Factors Associated With Zonular Instability During Cataract Surgery in Eyes With Acute Angle Closure Attack

Zonular ligament abnormalities intermingled in acute primary angle closure: A diagnostic and therapeutic challenge

Purpose

This study aims to investigate patient characteristics with lens zonular ligament abnormalities in Acute Primary Angle Closure (APAC), identifying related risk factors, and evaluating the efficacy of Pilocarpine, a miotic agent.

Design

Retrospective case-control study.

Methods

Conducted as a retrospective case-control study at Hebei Provincial Eye Hospital from January 1, 2019, to December 31, 2021, the study included APAC cases undergoing ultrasound phacoemulsification with or without glaucoma surgery. Zonular ligament status was determined by intraoperative indicators such as lens equator visibility post-mydriasis and anterior capsule wrinkling during capsulorhexis. Patients were categorized into APAC and APAC with Lens Subluxation (APACLS) groups. Demographic details, Central Anterior Chamber Depth (ACD), Axial Length (AL), ACD difference between eyes (ACDD), Lens Thickness (LT), Lens Position (LP), and Relative Lens Position (RLP) were recorded and compared. Pilocarpine's impact on intraocular pressure reduction was assessed. Statistical analysis involved bilateral t-tests (for normally distributed data comparing both eyes in each group), non-parametric tests (for comparing two groups with non-normally distributed data), binary logistic regression, and Receiver Operating Characteristic (ROC) curve analysis for cutoff value determination related to zonular abnormalities.

Results

The APAC and APACLS groups showed no significant difference in age of onset (70.11 ± 8.67 years vs. 70.11 ± 8.67 years, P = 0.159) or axial length of the eye (22.35 ± 0.64 mm vs. 22.36 ± 0.78 mm, P = 0.929). In the APACLS group, LT was greater (5.24 ± 0.37 mm vs. 5.01 ± 0.36 mm, P = 0.011), ACD was shallower (1.42 ± 0.24 mm vs. 1.69 ± 0.24 mm, P = 0.000), and ACDD was larger (0.38 ± 0.22 mm vs. 0.18 ± 0.18 mm, P = 0.000). The LP was lower (4.04 ± 0.32 vs. 4.20 ± 0.22, P = 0.013), and RLP was also lower (0.18 ± 0.02 vs. 0.19 ± 0.01, P = 0.015) in the APACLS group. A shallow ACD and a large ACDD were identified as risk factors associated with lens zonular abnormalities in the affected eyes (ACD OR value 63.97, P = 0.027; ACDD OR value 0.029, P = 0.027). Using ROC curve analysis, the cutoff value for ACDD was determined to be 0.375 mm, and for ACD, it was 1.6 mm. After pupil constriction with Pilocarpine eye drops, the proportion of patients whose intraocular pressure normalized was 75.36 % (52/69) in the APAC group and 71.43 % (25/35) in the APACLS group.

Conclusion

ACD and ACDD in the affected eye are indicative of increased risk for APACLS. An ACD <1.6 mm and ACDD >0.375 mm should prompt consideration of zonular ligament abnormalities. Pilocarpine as a miotic treatment is safe and effective for such patients.

Zonular instability-associated morphologic features in eyes with primary angle closure disease using the swept-source anterior segment - optical coherence tomography system

BACKGROUND

This study aims to investigate the morphologic features of the crystalline lens in Primary Angle Closure Disease (PACD) patients with zonular instability during cataract surgery using the swept-source CASIA 2 Anterior Segment-Optical Coherence Tomography (AS-OCT) system.

METHODS

A total of 398 eyes (125 PACD eyes with zonular instability, 133 PACD eyes with zonular stability, and 140 cataract patient controls) of 398 patients who underwent cataract surgery combined or not glaucoma surgery between January 2021 and January 2023 were enrolled. The crystalline lens parameters were measured by CASIA2 AS-OCT. Then, logistic regression was performed to evaluate the risk factors associated with zonular instability.

