Angle Recess Research Articles

Impact of Acute Short-term Hypobaric Hypoxia on Anterior Chamber Geometry

Précis: Hypobaric hypoxia, the major environmental factor at high altitudes, has been observed to induce pupil miosis and widening of the anterior chamber angle. This environment may be safe for individuals with narrow angle and deserves further study. Purpose: This study aimed to quantify anterior chamber biometric parameters before and after acute short-term, effortless exposure to hypobaric hypoxia (HH) in healthy lowlanders using swept-source anterior segment optical coherence tomography (SS AS-OCT). Methods: This prospective study included 25 healthy young lowlanders (50 eyes) who underwent SS AS-OCT measurements and intraocular pressure (IOP) assessments under baseline sea-level conditions (T1).They were then passively exposed to simulated 4000 m above sea level for 3 hours and underwent Acute mountain sickness (AMS) symptoms evaluation and IOP measurement after 2-hours exposure to HH (T2).Repeat SS AS-OCT measurements and IOP assessments were taken within 15 minutes after leaving the hypobaric chamber (T3). Anterior segment parameters including anterior chamber depth (ACD),lens vault (LV),angle opening distance (AOD500), trabecular-iris space area (TISA500), angle recess area (ARA500) at 500 μm from the scleral spur, iris curvature (IC), iris volume (IV), pupil diameter (PD), and central corneal thickness (CCT) were obtained through SS AS-OCT. These repeated measurements were compared using linear mixed model analysis. Results: In comparison to sea level, both IOP (16.4±3.4 vs. 14.9±2.4 mm Hg, P=0.029) and PD (5.36±0.77 vs. 4.78±0.89 mm, P=0.001) significantly decreased after exposure to HH. Significant post-HH changes (Mean difference (95% CI)) were observed in AOD500 (0.129 (0.006, 0.252), P=0.04), TISA500 (0.059 (0.008, 0.11), P=0.025), ARA500 (0.074 (0.008, 0.141), P=0.029), IV (1.623 (0.092, 3.154), P=0.038), and IC (−0.073 (−0.146, 0.001), P=0.047), while CCT, ACD, and LV remained stable. After adjusting for age, post-HH variations in AOD500 (Beta=0.553, 95% CI: 0.001, 1.105, P=0.048) and TISA500 (Beta=0.256, 95% CI: 0.02, 0.492, P=0.034) were associated with decreased IC but were not related to lowered arterial oxygen pressure or IV increase per millimeter of pupil miosis (IV/PD). These differences in anterior segment parameters were neither correlated with differences in IOP nor AMS. Conclusion: After short-term, effortless exposure to hypobaric hypoxia, pupil miosis occurred with widening of the anterior chamber angle and decreased IC. These changes in anterior chamber angle parameters were associated with decreased IC but did not correlate with the post-hypobaric variations in IV/PD, IOP, or AMS.

Diagnostic Abilities of Three-Dimensional Anterior Segment Optical Coherence Tomography in Detecting Angle Closure.

Three-dimensional (3D) angle parameters and cutoff values for detecting angle closure were proposed. The 3D parameters demonstrated excellent diagnostic performance. Certain horizontal two-dimensional (2D) parameters [ie, trabecular iris space area (TISA)-750, angle opening distance (AOD)-750, and AOD-500] can attain similar performance to their high-performing 3D counterparts. To investigate the diagnostic performance of single horizontal 2D versus 3D angle parameters from swept-source anterior segment optical coherence tomography (CASIA2) in detecting angle closure. The cross-sectional study included 118 phakic patients (59 open angles, 59 closed angles). AOD, angle recess area (ARA), and TISA at 250, 500, and 750μm from scleral spur were measured in 360-degree radial-scan images. The 3D information of each measurement was analyzed in 2 patterns: (1) average 3D parameter-the averaged value from 360-degree angle values and (2) estimate 3D parameter-the estimation of surface area of circumferential angle inlet (using AOD) or circumferential angle volume (using ARA and TISA). The areas under the receiver operating characteristic curve [areas under the curve (AUCs)] of eighteen 3D parameters were compared with 2D horizontal parameters. Among 3D parameters, AOD-500 estimate 3D gave the highest AUC (AUC: 0.950, cutoff: 6.09mm 2 ), followed by AOD-750 estimate 3D (AUC: 0.948, cutoff: 8.26mm 2 ). 3D parameters significantly increased the AUC of ARA-250 and TISA-250 (all P < 0.02) compared with the 2D parameters. No significant improvement in AUC was demonstrated for AOD-250 and all parameters at 500 and 750μm. No significant difference in AUC was found among the 6 maximum AUC parameters, which were AOD-750 horizontal 2D, AOD-500 estimate 3D, TISA-750 horizontal 2D, AOD-500 horizontal 2D, AOD-750 estimate 3D, and TISA-750 average 3D. The 3D-angle parameters had high performance in detecting angle closure. However, comparing a horizontal measurement to 3D parameters, the AUC improvement was mostly insignificant.

