Role of Optical Coherence Tomography in Assessing Anterior Chamber Angles (original) (raw)
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IP Innovative Publication Pvt. Ltd., 2019
Purpose: To evaluate the angle of anterior chamber with SD-OCT in patients above 40 years of age presenting to tertiary health care center in central India. Materials and Methods: 120 Consecutive patients (240 eyes) above 40 years of age presenting to ophthalmology OPD of tertiary health care center were enrolled in a cross-sectional study. All patients underwent comprehensive ocular examination with included best corrected visual acuity, slit lamp, fundus, gonioscopy, intraocular pressure (IOP), evaluation of angle (i.e. AOD, TISA, TIA) of anterior chamber with SD-OCT. The duration of study was one year six months. Result: The mean age was 53.94 years. There were 61 males & 59 females. It was noted that mean nasal & temporal AOD was less in females (0.4175 µm, 0.4142 µm) as compared to males (0.4583 µm, 0.4613 µm). We found that older people have a narrower anterior chamber angle i.e. from 40-60 years of age mean TIA nasal & temporal was 29.13, 27.53 degree & above 60 years of age mean TIA nasal & temporal was-24.13, 22.63 degrees. Conclusion: We found that AOD is less in female as compared to male. It was also noted that older people have a narrower anterior chamber angle as compared to younger people. The gonioscopy has been considered as the gold standard for characterizing the ACA, but it is contact procedure, subjective and requires the expertise while the OCT is rapid, quantitative, reproducibility, non-contact procedure with less interobserver variability will help us to accurately assess anterior chamber angle. Keywords: Anterior chamber angle measurement, Gonioscopy, Narrow angle, SD-OCT, Normal population.
Translational Vision Science & Technology
Purpose: To quantify interquadrant differences in anterior chamber angle (ACA) configuration assessed on gonioscopy, EyeCam, and anterior segment optical coherence tomography (AS-OCT) in a cohort of Chinese Americans. Methods: Subjects aged 50 years or older were recruited from the Chinese American Eye Study (CHES), a population-based epidemiologic study in Los Angeles, CA. Each subject underwent a complete ocular exam, including gonioscopy, EyeCam, and AS-OCT, under dark ambient lighting. Gonioscopy and AS-OCT imaging and EyeCam image grading were performed by trained ophthalmologists. Results: Seven hundred nine eyes from 709 subjects were analyzed. Less anatomic variation among the quadrants was detected on gonioscopy and EyeCam compared with AS-OCT (P , 0.05). The mean gonioscopy grade, EyeCam grade, and AS-OCT measurement for each quadrant varied by up to 10.3%, 6.4%, and 46.2% of the superior quadrant value, respectively. There were significant interquadrant differences (P , 0.05) among mean AOD750 measurements when grouping by quadrant and gonioscopy or EyeCam grade. Mean AOD750 measurements were smallest for the superior quadrant by between 14.3% and 38.1% and 17.4% and 37.9% on gonioscopy and EyeCam, respectively, compared with other quadrants. Conclusions: Gonioscopy and EyeCam significantly underrepresent anatomic variations of the ACA compared with AS-OCT. Gonioscopy or EyeCam grades from different quadrants do not appear to be comparable or interchangeable, which supports reconsideration of current definitions and methods used to diagnose and manage primary angle closure disease. Translational Relevance: AS-OCT imaging raises concerns about current clinical definitions and methods that rely gonioscopy or EyeCam to assess the ACA.
International Ophthalmology
Purpose To evaluate diagnostic capacity for occludable anterior chamber angle detection with anterior segment optical coherence tomography (AS-OCT) and Pentacam. Methods Observational cross-sectional study with AS-OCT and Pentacam. AS-OCT measures: angle opening distance from Schwalbe line (SL) perpendicular (AOD-SL-Perp) and vertical to iris (AOD-SL-Vert), and iridotrabecular angle (ITA). Pentacam measures: anterior chamber depth (ACD), anterior chamber volume (ACV), and anterior chamber angle (ACA). We analysed Spearman’s correlation with gonioscopic classification. Area under receiver operating characteristic curves (AUCs) for occludable angle detection were compared. Agreement between iridocorneal values of methods was evaluated. Results Seventy-four left eyes of 74 patients. Correlation between temporal AS-OCT and gonioscopy: 0.83 (p < 0.0001) AOD-SL-Perp temporal, 0.82 (p < 0.0001) AOD-SL-Vert temporal, and 0.69 (p < 0.0001) ITA temporal. Correlation between AS-OCT na...
