Prevalence of zonulopathy in primary angle closure disease

Deep learning-based automatic differentiation of acute angle closure with or without zonulopathy using ultrasound biomicroscopy: a comparison of diagnostic performance with ophthalmologists

OBJECTIVE

This study aims to develop ultrasound biomicroscopy (UBM)-based artificial intelligence (AI) models for preoperative differentiation of acute angle closure (AAC) with or without zonulopathy and to compare their comprehensive diagnostic performance against ophthalmologists as a cross-sectional study.

METHODS AND ANALYSIS

Three AI models were developed to differentiate AAC with or without zonular laxity or lens subluxation using UBM images and ocular parameters. Their diagnostic performances were analysed, with the best-performing model then compared with two diagnostic methods used by ophthalmologists (logistic regression and UBM image analysis). Additionally, a robustness validation dataset, including images from UBM and anterior segment optical coherence tomography (AS-OCT), was used to validate the robustness of the best-performing AI model.

RESULTS

A total of 537 eyes were included in this study. The best-performing AI model was image-based and achieved a macro-area under the curve (AUC) of 0.9046 with a diagnostic processing time of 0.03 s per image in differentiating AAC with or without zonulopathy. The manually calculated multinomial logistic regression model achieved a macro-AUC of 0.9373, requiring 1200.00 s per analysis. UBM image analysis achieved a mean accuracy and processing time of 64.17% and 20.13 s, respectively, per image. Robustness validation of the image-based AI model showed an accuracy of 66.67% and 61.11% for UBM and AS-OCT images.

CONCLUSIONS

AI models and ophthalmologists effectively differentiated AAC with or without zonulopathy. However, when evaluated in terms of both accuracy and efficiency, the AI model showed superior comprehensive diagnostic performance, demonstrating high clinical applicability for preoperative diagnosis.

Occult zonulopathy detected during cataract surgery in patients with acute primary angle closure: a retrospective study

Background

Whether occult zonulopathy contributes to the development of acute primary angle closure (APAC) remains elusive. This study aimed to determine the association between occult zonulopathy detected during cataract surgery and APAC and to investigate the biometric characteristics of APAC patients with or without occult zonulopathy.

Methods

Retrospective case-control study. A total of 27 Chinese unilateral APAC subjects and 132 control subjects with comprehensive ophthalmic examinations were recruited. Occult zonulopathy was identified with the intraoperative signs during cataract surgery. The proportion of occult zonulopathy was compared between the APAC and control groups. A multivariate logistic analysis was conducted to determine the association between occult zonulopathy and APAC. The ocular biometric parameters were compared between APAC and the contralateral eyes in APAC patients with or without occult zonulopathy.

Results

APAC patients (63.0%) had a significantly larger proportion of occult zonulopathy than control subjects (1.5%, P < 0.001). In the multivariate logistic analysis, occult zonulopathy was significantly associated with APAC after adjusting the axial length (AL) and sex (OR = 126.49, 95% CI [20.89-766.02]; P < 0.001). Compared to contralateral eyes, shallower central anterior chamber depth, more anterior lens position and relative lens position were found in APAC eyes both with and without occult zonulopathy (all P < 0.05), but no difference in AL and lens thickness.

Conclusion

A larger proportion of occult zonulopathy was significantly associated with APAC. Occult zonulopathy could be a risk factor for APAC by inducing forward shifting of the lens.

Progression of primary angle closure suspects: a systematic review and meta-analysis

This systematic review and meta-analysis examined the proportion of primary angle closure suspects (PACS) progressing to primary angle closure (PAC), acute angle closure (AAC), and primary angle closure glaucoma (PACG) and evaluated the impact of prophylactic laser peripheral iridotomy (LPI) on disease progression. A systematic search was performed on MEDLINE and EMBASE for studies published until November 2023 that reported on the proportion of PACS progressing to PAC. Using random-effects modelling, risk ratios and 95% confidence intervals estimated the proportion of progressing PACS between patients who received LPI versus those who did not. Two randomized-controlled-trials and three observational studies included a total of 1997 PACS patients. The weighted average age was 57.2 years with 74.7% females, and an average follow-up period of 6.2 years. Overall, 284 (14.2%) PACS patients progressed to either PAC (n = 258, 12.9%), AAC (n = 9, 0.5%), or PACG (n = 17, 0.9%). Patients receiving LPI displayed a 2.49-fold decrease in the risk of progression to PAC (RR: 2.49; 95% CI = 1.50-4.07; p < 0.001; NNT = 15), suggesting that there is a higher risk of disease progression without LPI. However, for the progressions to AAC and PACG, statistical significance was not reached. The present study provides valuable insights to the proportion of PACS who showed disease progression and underscores the potential benefit of prophylactic LPI in reducing the risk of angle closure disease progression. However, this study also addresses the issues surrounding the lack of demonstrated clinical efficacy for this intervention, thus advocating for a balanced approach in clinical decision-making.

