Hidden mechanisms beyond the pupillary block in acute angle closure: ultrasound biomicroscopic study

Suwan, Yanin; Jiamsawad, Sunpong; Supakontanasan, Wasu; Teekhasaenee, Chaiwat

doi:10.1111/ceo.12867

Cited by 10 publications

(9 citation statements)

References 27 publications

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“…Their results indicated that the most common occurrence mechanism of APAC was PB (35%), followed by TPIR (26%), PIC (23%), and ELV (17%). Through an analysis of UBM images, Suwan et al [27] found that besides the PB mechanism (23.6%), the main underlying nonpupillary block mechanism was the antedisplacement of the lens-iris diaphragm (including the crowded-angle mechanism and anterior lens subluxation mechanism) (68.1%), followed by the plateau iris mechanism. In another study, Wang et al [28] utilised UBM for the observation of anatomical structures related to the chamber angle and they found that the angle closure mechanisms for PACG can be classified as follows: (1) pupillary block factors (38.1%), (2) nonpupillary block factors (7.1%), and (3) combination of multiple mechanisms (54.8%).…”

Section: Discussionmentioning

confidence: 99%

Exploring the Occurrence Mechanisms of Acute Primary Angle Closure by Comparative Analysis of Ultrasound Biomicroscopic Data of the Attack and Fellow Eyes

Wang

2020

BioMed Research International

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Purpose. To explore the anatomical characteristics and occurrence mechanisms of acute primary angle closure (APAC) by comparing the quantitative data of UBM images of the APAC and fellow eyes. Methods. 131 patients (262 eyes) were studied over five years by retrospective analysis. The quantitative data from UBM images including angle opening distance at 500 μm (AOD500), trabecular-iris angle (TIA), iris convexity (IC), iris span (IS), iris-lens angle (ILA), iris-lens contact distance (ILCD), iris-ciliary process angle (ICPA), and limbus-ciliary body angle (LCBA) were retrospectively recorded; comparative analysis of the APAC and fellow eyes was performed. Results. The superior, inferior, nasal, temporal, and mean AOD500, TIA, IC, and LCBA (P<0.001) were significantly smaller in APAC than in fellow eyes. Values of the lens thickness (LT), lens/axial length factor (LAF), lens position (LP), and relative lens position (RLP) were lower in APAC than in fellow eyes (P=0.021; P=0.025; P<0.001; and P<0.001). In APAC eyes, AOD500 was significantly positively correlated with IC, ILCD, and LCBA; TIA was significantly positively significantly correlated with IC, ILCD, and LCBA. In fellow eyes, AOD500 was significantly negatively correlated with ILA and significantly positively correlated with ILCD, ICPA, LCBA, axial length (AL), central anterior chamber depth (CACD), and LP; TIA was significantly negatively correlated with ILA and significantly positively correlated with IS, ILCD, ICPA, LCBA, AL, CACD, LP, and RLP. Conclusions. Multiple nonpupillary block factors (plateau iris, anterior attachment and insertion of the iris root, anterior shift of the lens, and anterior rotation of the ciliary body) promote the occurrence of APAC, and abnormal positional relationships of the iris, ciliary body, and lens may contribute to APAC.

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Section: Discussionmentioning

confidence: 99%

Exploring the Occurrence Mechanisms of Acute Primary Angle Closure by Comparative Analysis of Ultrasound Biomicroscopic Data of the Attack and Fellow Eyes

Wang

2020

BioMed Research International

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“…Because of this, UBM is an ideal modality for evaluation of ciliary body pathology, small tumors in particular [49][50][51]. UBM has also been useful in identifying structural morphologies contributing to glaucoma, such as iris plateau syndrome [52]. These examples illustrate how high frequency, high resolution ultrasonic biomicroscopy can practically be applied to ocular evaluation and how this imaging can change practice and drive innovation.…”