RESULTS

The results revealed that PACD eyes had a more anterior lens equator position, a steeper anterior curvature of lens, shorter Axial Length (AL), shallower Anterior Chamber Distance (ACD), higher Lens Vault (LV) and thicker Lens Thickness (LT), when compared to eyes in the cataract control group. Furthermore, PACD eyes in the zonular instability group had steeper front R, front Rs and Front Rf, flatter back Rf, thicker lens anterior part thickness, higher lens anterior-to-posterior part thickness ratios, shallower ACD, and greater LV, when compared to PACD eyes with zonular stability. The logistic regression analysis, which was adjusted for age and gender, revealed that zonular instability was positively correlated with anterior part thickness, lens anterior-to-posterior part thickness ratio, and LV, but was negatively correlated with lens anterior radius and ACD.

CONCLUSION

Steeper anterior curvature, increased lens anterior part thickness, higher anterior-to-posterior part thickness ratio, shallower ACD, and greater LV are the anatomic features of PACD eyes associated with zonular instability.

Proportion and risk factors of zonulopathy in patients with age-related cataract

Purpose

To investigate the proportion of zonulopathy in patients with age-related cataract, and further explore demographics and ocular characteristics, as well as potential risk factors.

Methods

Hospital-based, observational, cross-sectional study. We enrolled consecutive patients who were 45 years or older and diagnosed with age-related cataract and underwent surgery between October 2022 and April 2023 at the Division of Cataract, Beijing Tongren Hospital. Zonulopathy was diagnosed based on intraoperative signs. We calculated the total proportion, age, and gender specific proportions of zonulopathy. We compared the demographic and ocular characteristics between the cases with and without zonulopathy. Univariate and multivariate logistic regression analyses were employed to determine the risk factors associated with the presence of zonulopathy in patients with age-related cataract.

Results

A total of 640 age-related cataract patients with a median age of 70.0 (64.0-77.0) were enrolled. Zonulopathy was diagnosed intraoperatively in 70 patients (10.9%). Compared with the patients having no zonulopathy, those with zonulopathy were likely to be older (P < 0.001), have a shallower central ACD (P < 0.001), a thicker lens (P < 0.001) and a shorter AL (P = 0.010). Logistic regression analyses showed that the risk predictors associated with the presence of zonulopathy in patients with age-related cataract were older age (OR, 1.042; P = 0.035) and shallower central ACD (OR, 0.834; P < 0.001).

Conclusion

Zonulopathy in age-related cataract patients is not an uncommon finding. Clinicians should be mindful of zonulopathy in patient population with advanced age and shallower ACD.

Zonulopathy Identified During Cataract Extraction in Patients With Primary Angle Closure Disease

PRCIS

The proportion, clinical characteristics, and risk factors of zonulopathy in primary angle closure disease (PACD) were analyzed. Zonulopathy is an underrecognized common finding in PACD, especially in patients with acute angle closure (AAC).

PURPOSE

To examine the proportion and risk factors associated with intraoperative zonulopathy in PACD.

PATIENTS AND METHODS

This is a retrospective analysis of 88 consecutive patients with PACD who underwent bilateral cataract extraction at Beijing Tongren Hospital from August 1, 2020 to August 1, 2022. Zonulopathy was diagnosed based on intraoperative findings including the presence of a lens equator, radial folds of the anterior capsule while making capsulorhexis, and other signs of the unstable capsular bag. The subjects were grouped based on their PACD subtype diagnoses: AAC, primary angle closure glaucoma (PACG), primary angle closure (PAC), or primary angle closure suspect (PACS). Multivariate logistic regression was performed to identify risk factors associated with zonulopathy. The proportion and the risk factors of zonulopathy were estimated in patients with PACD and in PACD subtypes.

RESULTS

Of 88 patients with PACD (67.3 ± 6.9 y old, 19 males and 69 females), the overall proportion of zonulopathy was 45.5% of patients (40/88) and 30.1% of eyes (53/176). Among the PACD subtypes, the proportion of zonulopathy was highest (69.0%) in AAC, followed by 39.1% in PACG, and 15.3% in PAC and PACS combined. AAC was an independent risk factor associated with zonulopathy ( P = 0.015, AAC vs PACG, PAC, and PACS combined; odds ratio: 0.340, CI: 0.142-0.814). Shallower anterior chamber depth ( P = 0.031) and greater lens thickness ( P = 0.036), but not laser iridotomy, were associated with an increased proportion of zonulopathy.

