Anterior Segment Dimensions Following Laser Iridotomy in Acute Primary Angle Closure and Fellow Eyes

Biometric Risk Factors for Angle Closure Progression After Laser Peripheral Iridotomy

Importance

Laser peripheral iridotomy (LPI) is the most common primary treatment for primary angle closure disease (PACD). However, there are sparse data guiding the longitudinal care of PAC suspect (PACS) eyes after LPI.

Objective

To elucidate the anatomic effects of LPI that are associated with a protective outcome against progression from PACS to PAC and acute angle closure (AAC) and to identify biometric factors that predict progression after LPI.

Design, Setting, and Participants

This was a retrospective analysis of data from the Zhongshan Angle Closure Prevention (ZAP) trial, a study of mainland Chinese people aged 50 to 70 years with bilateral PACS who received LPI in 1 randomly selected eye. Gonioscopy and anterior-segment optical coherence tomography (AS-OCT) imaging were performed 2 weeks after LPI. Progression was defined as the development of PAC or an acute angle closure (AAC) attack. Cohort A included a random mix of treated and untreated eyes, and cohort B included only eyes treated with LPI. Univariable and multivariable Cox regression models were developed to assess biometric risk factors for progression in cohorts A and B. Data were analyzed from January 4 to December 22, 2022.

Main Outcome and Measure

Six-year progression to PAC or AAC.

Results

Cohort A included 878 eyes from 878 participants (mean [SD] age, 58.9 [5.0] years; 726 female [82.7%]) of whom 44 experienced progressive disease. In a multivariable analysis, treatment (hazard ratio [HR], 0.67; 95% CI, 0.34-1.33; P = .25) was no longer associated with progression after adjusting for age and trabecular iris space area at 500 μm (TISA at 500 μm) at the 2-week visit. Cohort B included 869 treated eyes from 869 participants (mean [SD] age, 58.9 [5.0] years; 717 female [82.5%]) of whom 19 experienced progressive disease. In multivariable analysis, TISA at 500 μm (HR, 1.33 per 0.01 mm2 smaller; 95% CI, 1.12-1.56; P = .001) and cumulative gonioscopy score (HR, 1.25 per grade smaller; 95% CI, 1.03-1.52; P = .02) at the 2-week visit were associated with progression. Persistent angle narrowing on AS-OCT (TISA at 500 μm ≤0.05 mm2; HR, 9.41; 95% CI, 3.39-26.08; P <.001) or gonioscopy (cumulative score ≤6; HR, 2.80; 95% CI, 1.13-6.93; P =.04) conferred higher risk of progression.

Conclusions and Relevance

Study results suggest that persistent angle narrowing detected by AS-OCT or cumulative gonioscopy score was predictive of disease progression in PACS eyes after LPI. These findings suggest that AS-OCT and gonioscopy may be performed to identify patients at high risk of developing angle closure who may benefit from closer monitoring despite patent LPI.

Meta-Analysis of Phacoemulsification and Laser Peripheral Iridotomy in the Treatment of Primary Angle-Closure Glaucoma

Background

In this meta-analysis, we aimed to systematically compare the efficacy and safety of phacoemulsification and laser peripheral iridotomy (LPI) in the treatment of primary angle-closure glaucoma (PACG).

Method

We searched PubMed, MEDLINE, EMBASE, the Cochrane Library, the Chinese Journal Full-text Database (CNKI), the Wanfang database, and the China Science and Technology Journal Database for randomized controlled trials (RCTs) of phacoemulsification and LPI in the treatment of PACG published up to September 30, 2022. Postoperative intraocular pressure (IOP), anterior chamber depth (ACD), complications, corneal endothelial cell count, and best-corrected visual acuity (BCVA) were compared. The effective quantity of measurement data was measured by the mean difference (MD) and 95% confidence interval (CI). The effect of counting data was measured by the odds ratio (OR).

