the anterior chamber parameters before and after YAG LPI in pre-clinical stage of PACG eyes and fellow eyes of chronic PACG.The ACD deepens and ACV increases after LPI in glaucomous eyes,especially in the pre-clinical stage of PACG eyes.
ABSTRACT
?AlM:To investigate the sensitive parameters of the anterior chamber changes with Pentacam anterior segment analysis system before and after laser peripheral iridectomy (LPl) in primary angle-closure suspetive (PACS). ? METHODS: Sixty eyes of 33 PACS patients were enrolled in this study. Pentacam examination was performed before and 1d after LPl to measure the central anterior chamber depth ( CACD ) , the peripheral anterior chamber depth ( PACD ) , the anterior chamber volume ( ACV) and the peripheral anterior chamber angle ( ACA) . Statistical analysis used paired t test. ?RESULTS: There was no statistical significance on the changes of ACD. PACD and ACV increased significantly between before and 1d after LPl. ACA was widened from (22. 26o±5. 18o) to (26. 42o±5. 20o), which were increased significantly between before and 1d after LPl. ?CONCLUSlON: LPl can deepen the PACD and increase the ACV in PACS. PACD and ACV are the sensitive parameters of the anterior chamber changes with Pentacam anterior segment analysis system.
ABSTRACT
Objective To investigate the corneal posterior surface topography characteristics of keratoconus at early stages applying the Pentacam anterior segment analysis system. Methods The present study included 43 eyes of 43 patients with keratoconus at the subclinical stage (group A), 40 eyes of 40 suspected keratoconus patients (group B), and 143 normal eyes of 143 controls (group C). Based on an examination of the Pentacam anterior segment analysis system of each subject, a series of data, including the posterior surface refractive power, the posterior surface elevation were collected. The differences among the three groups, the correlation among indices, and the area under the receiver operating characteristic (ROC) curves were analyzed. Results The mean values of the posterior surface maximum refractive power in 3 groups were -6.2 D, Q=0.5;-5.6 D, Q=0.3;and -5.5 D, Q=0.3, respectively. The mean values of the posterior surface maximum elevation were 23 μm, Q=14;11 μm, Q=8.5;and 7 μm, Q=6, respectively. The posterior surface maximum refractive power and maximum elevation among three groups were statistically different. The area under ROC (AUR) of posterior maximum refractive power and the AUR of posterior maximum elevation were greater than that of other indices in the diagnosis of early keratoconus. Conclusions Based on the results from the Pentacam anterior segment analysis system, the changes of the posterior surface refractive power and elevation are important characteristics of early keratoconus.