Anterior Segment Optical Coherence Tomography Scans Research Articles

Comparison of Scheimpflug Corneal Tomography and Anterior Segment Optical Coherence Tomography Measurements in Corneal Cystinosis: A Case Series.

To report the clinical course and compare the utility of Scheimpflug tomography (ST) and anterior segment optical coherence tomography (AS-OCT) for central corneal thickness (CCT) and corneal densitometry (CD) assessment in patients with corneal crystals owing to nephropathic cystinosis. A retrospective chart analysis of three patients with nephropathic cystinosis and the presence of corneal cystine crystals in both eyes was performed. All patients underwent clinical examination and anterior segment photography, ST, and AS-OCT scans. Corneal densitometry was exported from built-in proprietary software for ST and from custom-made validated software for AS-OCT. Anterior segment optical coherence tomography images were rescaled to grayscale units from 0 (maximum transparency) to 100 (minimum transparency) to match built-in ST densitometry readings. Furthermore, the mean pixel intensity, representative of CD, was calculated from the pixels corresponding to the segmented cornea. All three patients had pathognomonic cystine crystals deposits in the cornea and were treated with cysteamine medications that resulted in clinical improvement. The CCT measured using ST exhibited a range from 560 to 958 μm. Conversely, when assessed with AS-OCT, the CCT varied within the range of 548 to 610 μm. Both examinations could be performed, but in the more severe cases, AS-OCT showed far greater utility to estimate CD. In four of six eyes examined, ST showed disproportionate CCT values, compared with the AS-OCT, whereas reliable CD measurements were only available in AS-OCT. The AS-OCT could be considered a baseline ocular measurement in cystinosis and in the evaluation of disease progression and treatment efficacy.

Reverse pupillary block, in contemporary scleral intraocular lens procedures.

To evaluate the frequency and anterior segment optical coherence tomography parameters of patients with scleral fixated intraocular lenses (IOL) and reverse pupillary block (RPB). Retrospective analysis at a tertiary care centre (Department for Ophthalmology and Optometry, Medical University of Vienna, Austria). We researched our records for patients who underwent scleral fixated IOL implantation from January 2018 till February 2023. Patients were included only if there was at least one adequate post-operative scan of anterior segment optical coherence tomography (AS-OCT) available. Initially, AS-OCT scans were assessed for IOL tilt and decentration employing a 3D scan and then later for anterior chamber angle (ACA), aqueous anterior chamber depth (AQD), pupil diameter and iris-IOL distance using the 2D scan at a 0° angle. Both an iris-IOL distance of 0 or less and an ACA of more than 70° were required to define an RPB. A total of 110 patients met the inclusion criteria, 41 were treated using the Carlevale, 33 the four flanged, 24 the Yamane and 12 the Scharioth technique, respectively. RPB was found in 32 patients (29%). Twenty patients with RPB were treated using YAG peripheral iridotomy, mean ACA decreased from 91.91° ± 13.77 to 61.02° ± 8.52, (p < 0.001), mean AQD decreased from 4.67 mm ± 0.47 to 4.31 ± 0.36 mm (p < 0.001) and mean iris-IOL distance increased from -0.09 ± 0.04 to 0.33 ± 0.30 (p < 0.001). RPB is found in a third of eyes who have undergone scleral fixated IOL implantation without iridectomy. YAG peripheral iridotomy is a potent option to treat RPB, and subsequently reduce the risk of iris chafing and secondary inflammation or glaucoma.

Enhancing the Automated Detection of Implantable Collamer Lens Vault Using Generative Adversarial Networks and Synthetic Data on Optical Coherence Tomography.

