Swept-source Anterior Segment Optical Coherence Research Articles

Automated quantification of anterior chamber cells using swept-source anterior segment optical coherence tomography

PurposeTo validate automated counts of presumed anterior chamber (AC) cells in eyes with histories of uveitis involving the anterior segment using swept-source (SS) anterior segment optical coherence tomography (AS-OCT) against manual counts and compare automated counts against Standardized Uveitis Nomenclature (SUN) criteria.MethodsEyes were imaged with the ANTERION SS AS-OCT device (Heidelberg Engineering). A fully automated custom algorithm quantified the number of hyper-reflective foci (HRF) in line-scan images. Automated and manual counts were compared using interclass correlation (ICC) and Pearson correlation coefficient. Automated counts were compared to SUN grades using a mixed-effects linear regression model.Results90 eyes (54 participants) were included; 67 eyes (41 participants) had histories of uveitis, while 23 eyes (13 healthy participants) served as controls. ICC comparing automated to manual counts was 0.99 and the Pearson correlation coefficient was 0.98. Eyes at each SUN grade with corresponding median HRF (interquartile range [IQR]) were: Grade 0, 42 eyes, 2 HRF (0,4); 0.5+, 10 eyes, 10 HRF (8,15); 1+, 9 eyes, 22 HRF (15,33); 2+, 3 eyes, 27 HRF; 3+, 2 eyes, 128 HRF; 4+, 1 eye, 474 HRF. For every 1-step increase in grade, automated count increased by 38 (p < 0.001) or 293% (Pearson correlation coefficient 0.80, p < 0.001). Automated counts differed significantly between clinically inactive eyes (2 HRF [0,4]) and controls (0 HRF [0,1], p = 0.02).ConclusionsOur algorithm accurately counts HRF when compared to manual counts, with strong correlation to SUN clinical grades. SS AS-OCT offers the advantage of imaging of the entire AC and may allow detection of subclinical inflammation in eyes that appear clinically inactive.

Prevalence of keratoconus and keratoconus suspect, and their characteristics on corneal tomography in a population-based study.

Keratoconus (KC) is a progressive corneal disorder resulting in severe visual impairment. We aimed to determine the prevalence and corneal tomographic characteristics of KC and keratoconus suspect (KCS) in a population-based study, and to construct discrimination models with or without corneal tomography. A total of 1,544 eyes (822 participants aged ≥35 years) were evaluated using data from the Yamagata Study (2015-2017). Systemic and ophthalmological examinations including corneal tomography with swept-source anterior segment optical coherence tomography (AS-OCT) were conducted to determine the prevalence and corneal tomographic characteristics of KC and KCS. In addition, data on 766 eyes were used to construct discrimination models with or without corneal tomography. In results, KC was diagnosed in six (0.85%) participants, and KCS was diagnosed in 27 (1.46%) participants. The values including corneal power, keratometric cylinder, corneal central and thinnest thickness, corneal asymmetry, higher-order irregularity, and their inter-eye differences were associated with KC and KCS. The areas under the receiver operating characteristic curves for the three multivariate discrimination models (without corneal tomography, with corneal tomography, and without corneal tomography + inter-eye difference models) for participants with KC or KCS were 0.848, 1.000, and 0.930, respectively. When corneal tomography is unavailable, inter-eye differences in corneal parameters may be useful screening tools for KC and KCS.

Corneal steep island formation after primary pterygium surgery.