Prospective study on the role of preoperative mannitol in capsulorhexis and reducing intraoperative complications in primary angle-closure disease surgery

OBJECTIVE

To evaluate the effect of preoperative intravenous mannitol on the capsulorhexis process and intraoperative complications in patients with primary angle-closure glaucoma (PACG).

METHODS

In this prospective randomized controlled trial, 65 PACG eyes were randomized into the mannitol and control groups. The capsulorhexis duration, number of forceps grasps, need for viscoelastic re-injection, and intraoperative complications were recorded.

RESULTS

The mannitol group had a significantly shorter capsulorhexis duration and fewer forceps grasps of the capsule. All intraoperative complications (18.2%) occurred in the control group. The patients with intraoperative complications had significantly higher intraocular pressure and lower best-corrected visual acuity than those without complications after surgery. Multivariate analysis found that intravenous mannitol (odds ratio [OR] = -14.263; 95% confidence interval [CI] =-26.713 to -1.813) reduced the capsulorhexis duration, whereas zonulopathy (OR = 14.477, 95% CI = 2.622-26.331) prolonged the duration.

CONCLUSION

Preoperative intravenous mannitol can reduce the risk of intraoperative complications and improve postoperative outcomes in patients with PACG. Factors including anterior chamber depth, incision location and method, and the zonule status significantly influence the capsulorhexis process.

Zonulopathy and Its Relation to Primary Angle Closure Disease: A Review

PRCIS

This paper aims to discuss the anatomical features of zonule fibers that center the lens in the eye and summarizes the relationship between zonulopathy and PACD.

ABSTRACT

The increasing lens vault (LV) and lens thickness (LT) is a recognized mechanism for primary angle closure glaucoma (PACG). Zonulopathy, causing the abnormal lens position, is an important factor in this mechanism. Several anatomically distinct sets of zonular fibers are present in primate eyes, including ciliary zonules, vitreous zonules, and attachments between the posterior insertion zone of the vitreous zonules and the posterior lens equator (PVZ INS-LE strands). Zonulopathy, as a clinical diagnosis, exhibits zonular laxity and loss, long anterior lens zonules (LAZ). Slit lamp, gonioscopy, ultrasound biomicroscopy (UBM), anterior segment optical coherence tomography (AS-OCT) aid in the diagnosis of zonulopathy. The proportion of underdiagnosed zonulopathy among primary angle closure disease (PACD) patients before operation is high. According to the intraoperative signs, zonulopathy could be determined better. There is a high prevalence of zonulopathy among PACD patients compared with the general population. Because of the different insertion zone in lens capsules, different zonular fibers play different parts in lens position and shape. Zonular laxity and loss cause the lens to be thicker and move anteriorly, forming narrow-angle and high intraocular pressure, and then the higher intraocular pressure damages zonule fibers further and causes angle closure. Loss of vitreous zonules may make the ciliary body rotate anterior excessively and pull iris forward, leading to iridotrabecular contact. LAZ eyes tend to be hyperopic and have short axial length, increased LT and anterior lens position, plateau iris configuration, and characteristics that are consistent with elevated risk for angle closure. Zonulopathy may be a risk for PACD. A clear knowledge of zonulopathy and its relation to PACD would be helpful to the diagnosis and treatment.