CONCLUSIONS

Zonulopathy is common in PACD, especially in patients with AAC. Shallow anterior chamber depth and thick lens thickness were associated with an increased proportion of zonulopathy.

Research progress of lens zonules

Background

The lens zonule, a circumferential system of fibres connecting the ciliary body to the lens, is responsible for centration of the lens. The structural, functional, and positional abnormalities of the zonular apparatus can lead to the abnormality of the intraocular structure, presenting a significant challenge to cataract surgery.

Main text

The lens zonule is the elaborate system of extracellular fibers, which not only centers the lens in the eye but also plays an important role in accommodation and lens immunity, maintains the shape of the lens, and corrects spherical aberration. The zonules may directly participate in the formation of cataract via the immune mechanism. Abnormal zonular fibers that affect the position and shape of the lens may play an important role in the pathogenesis of angle closure disease and increase the complexity of the surgery. Capsular tension rings and related endocapsular devices are used to provide sufficient capsular bag stabilization and ensure the safety of cataract surgery procedures. Better preoperative and intraoperative evaluation methods for zonules are needed for clinicians.

Conclusions

The microstructure, biomechanical properties, and physiological functions of the lens zonules help us to better understand the pathogenesis of cataract and glaucoma, facilitating the development of safer surgical procedures for cataract. Further studies are needed to carefully analyze the structure-function relationship of the zonular apparatus to explore new treatment strategies for cataract and glaucoma.

Evaluation of Multimodal Biometric Parameters for Diagnosing Acute Angle Closure Secondary to Lens Subluxation

INTRODUCTION

To evaluate the clinical characteristics and multimodal biometric parameters from ultrasound biomicroscopy (UBM) and IOL Master biometry of patients with acute secondary angle-closure due to lens subluxation (ASAC-LS), acute primary angle-closure (APAC), and cataract.

METHODS

This retrospective study included 22 eyes with ASAC-LS, 27 eyes with APAC, and 39 eyes with cataract. Gender, age, affected eye, best corrected visual acuity, axial length, central corneal thickness, and anterior chamber depth (ACD) assessed by UBM and IOL Master were measured and compared between the three groups. In addition, we compared the ratio of ACD (ACD ratio) and the difference of ACD (ACD difference) measured by the two instruments. Logistic regression analysis was conducted to evaluate the predictive factors for lens subluxation. Receiver operating characteristic (ROC) curves were plotted to obtain a suitable cutoff value of biometric parameters to separate ASAC-LS cases from APAC and cataract cases.

RESULTS

In the ASAC-LS group, the median (interquartile range [IQR]) ACD measured by IOL Master was 2.47 (IQR 1.85-2.92) mm while the median ACD measured by UBM was 3.11 (IQR 2.60-3.76) mm. The difference of ACD measured by the two instruments was statistically significant in the ASAC-LS group (P < 0.001) whereas the differences were not statistically significant in the APAC group (P = 0.521) and cataract group (P = 0.204). Subsequent pairwise comparison revealed that only the ACD difference (0.40 [IQR 0.22-1.08] mm) and ACD ratio (1.18 [IQR 1.07-1.40]) in the ASAC-LS group were significantly different from those in the APAC group (ACD difference 0.02 [IQR 0.01-0.07] mm; ACD ratio 1.01 [IQR 1.00-1.04]) and cataract group (ACD difference 0.09 [IQR 0.01-0.14] mm; ACD ratio 1.03 [IQR 1.00-1.04]) (all P < 0.001). The ACD difference and ACD ratio were significantly associated with lens subluxation in the multivariate logistic regression analysis (P < 0.001 and P = 0.001, respectively). Additionally, the ROC curve analysis showed that the ACD difference at 0.235 mm and the ACD ratio at 1.080 were the respective cut-off values for lens subluxation, with a sensitivity of 77.3% and specificity of 100.0%.

CONCLUSION

Our findings provide a new option for identifying lens subluxation. Specifically, combining the ACD from UBM and IOL Master may be helpful for differential diagnosis of ASAC-LS.

Glaucoma Progression After Lens Extraction in Primary Angle-closure Glaucoma According to Angle-closure Mechanism

PRCIS

Long-term prognosis of primary angle-closure was assessed after lens extraction (LE) according to different mechanisms of angle closure (AC). Patients with pupillary block (PB) had a higher probability of glaucomatous progression than patients with plateau iris configuration (PIC).