This study aimed to report corneal steep island (CSI) formation following primary pterygium surgery and to identify preoperative pterygium morphological features that predict the likelihood of CSI. A total of 93 eyes from 84 subjects with primary nasal pterygium, who underwent pterygium excision combined with conjunctival-limbal autograft, were included in this retrospective longitudinal cohort study. CSI was defined using anterior segment swept-source optical coherence tomography (AS SS-OCT). Eyes were divided into two groups: those with postoperative CSI formation (Group 1) and those without postoperative CSI (Group 2). We compared postoperative anterior corneal astigmatism (ACA, in diopters [D]) and root mean square (RMS) values of anterior corneal lower-order (LoA) and higher-order aberrations (HoA) between the groups. Baseline clinical severity grades of pterygium based on the pre-established pterygium body morphology and vascularity, ACA, and AS SS-OCT-guided pterygium morphological profiles (horizontal invasion length [HIL, mm], height [μm], thickness (μm), and residual corneal thickness [RCT]/central corneal thickness [CCT] ratio [RCT/CCT]) were also compared. Postoperative CSI occurred in 26 eyes (28.0%) with a maximum follow-up duration of 22.9±27.4 months. Group 1 exhibited significantly higher postoperative anterior corneal RMS LoA and HoA, as well as the RMS values of the 4th to 6th orders. Although clinical severity grades of pterygium did not differ between groups, baseline ACA was higher in Group 1 (4.56±5.49 D vs. 2.70±3.80 D, P = 0.009). HIL (4.49±0.84 mm vs. 3.77±1.29 mm, P = 0.010) was higher in Group 1, while pterygium height (930.8±84.4 μm vs. 999.3±128.0 μm, P = 0.015) and RCT/CCT ratio (1.07±0.13 vs. 1.14±0.16, P = 0.049) were lower in Group 1. CSI may develop after primary pterygium surgery, particularly in patients with relatively higher preoperative ACA, longer HIL, and shorter height. Given that CSI can significantly increase both lower and higher-order aberrations, it is crucial to anticipate CSI probability and inform patients before surgery.

Unveiling the Mysteries of the Chinese lens zonule balance tension: A statistical analysis

BackgroundThis study aims to provide an estimated dataset of lens zonule balance tension (LZBT) measurements in cataractous lenses among Chinese patients and to conduct a statistical analysis of anterior segment parameters. MethodsThis is a cross-sectional study. We included a total of 833 eyes from 833 Chinese participants aged 23–91 years who underwent cataract surgery. Anterior segment parameters were measured using swept-source anterior segment optical coherence tomography (SS-AS OCT) to calculate lens gravity (LG) and crystalline lens volume (VOL). Axial length (AL) was measured using IOL-Master 700. LZBT was calculated using force decomposition and synthesis methods. ResultsThe mean LZBT in the horizontal direction was 8.48E-05 ± 3.23E-05 N across all eyes. The LZBT in the subtemporal-supraspinal and supraspinal-temporal directions was 2 times greater than in the vertical direction. The balanced force on the suspensory ligament in the horizontal direction was twice as strong as in the vertical direction. Additionally, anterior segment parameters such as lens equivalent diameter (LE-dia), radius of the anterior lens surface curvature (RAL), radius of the posterior lens surface curvature (RPL), anterior chamber depth (ACD), iris area, iris volume, and iris thickness showed positive correlations with AL. ConclusionsAccounting for gravitational effects, we concluded that zonule force is asymmetrically distributed. Importantly, this study establishes the normal range of LZBT across different meridians using force synthesis and decomposition, offering new insights and feasibility for studying suspensory ligament biomechanics.

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.

Corneal Layer Thickness Mapping With Optical Coherence Tomography in Different Stages Reveals Pathologic Processes of Keratoconus.

The aim of this study was to characterize the corneal layer thickness profile in different stages of keratoconus (KC). Patients with clinical or subclinical KC without a history of contact lens use were retrospectively enrolled. We evaluated 164 eyes, including 69 clinical KC, 32 topographic KC (no clinical signs), 22 very asymmetric ectasia with normal topography and no clinical signs of ectasia (VAE-NT), and 41 control eyes. The corneal epithelial, stromal, and total thicknesses in a 10-mm diameter were evaluated using swept-source anterior segment optical coherence tomography. The epithelial thickness in the control and VAE-NT groups was thicker inferiorly than superiorly. While epithelial thickness parameters between the VAE-NT and control groups did not differ, significant stromal thinning was observed in the paracentral inferior and midperipheral temporal areas. The epithelium in the topographic and clinical KC groups was thinner than that in the control and VAE-NT groups, with focal thinning of the epithelium in the inferior-temporal area. In clinical KC, stromal thinning increased mainly in the central and paracentral inferior/temporal areas. With KC progression, the thinnest epithelial points tended to be placed temporally and inferiorly. Corneal layer thickness mapping using swept-source optical coherence tomography in a 10-mm diameter cornea across various severities of KC, from very mild to advanced, revealed that epithelial and stromal thicknesses changed with KC severity and was involved in the pathogenesis of KC progression. Pathological changes in the stroma may precede those in the epithelium. Epithelial compensatory mechanisms in clinical and topographic KC may not have fully emerged in VAE-NT.