Result

A total of 1731 potential studies were identified, and after screening, 8 RCT studies were included. The results of the meta-analysis showed that, compared to the LPI group, the patients in the phacoemulsification group showed lower IOP six and twelve months after operation (MD-3.39, 95% CI -4.15∼-2.63, P < 0.00001; -2.29, -3.52∼-1.06, 0.0003). The ACD in the phacoemulsification group was significantly deeper than that in the LPI group (1.59, 1.10∼2.09, 0.00001). Meanwhile, the incidence of complications in the phacoemulsification group was lower than that in the LPI group (OR = 0.46, 0.29∼0.72, 0.0006). There was no statistically significant difference between the phacoemulsification group and the LPI group in corneal endothelial cell count and BCVA at 6 and 12 months after operation (P=0.38; 0.11; 0.81).

Conclusion

Compared with LPI, phacoemulsification is safer and more effective in the treatment of PACG, especially in controlling IOP and minimizing postoperative complications.

Early outcomes of anterior segment parameters after implantable collamer lens V4c implantation

Background

This study investigated the early outcomes of anterior segment parameters after implanting an implantable collamer lens with a central hole (ICL V4c) in patients with myopia and determined the earliest follow-up time for detecting potential complications.

Methods

Sixty-two patients were included, and the following parameters were measured at baseline (preoperative), 1 day, 1 week, and 1, 3, and 6 months after the operation: intraocular pressure (IOP), endothelial cell density (ECD), central anterior chamber depth (CACD), anterior chamber volume (ACV), nasal and temporal anterior chamber angle (n-ACA and t-ACA), horizontal corneal diameter (white-to-white, WTW), and axial length (AL). The vault was measured at each post-operative timepoint.

Results

The postoperative IOP and ECD at the 6 months were both statistically similar to the baseline. The post-operative CACD and ACV were significantly less at all timepoints compared with the baseline (P < 0.001) and stayed stable from 1 day and 1 month after the operation, respectively. Postoperative n-ACA and t-ACA decreased significantly at 1 day and 1 week compared with the baseline (P < 0.001), while tended to stabilization at 1, 3, and 6 months. The vault kept decreasing significantly at 1 day, 1 week, and 1 month, but stayed stable at 3 and 6 months. The postoperative n-ACA and t-ACA positively correlated with the baseline ACA, CACD, and ACV.

Conclusions

The anterior chamber parameters tended to stabilization early after the operation. Thus, it is essential to evaluate patients’ anterior segment status at earlier timepoints and prevent complications with prompt and non-invasive intervention.

Classifications of Qualitative Characteristics on Angle Configurations via Ultrasound Biomicroscopy in Acute Primary Angle Closure

Purpose

To study the classifications of qualitative characteristics on the angle configurations in the acute primary angle closure (APAC) and fellow eyes by ultrasound biomicroscopy (UBM).

Methods

A total of 131 patients (262 eyes) were researched retrospectively. The qualitative parameters from UBM images were classified into iris form (IF), ciliary body configuration (CBC), basal iris thickness (BIT), iris convexity (IC), iris insert (II), iris angulation (IA), ciliary body size (CBS) and ciliary body position (CBP). Comparative analyses between the APAC (case group) and fellow (control group) eyes were performed.

Results

There were significant differences in IF, CBC, IC, II, CBS, CBP between the case group and control group in all quadrants (P<0.001). The IA of the case group and control group presented significant difference in all quadrants (P=0.001). However, there was not a significant difference in BIT between the case group and control group in all quadrants (P=0.495). The case group had fewer parallelogram-like and mushroom-like and more cone-like and hook-like CBCs than the control group (P<0.001).

Conclusion

Multiple ciliary body configurations can influence the stability of the lens and the anatomic configuration of the anterior chamber angle indirectly. New qualitative classification system of UBM may be more intuitionistic and refined to reflect the angle configurations to help clinical practice.

Bruch's membrane opening - minimum rim width measurement after acute primary angle-closure

PURPOSE

To evaluate Bruch's membrane opening - minimum rim width (BMO-MRW) and peripapillary retinal nerve fiber layer thickness (RNFLT) following an acute primary angle-closure attack (APAC).

MATERIALS AND METHODS

Nine consecutive patients with unilateral APAC were included. Patients with a bilateral attack, with signs of glaucomatous optic nerve damage or evidence of a previous APAC in either eye were excluded. Three months after the attack, all eyes underwent BMO-MRW and RNFLT measurements with SDOCT. APAC eyes were compared to the contralateral eyes.