PURPOSE

The aim was to investigate and compare the clinical characteristics and long-term prognosis of primary angle-closure disease (PACD) after LE according to different mechanisms of AC.

METHODS

In this retrospective observational cohort study, 118 eyes with PACD that underwent LE (mean follow-up; 6.0±3.5 y after surgery) were included. PACD eyes were categorized into three subgroups according to their dominant AC mechanisms, determined by anterior segment optic coherent tomography obtained before LE; PB, PIC, and exaggerated lens vault (ELV). Postoperative glaucomatous progression was determined according to functional (visual field) or structural (optic disc photographs or optic coherent tomography measured retinal nerve fiber layer thickness) criteria. Univariate and multivariate logistic regression analysis was performed to determine the risk factors associated with glaucomatous progression.

RESULTS

Fifty-two, 51, and 15 eyes with PB, PIC, and ELV, respectively, were included. All eyes showed significant intraocular pressure reduction, with a greater reduction in the ELV group than in the PB group after LE (27.0% vs. 12.5%, P=0.018). Lower baseline retinal nerve fiber layer thickness [odds ratio (OR): 0.966, P=0.004] and thinner central corneal thickness (OR: 0.985, P=0.021), and the PB group (OR: 2.891, P=0.022, reference to PIC group) were significantly associated with glaucomatous progression after LE.

CONCLUSIONS

In eyes with PACD, glaucoma progression was observed following LE despite reduced intraocular pressure. The probability of progression was highest in eyes with pupil block as a mechanism of AC. Close monitoring of glaucoma in these patients is suggested.

Comparison of Anterior Chamber Depth with Posture Change Between Primary and lens-induced Angle Closure Glaucomas

Purpose: To compare the changes in central anterior chamber depth between supine and sitting positions using an ultrasound biomicroscope among acute angle closure glaucoma, lens-induced angle closure glaucoma, and normal groups.Methods: This study included 18, 13, and 29 individuals with acute angle closure glaucoma, lens-induced angle closure glaucoma, and control, respectively. The central anterior chamber depth, trabecular iris angle, corneal curvature, and axial length were measured in the sitting and supine positions.Results: The central anterior chamber depth in the supine and sitting positions were 1.61 ± 0.47 mm and 1.55 ± 0.46 mm in the acute angle closure glaucoma, which were significantly smaller than those in the normal group (2.48 ± 0.49 mm and 2.47 ± 0.50 mm) (p = 0.01 and p = 0.009, respectively). In lens-induced angle closure glaucoma, the central anterior chamber depth in the supine and sitting positions were 1.65 ± 0.84 mm and 1.52 ± 0.82 mm, respectively, which were significantly smaller than those in the normal group (p < 0.001 for both). The absolute change in central anterior chamber depth with posture alteration was significantly larger in both acute angle closure glaucoma (0.15 ± 0.09 mm) and lens-induced angle closure glaucoma (0.25 ± 0.11 mm) than in the normal control (0.09 ± 0.08 mm) (p = 0.011, p < 0.001, respectively). The largest amount of change was shown in the lens-induced angle closure glaucoma (p = 0.012). The absolute change in anterior chamber angle with posture change wa not significantly different between the groups (p = 0.165).Conclusions: Compared to the control group, the central anterior chamber depth was smaller in both glaucoma groups. The absolute change in the anterior chamber depth with posture was significantly larger in the lens-induced angle closure glaucoma than in acute angle closure glaucoma.

Ocular Manifestations of Acute Secondary Angle Closure Associated With Lens Subluxation

Purpose:

To evaluate the clinical characteristics and ocular features of patients with acute secondary angle closure, associated with lens subluxation (ASAC-LS).

Methods:

We performed a retrospective study at the EENT Hospital of Fudan University, Shanghai, China. A total of 41 affected eyes from 41 patients were enrolled in this study. Furthermore, 20 affected eyes were part of the ASAC-LS cohort and 21 affected eyes were included in the acute primary angle closure (APAC) cohort. The best-corrected visual acuity (BCVA), intraocular pressure (IOP), axial length (AL), minimum corneal curvature (K1), maximum corneal curvature (K2), and anterior chamber depth (ACD) were measured and compared between the 2 cohorts. In addition, inter-eye (intraindividual) comparison was performed.