A Case of Acute Angle Closure Secondary to Pupillary Block Caused by a Dislocated Intraocular Lens-Capsular Tension Ring Complex

We report a case of acute angle closure secondary to pupillary block caused by a dislocated intraocular lens (IOL)-capsular tension ring (CTR) complex. A 68-year-old woman, who had undergone cataract surgery 28 months earlier, presented with acute right eye pain and blurred vision. Examination revealed elevated intraocular pressure (IOP) of 80 mmHg, corneal edema, and anterior chamber shallowing, with anterior displacement of the IOL-CTR complex observed on anterior-segment optical coherence tomography. An anterior chamber paracentesis and subsequent vitrectomy were performed to remove the dislocated complex. After scleral fixation of a new IOL and management of an epiretinal membrane, the patient's vision improved, with her best-corrected visual acuity reaching 1.2 and IOP stabilizing at 18 mmHg without medication. This case highlights the potential for IOL-CTR dislocation to cause pupillary block and acute angle closure, emphasizing the need for timely diagnosis and comprehensive surgical intervention to preserve visual function.

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.

Clinical and anatomic correlates of objectively measured zonular dehiscence in 427 postmortem pseudophakic eyes

OBJECTIVE

This study aims to objectively measure the degree of zonular dehiscence in postmortem eyes and to assess for clinical and anatomic correlates.

DESIGN

Cross-sectional study.

MATERIALS

Four hundred and twenty-seven postmortem pseudophakic human eyes.

METHODS

Eyes were obtained from the Lions Gift of Sight Eye Bank. Microscope photographs were taken of the eyes in Miyake-Apple view, and region-of-interest analysis was performed using ImageJ to measure the area, circumference, and diameter of the capsular bag, the ciliary ring, and the capsulorhexis. Clinical and anatomic parameters were assessed using simple linear regression analysis and one-way analysis of variance with post hoc Bonferroni testing. Zonular dehiscence was measured via 2 surrogates: capsule area over ciliary ring area ratio (CCR) and capsule-ciliary ring decentration (CCD). Low CCR and high CCD indicate more zonular dehiscence.

RESULTS

CCR was significantly inversely correlated with smaller capsulorhexi (p = 0.012), lower intraocular lens power (p < 0.00001), younger age at death (p = 0.00002), and a longer cataract-to-death time (p = 0.00786). CCR also was significantly lower in glaucomatous cases (p = 0.0291). CCD was significantly correlated with longer cataract-to-death time (p = 0.000864), larger ciliary ring area (p = 0.001), more posterior capsule opacification (p = 0.0234), and higher Soemmering's ring opacity (p = 0.0003). There was also significantly more decentration in male eyes than in female eyes (p = 0.00852).

CONCLUSIONS

CCR and CCD are novel measures of zonular dehiscence in postmortem eyes, with many interesting correlates. An enlarged ciliary ring area is possibly associated with zonular dehiscence in pseudophakic eyes and may be a quantifiable surrogate in vivo.

Ocular Biometric Characteristics in Preoperative Diagnosis of Acute Angle Closure With and Without Zonular Laxity

PRCIS

Biometric parameters, including binocular difference of anterior chamber depth (ACD), lens vault (LV) in affected eyes, and binocular difference of the LV, had high efficiency in diagnosing acute angle closure (AAC) with zonular laxity.

PURPOSE

To investigate the ocular biometric characteristics of eyes with AAC with zonular laxity to further explore the sensitive parameters for preoperative diagnosis.

METHODS

This study included 50 patients with AAC with zonular laxity and 54 patients with AAC without zonular laxity. Demographic data, ocular examination results, and biometric parameters on ultrasound biomicroscopy images were compared between the affected and fellow eyes in 2 groups. Parameters significant in the multiple linear regression model were included in a regression equation and the diagnostic efficiency was evaluated by area under the curve.

RESULTS

In patients with AAC with zonular laxity, the binocular difference of central ACD, LV in affected eyes, and binocular difference of the LV were significantly larger than those in patients without zonular laxity respectively and these three parameters were all significant in multiple linear regression analysis (all P <0.001). The area under the curve of binocular difference of ACD, LV in affected eyes, and binocular difference of LV were 0.972, 0.796, and 0.855, respectively, with the cutoff values of 0.23, 1.28, and 0.19 mm. The regression equation containing these three parameters was: ln ( P /(1- P ))=-4.322 + 1.222 [LV in affected eyes (mm)] + 3.657 [binocular difference of LV (mm)] + 6.542 [binocular difference of ACD (mm)], with the accuracy of prediction reaching 94.05%.