To investigate the efficacy of incorporating Generative Adversarial Network (GAN) and synthetic images in enhancing the performance of a convolutional neural network (CNN) for automated estimation of Implantable Collamer Lens (ICL) vault using anterior segment optical coherence tomography (AS-OCT). This study was a retrospective evaluation using synthetic data and real patient images in a deep learning framework. Synthetic ICL AS-OCT scans were generated using GANs and a secondary image editing algorithm, creating approximately 100,000 synthetic images. These were used alongside real patient scans to train a CNN for estimating ICL vault distance. The model's performance was evaluated using statistical metrics such as mean absolute percentage error (MAPE), mean absolute error (MAE), root mean squared error (RMSE), and coefficient of determination (R2) for the estimation of ICL vault distance. The study analyzed 4,557 AS-OCT B-scans from 138 eyes of 103 patients for training. An independent, retrospectively collected dataset of 2,454 AS-OCT images from 88 eyes of 56 patients, used prospectively for evaluation, served as the test set. When trained solely on real images, the CNN achieved a MAPE of 15.31%, MAE of 44.68 µm, and RMSE of 63.3 µm. However, with the inclusion of GAN-generated and algorithmically edited synthetic images, the performance significantly improved, achieving a MAPE of 8.09%, MAE of 24.83 µm, and RMSE of 32.26 µm. The R2 value was +0.98, indicating a strong positive correlation between actual and predicted ICL vault distances (P < .01). No statistically significant difference was observed between measured and predicted vault values (P = .58). The integration of GAN-generated and edited synthetic images substantially enhanced ICL vault estimation, demonstrating the efficacy of GANs and synthetic data in enhancing OCT image analysis accuracy. This model not only shows potential for assisting postoperative ICL evaluations, but also for improving OCT automation when data paucity is an issue. [J Refract Surg. 2024;40(4):e199-e207.].

Anterior Segment Optical Coherence Tomography in Uveitis-Glaucoma-Hyphema Syndrome

ABSTRACT Purpose Uveitis-Glaucoma-Hyphema (UGH) syndrome results from contact between the intraocular lens (IOL) and the iris or ciliary body, leading to uveal structure erosion and blood-aqueous barrier breakdown. Treatment involves various drugs, with IOL removal often being necessary. Diagnosis relies on clinical signs, but imaging techniques like ultrasound biomicroscopy (UBM) or anterior segment optical coherence tomography (AS-OCT) are crucial. AS-OCT accurately depicts IOL position and potential contact, emerging as a primary alternative to UBM in the diagnosis. Our study aimed to correlate AS-OCT findings with clinically detectable iris atrophy in pseudophakic patients with IOL-iris chafing and UGH syndrome. Methods The study retrospectively analyzed patients diagnosed with UGH syndrome presenting at the Ocular Immunology Unit of Reggio Emilia, Italy, from January 2019 to August 2023. Patients’ data were collected. Ophthalmological exams and imaging were performed. The peephole sign in AS-OCT images was evaluated. Statistical analyses were conducted, with a significance level of p ≤ 0.05. Results The study reviewed 22 eyes of 22 patients with UGH syndrome. Four eyes were excluded, leaving 18 patients (8 females, 10 males). Common misdiagnoses included idiopathic anterior uveitis (55.5%) and herpetic anterior uveitis (16.7%). All patients had iris transillumination defects, mostly focal (77.8%). AS-OCT revealed IOL chafing in all the eyes, with peephole sign correlation. More peephole signs occurred with IOL in the sulcus (p-value = 0.08). Conclusion The study recommends AS-OCT for UGH syndrome confirmation and UBM when IOL-iris chafing is not observed on AS-OCT scans.

Assessment of conjunctival, episcleral and scleral thickness in healthy individuals using anterior segment optical coherence tomography.