Results:

The ASAC-LS cohort exhibited younger ages, more frequent trauma history (35%), lower IOP (27.43 ± 13.86 mmHg vs. 41.27 ± 10.36 mmHg), longer AL (23.96 ± 2.60 vs. 22.49 ± 0.77 mm), shallower ACD (1.28 ± 0.38 vs. 1.58 ± 0.23 mm), and bigger ACD differences (0.99 ± 0.52 vs. 0.15 ± 0.19 mm), as compared with the APAC cohort (all p < 0.05). Moreover, eyes from the lens subluxation cohort experienced worse BCVA, higher IOP, and shallower ACD than their matched unaffected eyes (all p < 0.05). Although longer AL, shallower ACD, and bigger ACD differences were strongly correlated with lens subluxation in a univariate logistic regression analysis, only the ACD difference remained significant in the multivariate model (p = 0.004, OR = 1,510.50). Additionally, according to the receiver operating characteristic (ROC) curve analysis, both ACD and ACD differences had greater value in the differential diagnosis of ASAC-LS and APAC, with a cut-off value of 1.4 and 0.63 mm, respectively.

Conclusions:

Shallower ACD and larger ACD differences provide the promising diagnostic potential for patients with ASAC-LS.

Prevalence of zonulopathy in primary angle closure disease

Background

To determine the prevalence of zonulopathy in a large cohort of eyes with primary angle closure disease (PACD) that underwent cataract surgery.

Methods

Retrospective consecutive case series of PACD eyes (including primary angle closure suspect, primary angle closure, and primary angle closure glaucoma) that underwent phacoemulsification cataract surgery or clear lens extraction between 2009 and 2020 at a single ophthalmology centre. Those with risk factors for zonulopathy such as history of trauma, pseudoexfoliation syndrome, intraocular surgery, retinitis pigmentosa or connective tissue disorders were excluded. The primary outcomes included the prevalence of zonulopathy assessed intraoperatively and secondary pigment dispersion syndrome.

Results

In our cohort of 806 consecutive PACD eyes, the prevalence of zonulopathy was 7.3% (59 of 806 eyes) – significantly greater than the 0.46%–2.6% range reported for the general population (p < 0.001). Intraoperative signs of zonular weakness included floppy capsular bag (29 eyes, 3.6%), zonular laxity (25 eyes, 3.1%) and zonular dehiscence (11 eyes, 1.4%). Among these eyes, capsular tension ring was used in 23 eyes (39.0%), six eyes (10.2%) experienced vitreous prolapse intraoperatively and underwent anterior vitrectomy, and two eyes (3.4%) experienced posterior capsular rupture, one of which required a scleral‐fixated intraocular lens. Secondary pigment dispersion syndrome was observed in 141 eyes (17.5%).

Conclusions

This study evidenced a high prevalence of zonulopathy among a large cohort of PACD eyes and suggests zonulopathy as a possible under‐recognised cause of angle closure. Until more sophisticated imaging modalities become available, awareness about the prevalence of zonulopathy in angle closure disease coupled with careful preoperative examinations can help minimise or prevent the complications of zonulopathy.

Implications of the Relationship Between Refractive Error and Biometry in the Pathogenesis of Primary Angle Closure

Purpose

The purpose of this study was to investigate the relationship between refractive error and ocular biometry and its implication in the pathogenesis of primary angle closure (PAC).

Methods

We have retrospectively recruited 119 PAC eyes and 388 non-PAC eyes with an axial length (AL) of ≤25.0 mm and a spherical equivalent (SE) of ≥−6.0 diopters (D). Stepwise multiple regression was performed for keratometry value (K), AL, anterior chamber depth (ACD), and SE.