CONCLUSION

Binocular difference of ACD, LV in affected eyes, and binocular difference of LV had high efficiency in diagnosing AAC with zonular laxity.

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.

Intraocular lens power calculation in eyes with a shallow anterior chamber depth and normal axial length

We compared the accuracy of three intraocular lens (IOL) calculation formulas in eyes with a shallow anterior chamber depth (ACD) and normal axial length (AXL) and control eyes. We retrospectively reviewed eyes with a shallow ACD (<2.5 mm from the corneal epithelium) with normal AXL (22.5≤AXL<24.0 mm) and controls (3.0≤ACD<3.5 mm and normal AXL). Prediction error (PE) and median absolute error (MedAE) were evaluated with SRK/T, Barrett Universal II (BUII), and Kane formulas after adjusting the mean PE to zero for all patients. Percentages of eyes achieving a PE within 0.25 to 1.00 D, and correlations between ACD, lens thickness (LT), and PE were analyzed. Thirty-five shallow ACD and 63 control eyes were included. PE in the shallow ACD group showed more hyperopic results with BUII and Kane but not with SRK/T compared to controls. Within the shallow ACD group, PE showed more hyperopic results in BUII and Kane compared to SRK/T. However, the standard deviation (SD) of PE among formulas was not different. In the shallow ACD group, SRK/T showed a higher percentage of PE within 0.25 D than BUII and Kane, but the percentages within 0.50 to 1.00 D were similar. PE was negatively correlated with ACD in BUII and Kane, and positively correlated with LT in all formulas. BUII and Kane may induce slight hyperopic shift in eyes with a shallow ACD and normal AXL. However, the performance of the three formulas was comparable in the shallow ACD group in terms of MedAE, the SD of PE, and the percentage of eyes achieving PE within 0.50 D.

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.

Outcome of Cataract Surgery in Patients With Retinitis Pigmentosa

PURPOSE

To assess the visual outcome of cataract surgery in patients with retinitis pigmentosa (RP).

DESIGN

Retrospective, noncomparative clinical study.

METHODS

Preoperative, intraoperative, and postoperative data of patients with RP who were undergoing cataract surgery were collected from several expertise centers across Europe.

RESULTS

In total, 295 eyes of 226 patients were included in the study. The mean age at surgery of the first eye was 56.1 ± 17.9 years. Following surgery, best-corrected visual acuity (BCVA) improved significantly from 1.03 to 0.81 logMAR (ie, 20/214 to 20/129 Snellen) in the first treated eye (-0.22 logMAR; 95% CI = -0.31 to -0.13; P < .001) and from 0.80 to 0.56 logMAR (ie, 20/126 to 20/73 Snellen) in the second treated eye (-0.24 logMAR; 95% CI = -0.32 to -0.15; P < .001). Marked BCVA improvements (postoperative change in BCVA of ≥0.3 logMAR) were observed in 87 of 226 patients (39%). Greater odds for marked visual improvements were observed in patients with moderate visual impairment or worse. The most common complications were zonular dialysis (n = 15; 5%) and (exacerbation of) cystoid macular edema (n = 14; 5%), respectively. Postoperative posterior capsular opacifications were present in 111 of 295 eyes (38%).

CONCLUSION

Significant improvements in BCVA are observed in most patients with RP following cataract surgery. Baseline BCVA is a predictor of visual outcome. Preoperative evaluation should include the assessment of potential zonular insufficiency and the presence of CME, as they are relatively common and may increase the risk of complications.

Congenital ciliary body cysts causing lens abnormalities and secondary angle closure glaucoma in a child

Purpose

To report a case of congenital ciliary body cysts causing microspherophakia, ectopia lentis, and secondary angle closure glaucoma in an infant.

Observations

A 16-month-old male was found to have bilateral ciliary body cysts associated with zonular laxity or absence causing microspherophakia and ectopia lentis as demonstrated on multimodal imaging. Additionally, the patient had secondary angle closure glaucoma which was likely multi-factorial related to both lens abnormalities and anterior displacement of the iris from the cysts themselves. The patient underwent lensectomy and cyst removal which resulted in intraocular pressure stabilization and visual rehabilitation.

Conclusions and Importance

Congenital ciliary body cysts are a rare cause of lens abnormalities and secondary angle closure glaucoma in children. Information regarding genetic underpinnings or systemic associations is limited.