To determine the thickness of the conjunctiva, episclera and sclera in healthy individuals using anterior segment optical coherence tomography (AS-OCT). We prospectively included 107 healthy individuals of different age groups (18-39 years, 40-54 years, 55-69 years and ≥70 years). For each eye, AS-OCT scans of four quadrants (temporal, nasal, superior and inferior) were acquired. The thickness of the conjunctiva, episclera and sclera was measured for each scan. In addition, the axial length of both eyes was measured, and general characteristics, including smoking, allergies and contact lens use, were collected. The mean conjunctival thickness was significantly different between the nasal and superior quadrants (87 ± 30 μm vs. 77 ± 16 μm; p < 0.001), as well as the superior and inferior quadrants (77 ± 16 μm vs. 86 ± 19 μm; p = 0.001). The mean episcleral thickness was larger in the superior (174 ± 54 μm) and inferior (141 ± 43 μm) quadrants, compared to the nasal (83 ± 38 μm) and temporal quadrants (90 ± 44 μm). The mean scleral thickness of the inferior quadrant was the largest (596 ± 64 μm), followed by the nasal (567 ± 76 μm), temporal (516 ± 67 μm) and superior (467 ± 52 μm) quadrants (all p < 0.001). The averaged scleral thickness increased 0.96 μm per age year (0.41-1.47 μm, p < 0.001). This study provides an assessment of the thickness of scleral and adjacent superficial layers in healthy individuals determined on AS-OCT, which could enable future research into the use of AS-OCT in diseases affecting the anterior eye wall.

Repeatability and reliability of semi-automated anterior segment-optical coherence tomography imaging compared to manual analysis in normal and keratoconus eyes.

To assess the repeatability and reliability of semi-automated EyeMark Python program measurements compared to manual ImageJ image processing of anterior segment-optical coherence tomography (AS-OCT) structures in healthy and keratoconus eyes. Heidelberg AS-OCT was used to image 25 eyes from 14 healthy subjects and 25 eyes from 15 subjects with keratoconus between the ages of 20 and 80years, collected prospectively, in this observational case-control study. Visual axis scan containing vertical fixation light beam was selected from the 15-line AS-OCT scan raster. Central corneal thickness (CCT), anterior corneal radius of curvature (ACRC), posterior corneal radius of curvature (PCRC), and truncated anterior vault (TAV) were measured using ImageJ software and the EyeMark Python program. MedCalc and R were used to calculate the intraclass correlation coefficient (ICC) and generate Bland-Altman plots (BAP). When comparing the measurements of CCT, ACRC, PCRC, and TAV between manual ImageJ analysis and the EyeMark Python program, ICC values were consistently greater than 0.9, indicating excellent agreement. BAPs comparing the ImageJ and Python measurements of anterior segment structures show no systematic proportional bias and the average differences were near zero and within 95% of the limits of agreement. Semi-automated tools may provide the necessary efficiency for point-of-care quantitative corneal analysis of raw AS-OCT images. The semi-automated EyeMark Python program offers a repeatable and reliable tool compared to manual ImageJ analysis for measuring anterior segment structures from AS-OCT images among individuals with keratoconus.

Deep Learning–Based Estimation of Implantable Collamer Lens Vault Using Optical Coherence Tomography

To develop and validate a deep learning neural network for automated measurement of implantable collamer lens (ICL) vault using anterior segment optical coherence tomography (AS-OCT). Cross-sectional retrospective study. Multicentric. A total of 2,647 AS-OCT anonymized eye scans were used from 139 eyes of 82 subjects who underwent ICL surgery in 3 different centers. Using transfer learning, a deep learning neural network algorithm was trained and validated for the regression task of estimating the ICL vault on the MS-39 OCT (CSO, Florence, Italy). A trained operator separately reviewed all OCT scans and measured the central vault using a built-in OCT caliper tool. The model was then separately tested on 191 AS-OCT scans. A Bland-Altman plot was constructed and the mean absolute percentage error (MAPE), the mean absolute error (MAE), the root mean squared error (RMSE), the Pearson correlation coefficient (r), and the determination coefficient (R2) were calculated to evaluate the strength and validity of the model. On the test set, the model achieved a MAPE of 3.42%, an MAE of 15.82 µm, an RMSE of 18.85 µm, a Pearson correlation coefficient r of +0.98 (P-Value < .00001), and a coefficient of determination R2 of +0.96. There was no significant difference between the vaults of the test set labeled by the technician versus those estimated by the model: 478 ± 95 µm versus 475 ± 97 µm, respectively, P-Value = 0.064). Using transfer learning, our deep learning neural network was able to accurately compute the ICL vault from AS-OCT scans, overcoming the limitations of an imbalanced dataset and limited training data. Such an algorithm can assist the postoperative assessment in ICL surgery. PRéCIS: This study develops and validates a deep learning model to accurately estimate implantable collamer lens vault on optical coherence tomography using transfer learning, convoluted neural networks, and regression.

