Anterior Chamber Volume Measurements Research Articles

Identification of eyes at risk of acute primary angle-closure in elderly Japanese patients.

Purpose: To identify from the anterior segment the structural variables of the eyes that can be used to distinguish acute primary angle-closure (APAC) eyes or primary angle-closure suspect (PACS) eyes from normal eyes.Patients and methods: We used a Pentacam scanner to measure participants’ anterior eye segments. We assessed each anterior segment structure variable on the basis of receiver operating characteristic curves using the area under the curve (AUC).Results: AUCs for eyes in men with APAC were 1.000 for central anterior chamber depth (ACD), 0.982 for peripheral ACD, 0.916 for anterior chamber angle (ACA), and 0.992 for anterior chamber volume (ACV). AUCs for eyes in women with APAC were 0.997 for central ACD, 0.942 for peripheral ACD, 0.922 for ACA, and 0.946 for ACV. AUCs for eyes in men with PACS were 0.933 for central ACD, 0.930 for peripheral ACD, 0.887 for ACA, and 0.937 for ACV. AUCs for eyes in women with PACS were 0.960 for central ACD, 0.957 for peripheral ACD, 0.937 for ACA, and 0.937 for ACV. The negative predictive values (%) in men with APAC were 100 for all the four variables (central ACD, peripheral ACD, ACA, and ACV). The negative predictive values (%) in women with APAC were 100 for central ACD, 98.7 for peripheral ACD, 97.1 for ACA, and 97.9 for ACV. The negative predictive values (%) in men with PACS were 98.6 for central ACD, 100 for peripheral ACD, 98.5 for ACA, and 99.4 for ACV. The negative predictive values (%) in women with PACS were 100 for central ACD, 98.7 for peripheral ACD, 97.1 for ACA, and 97.9 for ACV.Conclusions: The central ACD, peripheral ACD, ACA, and ACV measurements seem to be excellent markers to identify eyes without APAC or PACS.

Evaluation of anterior chamber volume using Pentacam and anterior segment optical coherence tomography among normal subjects

Aim: To compare the anterior chamber volume measurements obtained with Pentacam and derived from anterior segment optical coherence tomography.
 Design: Cross-sectional study.
 Methods: We included normal subjects who underwent a comprehensive eye examination including refraction, keratometry, Goldmann applanation tonometry, gonioscopy, anterior segment optical coherence tomography (AS-OCT) (Carl Zeiss Meditec Inc.; Dublin, CA, USA) and Pentacam (Oculus Inc.; Lynnwood, WA, USA). Fifty scans were selected for Pentacam and 12 images were selected for calculation of anterior chamber volume. Only the right eye was considered for analysis.
 Results: One-hundred and nineteen eyes of 119 subjects were included for analysis. The mean age of the subjects was 42.58 ± 13.15 years, of which 74 were female and 45 were male. The mean anterior chamber volume measured using AS-OCT was 119.17 ± 26.56 mm3 and with Pentacam was 131.29 ± 34.26 mm3. The comparison of means between the two modalities was statistically significant (t = -8.857, Mean Difference (MD) = 12.11, 95% CI: (4.29, 19.95), p = 0.003). Bland-Altman plot showed poor agreement between the chamber volume measurements obtained by Pentacam and AS-OCT with MD of 12.1 mm3 (95 % CI: 41.4 to -17.1) and intra-class correlation between the two instruments was 0.94 (95% CI: 0.91, 0.96) (p < 0.0001).
 Conclusion: The anterior chamber volume can be measured using Pentacam as well as AS-OCT since these measurements were reliable. However, these measurements were not interchangeable due to poor levels of agreement.

Anizohipermetropik ambliyopisi olan yetişkinlerin ön segment parametrelerinin Sirius topografi ile değerlendirilmesi

Aim: To evaluate anterior segment parameters in the eyes of adults with anisohypermetropic amblyopia using the Sirius topography device.Materials and Methods: Forty-eight patients with anisohypermetropic amblyopia were prospectively evaluated along with a control group of 45 healthy patients. All patients were examined with the Sirius topography system under cycloplegic and non-cycloplegic conditions. The anterior and posterior mean keratometry values, central corneal thickness (CCT), anterior chamber depth (ACD), corneal volume (CV), and anterior chamber volume (ACV) measurements were compared among groups.Results: No significant difference was found in the anterior and posterior mean keratometry values, CCT, ACD, CV, and ACV measurements between amblyopic, fellow, and control eyes under cycloplegic and non-cycloplegic conditions (p>0.05).Conclusion: This study shows that the anterior segment parameters measured by the Sirius topography device among amblyopic, fellow, and control eyes do not differ under both cycloplegic and non-cycloplegic conditions.