Objective quantification of posterior capsule opacification using swept-source anterior segment optical coherence tomography.

To objectively quantify posterior capsule opacification (PCO) using swept-source anterior segment optical coherence tomography (SS-ASOCT) in pseudophakic eyes. Zhongshan Ophthalmic Center, Guangzhou, China. Prospective cross-sectional study. One hundred and eighty eyes with PCO (37 multifocal intraocular lenses [MfIOLs] and 143 monofocal intraocular lenses [MoIOLs]) were enrolled. The PCO Irregular Degree (PID), defined to evaluate the surface irregularity of PCO, the average and maximum thickness of PCO (AT-PCO, MT-PCO) were applied to quantify PCO based on SS-ASOCT (CASIA2) images. Corrected distance visual acuity (CDVA), high order aberrations (HOAs), modulation transfer function (MTF) and Strehl ratio were recorded. The associations between SS-ASOCT parameters and visual function parameters were assessed by Spearman's correlation analysis. PID, AT-PCO and MT-PCO showed significant correlations with CDVA, Strehl ratio and HOAs (CDVA: r = 0.702, 0.741, 0.736; Strehl ratio: r = -0.746, -0.719, -0.740; HOAs: r = 0.762, 0.734, 0.752). The correlations of these three parameters with Strehl ratio and HOAs were significantly higher than those of clinical PCO grading with Strehl ratio and HOAs (all P < 0.05). Particularly, PID demonstrated notable correlations with Strehl ratio and HOAs. In addition, patients with MfIOLs presented worse Strehl ratio and HOAs than those with MoIOLs after matching age, PID, AT-PCO and MT-PCO. This study provides a novel method for objectively quantifying PCO using successive cross-sectional SS-ASOCT images. AT-PCO, MT-PCO and PID are presented as new indicators to document PCO severity, with PID offering a unique perspective by considering the irregularity aspect of PCO.

The Influence of Corneal Thickness on Surgically Induced Corneal Astigmatism Derived from Total Keratometry Measured by Anterior Segment Swept-Source OCT.

The purposeof the study was to explore the possible correlations between the anterior segment parameters derived from anterior segment swept-source optical coherence tomography (AS-SS-OCT) with the surgically induced corneal astigmatism (CSIA) calculated from total keratometry (TK) measured by AS-SS-OCT. Seventy-one eyes of 67 patients with age-related cataract who underwent phacoemulsification combined with intraocular lens implantation with 2.2-mm incision were included. The CSIA values were calculated from anterior keratometry (CSIAKant) and TK (CSIATK) measured by AS-SS-OCT, respectively. Hotelling's T2 test was used to evaluate the difference. The correlation of CSIA with various parameters derived from AS-SS-OCT was tested with the Spearman correlation coefficient. The centroid of CSIAKant and of CSIATK were 0.31 ± 0.55 D @ 54° and 0.41 ± 0.59 D @ 51°, with no significant difference (F = 1.283, p = 0.281, Hotelling's T2). The mean absolute CSIAKant and CSIATK were 0.58 ± 0.24 D and 0.65 ± 0.28 D. Spearman test showed that the magnitude of CSIAKant was negatively correlated with preoperative peripheral corneal thickness (PCT, p = 0.045) and the magnitude of anterior keratometry (p = 0.044). The magnitude of CSIATK was negatively correlated with preoperative central corneal thickness (CCT, p = 0.003) and preoperative PCT (p = 0.015). The increased thickness of the peripheral cornea is correlated with the decrease in the magnitude of the CSIA. The correlation we identified between the corneal thickness and the CSIA indicated that certain preoperative parameters should be considered for the prediction of CSIA for a more precise refractive outcome.

Anterior Chamber Angle and Intraocular Pressure Control After Phacoemulsification in Primary Angle Closure With Different Mechanisms.