Scleral thickness in normal Indian eyes measured using spectral domain anterior segment optical coherence tomography.

To establish normative data on anterior scleral thickness using the spectral domain anterior segment optical coherence tomography (AS-OCT). In total, 200 eyes of 100 healthy subjects underwent AS-OCT scans in the temporal and nasal quadrants. The scleral + conjunctival complex thickness (SCT) was measured by a single examiner. Mean SCT was analyzed for differences across age groups, gender, and location (nasal versus temporal). Mean age was 46.4 ± 18.3 (21-84) years; male to female ratio was 54:46. Mean SCT (nasal + temporal) of the right eye (RE) was 682.3 ± 64.2 μm in males and 660.6 ± 57.1 μm in females. In the left eye (LE), it was 684.6 ± 64.9 μm in males and 661.8 ± 49.3 μm in females. These differences between male and female for both eyes were statistically significant (P = 0.006 and P = 0.002). The mean SCT of temporal and nasal quadrants in the RE was 678.54 ± 57.50 and 666 ± 66.2 μm, respectively. In the LE, the temporal mean SCT quadrant was 679.6 ± 55.8 μm, and the nasal was 668.6 ± 63.6 μm. Age had a negative correlation with SCT (-0.62 μm/year; P = 0.03), and males had a higher temporal SCT than females (22 μm higher; P = 0.03). After adjusting for age and gender in a multivariate analysis, temporal SCT was significantly (P < 0.001) higher than nasal SCT. In our study, mean SCT decreased with age and males had a higher temporal SCT. This is the first study to evaluate scleral thickness in the Indian population, and the data can be used as a baseline for comparing variations in scleral thickness in disease.

Role of swept-source anterior segment optical coherence tomography in imaging pediatric cataract

Purpose: To determine the morphology of pediatric cataracts and assess the status of the anterior and posterior capsules preoperatively on swept-source anterior segment optical coherence tomography (ASOCT) and compare the findings to those of intraoperative examination. Secondly, we aimed to obtain biometric measurements on ASOCT and compare them to those obtained on A-scan/optical methods. Methods: This was a prospective and observational study carried out at a tertiary care referral institute. ASOCT scans for anterior segment were obtained preoperatively for all patients, aged <8 years, scheduled for paediatric cataract surgery. The morphology of the lens and capsule and biometry were performed on ASOCT and the same were assessed intraoperatively. The main outcome measures were comparison of ASOCT findings to intraoperative findings. Results: The study included 33 eyes of 29 patients (range 3 months–8 years). The morphological characterization of cataract on ASOCT was accurate in 31/33 (94%) cases. ASOCT accurately identified fibrosis and rupture of the anterior and posterior capsules in 32/33 (97%) cases each. In 30% of eyes, ASOCT gave additional information preoperatively compared to the slit lamp. Intraclass correlation coefficient (ICC) calculation revealed a good agreement between the keratometry values obtained on ASOCT and those obtained preoperatively with a handheld/optical keratometer (ICC = 0.86, P = 0.001). Conclusion: ASOCT is a valuable tool that could provide complete preoperative information of the lens and capsule in pediatric cataract cases. In children as young as 3 months of age, intraoperative risks and surprises could be diminished. The keratometric readings are highly dependent on patient cooperation but show good agreement with the handheld/optical keratometer readings.