Section: Ultrasound Use In Ophthalmologymentioning

confidence: 99%

A Brief Overview of Ophthalmic Ultrasound Imaging

Rosen¹,

Conway²,

Ingram³

et al. 2019

Novel Diagnostic Methods in Ophthalmology

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Ultrasound is one of the oldest imaging modalities. Sound waves are emitted into the body, and the returning echoes can be interpreted. It has become widely used because it can easily be done at bedside with a relatively small apparatus and does not expose the patient to any ionizing radiation. While this technique has seen widespread acceptance in other fields such as cardiology or obstetrics and gynecology, the general use in ophthalmology has been somewhat limited. However, recent advancements in ultrasonic arrays can be a powerful tool in the evaluation of ophthalmic pathology. Such systems can quickly generate very high detail images and 3D reconstructions without the need for extensive manual scanning. The application of this technology includes evaluation of traumatic eye injuries; assessing presence and location of an intraocular foreign body; evaluation of intraocular tumors, including small tumors that have not yet caused visual distortion; evaluation of retinal detachment; and evaluation of vascular disease. The goal of this article is to briefly review the history and development of ultrasound and to provide an overview of the most current systems and applications of ultrasound use in ophthalmologic clinical evaluation.

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“…It is difficult to determine the zonular compromise in eyes with AAC attack before surgery. The role of the anteriorly positioned lens is an important factor in causing the acute angle closure [4,5]. Except for anteriorly positioned lens, differentiating the differences of anatomic features is helpful to precisely diagnose the eyes with lens subluxation induced AAC and to avoid missed diagnosis.…”

Section: Introductionmentioning

confidence: 99%

Comparisons of clinical characteristics of lens-subluxated eye with or without acute angle closure: A retrospective study

Lin

Qin

et al. 2019

Preprint

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BackgroundTo compare clinical characteristics of lens subluxation between eyes with or without acute angle closure (AAC).MethodsThis is a retrospective and case control study. Thirty-four cases with lens subluxation were recruited from 2015 to 2017. Patients with acute angle closure were assigned to the AAC group (n=17 eyes) and those without AAC were in the non-AAC group (n=17 eyes). Quantitative anterior segment was evaluated by ultrasound biomicroscopy (UBM). Axial length (AL) was measured with IOL master. All patients underwent lens extraction surgery and were followed up for 6 months. ResultsThe history of blunt trauma was accounted for 11 (64.7%) cases in the AAC group and 14 (82.3%) cases in the non-AAC group. Nine (52.9%) patients in the AAC group had LPI or SPI treatment history, and high intraocular pressure was recurred. The UBM analysis showed that the average central ACD of affected eyes in the AAC group was 1.75 mm, which was significantly shallower than the fellow eyes (2.39 mm, P < 0.05) or both eyes in the non-AAC group (affected eye 3.24mm vs fellow eye 3.81mm). Lens vault and AOD500 also showed a remarkable difference between affected eye than fellow eye (P < 0.001) in the AAC group. The both eyes in the AAC group presented a shorter AL and shallower anterior chamber, comparing with those in the non-AAC group. Besides, the affected eyes in the AAC group presented significantly higher LV. ConclusionsThe crowded anterior chamber structure and shorter AL might be an anatomic basis for the eye with lens subluxation induced AAC. Quantitative evaluation of these ocular structures to identify zonular compromise, increased LV and shorter AL are valuable for the diagnosis of lens subluxation induced AAC.

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Hidden mechanisms beyond the pupillary block in acute angle closure: ultrasound biomicroscopic study

Abstract: The most common mechanism contributing to AAC development in this Thai population was iridolenticular wrapping. From this study, we suggest that iridolenticular wrapping was the most common hidden mechanism beyond pupillary block among Thai patients.

Cited by 10 publications

References 27 publications

Exploring the Occurrence Mechanisms of Acute Primary Angle Closure by Comparative Analysis of Ultrasound Biomicroscopic Data of the Attack and Fellow Eyes

Exploring the Occurrence Mechanisms of Acute Primary Angle Closure by Comparative Analysis of Ultrasound Biomicroscopic Data of the Attack and Fellow Eyes

A Brief Overview of Ophthalmic Ultrasound Imaging

Comparisons of clinical characteristics of lens-subluxated eye with or without acute angle closure: A retrospective study

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