Anterior Segment Biometry During Accommodation After Posterior Chamber Phakic Implantable Collamer Lens Implantation.

To evaluate the dynamic changes in anterior segment parameters during accommodation following Implantable Collamer Lens (ICL) implantation with swept-source optical coherence tomography (SS-OCT). Under the accommodation of 0.00 diopters (D), 3.00 D, and maximum amplitude, SS-OCT was used to examine the anterior segment parameters, including ICL vault, ICL depth (the distance between the corneal endothelium and the posterior surface of ICL), crystalline lens thickness, anterior chamber depth, and various parameters of the anterior chamber angle, comprising angle opening distance, angle recess area, trabecular iris space area, and trabecular iris angle. During accommodation, the ICL vault showed a significant decrease from baseline (536 ± 278 μm) to 3.00 D (522 ± 281 μm), followed by an increase from 3.00 D to maximum amplitude (548 ± 306 μm) (analysis of variance [ANOVA], P < .001). Four eyes (2.61%) exhibited a decrease in ICL vault to less than 100 μm (47 ± 32 μm) at maximum accommodation. The ICL depth decreased significantly as accommodation increased (ANOVA, P < .001). Crystalline lens thickness increased, whereas anterior chamber depth decreased during accommodation (ANOVA, P < .001). The anterior chamber angle widened during 3.00 D of accommodation but narrowed at maximum accommodation, leading to significant changes in the angle opening distance, angle recess area, trabecular iris space area, and trabecular iris angle during accommodation (ANOVA, P < .001 for all). The anterior segment, including ICL vault and anterior chamber angle, undergo significant dynamic changes during accommodation. These accommodative changes may require careful monitoring for the surgery design of ICL implantation. [J Refract Surg. 2024;40(3):e164-e172.].

Long-Term Risk and Prediction of Progression in Primary Angle Closure Suspect

Identifying primary angle closure suspect (PACS) eyes at risk of angle closure is crucial for its management. However, the risk of progression and its prediction are still understudied in long-term longitudinal studies about PACS. To explore baseline predictors and develop prediction models for the 14-year risk of progression from PACS to primary angle closure (PAC). This cohort study involved participants from the Zhongshan Angle Closure Prevention trial who had untreated eyes with PACS. Baseline examinations included tonometry, ultrasound A-scan biometry, and anterior segment optical coherence tomography (AS-OCT) under both light and dark conditions. Primary angle closure was defined as peripheral anterior synechiae in 1 or more clock hours, intraocular pressure (IOP) greater than 24 mm Hg, or acute angle closure. Based on baseline covariates, logistic regression models were built to predict the risk of progression from PACS to PAC during 14 years of follow-up. The analysis included 377 eyes from 377 patients (mean [SD] patient age at baseline, 58.28 [4.71] years; 317 females [84%]). By the 14-year follow-up visit, 93 eyes (25%) had progressed from PACS to PAC. In multivariable models, higher IOP (odds ratio [OR], 1.14 [95% CI, 1.04-1.25] per 1-mm Hg increase), shallower central anterior chamber depth (ACD; OR, 0.81 [95% CI, 0.67-0.97] per 0.1-mm increase), and shallower limbal ACD (OR, 0.96 [95% CI, 0.93-0.99] per 0.01 increase in peripheral corneal thickness) at baseline were associated with an increased 14-year risk of progression from PACS to PAC. As for AS-OCT measurements, smaller light-room trabecular-iris space area (TISA) at 500 μm from the scleral spur (OR, 0.86 [95% CI, 0.77-0.96] per 0.01-mm2 increase), smaller light-room angle recess area (ARA) at 750 μm from the scleral spur (OR, 0.93 [95% CI, 0.88-0.98] per 0.01-mm2 increase), and smaller dark-room TISA at 500 μm (OR, 0.89 [95% CI, 0.80-0.98] per 0.01-mm2 increase) at baseline were identified as predictors for the 14-year risk of progression. The prediction models based on IOP and central and limbal ACDs showed moderate performance (area under the receiver operating characteristic curve, 0.69; 95% CI, 0.63-0.75) in predicting progression from PACS to PAC, and inclusion of AS-OCT metrics did not improve the model's performance. This cohort study suggests that higher IOP, shallower central and limbal ACDs, and smaller TISA at 500 μm and light-room ARA at 750 μm may serve as baseline predictors for progression to PAC in PACS eyes. Evaluating these factors can aid in customizing PACS management.