Automatic quantifying and monitoring follow-ups for implantable collamer lens implantation using AS-OCT images

Purpose: To develop a deep learning method to automatically monitor the implantable collamer lens (ICL) position and quantify subtle alterations in the anterior chamber using anterior segment optical coherence tomography (AS-OCT) images for high myopia patients with ICL implantation.Methods: In this study, 798 AS-OCT images of 203 patients undergoing ICL implantation at our eye center from April 2017 to June 2021 were involved. A deep learning system was developed to first isolate the corneoscleral, ICL, and lens, and then quantify clinical important parameters in AS-OCT images (central corneal thickness, anterior chamber depth, and lens vault).Results: The deep learning system was able to accurately isolate the corneoscleral, ICL, and lens with the Dice coefficient ranging from 0.911 to 0.960, and all the F1 scores &gt;0.900. The relative error between automated measurements and the ground truth for 95% (188 images out of 198) of LVs was within 10%. Intraclass correlation coefficients (ICCs) of the machine-ground truth measurements ranged from 0.928 to 0.995. The deep learning method also showed better repeatability than human graders.Conclusion: The deep learning method provides reliable detection and quantification of AS-OCT scans for postoperative ICL implantation, which can simplify and optimize the management of clinical outcomes of ICL implantations. Also, this is a step towards an objective measurement of the postoperative vault, making the data more comparable and repeatable to each other.

Recombinant Human Nerve Growth Factor (Cenegermin)-Driven Corneal Wound Healing Process: An Evidence-Based Analysis.

Purpose: To evaluate anterior segment optical coherence tomography (AS-OCT) to detect the wound healing process as per monitoring the effectiveness of cenegermin to treat moderate to severe neurotrophic keratoplasty. Methods: A retrospective chart review was realized to identify patients treated with cenegermin at the Clinica Oculistica, University of Genoa, Italy. All patients underwent careful examinations at baseline and follow-up visits. AS-OCT scans centered on the minimum corneal thickness (CT) area were always performed. We compared findings of AS-OCT with the findings from the slit-lamp examination. A linear regression analysis was used to evaluate factors associated with corneal healing. A further analysis, including a control group treated with 50% autologous serum (AS), was done to investigate and compare the efficacy of cenegermin. Results: Data from 16 eyes were studied. The average patients' age was 60.9 ± 21.1 years; five (31.2%) eyes experienced persistent epithelial defect and 11 (68.8%) eyes had neurotrophic corneal ulcer. The average reepithelialization time was 3.9 ± 0.5 weeks in the cenegermin group versus 5.9 ± 1.9 weeks in the AS group (p < 0.01). The AS‐OCT scans revealed an average CT at the thinnest point of 276.3 ± 74.1 μm before treatment with an average increase of 176.5 ± 60.3 μm at the end of the cenegermin treatment (B = −0.15; p = 0.035). The AS-OCT percentage increase in corneal thickness between the two groups was statistically significant (p < 0.02). Conclusion: Understanding the cascade of events involved in the nerve growth factor–driven corneal wound healing process is clinically meaningful for the clinician. AS-OCT is an effective tool for systematic anterior segment imaging, allowing the detailed detection of the front-to-back layered corneal structure for quantitative analysis and monitoring of the healing process.

Longitudinal Changes in Corneal Epithelial Thickness and Reflectivity following Simple Limbal Epithelial Transplantation: An Optical Coherence Tomography-Based Study