RESULTS

Three months after the attack, mean BMO-MRWs were 281.22 ± 56.88 μm and 313.78 ± 43.48 μm (P = 0.009) and mean RNFLTs were 78 ± 15.36 μm vs 95.78 ± 10.81 μm (P = 0.008) in the APAC and contralateral eyes, respectively. RNFLT and BMO-MRW measurements had a strong positive correlation (R = 0.7436, P = 0.013). APAC eyes had a shorter axial length (21.85 ± 1.21 vs 22 ± 1.07, P = 0.042) and shallower anterior chamber depth (2.29 ± 0.21 vs 2.41 ± 0.12, P = 0.039) than contralateral eyes. IOP at presentation showed a strong negative correlation with both BMO-MRW (R = -0.7669, P = 0.009) and RNFLT measurements (R = -0.7723, P = 0.008).

CONCLUSION

BMO-MRW and RNFLT measurements are significantly reduced 3 months after an APAC when compared to the contralateral eye. IOP at presentation may have an impact on the reduction of these parameters.

Progression rate to primary angle closure following laser peripheral iridotomy in primary angle-closure suspects: a randomised study

AIM

To report the progression rate (PR) to primary angle closure (PAC) following laser peripheral iridotomy (LPI) in PAC suspects (PACS).

METHODS

Prospective, randomized controlled interventional clinical trial conducted at the Handan Eye Hospital, China. Totally 134 bilateral PACS, defined as non-visibility of the posterior trabecular meshwork for ≥180 degrees on gonioscopy were randomly assigned to undergo LPI in one eye. Gonioscopy and Goldmann applanation tonometry were performed prior to, on day 7 and 12mo post LPI.

RESULTS

Eighty of 134 patients (59.7%) could be followed up at one year. The mean intraocular pressure (IOP) in treated eyes was 15.9±2.6 mm Hg at baseline, 15.4±3.0 mm Hg on day 7; 16.5±2.9 mm Hg at one month, and 15.5±2.9 mm Hg at 12mo; the IOP in untreated eyes was similar (P=0.834). One or more quadrants of the angle opened in 93.7% of the LPI treated eyes, but 67.0% (53/79) remained closed in two or more quadrants. The PR to PAC in untreated eyes was 3.75% and one developed acute angle-closure glaucoma (AACG); the PR to PAC in treated eyes was 2.5% and none had developed peripheral anterior synechia (PAS) or AACG.

CONCLUSION

LPI can open some of the occludable angle in the majority of eyes with PACS, but 67% continue to have non-visibility of the trabecular meshwork for over 180 degrees.

The Use of Anterior-Segment Optical-Coherence Tomography for the Assessment of the Iridocorneal Angle and Its Alterations: Update and Current Evidence

The introduction of anterior-segment optical-coherence tomography (AS-OCT) has led to improved assessments of the anatomy of the iridocorneal-angle and diagnoses of several mechanisms of angle closure which often result in raised intraocular pressure (IOP). Continuous advancements in AS-OCT technology and software, along with an extensive research in the field, have resulted in a wide range of possible parameters that may be used to diagnose and follow up on patients with this spectrum of diseases. However, the clinical relevance of such variables needs to be explored thoroughly. The aim of the present review is to summarize the current evidence supporting the use of AS-OCT for the diagnosis and follow-up of several iridocorneal-angle and anterior-chamber alterations, focusing on the advantages and downsides of this technology.

Trends in the characteristics of acute primary angle closure in Korea over the past 10-years

Purpose

To investigate the changes in the demographic, clinical, and biometric characteristics of APAC patients in South Korea during the last decade.

Methods

Medical records of patients with APAC who visit the emergency department or the glaucoma clinic of Chonnam National University Hospital, a tertiary referral center in Gwangju, South Korea in 2007 and 2017 were analyzed. Demographics, clinical characteristics, and treatment modality were compared between the APAC patients in 2007 and 2017.