Seasonal variations in anterior segment angle parameters in myopes and emmetropes

ABSTRACT Clinical relevance Seasonal variations are known to occur in a range of ocular parameters and in conditions including refractive error and glaucoma. It is of clinical importance to know if seasonal changes also occur in anterior segment angle parameters, given that they can influence these conditions. Background The study aimed to examine the seasonal variations in anterior segment angle parameters in healthy young adults. Methods Twenty-three emmetropic participants with a mean age of 26.17 ± 4.43 years and 22 myopic participants with a mean age of 27.27 ± 4.47 years completed four seasons of data collection. Anterior segment angle parameters were measured using swept-source anterior segment optical coherence tomography. Intraocular pressure (IOP) and objective refraction were also measured. Repeated-measures analysis of variance was used to determine the effect of season and refractive error on the various ocular parameters. Results A significant main effect of season was found for the majority of anterior segment angle parameters, including the angle opening distance at 500 and 750 µm from the scleral spur (p = 0.02, p = 0.006, respectively), angle recess area at 500 and 750 µm from the scleral spur (both p = 0.002), and trabecular iris space area at 500 and 750 µm from the scleral (p = 0.02, p = 0.008, respectively). However, measures of anterior chamber depth and trabecular iris angle did not exhibit statistically significant seasonal variations (all p > 0.05). A significant main effect of season was also found for the changes in IOP (p = 0.004) and objective refraction (p < 0.001). There was no season by refractive group interaction for any anterior segment angle parameter or IOP (all p > 0.05). Conclusion There is a small but significant seasonal changes in the anterior segment angle parameters, refractive error, and IOP in healthy young adult males, in which the anterior segment angle dimensions are narrower, the IOP is higher, and the refraction is more myopic during winter.

Progressive Changes in the Anterior Segment and Their Impact on the Anterior Chamber Angle in Primary Angle Closure Disease

To investigate longitudinal changes in the anterior segment (AS) using serial optical coherence tomography (OCT) images and determine the impact of these changes on the anterior chamber angle (ACA) in eyes with primary angle closure disease (PACD) treated with laser peripheral iridotomy (LPI). Retrospective clinical cohort study. This study included 103 patients with PACD who underwent LPI and were followed up by a mean 6.7 ± 1.7 AS-OCT examinations for a mean 6.5 ± 2.9 years. Temporal changes in AS-OCT parameters, including anterior chamber depth (ACD), angle opening distance (AOD750), angle recess area (ARA750), iris thickness (IT750), lens vault (LV), and pupil diameter (PD), were analyzed by multivariate linear mixed effects models (LMEMs). Multivariate LMEMs showed that decrease in AOD750 was not significant (-1.59 µm/y, P=.222); however, ARA750 decreased over time (-2.3×103 µm2/y, P=.033) and SSA showed marginal significance (-0.20°/y, P=.098), and LV increased significantly (11.6 µm/y, P < .001) after LPI. Mean LV change was negatively associated with AOD750, ARA750, and SSA, whereas PD was negatively associated with ARA750 (P < .001 each). PD decreased with aging (-13.7 µm/y, P=.036), accompanied by thinning of IT750 (-1.7 µm/y, P=.063). LV tends to increase with aging, which contributes to the shallowing of the anterior chamber and narrowing of ACA in PACD eyes treated with LPI. In the meantime, pupillary constriction and subsequent peripheral iris thinning associated with aging could possibly offset the effect of ACA narrowing.

Comparative study of the effects of laser peripheral iridotomy and cataract surgery on anterior chamber angle parameters in primary angle closure suspect patients

IntroductionProphylactic laser peripheral iridotomy (LPI) and cataract surgery are considered the primary treatments for primary angle closure suspect (PACS) as they have proven effectiveness in widening the iridocorneal angle and...

Evaluation of the Effect of Scleral Buckling on Anterior Segment and Refractive Changes Using Anterior Segment Optical Coherence Tomography

