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

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.

Ciliary muscle and anterior segment characteristics in pre-presbyopic adults with Down syndrome.

PURPOSE: Previous research has shown that accommodation deficits are common in individuals with Down syndrome (DS), but the origin and mechanisms behind these deficits are still unknown. The aim of this study was to investigate the characteristics of different ocular structures involved in accommodation, in particular the ciliary muscle (CM), in a population of individuals with DS to further understand this deficit and its mechanisms. METHODS: Thirty-two volunteer participants of pre-presbyopic age with (n = 16) and without DS (n = 16) were recruited. Temporal and nasal images of the CM were acquired using anterior segment optical coherence tomography (AS-OCT) while participants fixated an eccentrically located target. Analysis of CM parameters was undertaken using validated semi-automated software. Axial length, anterior chamber depth, lens thickness and corneal curvature were obtained with the Topcon Aladdin Optical Biometer and Corneal Topographer. Non-cycloplegic refractive error and accommodative ability were obtained with an open-field autorefractor and dynamic retinoscopy, respectively. Independent t-tests were conducted to determine differences in CM and other anterior segment parameters between participants with and without DS. RESULTS: No significant differences were found in the CM parameters studied between participants with and without DS (p > 0.05). In contrast, significant differences were found in visual acuity (p < 0.001), accommodative response (p < 0.001) and corneal curvature (K1 p = 0.003 and K2 p < 0.001) between participants with and without DS. CONCLUSIONS: Despite having poorer accommodation, pre-presbyopic adults with DS do not have a different CM morphology to that found in typically developing adults. These findings suggest that the accommodative deficit found in this population is not due to a mechanical deficit of the CM.

Intraocular medulloepithelioma clinical features and management of 11 cases.

AIMS: To describe the clinical features, imaging characteristics, histopathology, treatment and outcomes of intraocular medulloepithelioma. METHODS: Medical records of 11 patients with clinically or histopathologically confirmed medulloepithelioma were retrieved and reviewed. Clinical features, diagnostic challenges, imaging characteristics, management, histopathology and prognosis were assessed. RESULTS: The median age of the patients at initial diagnosis was 4 years, with the most common manifestations being leukocoria (five eyes), loss of vision (four eyes), ocular pain (one eye) and ophthalmic screening (one eye). The clinical signs include a grey-white ciliary body lesion, cataract or lens subluxation, secondary glaucoma and evident cysts. The ultrasound biomicroscopy (UBM) imaging most commonly displays ciliary body mass with intratumoural cysts (nine eyes). Three patients underwent surgery for cataract or glaucoma while the tumours were incidentally found. Two of the three patients managed by eye preserve treatments eventually required enucleation because of local tumour recurrence or phthisis. One patient treated with intra-arterial chemotherapy and cryotherapy had successful tumour regression and globe salvage. CONCLUSIONS: Initial misdiagnosis, delay in diagnosis and subsequent misdirected management is not uncommon in medulloepithelioma. The presence of multiple cysts in the tumour and retrolental neoplastic cyclitic membrane detected by UBM can offer certain information. Selective intra-arterial melphalan may prevent further tumour growth, but longer follow-up is necessary until treatment efficacy is fully evaluated.

The correlation of anterior segment structures in primary congenital glaucoma by ultrasound biomicroscopy with disease severity and surgical outcomes.

PURPOSE: To evaluate the anterior segment structures using ultrasound biomicroscopy (UBM) in primary congenital glaucoma (PCG) and explore their correlation with disease severity and surgical outcomes. METHODS: Clinical information of PCG patients who underwent UBM prior to their first glaucoma surgeries from September 2014 to March 2021 were reviewed. The study included 214 UBM images of 154 PCG eyes and 60 fellow unaffected eyes. Anterior segment characteristics were analyzed. UBM parameters, including the iris thickness (IT) at variant distances from the pupil edge and iris root, anterior chamber depth (ACD), and pupil diameter (PD), were compared between two groups and their relationship with clinical factors and surgical outcomes were analyzed in PCG eyes. RESULTS: PCG eyes had unclear scleral spur, thin iris, wide anterior chamber angle, deep anterior chamber, rarefied ciliary body, elongated ciliary processes, and abnormal anterior iris insertion. ITs were thinner, ACD was deeper, and PD was larger in PCG eyes than fellow unaffected eyes (all P < 0.001). In PCG eyes, thinner ITs correlated with bilateral involvement and earlier age at presentation, and larger PD correlated with earlier age at presentation (P = 0.030) and higher intraocular pressure (P < 0.001). Thinner IT2 (P = 0.046) and larger PD (P = 0.049) were identified as risk factors for surgical failure. CONCLUSION: UBM is a powerful technique to exam anterior segment structures in PCG. The anatomical features are associated with disease severity and surgical outcomes, providing essential clinical insights.