Different mechanisms of angle closure represented distinct aspects of intraocular pressure (IOP) control after phacoemulsification. Classification of angle closure mechanisms is necessary for postoperative IOP management and glaucoma progression in primary angle closure eyes. To investigate the relationship between the anterior chamber angle (ACA) characteristics, measured by swept-source anterior segment optical coherence tomography (SS AS-OCT), and intraocular pressure (IOP) control after phacoemulsification in eyes with primary angle closure disease (PACD) with different angle closure mechanisms. PACD eyes were classified into 3 groups according to angle closure mechanisms using preoperative SS AS-OCT images; pupillary block (PB), plateau iris configuration (PIC), exaggerated lens vault (ELV). This retrospective, clinical cohort study included eighty-five eyes of 85 PACD patients: 34 with PB, 23 with PIC, and 28 with ELV. ACA parameters were measured preoperatively and 1 month postoperatively using SS AS-OCT. IOP measurements were performed preoperatively and during 6 months postoperatively. Postoperative IOP reduction and fluctuation were calculated, and their correlations with SS AS-OCT parameters were analyzed. PIC group showed the lowest postoperative IOP reduction compared with the other groups ( P =0.023). Preoperative ACA measurements were significantly associated with postoperative IOP reduction in ELV and PB groups, while postoperative measurements were in PIC group. Preoperative and postoperative change of iridotrabecular contact (ITC) index and area were correlated with postoperative IOP reduction in PB and ELV groups but not in PIC group. Postoperative ITC index ( P =0.031) and area ( P =0.003) showed significant correlations with postoperative IOP fluctuation only in PIC group. SS AS-OCT parameters including ITC index and area showed different associations with postoperative IOP control, which should be considered in determination of lens extraction and treatment of PACD eyes.

Examination of the Vitreolenticular Interface in Relation to Uneventful Phacoemulsification over One-Year Postoperative Period.

Background: Swept-source anterior segment optical coherence tomography (SS-AS-OCT) is a suitable examination for the vitreolenticular interface. Methods: In a prospective study using Anterion (Heidelberg Engineering, Heidelberg, Germany), 102 eyes of 102 patients were examined in pupil dilation, preoperatively and 6 times over 1-year follow-up. Preoperatively anterior hyaloid membrane (AHM) visibility was determined with Imaging App with high reliability. Postoperatively capsular bag-AHM distance was measured on six points by using Metrics App. Results: The AHM was visible in 18.6% preoperatively and postoperatively as well (Group 1), 49% of the preoperatively adherent AHMs became visible (Group 2A), 32.4% remained attached (Group 2B). Group 1: the average deepest point on the first day was 782.5 ± 324.1 microns, and it significantly differed from the later follow-up values. Group 2A: the average deepest value was 184.1 ± 220.1 microns, and there was no statistically significant difference between the postoperative visit values. The difference between the groups was statistically significant at every location and at each time point. Conclusions: AS-SS-OCT can be used to check BS both preoperatively (with limitations) and postoperatively.

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.

Effect of Temporal Decentration of Orthokeratologic Lens on Corneal Aberrations in Swept-source Optical Coherence Tomography

Purpose: This study used anterior segment swept-source optical coherence tomography (AS SS-OCT) to explore the effect of temporal decentration within the orthokeratologic lens treatment zone on corneal aberrations.Methods: After lens placement, AS SS-OCT was used to evaluate anterior, posterior, and total corneal astigmatism and the magnitudes of the individual 1st- to 4th-order aberrations of the anterior and entire corneal fields. Also, the 4th-to 7th-order root mean square (RMS), and the low- and high-ordered RMSs of both the anterior and entire corneal areas were recorded. We compared subjects lacking (the no decentration [ND] group) to those exhibiting (the temporal decentration [TD] group) temporal decentration.Results: In all, 61 eyes of 32 patients (44 eyes in the ND group and 17 in the TD group) were included. In the TD group, the average temporal decentration was 0.74 ± 0.15 mm. The baseline axial length, spherical equivalent, anterior mean corneal power, and anterior corneal astigmatism did no difference between the two groups. However, the TD group exhibited more anterior and total corneal horizontal tilts, and horizontal coma, than the ND group. That group also had less with-the-rule (WTR)/against-therule (ATR) astigmatism, elevated anterior and total corneal 5th-order RMS values, and greater low- and high-ordered RMS levels. However, despite these differences, the extent of myopia correction did not significantly differ between the groups.Conclusions: Although myopia reduction was not significantly compromised by temporal decentration of an orthokeratologic lens, the anterior and total corneal low- and high-ordered RMS values increased. In terms of individual aberrations, the low-ordered horizontal tilt and the high-ordered horizontal coma increased.