ABSTRACT Purpose To evaluate the changes of anterior segment and refractive parameters after scleral buckling (SB) surgery for uncomplicated rhegmatogenous retinal detachment (RRD) using anterior segment optical coherence tomography (AS-OCT). Methods Thirty-six RRD eyes were consecutively enrolled. Analysis concerned the central corneal thickness (CCT), anterior chamber depth (ACD), anterior chamber volume (ACV), iris-trabecular contact (ITC), angel opening distance (AOD), angle recess area (ARA), trabecular-iris space area (TISA)，trabecular iris angle (TIA) and refractive parameters, including average keratometry (AvgK), cylindrical power (CYL), regular astigmatism, asymmetry and high order irregularity (HOI) at baseline and 1 day, 1 month, 2 months, 6 months and 12 months postoperatively. AS-OCT was performed at RRD diagnosis and day 1, week 1, month 1 and month 6 after SB to evaluate the scleral buckling. Results A statistically significant postoperative CCT increase, ACD and ACV decrease were observed at 1 day and 1 month postoperatively. ITC analysis showed that the angle of the entire circumference narrowed at 1 month postoperatively. There was a significant decrease in all the angle parameters (AOD500/750, ARA500/750, TISA500/750, and ARA500/750) at 1 day and 1 month after SB surgery. However, all of the above parameters returned to the preoperative level at 12 months. Refractive parameters including AvgK, regular astigmatism, CYL, asymmetry, and HOI of anterior corneal surface and total corneal increased on the 1 day and 1 month after SB surgery and persisted even after 12 months follow-up. However, there was no significant difference in refractive parameters of posterior corneal surface during follow-up. Conclusion The changes in the structure of anterior segments after SB surgery were almost returned to the preoperative levels at 12 months postoperatively. However, SB surgery has a long-term effect on refractive parameters throughout a 12-month follow-up.

Evaluation of biometric indicators of anterior segment parameters after ICL implantation by swept-source optical coherence tomography

BackgroundTo evaluate anterior segment structural alterations after implantable collamer lens (ICL) implantation in myopic patients using swept-source quantitative optical coherence tomography (SS-OCT).MethodsThis prospective study included 47 eyes in 24 patients with preoperative spherical equivalent ≥ -3.00 D. Patients underwent ICL implantation at Department of Ophthalmology, Peking University Third Hospital, from May 2021 to December 2022. SS-OCT was used to measure anterior chamber width (ACW), angle opening distance (AOD), angle recess area (ARA), trabecular-iris area (TISA), trabecular-iris angle (TIA), iridotrabecular contact (ITC) area, and ITC Index before ICL implantation surgery and at 1 month follow-up. The correlations among the ITC index, vault, and angle parameters were analysed. Receiver operating characteristic (ROC) analysis was used to explore the ability of the vault to identify eyes with suspected angle-closure.ResultsAt one month following ICL implantation, the ITC area was 0.396 ± 0.37 mm2, and the ITC index is 8.143 ± 5.439%. All angle parameters, except ACW, showed a statistically significant reduction on SS-OCT (P < 0.05). Mean AOD500, AOD750, ARA500, ARA750, TISA500, TISA750, TIA500, and TIA750 values at one month postoperatively decreased by 60.0%, 60.4%, 58.1%, 59.2%, 57.3%, 58.7%, 48.8%, and 50.7%, respectively. The vault was positively correlated with the ITC index and percent change in anterior chamber angle parameters. A vault of > 0.659 mm was found to be optimal for angle-closure suspect with a sensitivity of 85.2% and a specificity of 53.9%.ConclusionsAnterior chamber angle parameters decreased one month after ICL implantation, and their percentage changes and ITC index correlated with the vault. When the vault is larger than 0.659 mm, it is necessary to be alert to possible closed angle suspicion.

Changes in Anterior Segment Morphology and Intraocular Pressure after Cataract Surgery in Non-glaucomatous Eyes

It is known that cataract extraction is associated with a significant reduction in intraocular pressure, especially in narrow angled eyes; however, the modifications of anterior segment parameters associated with this phenomenon have still not been completely defined. The purpose of this study was to evaluate changes in anterior segment anatomy and intraocular pressure after cataract surgery in non-glaucomatous eyes. This retrospective case series study included 64 eyes of 64 consecutive patients who underwent phacoemulsification with intraocular lens implantation. Anterior segment parameters and intraocular pressure were assessed and compared before and 6 months after surgery. Anterior segment imaging was performed using Casia SS-1000 anterior segment optical coherence tomography (Tomey, Nagoya, Japan). Anterior segment measurements included anterior chamber depth, anterior chamber width, anterior chamber volume, angle opening distance at 500 µm anterior to the scleral spur, angle recess area 750 µm from the scleral spur, lens vault, trabecular iris space area at 500 µm from the scleral spur, and trabecular iris angle at 500 µm from the scleral spur. Intraocular pressure was measured using the Goldmann applanation tonometer (Model AT 900 C/M, Haag-Streit, Bern, Switzerland). Anterior segment parameters and the relationship of changes in intraocular pressure were also evaluated. All anterior segment parameters increased significantly after surgery (p < 0.05). Both angle opening distance at 500 µm anterior to the scleral spur and anterior chamber depth changes were positively correlated with the preoperative lens vault. The mean intraocular pressure significantly decreased from 14.91 mmHg (± 2.8 SD) to 12.91 mmHg (± 3.13 SD) (p < 0.001). Changes in intraocular pressure correlated negatively with values for the width of the preoperative anterior chamber (r = - 0.533; p = 0.001). Cataract surgery led to significant widening of the anterior chamber angle and lowering of intraocular pressure. Further investigations are needed to better understand whether anterior chamber width may be a new independent predictive factor for reduction in postoperative intraocular pressure.