Ophthalmology, 2008
To compare the performance of gonioscopy and anterior segment (AS) optical coherence tomography (OCT) in detecting angle closure in the different quadrants of the anterior chamber angle (ACA). Design: Cross-sectional observational study. Participants: Five hundred two consecutive subjects more than 50 years of age with no previous ophthalmic problems recruited from a community clinic in Singapore. Methods: All subjects underwent gonioscopy and AS OCT imaging in the dark. Using gonioscopy, the ACA was graded using the Scheie system by a single examiner masked to AS OCT findings. Main Outcome Measures: The ACA in a particular quadrant was classified as closed if the posterior trabecular meshwork could not be seen on gonioscopy. A closed ACA on AS OCT imaging was defined by the presence of any contact between the iris and angle wall anterior to the scleral spur. Results: After excluding eyes with poor image quality, a total of 423 right eyes were included in the analysis. A closed angle in at least 1 quadrant was observed in 59% of the eyes by AS OCT and in 33% of the eyes by gonioscopy (PϽ0.001), with fair agreement between the two methods (ϭ 0.40). The frequency of closed angles by AS OCT and gonioscopy were 48% versus 29% superiorly, 43% versus 22% inferiorly, 18% versus 14% nasally, and 12% versus 20% temporally, respectively. Of the 119 of 1692 quadrants that were closed on gonioscopy but open on AS OCT, a steep iris profile was present in 61 (51%) of 119 quadrants on AS OCT, and of the 276 of 1692 quadrants that were open on gonioscopy but closed on AS OCT, 196 (71%) of 276 quadrants showed short iridoangle contact on AS OCT. Conclusions: The highest rates of closed angles on gonioscopy and AS OCT images were observed in the superior quadrant. Anterior segment OCT tended to detect more closed ACAs than gonioscopy, particularly in the superior and inferior quadrants. Variations in the iris profile and level of iridoangle contact also may explain some of the differences seen between gonioscopy and AS OCT.
Eye, 2009
Aims To compare the diagnostic performance of two anterior segment optical coherence tomography (AS-OCT) devices in assessing the anterior chamber angle (ACA). Methods Visante-OCT and slit-lamp-OCT (SL-OCT) were performed on 101 patients by a single operator. The AS-OCT images were processed by customised 'dewarping' software and assessed by two glaucoma specialists masked to clinical findings. A closed ACA was defined by the presence of contact between the iris and angle anterior to the scleral spur. Measurements of the ACA, anterior chamber depth (ACD), and pupil diameter were analysed. Gonioscopy was performed by another examiner masked to AS-OCT findings. Results Qualitative analysis could be carried out in 83 (83%) eyes and quantitative analysis in 61 (60%) eyes. A closed angle in at least one quadrant of the eye was observed in 30 eyes with gonioscopy; Visante-OCT imaging identified 29 of 30 (97%) and SL-OCT imaging identified 27 of 30 (90%) of these eyes (P ¼ 0.50, McNemar test). Visante-OCT detected more eyes with at least one closed quadrant than SL-OCT (55 vs 46 eyes, respectively, P ¼ 0.01). Overall, SL-OCT had better agreement with gonioscopy than with Visante-OCT. Both AS-OCTs showed good agreement for ACD measurements; however, SL-OCT tended to provide consistently higher ACA measurements and smaller pupil diameters than did Visante-OCT. Conclusions Both AS-OCT devices detected most of the eyes with closed ACA on gonioscopy. However, Visante-OCT detected more closed ACAs than did SL-OCT. The better agreement between SL-OCT and gonioscopy is likely because of the use of visible light during both examinations. The ACA measurements obtained with each device are not interchangeable.
Optometry and Vision Science, 2019
In our intermediate-tier glaucoma care clinic, we demonstrate fair to moderate agreement in gonioscopy examination between optometrists and ophthalmologists, but excellent agreement when considering open versus closed angles. We highlight the need for increased consistency in the evaluation and recording of angle status using gonioscopy. PURPOSE: The consistency of gonioscopy results obtained by different clinicians is not known but is important in moving toward practice modalities such as telemedicine and collaborative care clinics. The purpose of this study was to evaluate the description and concordance of gonioscopy results among different practitioners. METHODS: The medical records of 101 patients seen within a collaborative care glaucoma clinic who had undergone gonioscopic assessment by two clinicians (one optometrist and either one general ophthalmologist [n = 50] or one glaucoma specialist [n = 51]) were reviewed. The gonioscopy records were evaluated for their descriptions of deepest structure seen, trabecular pigmentation, iris configuration, and other features. These were compared between clinicians (optometrist vs. ophthalmologist) and against the final diagnosis. RESULTS: Overall, 51.9 and 59.8% of angles were graded identically in terms of deepest visible structure when comparing between optometrist versus general ophthalmologist and optometrist versus glaucoma specialist, respectively. The concordance increased when considering ±1 of the grade (67.4 and 78.5%, respectively), and agreement with the final diagnosis was high (>90%). Variations in angle grading other than naming structures were observed (2.0, 30, and 3.9% for optometrist, general ophthalmologist, and glaucoma specialist, respectively). Most of the time, trabecular pigmentation or iris configuration was not described. CONCLUSIONS: Fair to moderate concordance in gonioscopy was achieved between optometrists and ophthalmologists in a collaborative care clinic in which there is consistent feedback and clinical review. To move toward unified medical records and a telemedicine model, improved consistency of record keeping and angle description is required.