Results

The number of patients with APAC increased from 54 in 2007 to 68 in 2017. Female patients in their 60s were most common in both groups and there was no significant difference in IOP, cataract grade, gonioscopic grading, PAS, or optic nerve damage between the two groups at baseline visit (all P > 0.05). However, APAC eyes in 2017 had a shallower ACD (1.74 ± 0.28 mm vs 1.87 ± 0.35 mm; P = 0.024) and greater LV (1.05 ± 0.26 mm vs 0.93 ± 0.19 mm; P = 0.001) than those of APAC eyes in 2007. During one year follow-up, 25 patients (51.02%) received LPI only, and 18 patients (36.73%) required LE, and 6 patients (12.24%) required phacotrabeculectomy or sequential LE and trabeculectomy. However, in 2017, LPI alone was sufficient in 23 patients (38.33%), 29 patients (48.33%) required further LE, and 8 patients (13.33%) required phacotrabeculectomy or sequential LE and trabeculectomy for the treatment of APAC (P = 0.015).

Conclusions

Compared to older cases of APAC, recent cases received LE more frequently, which suggests an increasing trend of LE as a treatment option for APAC. In addition, recent cases had a greater LV and shallower ACD than older cases and these biometric differences may be one of the reasons for increasing rate of LE in this study.

Clock position-based iris bow configuration after laser peripheral iridotomy in Chinese angle closure eyes: a swept source optical coherence tomography study

BACKGROUND

To determine how many measurements should be evaluated to determine the iris bow and evaluate changes of iris bow at 12 clock positions after LPI in primary angle closure eyes.

METHODS

A total of 93 primary angle closure eyes in 93 Chinese patients were enrolled. Anterior iris bowing was evaluated at 12 clock positions and 4 clock positions (3, 6, 9, and 12 o'clock) before, 1 week and 3 months after LPI using swept source optical coherence tomography.

RESULTS

At baseline, almost all of the eyes exhibited an iris bow when measured using 12 clock positions, consistent with results obtained from measurements at 4 clock positions (Cronbach's alpha = 0.99). LPI caused a relative unified change in all of the clock positions (Cronbach's alpha = 0.91) except the LPI site. After LPI, there was no significant difference between 12 and 4 clock position measurements for the iris bow (both p > 0.05), with ~34.1% vs. 33% of the patients remained iris bow at 1 week and 34% vs. 31.9% of the patients remained iris bow at 3 months. However, the coexisting iris bow configuration was more common when measured using 4 clock positions (16.5% vs. 3.3% at 1 week and 25.5% vs. 10.6% at 3 months).

CONCLUSIONS

There was excellent consistency when measuring the iris bow at 4 or 12 clock positions. LPI caused a relatively unified iris bow change at 12 clock positions, and a single LPI relieved only ~2/3 of the iris bow configurations.

Effects of lens extraction versus laser peripheral iridotomy on anterior segment morphology in primary angle closure suspect

PURPOSE

To compare the anatomical effects on anterior segment by lens extraction (LE, phacoemulsification with posterior chamber intraocular lens implantation) and laser peripheral iridotomy (LPI) in primary angle closure suspect (PACS) eyes.

METHODS

This prospective comparative cohort trial included a total of 122 consecutive patients identified as PACS aged 52 to 80 years. LE or LPI was performed based on each patient's choice. The anterior segment optical coherence tomography (ASOCT) and gonioscopy were conducted at baseline and 4 weeks post-operation. Outcome measures include percentage of residual angle closure, mean angle width (modified Shaffer grade), angle opening distance (AOD), trabecular iris angle (TIA), trabecular iris space area (TISA), anterior chamber depth (ACD), iris curvature (I-Curve), lens vault (LV), intraocular pressure (IOP), and best-corrected visual acuity (BCVA).