Swept-source optical coherence tomography and ultrasound biomicroscopy study of anterior segment parameters in primary angle-closure glaucoma.

To evaluate the agreement between swept-source OCT (CASIA2) and UBM in primary angle-closure glaucoma. Eighty eyes of 40 participants diagnosed with primary angle-closure glaucoma were examined. Parameters measured included angle opening distance (AOD), angle recess area (ARA), trabecular iris space area (TISA), trabecular iris angle (TIA), lens vault (LV), anterior chamber depth (ACD), and anterior chamber width (ACW). Angle images of nasal, temporal, superior, and inferior were acquired by the anterior segment mode of CASIA2 and UBM. One-way analysis of variance and paired t-test were used for statistical analysis, and the agreement was analyzed by internal correlation coefficient (ICC) and Bland-Altman method. One-way ANOVA pairwise comparison showed that CASIA2 or UBM had the narrowest superior chamber angle and the widest temporal chamber angle in patients with primary angle-closure glaucoma. The paired t-test showed that inter-device AOD, TIA, ARA, and TISA of superior chamber angle had significant differences (p < 0.001). There was no significant difference in the measured values of LV, ACD, and ACW (p > 0.05). The agreement of all parameters is good through the Bland-Altman method comparison. ICC result showed moderate agreement in other angle parameters except for superior ARA500 (0.739). In the anterior chamber angle measurement process, we should pay more attention to the superior chamber angle covered by eyelids. Although the agreement is acceptable between CASIA2 and UBM, the measurements could not be considered interchangeable due to the tremendous statistical difference between the two devices.

Clinical Profile and Treatment Outcome of Patients with Trigeminal Neuralgia: A Retrospective study in a Tertiary Hospital of Eastern Nepal

Introduction: Neuropathic orofacial pain is common non-dontogenic pain. Diagnosis relies primarily on history taking with less of pathologic change visible. Trigeminal neuralgia (TGN) is a common neuropathic pain affecting the maxillofacial region of fifth cranial nerve (V). Objective: To assess clinical characteristics, effective therapeutic regimen, side effect, radiographic and laboratory investigation inTrigeminal neuralgia patients. Methods: Retrospective study included all patients visiting the department with records from 2014 to 2021. After ethical approval forstudy, eighty patients were diagnosed based on ICHD3 criteria. Patient with atypical feature with sensory deficit underwent CT OR MRI to rule of mass or lesion along the cerebello-pontine angle recess and other organic cause. The data were analysed using SPSS version 11.5 and Microsoft Excel 2017. Results: A total of 80 patients were retrieved. The common side affected were right 46 (57.5%) followed by left 28 (35%), bilateral four(5%) and anterior region two (2.5%). The most common branch involved was mandibular followed by maxillary branch and combination. Management was primarily done by carbamazepine (CBZ) or in combination. Common side effects were drowsiness, dizziness, nausea and diplopia. CT scan and MRI showed space occupying lesion in three cases. Refractory cases underwent neurolysis and symptomatic and few classical TGN cases were sent for surgical management. Conclusions: Diagnosis of Trigeminal neuralgia is primarily based on clinical characteristic due to high cost and unavailability of imaging and nerve testing. Treatment is by single or multiple drugs with adjunct therapy.

In vivo identification of angle dysgenesis

AbstractAnterior segment Spectral domain–optical coherence tomography (SD‐OCT) is being increasingly used in glaucoma patients, primarily to investigate the anterior chamber angle and visualize the trabecular meshwork (TM) and Schlemm's canal (SC) in vivo. With the advent of angle surgery for glaucoma much interest has been generated in the aqueous outflow pathways. Our studies have shown that in vivo imaging of anterior chamber angle with ASOCT can been used to detect gross features of angle dysgenesis in primary congenital glaucoma (PCG), juvenile onset open angle glaucoma (JOAG) and adult onset primary open angle glaucoma (POAG), which has been described either as an absence of SC and/or the presence of abnormal tissue or a hyper‐reflective membrane within angle recess. This membrane is similar to what Barkan had described in PCG and was later described to be an angle cicatrization that portends a poorer success with goniotomy. Absence of development of SC was also shown by Hollander et al to be associated with a severe form of goniodysgenesis while its presence was seen in less severe goniodysgenesis on histopathological studies involving PCG. In fact, angle dysgenesis on ASOCT (ADoA), can be observed even in eyes with gonioscopically normal appearing angles. It is known that gonioscopy provides only a superficial representation of the histopathological anomalies affecting the angle. The presence of a thick compact tissue in the TM samples of Juvenile glaucoma patients has been observed, irrespective of whether they had an apparent goniodysgenesis or not. Hence, what appears to be morphologically normal angle on gonioscopy may harbour dysgenesis of the TM or even the SC. Primary congenital glaucoma, JOAG and adult onset POAG form a spectrum in terms of severity of angle dysgenesis. While most of the PCG eyes have features of ADoA, the same are present in 40% of JOAG eyes and in up to 35% of adult onset POAG. The size of the SC has also shown to be decreased in patients with adult‐onset open angle glaucoma based on in vivo OCT studies. We also present interesting observations of angle dysgenesis in fellow eyes of children with unilateral PCG.