Anterior segment swept-source optical coherence tomography and ultrasound biomicroscopy in iris and ciliary body lesions

ABSTRACT Objectives Differentiation of iris and ciliary body lesions as benign or malignant and cystic or solid is important. The aim of this study was to compare anterior segment swept-source optical coherence tomography (AS SS-OCT) and ultrasound biomicroscopy (UBM) findings in iris and ciliary body tumors. Research design and methods Forty-two eyes of 38 cases with iris and ciliary body tumors imaged with UBM and AS SS-OCT between September 2018 and September 2023 were evaluated retrospectively. Results Of 42 eyes, 14 had melanoma, 14 iris pigment epithelial (IPE) cysts, 7 nevi, 3 Lisch nodules, 2 iris stromal cysts, 1 pars plana cysts, and 1 iris mammillations. An equivalent (100%) visualization of the anterior tumor margin was obtained with both techniques. Compared to AS SS-OCT, UBM was superior for posterior margin visualization in melanocytic tumors and IPE cysts. Bland-Altman plots demonstrated good agreement between UBM and AS SS-OCT for melanocytic tumors < 2.5 mm in base diameter and < 2 mm in thickness. Conclusions Although, UBM is the gold standard for ciliary body and iridociliary tumors. AS SS-OCT should be considered as an excellent alternative to UBM, especially in minimally elevated iris lesions.

Timing optimization for primary pterygium excision with conjunctival-limbal autograft to restore the corneal optical properties.

To propose the optimal value of baseline corneal astigmatism and pterygial morphological profiles for primary pterygium surgery to restore the corneal optical properties. We analysed 93 eyes from 84 subjects with nasal-only primary pterygium who underwent pterygium excision with conjunctival-limbal autograft and were assessed perioperatively using anterior segment swept-source optical coherence tomography (AS SS-OCT). We collected data on anterior corneal astigmatism (ACA) and root mean square (RMS) values for anterior corneal lower- (LoA) and higher-order aberrations (HoA) as corneal optical properties using AS SS-OCT. Using preoperative ACA and four pterygial morphological profiles (horizontal invasion length [HIL], height, thickness and the ratio of residual corneal thickness [RCT] to central corneal thickness [CCT]) measured in AS SS-OCT, we plotted receiver operating characteristic (ROC) curves. These curves aimed to determine cut-off values predicting a perioperative decrease exceeding 50% in ACA, RMS LoA and RMS HoA, as well as postoperative residual ACA higher than 1.25D. Preoperative ACA > 1.42D (AUC = 0.934) and >3.60D (AUC = 0.946) proved most effective in identifying subjects with perioperative decrease exceeding in ACA and RMS LoA, respectively. HIL > 3.34 mm (AUC = 0.941) was most effective in distinguishing subjects with perioperative reduction exceeding 50% in RMS HoA. Preoperative ACA > 5.78D (AUC = 0.776) and HIL > 5.03 mm (AUC = 0.700) significantly distinguished subjects with postoperative residual ACA higher than 1.25D. Optimizing the restoration of corneal astigmatism and aberrations after pterygium surgery may be facilitated by determining the optimal surgical timing based on preoperative ACA and HIL values.

Effects of cycloplegia on crystalline lens morphology and location in acute acquired concomitant esotropia.