ABSTRACTPurposeTo describe the changes in corneal epithelial thickness and reflectivity following simple limbal epithelial transplantation (SLET) using anterior segment optical coherence tomography (ASOCT).MethodsThis was a prospective imaging study of 31 eyes of 29 patients who had undergone autologous or allogeneic SLET for limbal stem cell deficiency and had stable, avascular surfaces postoperatively. ASOCT scans of all four quadrants were taken preoperatively and at 1-week, 1-month, 3-month, 6-month, and 1-year postoperative time points in the eyes undergoing SLET. Baseline scans were also taken from the normal eye in unilateral cases. The following parameters were obtained from the scans: (i) epithelial thickness (ET), (ii) stromal thickness, (iii) total corneal thickness, (iv) epithelial reflectivity (ER), (v) stromal reflectivity, and (vi) epithelial/stromal (ES) reflectivity ratio.ResultsChemical injury (24 eyes, 77.4%) was the most common indication for surgery. There was a significant improvement in the ET (184.8 ± 117.1 vs 60.3 ± 10 µm, p < .0001) and ER (144.5 ± 26.4 vs 120.9 ± 28.9, p < .0001) within the initial postoperative period following SLET, which remained stable at the end of 1 year follow-up. There was no difference in the ET of the post-SLET and normal eyes after the 3-month timepoint and this normalization was maintained until the end of the first year. A significant normalization was also noted in the ES reflectivity ratio at the end of 1 year (2.1 ± 0.8 vs 1 ± 0.2, p < .001). A significant correlation was found between the final visual acuity and the total corneal thickness (r = 0.942, p = .005).ConclusionThere is a significant improvement in the epithelial thickness and reflectivity of the cornea in eyes undergoing SLET. ASOCT provides a reliable objective measure of these changes and can be used to monitor the outcomes in these eyes postoperatively.

Evaluation of Demarcation Line after Epithelium-Off Iontophoresis Corneal Collagen Cross-Linking for Progressive Keratoconus.

The aim of the study was to visualize and evaluate the characteristics and depth of the demarcation line with anterior segment optical coherence tomography (AS-OCT) after epithelium-off iontophoresis corneal collagen cross-linking (epi-off I-CXL). In this prospective, consecutive, single center study 18 eyes of 18 patients with keratoconus were involved. One month after epi-off I-CXL, all the patients underwent an AS-OCT scan to search for a demarcation line and its characteristics. The corneal stromal demarcation line was identified in all the eyes. Mean depth of the corneal stromal demarcation line was 261.8 ± 46.7 μm (range: 184 to 362 μm), at 56.7 ± 12% corneal depth. In conclusion, epi-off I-CXL determines a demarcation line that can be visualized with AS-OCT, which seems clearly distinguishable and similar to that created in standard CXL.

In Vivo Imaging of the Schlemm's Canal and the Response to Selective Laser Trabeculoplasty

To evaluate the presence of angle dysgenesis on ASOCT (anterior segment optical coherence tomography) (ADoA) as a predictive factor in determining outcomes of selective laser trabeculoplasty (SLT). A prospective clinical cohort study. Patients with juvenile-onset open-angle glaucoma (JOAG) without angle dysgenesis on gonioscopy. JOAG patients with uncontrolled intraocular pressure (IOP), who were to undergo SLT, were evaluated for the presence or absence of ADoA, which was defined as the absence of Schlemm's canal (SC) and/or presence of a hyperreflective membrane (HM) over the trabecular meshwork, as identified on ASOCT before the SLT procedure. Furthermore, the number of ASOCT B-scans in which SC was identified as present, were then quantified. Success of SLT was defined as a reduction of IOP by 20% or more from pre-laser value at 6-month follow-up without any further IOP-lowering medication or surgery. Only 1 repeat SLT was admissible for defining SLT success over the 6-month period. A successful reduction in IOP at 6-month follow-up was correlated with the extent of ADoA. In comparison to pre-SLT IOP, 57.1% eyes (20/35) showed more than 20% reduction in IOP at 6 months with a mean reduction of 7.6 ± 1.8 mm Hg (29.6%). When all 3 observers agreed, SC was identified in 90% eyes (18/20) with success vs 26.6% eyes (4/15) with failure (P < .001). All eyes (5/5) with presence of HM showed failure (P < .001). All eyes (19/19) in which SC was present in >50% ASOCT B scans (>25/50 scans/eye) showed success (P < .001). On a bias-reduced regression analysis, the identification of SC on any 2 consecutive scans increased the chances of success at 6 months by 8.3 times, whereas the identification of SC in >50% of ASOCT scans was associated with a 21.4 times greater chance of success. The presence of SC on ASOCT is a strong predictor for successful IOP reduction after SLT in JOAG eyes.