Repeatability of quantitative measurements of anterior segment analysis with swept‐source AS‐OCT in dry eye, ocular surface disease and healthy eyes

AbstractPurpose: Dry eye and ocular surface disease (OSD) are the most common causes of eye discomfort with up to 50%1 of the global population affected. Anterior segment optical coherence tomography (AS‐OCT) is essential to diagnose and track ocular surface changes. This study aims at assessing the precision of a modern swept source AS‐OCT in OSD vs healthy control.Methods: Five clinical groups were included: G1 = Sjögren's syndrome (n = 46); G2 = Ocular Mucous Membrane Pemphigoid, Graft‐versus‐Host Disease, etc. (n = 58); G3 = Meibomian Gland Disease (n = 47); G4 = Miscellaneous (Neurotrophic, Exposure, Transplant, etc.) (n = 36); G5 healthy controls (n = 41). Three consecutive measurements using a radial scan mode were collected using the AS‐OCT Casia2 (Tomey, Japan) and the repeatability limits (RLs) were calculated. The following parameters were obtained: anterior chamber depth (ACD), AC width (ACW), angle opening distance (AOD) and angle recess area (ARA) both at 250, 500 and 750 μm, angle to angle (ATA), central thickness apex (CTapex), lens vault (LV), trabecular iris angle (TIA) and trabecular iris‐space area (TISA) both at 250, 500 and 750 μm. Dry eye metrics such as OSDI® questionnaire, fluorescein break‐up time (FBUT), tear meniscus height (TMH), conjunctival inflammation (INFLCONJ) and ocular surface staining (OSS) were considered.Results: The higher RLs values were observed within the G4 cohort considering AOD (0.28, 0.29, 0.36, 0.35, 0.43 vs G5 0.18, 0.21, 0.18, 0.20, 0.26 mm),ARA (0.08, 0.10, 0.16, 0.18, 0.25, 0.27 vs. G5 0.06, 0.06, 0.09, 0.10, 0.14, 0.15 mm2), CTapex (66.12 vs. G5 13.55 μm), TIA (33.90, 22.57, 14.55, 20.02 vs. G5 30.94, 18.31, 9.44, 14.76 degrees) and TISA (0.06, 0.07, 0.14, 0.15, 0.23, 0.24 vs. G5 0.04, 0.05, 0.08, 0.09, 0.12, 0.14 mm2). G1 cohort reported the worst dry eye metrics (OSDI 52.90 ± 20.58 score, FBUT 3.51 ± 2.36 s, TMH 0.10 ± 0.07 mm, INFLCONJ 1.07 ± 1.78 score, OSS 4.27 ± 2.35 score).Conclusions: This is the first study to consider anterior segment analysis repeatability limits in OSD vs healthy cohorts with the AS‐OCT Casia2. Despite G1 cohort reported the worse dry eye metrics, the higher repeatability limits were observed in the G4 Miscellaneous group.Reference1. Stapleton, F. et al. TFOS DEWS II Epidemiology Report. Ocular Surface 15, 334–365, doi:10.1016/j.jtos.2017.05.003 (2017).

Apport de la tomographie en cohérence optique dans l’évaluation de l’angle irido-cornéen du camerounais