The study aims to compare morphology and location of crystalline lens between acute acquired concomitant esotropia (AACE) patients and control subjects, both before and after cycloplegia. This is a prospective and observational clinical study. Morphological and locational parameters of the crystalline lens in 53 AACE patients and 32 control subjects were assessed before and after cycloplegia using CASIA2 system, which represents the latest swept-source anterior segment optical coherence tomography. Cycloplegic refraction was recorded by administering 1% atropine in patients younger than 12years and 1% cyclopentolate in those > 12years old. Morphological parameters included anterior radius of curvature (ARC), posterior radius of curvature (PRC), lens thickness (LTH), and equivalent diameter of lens (LED). Locational parameters comprised lens decentration (LD) and lens tilt (LT). Comparison of these parameters before and after cycloplegia were conducted between AACE and controls. Additionally, the study analyzed and compared the changes in these parameter post-cycloplegia. Our findings suggest no significant difference in morphological parameters including ARC, PRC, LTH and LED between AACE patients and controls before or after cycloplegia. However, 2D-modeling data in the 0° meridian revealed that variation post-cycloplegia of LD (lens shift) in right eyes was different in AACE patients, measuring - 0.03(0.08) [median(interquartile range)] which was significantly distinct from the control group, exhibiting a measurement of 0.01(0.06) (z = - 2.373, p = 0.018). In left eyes, a similar trend was observed with lens shift in the 0° meridian being 0.02(0.06) in AACE, significantly differing from control group's measurement of - 0.02(0.08) (z = - 2.809, p = 0.005). Further, correlation analysis revealed that larger temporal shift of lens was associated with greater changes in ARC (r = 0.294, p = 0.006) and LTH (r = - 0.230, p = 0.031). The morphological features of the crystalline lens were similar in AACE patients and controls; however, the change of lens location by cycloplegia was observed only in AACE patients, suggesting an association with excessive accommodation.

Correlation of anterior segment optical coherence tomography and ultrasound biomicroscopy in congenital corneal opacity

To investigate the correlation between swept-source anterior segment optical coherence tomography (AS-OCT) and ultrasound biomicroscopy (UBM) in congenital corneal opacity (CCO). All children with unilateral or bilateral congenital corneal opacities who underwent examination under anesthesia (EUA) and anterior segment optical coherence tomography (AS-OCT) imaging from January 1, 2022, to December 31, 2022, were included. Main outcome measures were corneal and anterior segment evaluation and correlation of UBM and AS-OCT findings. A total of 22 eyes of 15 patients were imaged using both technologies. The age at first EUA ranged from 11 days to 4 years. Different phenotypes were classified based on the clinical examination, UBM, and AS-OCT findings. Fourteen eyes were diagnosed with Peters anomaly, congenital corneal staphyloma was observed in 4 eyes, 2 eyes had coloboma, 1 eye had peripheral sclerocornea, and 1 eye was diagnosed with congenital primary aphakia. AS-OCT and UBM findings were closely correlated in 18 of 22 eyes (82%) but AS-OCT failed to provide detailed information in 4 eyes (18%) where UBM revealed more details. Although AS-OCT offers valuable preliminary data for initial assessment and counseling, it may not consistently provide precise assessments in all cases. Therefore, UBM should be considered for definitive evaluation.

Biomechanical properties measured with dynamic Scheimpflug analyzer in central serous chorioretinopathy.

Recent evidence suggests that venous congestion at the vortex vein significantly contributes to the development of central serous chorioretinopathy (CSCR), and sclera is observed to be thicker in affected eyes. This study aims to investigate whether eyes with CSCR exhibit stiff corneas, measured using Corneal Visualization Scheimflug Technology (Corvis ST), which may serve as an indicator of scleral stiffness. This retrospective case-control study comprises 52 eyes from 33 patients diagnosed with CSCR and 52 eyes from 32 normal controls without CSCR. We compared biomechanical parameters measured with Corvis ST and anterior scleral thickness measured using anterior segment swept-source optical coherence tomography between the two groups. Age, sex, axial length, intraocular pressure, and central corneal thickness showed no significant differences between the two groups (p > 0.05, linear mixed model). Three biomechanical parameters-peak distance, maximum deflection amplitude, and integrated inverse radius-indicated less deformability in CSCR eyes compared to control eyes. The stress-strain index (SSI), a measure of stiffness, and anterior scleral thickness (AST) at temporal and nasal points were significantly higher in the CSCR eyes. SSI and AST were not correlated, yet both were significantly and independently associated with CSCR in a multivariate logistic regression model. Eyes affected by CSCR have stiffer corneas, irrespective of thicker scleral thickness. This suggests that stiffer sclera may play a role in the pathogenesis of CSCR.