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

OBJECTIVE: To characterize and compare the ciliary muscle thickness (CMT) between low and high myopes using swept-source anterior segment optical coherence tomography (AS-OCT). METHODS: 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). RESULTS: 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. CONCLUSION: 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.

Peering into the eye: A comprehensive look at ultrasound biomicroscopy (UBM) and its diagnostic value in anterior segment disorders.

Background: Ultrasound biomicroscopy (UBM) is a noninvasive imaging modality that enables in-vivo visualization of the structures of the anterior segment of the eye. Unlike routine ophthalmic diagnostic ultrasound which uses frequencies of 5-10 MHz, UBM utilizes ultrasound frequencies in the range of 50-100 MHz. The high-frequency probes in UBM allows for higher resolution and better visualization of subsurface ocular structures, even in the presence of anatomic or pathological obscuration. UBM has qualitative as well as quantitative applications in various disorders affecting the anterior segment of the eye. Despite its huge importance, many clinicians lack in knowledge about the technique and its clinical usefulness. The current educational video aims to address this gap in knowledge by highlighting the technique and various clinical indications of UBM. Purpose: The purpose of this video is to demonstrate the technique of UBM and showcase its quantitative and qualitative implications and importance through various clinical cases. Synopsis: UBM is an imaging technique that assesses the depth of tissue structures by measuring the time delay of the returning ultrasound signal. This modality is capable of measuring the size of various structures within the eye, such as the cornea, iris, ciliary body, sclera, and the depth of the anterior and posterior chamber. To perform a UBM, a transducer is inserted into a specially designed eye cup filled with distilled water, creating a water bath environment. Axial and longitudinal scans can be performed in a similar fashion as in routine diagnostic B-scan ultrasound. Quantitative indications for UBM depicted in this video include measurements of corneal thickness, depth of the anterior chamber, and the width of the angle. The video also showcases how UBM can aid in the diagnosis and management of various anterior segment disorders like angle-closure glaucoma, plateau iris configuration, secondary glaucoma, and anterior uveitis with complicated cataract. Qualitative indications for UBM highlighted in this video include its role in intermediate uveitis, ocular hypotony, ocular surface tumors, cystic lesions of iris, and identifying the location and type of intraocular foreign bodies in the anterior segment based on the type of artifact seen. Additionally, the video shows the applications of UBM in scleral and episcleral pathologies. Highlights: This video will educate clinicians about the technique of UBM and showcase a bouquet of UBM findings in various case scenarios, helping one to better understand the potential of this modality in clinical practice. Video link: https://youtu.be/F626TMbJXoU.

Lens factor as an underlying mechanism in primary angle closure with gonioscopically-visualized ciliary body processes.

PURPOSE: To compare the differences in anterior segment parameters between eyes with primary angle closure (PAC) with and without gonioscopically-visualized ciliary body processes (CBP). STUDY DESIGN: Prospective, observational, comparative clinical study. METHODS: Detailed ocular examinations and gonioscopy were performed in 89 eyes of 89 patients with PAC to determine the visibility of the CBP. Anterior chamber depth (ACD), anterior chamber width, lens thickness (LT), lens vault (LV) and pupil diameter were determined using ultrasound biomicroscopy. The lens-axial length factor (LAF) and relative lens position (RLP) were calculated. All parameters were compared between eyes with and without gonioscopically visible CBP (PAC+CBP and PAC-CBP groups) after adjusting for age and gender. The association of the parameters with visible CBP was analyzed by univariate logistic regression analysis. RESULTS: PAC+CBP group included 41 eyes and the PAC-CBP group, 48 eyes. The axial length and ACD were statistically significantly smaller (p = 0.009 and p = 0.005, respectively) and LT, LV and LAF were statistically significantly greater (p = 0.03, p = 0.008 and p = 0.004, respectively) in the PAC+CBP group. In the PAC eyes with glaucoma, the LT, LV and LAF were statistically significantly greater in the PAC+CBP group (p = 0.02, p = 0.001 and p = 0.02, respectively). The LAF had the strongest association with visible CBP in the regression analysis (Odds ratio = 141.70, p = 0.002). CONCLUSION: Gonioscopical visualization of ciliary processes may suggest that anterior segment crowding, especially lens factor is the underlying mechanism in PAC. It may provide a practical gonioscopic examination method for predicting the predominant pathophysiology of PAC.