Our work was aimed at determining the sensitivity and specificity of anterior segment OCT (AS-OCT) in the evaluation of the iridocorneal angle (ICA) in Cameroon. We conducted a cross-sectional, analytical study from January 2 to June 30, 2019 in Yaoundé. One hundred and twenty five patients over 35 years of age underwent three-mirror manual glass gonioscopy and AS-OCT. The angle was defined as occludable on manual gonioscopy if the posterior trabecular meshwork, was not visible and on OCT if there was contact between the iris root and the posterior surface of the peripheral cornea. Quantitative parameters (angle opening distance, angle recess area, and trabecular-iris space area) in the nasal and temporal quadrants were recorded for the analysis. Men accounted for 56.20% of the 96 patients selected (192 eyes). The mean age was 54.78±10 years. The prevalence of occludable angles was 18.75% (18/96 patients) and 28.125% (27/96 patients) on manual and automated gonioscopy respectively. Schaeffer-Etienne grades ≤2 were identified in 43/192 (21.94%) nasal quadrants and 33/192 (19.18%) temporal quadrants. The area under the curve (AUC) was maximal for the 500 μm goniometric parameters (> 0.8). An Angle Opening Distance ≤333.50 μm was found in 52/192 nasal quadrants (27.10%) and 53/192 (27.60%) temporal. The sensitivity and specificity of AS-OCT in the detection of occludable angles at 500 μm, were 62.8% and 83.2% respectively in the nasal quadrant, and 66.7% and 80.5% respectively in the temporal quadrant. There was a positive correlation between goniometric parameters on AS-OCT and gonioscopy (P=0.01). Given its higher specificity, AS-OCT should be a supplemental examination in the analysis of an angle which appears closed on manual gonioscopy.

Characteristics of Anterior Segment in Congenital Ectopia Lentis: An SS-OCT Study.

Purpose To investigate the characteristics of anterior chamber angle parameters in congenital ectopia lentis (CEL) patients and to evaluate the sensitivity and specificity of anterior segment parameters in distinguishing CEL from healthy controls. Setting. Zhongshan Ophthalmic Center, Guangzhou, China. Design Cross-sectional study. Methods 35 CEL patients and 35 age- and sex-matched healthy controls were recruited. Axial length (AL) and anterior segment parameters including anterior chamber width (ACW), angle open distance (AOD), angle recess area (ARA), trabecular-iris space area (TISA), and trabecular-iris angle (TIA) were measured. All the above parameters and the ratio index of angle parameters, which was defined as the angle parameter value of the narrower side to that of the contralateral side, were compared between CEL and controls. Receiver operating characteristic (ROC) curves were also plotted to evaluate the diagnostic performance of anterior chamber angle parameters in CEL patients. Results All angle parameters of the contralateral side to the dislocated lens side were significantly smaller than those of the dislocated lens side in CEL (all P < 0.05). For the diagnostic performance of anterior chamber angle parameters, the ratio index of TIAr500 combined with TIAr750 had the best diagnostic performance for CEL screening (AUC = 0.798), and TIAr500 of 0.887 and TIAr750 of 0.917 were detected to be the optimal cut-off points, representing a sensitivity of 89.8% and specificity of 68.7%. Conclusion The contralateral side to the dislocated lens side in the CEL had a narrower anterior chamber angle. TIAr500 combined with TIAr750 is the optimal combination strategy for ectopia lentis screening.

Optical coherence tomography analysis of anterior segment parameters before and after laser peripheral iridotomy in primary angle-closure suspects by using CASIA2

BackgroundLaser peripheral iridotomy (LPI) is effective in primary angle-closure suspects (PACS); however, predictors for anterior segment alterations after LPI are limited. We aimed to evaluate the anterior segment biometric parameters before and after LPI in PACS using the recently developed, CASIA 2 device of anterior segment optical coherence tomography (AS-OCT).MethodsWe performed LPI in 52 PACS. Anterior segment parameters, including anterior chamber depth (ACD), anterior chamber width (ACW), anterior chamber volume (ACV), iris curvature (ICURVE), iridotrabecular contact (ITC), lens vault (LV), lens thickness (LT), radius of the lens, angle opening distance (AOD), angle recess area (ARA), trabecular iris space area (TISA), and trabecular iris angle (TIA) at different distances (i.e., 500 μm from the sclera spur), were evaluated before and after LPI using CASIA 2.ResultsEyes of PACS after LPI had a greater ACV, AOD, ARA, TISA, and TIA, and a lower ITC and ICURVE (all p < 0.001) than those before LPI. On a 360° scan, the anterior chamber angle in the superior quadrant increased the most after the LPI. A higher baseline LT was significantly associated with a greater postoperative increase in AOD 500, ARA 500, TISA 500, and TIA 500 (p = 0.001, p = 0.010, p = 0.004, and p < 0.001, respectively).ConclusionsWe found that LPI widens the anterior chamber angle in the PACS, especially, in the superior quadrant around the iridotomy hole. Eyes with a thicker lens are more likely to experience angle opening because of the LPI.

Prevalence of Plateau Iris in Primary Angle Closure Glaucoma: An Egyptian Hospital Based Ultrasound Biomicroscopy Study.