Results

PAC eyes were more likely to be in women and have a higher IOP and shorter AL than non-PAC eyes. In a multiple regression analysis, SE was not associated with PAC. The associations between AL and SE or AL and ACD were not different in PAC eyes compared with non-PAC eyes. However, the cornea was flatter in PAC eyes (β = −0.448, P < 0.001), and a flatter cornea was associated with more hyperopic refraction (β = −0.454, P < 0.001) and shallower ACD (β = 0.073, P < 0.001) in PAC eyes. ACD was not associated with SE in non-PAC eyes, but shallower ACD was associated with greater myopic refraction in PAC eyes (β = 1.117, P = 0.006).

Conclusions

PAC eyes seem to have flatter cornea compared with non-PAC eyes. A shallower ACD seems to be associated with greater myopic refraction in PAC eyes, but not in non-PAC eyes.

Management of the subluxated crystalline lens: A review

Cataract surgery for the subluxated crystalline lens is challenging. A thorough preoperative evaluation is important to determine the appropriate surgical approach for lens removal and the subsequent technique of intraocular lens placement. Important considerations include the extent and location of zonular weakness, and whether the zonular deficiency is caused by a static or progressive disease. The capsular bag should be preserved where possible. Creating a good-sized and centred continuous curvilinear capsulorhexis is crucial to facilitate the use of capsular retractors and capsular tension devices, which provide capsular stability. Nucleus sculpting and rotation should be minimised to reduce zonular stress. Being cognisant of the possible intraoperative complications that may occur at each stage of the surgery and knowing how to reduce the risk of these complications occurring will enable surgeons to perform safe cataract surgery in these complex cases.

Lessons From Management: Perioperative Phacoemulsification Planning Following Resolution of Acute Angle Closure

Patients with loose zonular apparatus after acute angle closure may require phacoemulsification cataract surgery. The authors' experience from management of such patients provides excellent instruction on the surgical intervention for their cataracts. This is because patients who have recovered from acute angle closure glaucoma may not have evident zonular laxity preoperatively, as the iris may be taut secondary to the effects of associated ischaemia. If the surgeon’s preoperative planning is directed to the possibility of loose zonular apparatus, then appropriate preoperative, intraoperative, and postoperative planning and management can be effected. This may permit preoperative patient counselling regarding the potentially increased complexity of the case. Intraoperatively, deliberately gentle capsulorrhexis, the use of iris hooks or a pupil expander to dilate the pupil, iris hooks to support the capsular bag, and the employment of a capsular tension ring may be helpful. Postoperatively, due to the previous ocular ischaemia, intraocular pressure elevation may ensue, and should be actively managed. The authors provide a summary of factors that require consideration in patients undergoing cataract surgery following acute angle closure.

Posture-Related Changes of Intraocular Pressure in Patients With Acute Primary Angle Closure

Purpose

To evaluate the posture-related change in intraocular pressure (IOP) of eyes with angle-closure disease and the associated factors.

Methods

Eyes were prospectively enrolled and divided into three groups: eyes with acute primary angle-closure (APAC), fellow eyes of acute primary angle-closure (FAPAC), and eyes with nonacute primary angle-closure disease (PACD). All of them had been treated with laser peripheral iridotomy. IOP was measured in the sitting, supine, and lateral decubitus positions (LDP) five minutes after posture change. Anterior chamber angle parameters and angle-closure mechanism were evaluated by anterior segment optical coherence tomography.

Results

Forty-four eyes were enrolled into each group. APAC eyes showed more LDP-Sitting IOP increase than fellow eyes (5.7 ± 2.7 vs. 2.2 ± 1.4 mm Hg, P < 0.001) and nonacute PACD eyes (3.6 ± 2.0 mm Hg, P < 0.001). LDP-sitting IOP change was higher in eyes with exaggerated lens vault (having shallow anterior chamber and volcano-like iris-lens configuration) than in those without it (APAC: 6.3 ± 2.6 vs. 3.9 ± 2.1 mm Hg, P = 0.011). Linear regression revealed that LDP-sitting IOP change in the APAC group was negatively associated with angle opening distance (AOD), trabecular iris space area, scleral spur angle, and anterior chamber depth (ACD1000). With multivariable stepwise regression analysis, AOD750 remained statistically significant (beta-coefficient = −8.36, P = 0.014).

Conclusions

APAC eyes had significant posture-related IOP changes, associated with narrower angle structures and exaggerated lens vault.