Evaluation of ciliary body morphology and position of the implantable collamer lens in low-vault eyes using ultrasound biomicroscopy.

PURPOSE: To investigate the ciliary body anatomy and position of the implantable collamer lens (ICL) in low-vault eyes and analyze factors related to insufficient vault. SETTING: Zhongshan Ophthalmic Center, Guangzhou, China. DESIGN: Retrospective case-control observational study. METHODS: In this study, 73 eyes of 73 patients with an insufficient vault (<250 µm) were matched with 73 eyes with an ideal vault (250 to 750 µm). Ultrasound biomicroscopy was used to determine the ciliary body morphology and ICL position. The biometric parameters acquired by Scheimpflug tomography were compared. The correlation between the vault and these factors was analyzed, and the least absolute shrinkage and selection operator method was used to screen the risk factors for low vault. RESULTS: The low-vault group had a steeper corneal curvature, thicker lens thickness (LT), higher crystalline lens rise, and shorter axial length (AL) (all P < .005). The ciliary process length (CPL) and maximum ciliary body thickness (CBTmax) were significantly smaller, and the trabecular-ciliary angle (TCA), iris-ciliary angle (ICA), and ciliary sulcus width (CSW) were significantly greater in the low-vault eyes (all P < .005). The low-vault group had more ICL haptics below the ciliary process, and TCA, ICA, CPL, CBTmax, CSW, and haptic position were related to the postoperative vault (all P < .05). CPL, AL, and LT were identified as predictors of a low vault. CONCLUSIONS: Malposition of ICL haptics behind the ciliary process is a risk factor for low vault. A shorter CPL, thicker LT, and shorter AL are significant risk factors for the postoperative low vault.

Qualitative ultrasound biomicroscopy in glaucoma.

Background: UBM is a high-resolution ultrasound technique which allows non-invasive, in vivo imaging of the anterior segment and iridocorneal angle. Purpose: This video is compilation of short video clips and images which gives description on identification of angle closure due to pupillary block, peripheral anterior synechiae, iris bombe, plateau iris, supra ciliary effusion, and malignant glaucoma. It also shows video demonstrating partially and fully patent iridotomy and features of trabeculectomy bleb. Synopsis: This video summarizes importance of UBM application in angle closure glaucoma to understand its pathophysiology by showing the relationship between the peripheral iris, trabecular meshwork and ciliary processes. Highlights: UBM provides two-dimensional, grayscale images of the angle structures and allows identification of non-pupillary block mechanism in angle closure glaucoma, which can be recorded for qualitative and quantitative analyses. Video Link: https://youtu.be/prsmGnR8jYc.

Quantitative ultrasound biomicroscopy of iridocorneal angle.

Background: Ultrasound biomicroscopy (UBM) is a high-resolution ultrasound technique, which allows noninvasive, in vivo imaging of the ocular anterior segment structures. Purpose: This video gives a description of the identification of the iridocorneal angle structures in the cross-sectional view in a radial scan through a typical ciliary process and a guide toward measuring the angle parameters. Synopsis: UBM provides two-dimensional, grayscale images of the iridocorneal angle. The real-time image is displayed on a video monitor and can be recorded for qualitative and quantitative analysis. The angle parameters can be measured by in-built calipers in the machine software and manipulated by the examiner. Highlights: This video demonstrates UBM caliper positions as displayed on the monitor and marked by the examiner for the measurement of various anterior segment parameters of the eye. Video link: https://youtu.be/WTXMupYoyww.

Qualitative ultrasound biomicroscopy of the normal anterior segment.

