Laser peripheral iridotomy versus laser peripheral iridotomy plus laser peripheral iridoplasty in the treatment of multi-mechanism angle closure: study protocol for a randomized controlled trial

Efficacy and Safety of Surgical Peripheral Iridectomy, Goniosynechialysis, and Goniotomy for Advanced Primary Angle Closure Glaucoma Without Cataract: 1-Year Results of a Multicenter Study

PRCIS

The combination of surgical peripheral iridectomy, goniosynechialysis, and goniotomy is a safe and effective surgical approach for advanced primary angle closure glaucoma without cataract.

PURPOSE

To evaluate the efficacy and safety of surgical peripheral iridectomy (SPI), goniosynechialysis (GSL), and goniotomy (GT) in advanced primary angle closure glaucoma (PACG) eyes without cataract.

PATIENTS AND METHODS

A prospective multicenter observational study was performed for patients who underwent combined SPI, GSL, and GT for advanced PACG without cataract. Patients were assessed before and after the operation. Complete success was defined as achieving intraocular pressure (IOP) between 6 and 18 mm Hg with at least a 20% reduction compared with baseline, without the use of ocular hypotensive medications or reoperation. Qualified success adopted the same criteria but allowed medication use. Factors associated with surgical success were analyzed using logistic regression.

RESULTS

A total of 61 eyes of 50 advanced PACGs were included. All participants completed 12 months of follow-up. Thirty-six eyes (59.0%) achieved complete success, and 56 eyes (91.8%) achieved qualified success. Preoperative and postsurgical at 12 months mean IOPs were 29.7±7.7 and 16.1±4.8 mm Hg, respectively. The average number of ocular hypotensive medications decreased from 1.9 to 0.9 over 12 months. The primary complications included IOP spike (n=9), hyphema (n=7), and shallow anterior chamber (n=3). Regression analysis indicated that older age (odds ratio [OR]=1.09; P =0.043) was positively associated with complete success, while a mixed angle closure mechanism (OR=0.17; P =0.036) reduced success rate.

CONCLUSIONS

The combination of SPI, GSL, and GT is a safe and effective surgical approach for advanced PACG without cataract. It has great potential as a first-line treatment option for these patients.

Rethinking Prophylactic Laser Peripheral Iridotomy in Primary Angle-Closure Suspects: A Review

PURPOSE

To examine the generalizability, discuss limitations, and critically appraise recommendations on the management of primary angle-closure suspects (PACSs) that emerged as a result of recent randomized clinical trials challenging the widely accepted clinical practice of offering laser peripheral iridotomy (LPI) to PACS patients. To synthetize findings from these and other studies.

DESIGN

Narrative review.

SUBJECTS

Patients classified as PACS.

METHODS

The Zhongshan Angle-Closure Prevention (ZAP)-Trial and the Singapore Asymptomatic Narrow Angle Laser Iridotomy Study (ANA-LIS) along with accompanying publications were reviewed. Epidemiologic studies reporting on the prevalence of primary angle-closure glaucoma and other precursor forms of the disease were also analyzed along with publications reporting on the natural course of the disease or studies reporting on outcomes after prophylactic LPI.

MAIN OUTCOME MEASURES

Incidence of progression to more severe forms of angle closure.

RESULTS

Patients recruited in recent randomized clinical trials are asymptomatic, do not have cataracts, may be younger, and have, on average, deeper anterior chambers depth compared with patients treated with LPI in clinics.

CONCLUSIONS

The ZAP-Trial and ANA-LIS clearly represent the best available data on PACS management, additional parameters however may need to be considered when physicians face patients in clinic. PACS patients encountered at tertiary referral centers may represent more advanced cases with respect to ocular biometric parameters and may be at higher risk for disease progression compared with those recruited through population-based screening.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Predictive Equation for Angle Opening Distance at 750 μm After Laser Peripheral Iridotomy in Primary Angle Closure Suspects

Aim: The aim of this study was to investigate the changes in anterior segment parameters as assessed by ultrasound biomicroscopy (UBM) after laser peripheral iridotomy (LPI) and to propose a prediction equation for the width of the angle after LPI. Design: This was a prospective study. Participants: The participants included 100 subjects with primary angle closure suspect (PACS). Methods: Anterior segment UBM parameters were measured, whereas AOD750 was chosen to indicate the width of the angle associated with gonioscopic angle closure, as found in a prior study. Main Outcome Measures: Angle parameters, iris parameters, anterior chamber parameters and ciliary body parameters. Results: All angle parameters increased after LPI, including the mean angle opening distance at 750 μm (AOD750), mean angle opening distance at 500 μm from the scleral spur (AOD500), mean angle opening distance at 750 μm from the scleral spur (AOD750), and mean angle recess area at 750 μm from the scleral spur (ARA750). Among iris parameters and ciliary body parameters, the iris thickness at 2,000 μm (IT2000), iris curvature (IC), and trabecular-ciliary process distance (ICPD) were reduced after LPI. The final equation consisted of four parameters: anterior chamber depth (ACD), iris thickness at 750 μm from the scleral spur (IT750), AOD750, and lens vault (LV). This equation explained 42.7% of the variability in the angle opening indicator AOD750 after LPI, whereas in the plateau iris configuration subgroup, the accuracy of the prediction equation reached the highest a maximum of 68.6%. Conclusions: There was an increase in angle opening and iris flattening after LPI. An equation involving four angle parameters was constructed, this equation which could explained 42.7% of the variability in the angle opening indicator AOD750 after LPI whereas in the plateau iris configuration subgroup, the accuracy of the prediction equation reached a maximum of 68.6%.