The disposable bandage soft contact lenses therapy and anterior segment optical coherence tomography for management of ocular graft-versus-host disease

PurposeTo identify the ocular surface changes of ocular graft-versus-host disease (GVHD) using anterior segment optical coherence tomography (AS-OCT) and examine the efficacy of disposable bandage soft contact lens (BSCL) treatment in ocular GVHD patients.MethodsThis study is a prospective, Phase II clinical trial. Nineteen patients diagnosed with chronic GVHD based on the NIH criteria and ocular symptoms of NIH eye score 2 or greater were enrolled. Disposable BSCL was applied to the GVHD-affected eyes with topical antibiotic coverage. Ocular exams, eye symptom surveys, and AS-OCT were performed with signed informed consent. Patients were followed for one to three months.ResultsThirty-eight eyes of 19 patients with ocular GVHD underwent BSCL treatment in this study. AS-OCT scans were done in 14 out of 19 patients. The mean best-corrected visual acuity at enrollment, 2-week, and 4-week visits was 0.180, 0.128, and 0.163 logMAR, respectively. Twenty-four out of 25 eyes (96 %) that initially presented with conjunctival inflammation, twenty-three out of 30 eyes (76.7 %) that initially presented with punctate epithelial erosion, and 8 out of 15 (53.3 %) eyes that initially presented with filamentous keratopathy showed improvement after wearing BSCL for 2 to 4 weeks. AS-OCT revealed corneal epithelial irregularity, abnormal meibomian gland orifice, and conjunctival hyperemia, in patients with ocular GVHD.ConclusionsBSCL treatment provided significant subjective and objective improvements in ocular GVHD patients. Meanwhile, we found that AS-OCT can be a promising diagnostic tool to characterize the ocular surface changes associated with ocular GVHD.

Iris thickness and volume be measured using iris base instead of scleral spur as reference in anterior optical coherence tomography scan.

PURPOSE:To compare the iris parameters (iris thickness [IT] and volume) measured at different locations on iris determined using iris base (IB) and scleral spur (SS) in healthy Saudi eyes and factors affecting the differences.METHODS:Healthy eyes of Saudi persons were evaluated using anterior segment optical coherence tomography (AS-OCT). The IT was measured using Image J software and OCT scans in the horizontal axis in light on and light off condition. First IB was used as reference, and then, SS was used as reference for these measurements.RESULTS:One hundred healthy eye's AS-OCT scan was studied. The IT at the temporal side of the horizontal axis at 750 µ away from IB with lights on was 0.526 ± 0.08 µ, whereas it was 0.52 ± 0.08 µ from SS. The difference was significantly more in IB than SS method (P = 0.005). This difference if IT in SS and IB method was not affected by gender (Mann–Whitney P = 0.3), type of refractive error (K W P = 0.7), and level of illumination (K W P = 0.7).CONCLUSION:IT and IV measured using IB provided reliable data but overestimates compared to SS method. In the absence of SS visibility, IB could be alternative to assess iris parameters.

Deep learning algorithms to isolate and quantify the structures of the anterior segment in optical coherence tomography images

Background/AimsAccurate isolation and quantification of intraocular dimensions in the anterior segment (AS) of the eye using optical coherence tomography (OCT) images is important in the diagnosis and treatment of many...

In vivo evaluation of a 1-piece foldable sutureless intrascleral fixation intraocular lens using ultrasound biomicroscopy and anterior segment OCT.