Background: Ultrasound biomicroscopy (UBM) is a high-resolution ultrasound technique that allows noninvasive, in vivo imaging of the ocular anterior segment structures. Before interpreting the UBM images of the diseased eyes, it is essential to understand the structures seen in the UBM image of the normal eye. Purpose: This video is a compilation of short video clips that gives description of identification of the anterior segment structures in the axial scan, a cross-sectional view through the anterior chamber angle region of a normal subject in a radial scan, and identification of ciliary processes in the transverse scan. Synopsis: UBM provides two-dimensional, grayscale images of the various anterior segment structures and allows all these structures to be imaged simultaneously, in their normal state, as they occur in the living eye. The real-time image is displayed on a video monitor and can be recorded for qualitative and quantitative analysis. Highlights: The video gives an overview of identification of normal anterior segment structures on UBM. Video link https://youtu.be/3KooOp2Cn30.

Imaging iridotrabecular contact in angle closure.

Background: With ultrasound biomicroscopy (UBM), radial scans are taken by using a typical ciliary process, to show the details of the iridocorneal angle, the anterior surface of the ciliary body, and its relation to the posterior iris. Appositional closure represents potentially reversible contact between the peripheral iris and trabecular meshwork. The appositional closure can further be classified according to the configuration of iridotrabecular contact (ITC). UBM can be performed in dark and light conditions, which has been shown to be useful for detecting changes in iridocorneal angle configuration associated with dark and light. Purpose: To image ITC configuration in appositional angle closure and also image iridocorneal angle in dark and bright light room illumination. Synopsis: UBM demonstrates two types of ITC configuration in appositional closure which are, B-type and S-type. It can also demonstrate the presence of sinus of Mapstone in S-type of ITC. Highlights: UBM allows imaging of dynamic changes in the iris and shows that the degree of appositional angle closure is a dynamic process that can change rapidly depending on the lighting conditions. Video link: https://youtu.be/tgN4SLyx6wQ.

Impact of accommodative insufficiency and accommodative/vergence therapy on ciliary muscle thickness in the eye.

PURPOSE: Recent evidence suggests that the ciliary muscle apical fibres are most responsive to accommodative load; however, the structure of the ciliary muscle in individuals with accommodative insufficiency is unknown. This study examined ciliary muscle structure in individuals with accommodative insufficiency (AI). We also determined the response of the ciliary muscle to accommodative/vergence therapy and increasing accommodative demands to investigate the muscle's responsiveness to workload. METHODS: Subjects with AI were enrolled and matched by age and refractive error with subjects enrolled in another ciliary muscle study as controls. Anterior segment optical coherence tomography was used to measure the ciliary muscle thickness (CMT) at rest (0D), maximum thickness (CMTMAX) and over the area from 0.75 mm (CMT0.75) to 3 mm (CMT3) posterior to the scleral spur of the right eye. For those with AI, the ciliary muscle was also measured at increasing levels of accommodative demand (2D, 4D and 6D), both before and after accommodative/vergence therapy. RESULTS: Sixteen subjects with AI (mean age = 17.4 years, SD = 8.0) were matched with 48 controls (mean age = 17.8 years, SD = 8.2). On average, the controls had 52-72 µm thicker ciliary muscles in the apical region at 0D than those with AI (p = 0.03 for both CMTMAX and CMT 0.75). Differences in thickness between the groups in other regions of the muscle were not statistically significant. After 8 weeks of accommodative/vergence therapy, the CMT increased by an average of 22-42 µm (p ≤ 0.04 for all), while AA increased by 7D (p < 0.001). CONCLUSIONS: This study demonstrated significantly thinner apical ciliary muscle thickness in those with AI and that the ciliary muscle can thicken in response to increased workload. This may explain the mechanism for improvement in signs and symptoms with accommodative/vergence therapy.

Morphometric Assessment of the Ciliary Body in Patients With Marfan Syndrome and Ectopia Lentis: A Quantitative Study Using Ultrasound Biomicroscopy.