Comparison of Anterior Chamber Parameters between Normal and Keratoconus Eyes using Scheimpflug Photography

ABSTRACT Aim To evaluate anterior chamber indices including anterior chamber depth (ACD) and anterior chamber volume (ACV) with the progression of keratoconus using a rotating Scheimpflug camera to determine the sensitivity and specificity of these parameters in discriminating keratoconus from normal eyes. Materials and methods After full ophthalmological examination in the Memorial Institute of Ophthalmic Research, the patients are divided into two groups: Group I consisting of 50 eyes of normal control. Group II consists of 50 eyes of moderate keratoconus. All the subjects were evaluated with a Pentacam Scheimpflug camera (Oculus, Wetzlar, Germany). Keratoconic eyes were evaluated by vertical asymmetry (VI), keratoconus index (KI), thinnest corneal thickness (TCT) with front elevation at thinnest location (F.Ele.Th) and back elevation at thinnest location (B.Ele.Th) and then divided into three groups according to mean keratometer (K) readings: Mild (K = less than 47.0 D), moderate (K = 47.0 to 52.0 D), and severe (K = 52.0 D or higher), and ACD and ACV were obtained after exclusion of mild and severe cases. Results With the progression of the disease, there was statistically significant differences in ACD and ACV measurements between the normal and moderate keratoconus eyes with progressive increase in the ACD and ACV with disease progression. Conclusion Anterior chamber parameters including depth and volume showed significant increase with moderate keratoconus than control. How to cite this article Ali NH, AbdElKhalek MO, El Ghonemy HM. Comparison of Anterior Chamber Parameters between Normal and Keratoconus Eyes using Scheimpflug Photography. Int J Kerat Ect Cor Dis 2016;5(3):105-108.

Influences of Tropicamide on Anterior Segment Parameters with Pentacam in Healthy Individuals

This study aims to investigate the effects of tropicamide 1% on the main numerical parameters of anterior segment with the Pentacam rotating Scheimpflug camera in healthy individuals. Pentacam measurements of 50 (25 female and 25 male) healthy individuals before and after 25 min of tropicamide 1% instillation were performed and compared. For comparison of the test parameters, paired t-test was used in the groups. Mean age in the study group was 28.40±4.58 years (range 18-35 years). Measurements between 2 sessions were significantly different for the parameters of anterior chamber depth (ACD) and anterior chamber volume (ACV) (P<0.05). Tropicamide 1% instillation leads to a significant increment in ACD and ACV measurements. Effects of tropicamide on these parameters for Pentacam measurements should be considered to ensure exact clinical interpretation in ophthalmologic practice.

Comparison of Scheimpflug imaging and spectral domain anterior segment optical coherence tomography for detection of narrow anterior chamber angles

To compare the performance of anterior chamber volume (ACV) and anterior chamber depth (ACD) obtained using Scheimpflug imaging with angle opening distance (AOD500) and trabecular-iris space area (TISA500) obtained using spectral domain anterior segment optical coherence tomography (SD-ASOCT) in detecting narrow angles classified using gonioscopy. In this prospective, cross-sectional observational study, 265 eyes of 265 consecutive patients underwent sequential Scheimpflug imaging, SD-ASOCT imaging, and gonioscopy. Correlations between gonioscopy grading, ACV, ACD, AOD500, and TISA500 were evaluated. Area under receiver operating characteristic curve (AUC), sensitivity, specificity, and likelihood ratios (LRs) were calculated to assess the performance of ACV, ACD, AOD500, and TISA500 in detecting narrow angles (defined as Shaffer grade ≤1 in all quadrants). SD-ASOCT images were obtained at the nasal and temporal quadrants only. Twenty-eight eyes (10.6%) were classified as narrow angles on gonioscopy. ACV correlated with gonioscopy grading (P<0.001) for temporal (r=0.204), superior (r=0.251), nasal (r=0.213), and inferior (r=0.236) quadrants. ACV correlated with TISA500 for nasal (r=0.135, P=0.029) and temporal (P=0.160, P=0.009) quadrants and also with AOD500 for nasal (r=0.498, P<0.001) and temporal (r=0.517, P<0.001) quadrants. For detection of narrow angles, ACV (AUC=0.935; 95% confidence interval (CI) =0.898-0.961) performed similar to ACD (AUC=0.88, P=0.06) and significantly better than AOD500 nasal (AUC=0.761, P=0.001), AOD500 temporal (AUC=0.808, P<0.001), TISA500 nasal (AUC=0.756, P<0.001), and TISA500 temporal (AUC=0.738, P<0.001). Using a cutoff of 113 mm(3), ACV had 90% sensitivity and 88% specificity for detecting narrow angles. Positive and negative LRs for ACV were 8.63 (95% CI=7.4-10.0) and 0.11 (95% CI=0.03-0.4), respectively. ACV measurements using Scheimpflug imaging outperformed AOD500 and TISA500 using SD-ASOCT for detecting narrow angles.