Investigative Ophthalmology & Visual Science, 2011
To evaluate the reproducibility of anterior chamber angle measurements obtained by swept-source optical coherence tomography (OCT) and to identify factors associated with its measurement variability. METHODS. One eye from each of 30 healthy subjects was randomly selected for anterior segment OCT imaging (Casia SS-1000 OCT; Tomey, Nagoya, Japan) in three separate visits within a week. The angle opening distance (AOD), the trabecular iris space area (TISA), and the trabecular-iris angle (TIA) at the superior (90°), nasal (0°), inferior (270°), and temporal (180°) angles were measured. The intraobserver and interobserver reproducibility coefficient (RC) and intraclass correlation coefficient (ICC) were calculated. Generalized linear latent and mixed modeling was used to examine the association between the variance of angle measurements and each of the following: angle width, pupil diameter, pupil diameter variance, iris thickness, iris thickness variance, axial length, anterior chamber depth, scan location, scleral spur visibility, and age. RESULTS. The intervisit, intraobserver RCs ranged between 0.140 mm and 0.252 mm for AOD, 0.050 mm 2 and 0.090 mm 2 for TISA, and 7.7°and 9.5°for TIA, and the interobserver RCs were between 0.103 mm and 0.187 mm, 0.049 mm 2 and 0.101 mm 2 , and 8.5°and 13.7°, respectively. The ICCs were all Ն0.83. Increased iris thickness, increased iris thickness variance, angle measured at the superior and inferior quadrants, increased angle width, and long axial length were associated with increased variance of angle measurements. CONCLUSIONS. Although the swept-source OCT had high reproducibility for angle measurement, differences in iris thickness, angle width, measurement location, and axial length may influence its variability. (Invest Ophthalmol Vis Sci. 2011;52: 8598 -8603)
Investigative Ophthalmology & Visual Science, 2008
To compare anterior chamber angle measurements obtained from two anterior segment optical coherence tomography (OCT) instruments and to evaluate their agreements and interobserver reproducibility. METHODS. Forty-nine eyes from 49 healthy normal subjects were studied. The anterior chamber angle was imaged with the Visante anterior segment OCT (Carl Zeiss Meditec, Dublin, CA) and the slit lamp OCT (SLOCT, Heidelberg Engineering, GmbH, Dossenheim, Germany) on one randomly selected eye in each subject and measured by two independent observers. The angle-opening distance (AOD 500), the trabecular-iris angle (TIA 500), and the trabecular-iris space area (TISA 500) at the nasal and temporal angles were measured. The agreements between SLOCT and Visante OCT measurements and the interobserver reproducibility were evaluated. RESULTS. The mean nasal/temporal anterior chamber angles measured by Visante OCT and SLOCT were 527 Ϯ 249/572 Ϯ 275 m (AOD), 0.180 Ϯ 0.091/0.193 Ϯ 0.102 mm 2 (TISA), and 38.1 Ϯ 12.3/39.6 Ϯ 13.2°(TIA); and 534 Ϯ 234/628 Ϯ 254 m (AOD), 0.191 Ϯ 0.089/0.217 Ϯ 0.093 mm 2 (TISA), and 37.8 Ϯ 10.1/40.6 Ϯ 10.7°(TIA), respectively. No significant difference was found between Visante OCT and SLOCT measurements except the temporal TISA (P ϭ 0.034). The interobserver coefficient of variation ranged between 4.4% and 7.8% for Visante OCT and 4.9% and 7.0% for SLOCT. The spans of 95% limits of agreement of the nasal/temporal angle measurements between Visante OCT and SLOCT were 437/531 mm 2 , 0.174/ 0.186 mm 2 , and 25.3/28.0°for AOD, TISA, and TIA, respectively. CONCLUSIONS. Although Visante OCT and SLOCT demonstrate high interobserver reproducibility for anterior chamber angle measurements, their agreement was poor. (Invest Ophthalmol Vis Sci. 2008;49:3469 -3474)
Eye, 2011
Purpose 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. Methods 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 r1 in all quadrants). SD-ASOCT images were obtained at the nasal and temporal quadrants only. Results Twenty-eight eyes (10.6%) were classified as narrow angles on gonioscopy. ACV correlated with gonioscopy grading (Po0.001) for temporal (r ¼ 0.204), superior (r ¼ 0.251), nasal (r ¼ 0.213), and inferior (r ¼ 0.236) quadrants. ACV correlated with TISA500 for nasal (r ¼ 0.135, P ¼ 0.029) and temporal (P ¼ 0.160, P ¼ 0.009) quadrants and also with AOD500 for nasal (r ¼ 0.498, Po0.001) and temporal (r ¼ 0.517, Po0.001) quadrants. For detection of narrow angles, ACV (AUC ¼ 0.935; 95% confidence interval (CI) ¼ 0.898-0.961) performed similar to ACD (AUC ¼ 0.88, P ¼ 0.06) and significantly better than AOD500 nasal (AUC ¼ 0.761, P ¼ 0.001), AOD500 temporal (AUC ¼ 0.808, Po0.001), TISA500 nasal (AUC ¼ 0.756, Po0.001), and TISA500 temporal (AUC ¼ 0.738, Po0.001). 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 ¼ 7.4-10.0) and 0.11 (95% CI ¼ 0.03-0.4), respectively. Conclusions ACV measurements using Scheimpflug imaging outperformed AOD500 and TISA500 using SD-ASOCT for detecting narrow angles.