Biometric indicators of eyes with occult lens subluxation inducing secondary acute angle closure

BACKGROUND

To compare the anterior biometrics in eyes with secondary acute angle closure induced by occult lens subluxation (ASAC-LS), misdiagnosed as acute primary angle closure (APAC) at the first visit with APAC, chronic primary angle closure glaucoma (CPACG), and cataract.

METHODS

This retrospective case study included 17 eyes with angel closure due to occult LS, who were misdiagnosed as APAC on their first visit, 56 APAC eyes, 54 CPACG eyes, and 56 cataract eyes. Axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), aqueous depth (AD) and lens thickness (LT) were recorded. Lens position (LP), relative lens position (RLP), corrected lens position (CLP) were calculated. Quantitative data were subject to one-way analysis of variance and correlation analysis. Categorical data were analyzed using the chi-squared test. Receiver operating characteristic (ROC) curves were plotted to obtain a suitable cutoff value of ocular biometrics.

RESULTS

The ASAC-LS patients had a longer ocular axial length than APAC and CPACG patients. Central corneal thickness of the ASAC-LS patients was not significantly different from APAC patients, but was significantly different from CPACG and cataract patients. The APAC patients had the smallest ACD, while the ASAC-LS patients had the smallest AD. The ASAC-LS patients had the largest lens thickness. According to ROC curve analysis, RLP, ACD, AD, CLP, LP had high power of discrimination.

CONCLUSIONS

This study revealed that LS secondary PAC patients had a shallower AD, thicker CCT comparing to those of APAC, CPACG and cataract patients. For patients with acute angle-closure glaucoma, it is necessary to exclude lens zonula relaxation.

TRIAL REGISTRATION

NCT03752710, retrospectively registered.

Comparisons of Ocular Anatomic Differences of Lens-Subluxated Eye with or without Acute Angle Closure: A Retrospective Study

PURPOSE

To compare ocular anatomy differences of lens subluxation between eyes with or without acute angle closure (AAC).

METHODS

This is a retrospective and case-control study. Sixty cases with mild lens subluxation were recruited. Among them, 30 eyes with acute angle closure were assigned to the AAC group and 30 eyes without AAC were assigned to the non-AAC group. The anterior segment was quantitatively evaluated by ultrasound biomicroscopy (UBM). The axial length (AL) was measured with IOL Master. All patients underwent lens extraction surgery and were followed up for six months.

RESULTS

The history of blunt trauma accounted for 22 (73.3%) cases in the AAC group and 21 (70%) cases in the non-AAC group. Fifteen (50%) patients in the AAC group had iridotomy history, and high intraocular pressure recurred. The UBM analysis showed that the average central chamber depth of the affected eyes in the AAC group was 1.82 mm, which was significantly shallower than that in the fellow eyes (2.58 mm, P < 0.05) or both eyes in the non-AAC group.Both eyes in the AAC group presented a shorter AL and shallower anterior chamber than the eyes in the non-AAC group.

CONCLUSIONS

An asymmetrical anterior chamber between bilateral eyes is an important feature in lens subluxation-induced AAC. The crowded anterior chamber and shorter AL might be the anatomic basis for the eye with lens subluxation-induced AAC.

Vitreous Zonule and its Relation to Anterior Chamber Angle Characteristics in Primary Angle Closure

PRECIS

Primary angle-closure (PAC) eyes with no vitreous zonule (VZ) appear to have a narrower angle despite similar lens vault and iris configuration than eyes with visible VZ.

PURPOSE

To assess the clinical significance of the VZ in PAC.

METHODS

Medical records of 91 eyes of 91 participants with PAC or PAC glaucoma were retrospectively reviewed. Anterior segment parameters were measured using anterior segment optical coherence tomography; presence of the VZ was assessed with ultrasound biomicroscopy. Parameters were compared between eyes with vitreous zonule group (VZG) and no vitreous zonule group (NVZG). Factors associated with VZ presence were determined using logistic regression analysis.