PURPOSE: To explore the biometric characteristics of the ciliary body in patients with Marfan syndrome (MFS) and ectopia lentis (EL). DESIGN: Cross-sectional study. METHODS: Seventy-two consecutive patients with MFS and EL and 72 nondiseased control subjects were recruited. Ciliary body biometric parameters such as ciliary muscle cross-sectional area at 2000 µm from the scleral spur (CMA2000), ciliary muscle thickness at 1000 µm from the scleral spur (CMT1000), and maximum ciliary body thickness (CBTmax) were measured from multiple directions with ultrasound biomicroscopy (UBM). The relationship between ciliary body parameters and other ocular characteristics was also evaluated. RESULTS: Average CMA2000, CMT1000, and CBTmax were 0.692 ± 0.015 mm2, 0.405 ± 0.010 mm, and 0.855 ± 0.023 mm in eyes of patients with MFS, respectively, and were significantly smaller than these values in control subjects (all P < .001). The prevalence of ciliary body thinning was 22.2% in the MFS group vs 0 in the control group (P < .001); eyes with more severe EL had smaller CMA2000 (P = .050), thinner CMT1000 (P = .022), and shorter CBTmax (P = .015). Patients with microspherophakia (MSP) had even smaller CMA2000 (P = .033) and CMT1000 (P = .044) than those without MSP. The most common subluxation direction was in the superonasal quadrant (n = 25; 39.7%), which probably correlates with the thinnest CMT1000 in the inferotemporal quadrant (P = .005). CONCLUSIONS: Patients with MFS and EL had thinner ciliary muscles, shorter ciliary processes, and a higher prevalence of ciliary body thinning, especially those with MSP. Both the extent and direction of subluxation were associated with ciliary body biometry..

Lens Thickness Microfluctuations in Young and Prepresbyopic Adults During Steady-State Accommodation.

Purpose: To determine whether lens mechanical dynamics change with age and with accommodative demands. Methods: Lens thickness microfluctuations were measured using a high-speed custom-built spectral domain optical coherence tomography system in five young adults (20 to 25 years old) at 0 diopters (D), 2 D, 4 D, and maximum accommodative demand and in five prepresbyopes (38 to 45 years old) under relaxed and maximal accommodation. For each state, the measurements were repeated four times during the same session. Images of the central 2-mm zone of the lens comprising 170 A-lines/frame were acquired for 10 seconds, and axial lens thickness change was measured. Lens thickness microfluctuations (µm²/Hz) were assessed by integrating the power spectrum of lens thickness microfluctuations between 0 and 4 Hz. Results: The amplitude of lens microfluctuations was higher in the accommodated states than in the relaxed state in both age groups. Lens microfluctuations were higher in young adult participants than in prepresbyopes, with a significant difference in relaxed and maximally accommodated states (P = 0.04 and P = 0.04). In the young participants, the amplitude of microfluctuations reached a plateau at maximum accommodation. Conclusions: Lens mechanical dynamics are both age and accommodation dependent. The decrease in lens thickness microfluctuations with age is consistent with an age-related increase in lens stiffness or decrease of the ciliary muscle displacement. The lens does not contribute to the high-frequency component of ocular dioptric microfluctuations.

Iridociliary measurements using the Anterion swept-source optical coherence tomography.

Purpose: Anterior segment optical coherence tomography (AS-OCT) by a swept source can visualize the ciliary body. The study was performed for analyzing the feasibility of a new swept-source OCT (Anterion) device for measuring iris ciliary sulcus, ciliary body thickness, and iris thickness. Methods: It is a pilot study among 30 normal young participants and hospital employees with their consent. The ciliary body, iris thickness, and ciliary sulcus were measured and compared to the results in the literature. We obtained 28 good-quality results. The main outcome measures were iris thickness (near and away from the pupillary margin), ciliary body thickness, and iridociliary sulcus measurement. Results: The iris thickness 2.5 mm from the pupillary margin was 0.70 ± 0.10 mm in the right eye and 0.68 ± 0.11 in the left eye. Closer to the root, the iris thickness varied from 0.55 ± 0.16 mm (right eye) and 0.57 ± 0.12 (left eye). Ciliary body thickness: Right eye 0.59 ± 0.14mm (28 good images), left eye 0.58 ± 0.13mm; ciliary sulcus (inner angle): right eye 82.65 ± 26.6°, left eye 83.66 ± 30.1°. Conclusion: Anterion OCT is feasible in our setting for various measurements and can provide valuable inputs to ophthalmologists for the treatment of ocular diseases.