Repeatability and reproducibility of anterior chamber volume measurements using 3-dimensional corneal and anterior segment optical coherence tomography

To evaluate the repeatability and reproducibility of anterior chamber volume (ACV) measurements using swept-source 3-dimensional corneal and anterior segment optical coherence tomography (CAS-OCT) and dual Scheimpflug imaging. Department of Ophthalmology, Institute of Clinical Medicine, University of Tsukuba, Ibaraki, Japan. Nonrandomized clinical trial. Measurements were taken in normal eyes (subject group) and in eyes with primary angle closure (PAC) (patient group). In the subject group, the entire ACV and the central 8.0 mm diameter ACV were measured using CAS-OCT and dual Scheimpflug imaging. In the patient group, the entire ACV and 8.0 mm ACV were measured using CAS-OCT. The coefficient of variation and intraclass correlation coefficient (ICC) were calculated to evaluate repeatability and reproducibility, and the correlation between the 2 devices was assessed. In the subject group, the mean 8.0 mm ACV was 110.14 mm(3) ± 12.57 (SD) using CAS-OCT and 114.51 ± 14.69 mm(3) using Scheimpflug imaging; there was a significant linear correlation (r = 0.878, P < .0001). The mean entire ACV on CAS-OCT was 165.15 ± 29.29 mm(3). The ICCs of the 8.0 mm and entire ACV measurements were greater than 0.94. The coefficients of repeatability and reproducibility of the 8.0 mm ACV and entire ACV measurements were less than 5%. In the patient group, the 8.0 mm and entire ACV measurements showed good reproducibility and repeatability. The CAS-OCT method allowed noninvasive measurement of the entire ACV with sufficient repeatability and reproducibility. The 8.0 mm ACV measurements with CAS-OCT and Scheimpflug imaging were comparable.

Evaluation of anterior segment parameter changes using the Pentacam after uneventful phacoemulsification

This study set out to evaluate the influences of uneventful phacoemulsification on the anterior segment parameters obtained with the Pentacam rotating Scheimpflug camera and intraocular pressure (IOP). A total of 42 eyes of 34 patients (26 men, eight women) were evaluated preoperatively, and at 1, 3 and 6 months postoperatively with the Pentacam. Intraocular pressure was measured with the Goldmann applanation tonometer. The non-parametric paired t-test was used to compare preoperative and 1-, 3- and 6-month postoperative measurements of anterior chamber depth (ACD), anterior chamber volume (ACV), anterior chamber angle (ACA) width, central corneal thickness (CCT), the central 3-, 5- and 7-mm corneal volume (CV), pupil size, and IOP. Pearson's correlation test was used to evaluate the relationships between IOP and ACD, ACV and ACA width. The differences between ACD, ACV, ACA and IOP values taken preoperatively and those taken postoperatively at 1, 3 and 6 months were statistically significant (p<0.05). The differences between CCT, central 3-, 5- and 7-mm CV, and pupil size measurements taken preoperatively and those taken postoperatively at 1, 3 and 6 months were not statistically significant (p>0.05). The decrease in IOP was not correlated with the changes in ACD, ACV and ACA (p>0.05). Uneventful phacoemulsification significantly reduced IOP, increased ACD and ACV, and widened the ACA. However, alterations in CV, CCT and pupil size values were not statistically significant. Alterations in ACD, ACV, ACA and IOP remain stable after the first month of surgery.

Anterior chamber volume measurements with Visante optical coherence tomography and Pentacam: repeatability and level of agreement

The purpose of this study is to examine the repeatability of Pentacam-derived anterior chamber volume measurements, and assess the level of agreement of anterior chamber volume measurements obtained with the Visante and the Pentacam imaging devices. Anterior chamber volume was calculated with the Pentacam device and the Visante using the Wang formula. Results were analysed by means of the Wilcoxon signed rank test, Bland-Altman analysis, Cronbach's alpha test and intraclass correlation coefficient. P-values <0.01 were considered statistically significant. One randomly selected eye from each of 20 persons was analysed. Spherical equivalent ranged between -2.50 and +1.50 D, and their age ranged from 25 to 79 years (mean +/- SD: 54.4 +/- 19.2 years). Mean anterior chamber volume measured with Pentacam was 171.1 +/- 39.6 microL (minimum: 103.0 microL, maximum: 236.0 microL), and mean anterior chamber volume measured by Visante was 171.4 +/- 42.4 microL (minimum: 96.4 microL, maximum: 245.5 microL). There was no statistically significant difference between Pentacam and Visante measurements of the anterior chamber volume (P = 0.691, Wilcoxon signed rank test). Cronbach's alpha and intraclass correlation coefficient for Pentacam were 0.998 and 0.991, respectively. Anterior chamber volume measurements obtained with the Visante using the Wang formula were in good agreement with the corresponding ones obtained with Pentacam. This recently described method is easy to perform and might contribute to both clinical and research settings.