PurposeTo determine the distribution and the anatomical characteristics of plateau iris (PI) in primary angle closure glaucoma (PACG) using ultrasound biomicroscopy (UBM).MethodsFifty UBM images of PACG cases were studied over one year by retrospective analysis. The data from UBM images including angle opening distance at 500 and 750 μm (AOD500 and AOD750), trabecular-iris angle (TIA), angle recess area at 750 μm (ARA750), maximum ciliary body thickness (CBTmax), anterior placement of ciliary processes (APCP), central anterior chamber depth (CACD), axial lens thickness (ALT), and ciliary sulcus status were analyzed and compared between the PI and non-PI cases.ResultsEighteen cases had PI (36%). The mean AOD500, AOD750, and TIA were significantly smaller in PI than in non-PI eyes (P = 0.01; P = 0.046; and P = 0.026). Values of the ARA750 and CBTmax were not significantly different between the two groups (P = 0.208 and P = 0.368). CACD was deeper in the PI group (P = 0.011). ALT was higher in the non-PI group (P = 0.001). The mean APCP of the PI group was more than those of the non-PI group (P < 0.001). The number of cases with obliterated ciliary sulcus in more than two quadrants was significantly more in the PI group (P < 0.001).ConclusionAround one-third of PACG eyes were found to have PI on UBM imaging. The number of obliterated ciliary sulcus and APCP were important UBM parameters that help in PI diagnosis.

Repeatability and Agreement of Two Swept-Source Optical Coherence Tomographers for Anterior Segment Parameter Measurements.

The aim was to evaluate the repeatability and agreement of two swept-source optical coherence tomographers for anterior segment parameters in healthy subjects. Automated mark of scleral spur and angle recess for the CASIA2 and manual mark of scleral spur and angle recess for the Anterion were performed, and then the measurement values of the related parameters were automatically generated. Subjects with pupil diameter (PD) differing by <15% between the 2 devices were included. PD, lens vault (LV), anterior chamber depth (ACD), angle to angle distance (ATA), anterior chamber width (ACW), anterior chamber angle (ACA), angle opening distance (AOD), and trabecular iris space area (TISA) were measured in the horizontal images with both CASIA2 and Anterion. Intraclass correlation coefficient (ICC) was used to evaluate intradevice repeatability. Bland-Altman plots were performed to assess the agreement between the 2 devices. Thirty-five right eyes of 35 subjects were included with a mean age of 25.60±3.00 years. The CASIA2 showed moderate to good intradevice repeatability (ICCs ranged from 0.786 to 0.989) whereas the Anterion showed good intradevice repeatability (ICCs ranged from 0.921 to 0.998) for anterior segment parameters. Compared with the CASIA2, the Anterion offered larger values of ACA500/750, AOD500/750, and TISA500/750 but smaller values of PD, LV, ACD, ATA, and ACW. Good agreement for PD, ACD, ATA, and ACW was detected with 95% limits of agreement of -1.02 to 1.02 mm, -0.11 to 0.14 mm, -0.17 to 0.19 mm, -0.13 to 0.28 mm, respectively. Poor agreement for LV, ACA500/750, AOD500/750, and TISA500/750 was achieved with the 2 devices. Anterion outperformed CASIA2 on intradevice repeatability. While agreement was noted for some parameters using manual Anterion and automated CASIA2 approaches, poor agreement of LV and angle parameters indicates that measurements from these optical coherence tomography devices should not be considered interchangeable.

Segmentation Errors in the Measurement of Volumetric Parameters by Swept-Source Anterior Segment Optical Coherence Tomography.

Purpose: To investigate the error rate of segmentation in the automatic measurement of anterior chamber volume (ACV) and iris volume (IV) by swept-source anterior segment optical coherence tomography (SS-ASOCT) in narrow-angle and wide-angle eyes.Methods: In this study, fifty eyes from 25 narrow-angle subjects and fifty eyes from 25 wide-angle subjects were enrolled. SS-ASOCT examinations were performed and each SS-ASOCT scan was reviewed, and segmentation errors in the automatic measurement of ACV and IV were classified and manually corrected. Error rates were compared between the narrow-angle and the wide-angle groups, and ACV and IV before and after manual correction were compared.Results: A total of 12,800 SS-ASOCT scans were reviewed. Segmentation error rates of angle recess, iris root, posterior surface of the iris, pupil margin, and anterior surface of the lens were 84.06, 93.30, 13.15, 59.21, and 25.27%, respectively. Segmentation errors of angle recess, iris root, posterior surface of the iris, and pupil margin occurred more frequently in narrow-angle eyes, while more segmentation errors of the anterior surface of the lens were found in wide-angle eyes (all P < 0.001). ACV decreased and IV increased significantly after manual correction of segmentation errors in both groups (all P < 0.01).Conclusion: Segmentation errors were prevalent in the volumetric measurement by SS-ASOCT, particularly in narrow-angle eyes, leading to mismeasurement of ACV and IV.