RESULTS

The NVZG was more likely to have PAC glaucoma than PAC (51.4% vs. 25.0%; P=0.010) and use more glaucoma medications (0.77 vs. 0.36; P=0.004) than the VZG. The NVZG had a smaller anterior chamber area than the VZG (13.6 mm vs. 15.1 mm; P=0.020) but there were no significant between-group differences in anterior chamber depth (1.97 vs. 2.08 mm; P=0.119) and lens vault (1.21 vs. 1.13 mm; P=0.337). NVZG had a smaller scleral spur angle (11.5 vs. 17.4 degrees; P<0.001), angle opening distance at 500 μm (AOD500, 105 vs. 168 μm; P<0.001), and trabecular-ciliary process angle (75.7 vs. 81.9 degrees; P=0.029) than VZG. Older age [odds ratio (confidence interval), 1.087 (1.014-1.164); P=0.018], less AOD500 (0.984 (0.975-0.993); P<0.001), and less trabecular-ciliary process angle (0.938 (0.901-0.977); P=0.002) were independently associated with an absence of VZ.

CONCLUSIONS

PAC eyes with no VZ had a narrower angle and required more glaucoma medications than eyes with a VZ.

Characteristic Manifestations regarding Ultrasound Biomicroscopy Morphological Data in the Diagnosis of Acute Angle Closure Secondary to Lens Subluxation

Purpose

To investigate the mechanisms underlying the occurrence of acute angle closure (AAC) and to further explore the sensitive indicators for clinical diagnosis of acute angle closure secondary to lens subluxation (AACSLS) through qualitative and quantitative analysis of ultrasound biomicroscopy (UBM) imaging features of eyes with AAC to provide a theoretical basis for the selection of treatment schemes.

Methods

A retrospective analysis was conducted from 2013 to 2018 on 160 eyes (160 patients) with uniocular acute angle closure crisis (AACC) complicated by cataract. The case group consisted of 29 eyes (29 patients) with lens subluxation and the control group consisted of 131 eyes (131 patients) without lens subluxation. Before the operation, computer optometry, best corrected visual acuity, intraocular pressure, slit lamp, gonioscopy, preset lens, A-mode ultrasonography, and UBM were performed. All the enrolled subjects underwent cataract surgery with or without other operations. The pupil was fully dilated, and the position of the lens was recorded before the operation. The zonular rupture and lens subluxation were further confirmed during operation. SPSS version 20.0 was used to analyze UBM imaging data from the lens subluxation group and non-lens subluxation group.

Results

The iris span (IS) value in the whole quadrant of the lens subluxation group was significantly higher than that of the non-lens subluxation group (P=0.033, 95%CI 0.01 to 0.31). The iris lens angle (ILA) in the lens subluxation group was significantly lower than that in the non-lens subluxation group in the upper, lower, nasal, temporal, and whole quadrants (P<0.001, 95%CI -8.79 to -2.78; P=0.001, 95%CI -8.36 to -2.27; P<0.001, 95%CI -9.85 to -4.98; P=0.015, 95%CI -6.67 to -0.72; P<0.001, 95%CI -8.74 to -5.83, respectively). However, the ILA of the maximum difference among the four quadrants in the lens subluxation group was significantly higher than that in the non-lens subluxation group (P<0.001, 95%CI 4.74 to 9.86). The ILA and iris lens contact distance (ILCD) showed significant negative correlations in both the lens subluxation group and non-lens subluxation group (Y=20.984-7.251X, R=0.520, and P<0.001; Y=19.923-3.491X, R=0.256, and P<0.001, respectively). The risk ratio of lens subluxation in exposed eyes with ILA=0 in one quadrant at least was significantly higher than that in nonexposed eyes without ILA=0 in all quadrants (X²=87.859, P<0.001, and odds ratio (OR)=79.200, 95% CI 23.063 to 271.983). The risk ratio of zonular rupture in exposed quadrants with ILA=0 was significantly lower than that in nonexposed eyes without ILA=0 (X²=33.884, P<0.001, OR=0.122, and 95% CI 0.053 to 0.278). The risk ratio of zonular rupture in exposed quadrants with nonforward convexity of iris was significantly lower than that in nonexposed quadrants with forward convexity of iris (X²=6.413, P=0.011, and OR=0.381; 95% CI 0.176 to 0.825).

Conclusions

ILA=0 and nonforward convexity of iris as UBM sensitive and characteristic indicators for screening lens subluxation and zonular rupture can provide new ideas and hints for clinical diagnosis of acute angle closure secondary to lens subluxation.