RESULTS

All anterior angle parameters (AOD, TIA, and TISA) were significantly greater after LE than LPI (P < 0.001 for all). ACD (P < 0.001) increased, LV (P < 0.001) decreased, IOP (P < 0.001) decreased, and BCVA (P < 0.001) increased after LE. However, no significant changes were found in ACD (P = 0.782), LV (P = 0.616), IOP (P = 0.112), and BCVA (P = 0.131) after LPI. In both groups, I-Curve decreased after the operation, but the iris was flatter after LE than LPI (P < 0.001). Gonioscopically, the LE group achieved a larger post-operative angle width (modified Shaffer grade) than LPI (P < 0.001) and all anterior chamber angles were open (defined as posterior pigmented trabecular meshwork (PTM) visible with static gonioscopy) after operation. Nevertheless, after LPI, 12 eyes (20.0%) still had two or more quadrants and 32 eyes (53.3%) still had at least one quadrant in which the posterior PTM could not be observed.

CONCLUSIONS

Compared with LPI, LE resulted in a wider anterior chamber angle, a deeper anterior chamber, and a lower IOP in PACS eyes. Moreover, no residual angle closure was observed after LE, which could morphologically prevent the progress of angle closure.

TRIAL REGISTRATION

ChiCTR1800016511.

Factors Associated with Interventions after Laser Peripheral Iridotomy for Primary Angle-Closure Spectrum Diagnoses

PURPOSE

To assess factors associated with receipt of subsequent medical, laser, or surgical interventions after laser peripheral iridotomy (LPI).

DESIGN

Retrospective review.

PARTICIPANTS

A total of 1271 eyes in 692 subjects with narrow angles (NAs) that were treated with LPI.

METHODS

Demographic and clinical factors associated with primary angle-closure (PAC) or PAC glaucoma (PACG) versus PAC suspect (PACS) diagnosis and use of glaucoma medications at the time of LPI, as well as factors predictive of subsequent addition of glaucoma medications, and receipt of selective laser trabeculoplasty (SLT), cataract surgery, and glaucoma surgery were assessed using logistic regression with generalized estimating equations. Kaplan-Meier curves and Cox proportional-hazards regression analysis were used to assess baseline factors affecting the time to SLT, cataract surgery, or glaucoma surgery.

MAIN OUTCOME MEASURES

Diagnosis of PAC/PACG and medical, laser, or surgical interventions after LPI.

RESULTS

African Americans (odds ratio [OR], 2.12; P < 0.001) were significantly more likely than whites to have PAC/PACG than PACS and to already be taking glaucoma medications (OR, 2.25, P < 0.001) at the time of LPI. In multivariable logistic regression analysis, African Americans were significantly more likely to be prescribed additional glaucoma medications after LPI (OR, 1.73; P = 0.025) and receive glaucoma surgery (OR, 2.7; P = 0.007), but were less likely to receive SLT (OR, 0.37; P = 0.009). In multivariate Cox proportional-hazards regression analysis, African Americans had longer time to SLT than whites (hazard ratio [HR], 0.41; P = 0.022), but a shorter time to glaucoma surgery (HR, 2.57; P = 0.004). There was no significant association between race and the likelihood of cataract surgery or time to cataract surgery (P > 0.10).

CONCLUSIONS

African Americans were more likely than whites to carry a diagnosis of PAC or PACG at the time of LPI and were significantly more likely to be prescribed additional glaucoma medications and require glaucoma surgery after LPI. Improved screening methods that target African Americans with NAs are needed so that preventive interventions such as LPI can be performed earlier to decrease the risk of progression.

Contemporary approach to the diagnosis and management of primary angle-closure disease

The primary angle-closure disease spectrum varies from a narrow angle to advanced glaucoma. A variety of imaging technologies may assist the clinician in determining the pathophysiology and diagnosis of primary angle closure, but gonioscopy remains a mainstay of clinical evaluation. Laser iridotomy effectively eliminates the pupillary block component of angle closure; however, studies show that, in many patients, the iridocorneal angle remains narrow from underlying anatomic issues, and increasing lens size often leads to further narrowing over time. Recent studies have further characterized the role of the lens in angle-closure disease, and cataract or clear lens extraction is increasingly used earlier in its management. As a first surgical step in angle-closure glaucoma, lens extraction alone often effectively controls the pressure with less risk of complications than concurrent or stand-alone glaucoma surgery, but may not be sufficient in more advanced or severe disease. We provide a comprehensive review on the primary angle-closure disease nomenclature, imaging, and current laser and surgical management.