Documentation of capsular block syndrome with swept-source anterior segment optical coherence tomography

A turbid white fluid was noticed in the retrolental space in the right eye of a 57-year-old male who had undergone cataract surgery 4 years ago. With clinical suspicion of capsular block syndrome (CBS), a swept-source anterior segment optical coherence tomography (SS-ASOCT) was conducted. Hyperreflective echo was detected between the posterior surface of the intraocular lens and the posterior capsule. Prompt relief from CBS was achieved through Nd: YAG laser treatment. The advent of SS-ASOCT allows rapid and detailed assessment of the eye’s anterior segment owing to its deeper ocular tissue penetration and better axial resolution within a few seconds.

Characteristics of ciliary muscle profile in high myopes measured by swept-source anterior segment optical coherence tomography.

To characterize and compare the ciliary muscle thickness (CMT) between low and high myopes using swept-source anterior segment optical coherence tomography (AS-OCT). Forty visually healthy young Chinese adults aged 18-25 years were divided into two groups based on refractive errors: low myopia (n = 20, spherical-equivalent refractive error (SER) between -0.50 D to -3.00 D) and high myopia (n = 20, SER ≤ -6.00 D). Cycloplegic refractions were performed before axial length (AL) and CMT were measured using a partial coherence laser interferometer and an AS-OCT respectively. CMT was measured perpendicularly to the sclera-ciliary muscle interface at 1 mm (CMT_1), 2 mm (CMT_2), and 3 mm (CMT_3) posterior to the scleral spur, and at the location with maximal thickness (CMT_MAX). High myopes demonstrated thicker CMT at 2 mm (CMT_2, p = 0.035) and 3 mm (CMT_3, p = 0.003) posterior to the scleral spur, but thinner maximal CMT (CMT_MAX, p = 0.005) than low myopes. The apical CMT_1 and CMT_MAX were also thinner in high myopes than in low myopes (both p< 0.001). CMT_MAX, apical CMT_1, and apical CMT_MAX correlated directly with SER and inversely with AL; in contrast, CMT_2 and CMT_3 showed inverse correlations with SER but direct correlations with AL. Our findings revealed significant differences in CMT between low and high myopes, with high myopes showing thicker CMT at 2 mm and 3 mm posterior to the scleral spur, but thinner maximal CMT. These results provide new evidence of the potential structural differences in ciliary muscles during myopia development and progression.

Swept-Source Anterior Segment Optical Coherence Tomography Imaging and Quantification of Bleb Parameters in Glaucoma Filtration Surgery.

This paper describes a technique for using swept-source anterior segment optical coherence tomography (AS-OCT) to visualize internal bleb microstructure and objectively quantify dimensions of the scleral flap and trabeculo-Descemet window (TDW) in non-penetrating glaucoma filtration surgery (GFS). This was a cross-sectional study of 107 filtering blebs of 67 patients who had undergone deep sclerectomy surgery at least 12 months prior. The mean post-operative follow-up duration was 6.5 years +/- 4.1 [standard deviation (SD)]. The maximal bleb height was significantly greater in the complete success (CS) blebs compared to the qualified success (QS) and failed (F) blebs (1.48 vs. 1.17 vs. 1.10 mm in CS vs. QS vs. F, one-way ANOVA, p < 0.0001). In a subcohort of deep sclerectomy blebs augmented by intraoperative Mitomycin-C, the trabeculo-Descemet window was significantly longer in the complete success compared to the qualified success group (613.7 vs. 378.1 vs. 450.8 µm in CS vs. QS vs. F, p = 0.004). The scleral flap length, thickness, and width were otherwise similar across the three outcome groups. The quantification of surgical parameters that influence aqueous outflow in non-penetrating GFS can help surgeons better understand the influence of these structures on aqueous outflow and improve surgical outcomes.