To evaluate the optic plate and haptics of a specially designed sutureless intrascleral-fixated intraocular lens (IOL) using ultrasound biomicroscopy and anterior segment optical coherence tomography (AS-OCT). Department of Ophthalmology, San Marino Hospital, Republic of San Marino. Retrospective observational case series. Eyes that underwent intrascleral fixation with IOL implantation (Carlevale) were included. Preoperative and postoperative refractive outcomes were reported. Optic plate tilt and haptics position were assessed with ultrasound biomicroscopy, whereas intrascleral plug depth and conformation were evaluated with AS-OCT. The study comprised 10 aphakic eyes. Postoperative visual acuity improved in all patients. At postoperative month 3, 3 eyes (30%) had a vertical tilt of more than 100 μm, whereas no horizontal tilt was observed in any patient. The mean vertical intraocular tilt was 0.19 ± 0.22 mm. Of 20 haptics, 13 (65%) passed through the ciliary sulcus, 4 (20%) posterior to the ciliary body, and 3 (15%) through the ciliary body. AS-OCT scans showed a mean intrascleral plug depth of 247.20 ± 62.82 μm in the nasal sector and 265.50 ± 30.11 μm in the temporal sector, with adequate integration of the T-shaped plugs in the scleral tissue. This secondary IOL showed good intraocular stability and safe haptics fixation, making it suitable for the intrascleral fixation technique. The specific foldable design results in a low predisposition to optic plate tilt and haptic torsion. In long eyes, the sulcus-to-sulcus distance should be carefully evaluated preoperatively because the flexible structure of the IOL could be subjected to excessive stretching.

Automated diagnosis and staging of Fuchs\u2019 endothelial cell corneal dystrophy using deep learning

BackgroundTo describe the diagnostic performance of a deep learning algorithm in discriminating early-stage Fuchs’ endothelial corneal dystrophy (FECD) without clinically evident corneal edema from healthy and late-stage FECD eyes using high-definition optical coherence tomography (HD-OCT).MethodsIn this observational case-control study, 104 eyes (53 FECD eyes and 51 healthy controls) received HD-OCT imaging (Envisu R2210, Bioptigen, Buffalo Grove, IL, USA) using a 6 mm radial scan pattern centered on the corneal vertex. FECD was clinically categorized into early (without corneal edema) and late-stage (with corneal edema). A total of 18,720 anterior segment optical coherence tomography (AS-OCT) images (9180 healthy; 5400 early-stage FECD; 4140 late-stage FECD) of 104 eyes (81 patients) were used to develop and validate a deep learning classification network to differentiate early-stage FECD eyes from healthy eyes and those with clinical edema. Using 5-fold cross-validation on the dataset containing 11,340 OCT images (63 eyes), the network was trained with 80% of these images (3420 healthy; 3060 early-stage FECD; 2700 late-stage FECD), then tested with 20% (720 healthy; 720 early-stage FECD; 720 late-stage FECD). Thereafter, a final model was trained with the entire dataset consisting the 11,340 images and validated with a remaining 7380 images of unseen AS-OCT scans of 41 eyes (5040 healthy; 1620 early-stage FECD 720 late-stage FECD). Visualization of learned features was done, and area under curve (AUC), specificity, and sensitivity of the prediction outputs for healthy, early and late-stage FECD were computed.ResultsThe final model achieved an AUC of 0.997 ± 0.005 with 91% sensitivity and 97% specificity in detecting early-FECD; an AUC of 0.974 ± 0.005 with a specificity of 92% and a sensitivity up to 100% in detecting late-stage FECD; and an AUC of 0.998 ± 0.001 with a specificity 98% and a sensitivity of 99% in discriminating healthy corneas from all FECD.ConclusionDeep learning algorithm is an accurate autonomous novel diagnostic tool of FECD with very high sensitivity and specificity that can be used to grade FECD severity with high accuracy.

Association of anterior segment parameters and 5-year incident narrow angles: findings from an older Chinese population

PurposeTo assess the association of anterior segment optical coherence tomography (AS-OCT) parameters and 5-year incident narrow angle in China.MethodsThis was a prospective cohort study of people aged 50 and older...