Altered spontaneous neuronal activity and functional connectivity pattern in primary angle-closure glaucoma: a resting-state fMRI study

PURPOSE

To explore the alterations of spontaneous neuronal activity and functional connectivity pattern using fractional amplitude of low-frequency fluctuation (fALFF) and functional connectivity (FC) in patients with primary angle-closure glaucoma (PACG) and fALFF relationship with the glaucoma clinical indices.

MATERIALS AND METHODS

Forty-two PACG patients and 21 normal controls were enrolled in this study. Resting-state functional magnetic resonance imaging was firstly analyzed by fALFF and brain regions with altered fALFF between groups were selected as seeds for the further FC analysis. The relationships between fALFF/FC values of abnormal regions and ophthalmological measures, including mean deviation of visual field (MDVF) and retinal nerve fiber layer (RNFL) thickness, were also analyzed.

RESULTS

Compared with NC, PACG had significant lower fALFF values in the left cuneus, left middle temporal gyrus, right middle temporal gyrus, and right precentral gyrus, while higher fALFF values in the bilateral superior frontal gyrus (P < 0.05 after correction). Furthermore, PACG showed increased FC between left cuneus and bilateral superior frontal gyrus/bilateral posterior cingulate gyrus; between left middle temporal gyrus and bilateral superior frontal gyrus; and between right middle temporal gyrus and bilateral insular (P < 0.05 after correction). In addition, in the PACG group, the mean fALFF values of the left cuneus were positively correlated with MDVF (R = 0.419, P = 0.005) and RNFL thickness (R = 0.322, P = 0.038). Meanwhile, the mean fALFF values of bilateral superior frontal gyrus were negatively correlated with MDVF (R = - 0.454, P = 0.003) and RNFL thickness (R = - 0.556, P < 0.001).

CONCLUSIONS

PACG exhibited abnormal spontaneous neural activity and connectivity in several brain regions mainly associated with visual and visual-related functions. In addition, the fALFF values of the left cuneus and bilateral superior frontal gyrus may be complementary biomarkers for assessing the disease severity.

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.

Argon Laser Peripheral Iridoplasty and Argon Laser Pupilloplasty: Alternative Management for Medically Unresponsive Acute Primary Angle Closure

Objective

To introduce the combined laser technique, argon laser peripheral iridoplasty (ALPI) and argon laser pupilloplasty (ALPP), in the management of medically unresponsive acute primary angle closure (APAC).

Design

Retrospective study.

Methods

We retrospectively reviewed the records of 23 patients (27 eyes) with APAC, who were applied ALPI and ALPP when traditional treatment failed. The visual acuity and intraocular pressure (IOP) were monitored before surgery and at 1, 2, 12, 24, and 48 h after surgery. Additionally, the angle-opening status was monitored before surgery and 48 h after the treatment by using an ultrasonic biological microscope (UBM), and the presurgical and postsurgical cornea edema statuses were observed by using a slit lamp. We also documented the complications of laser treatment.

Results

For the ALPI + ALPP laser-effective group, the presurgical IOP was 52.1 ± 9.3 mmHg and the postsurgical IOP was 37.6 ± 10.9 mmHg (1 h), 28.4 ± 12.4 mmHg (2 h), 19.9 ± 9.0 mmHg (6 h), 16.8 ± 7.3 mmHg (12 h), 15.9 ± 5.9 mmHg (24 h), and 14.9 ± 5.0 mmHg (48 h), with statistically significant differences (p < 0.05) in each time point. It was observed in all the patients that the corneal edema alleviated, the angles opened, and visual acuity recovered with varying degrees at 48 h after applying combined laser treatment. For the ALPI + ALPP laser-ineffective group, further interventions were taken. Definite treatment was given in both groups to maintain the long-term IOP control.

Conclusions

Although the combination of ALPI and ALPP is a temporizing therapeutic strategy for APAC, it is effective in relieving pupillary block which is unresponsive to miotic agents, opening the closed angle to a certain extent, restoring the transparency of cornea, and reducing IOP to a safe level for further definitive treatment.

Outflow facility and extent of angle closure in a porcine model

PURPOSE

To establish the extent of anterior chamber angle circumference needed to maintain a physiological outflow facility (C). This could create a model to investigate focal outflow regulation.

METHODS

Twenty anterior segments of porcine eyes were assigned to five groups, each with a different degree of cyanoacrylate-mediated angle closure: 90° (n = 4), 180° (n = 4), 270° (n = 4), 360° (n = 4), and four unoccluded control eyes. The outflow facility was measured at baseline, 3, 12, 24, and 36 h after angle closure. Outflow patterns were evaluated with canalograms and the histomorphology was compared.

RESULTS

Baseline outflow facilities of the five groups were similar (F = 0.922, p = 0.477). Occlusion of 360° induced a significant decrease in facility from baseline at all time-points (p ≤ 0.023 at 3, 12, 24, and 36 h). However, no difference from baseline was found in any of the partially occluded (0-270°) groups (F ≥ 0.067, p ≥ 0.296 at 3, 12, 24, and 36 h). The canalograms confirmed the extent of occlusion with flow through the unblocked regions. Histology revealed no adverse effects of blockage on the TM or aqueous plexus in the unoccluded angle portions. The unoccluded TM appeared normal.

CONCLUSION

Cyanoacrylate-mediated angle occlusion created a reproducible angle closure model. Ninety degrees of unoccluded anterior chamber angle circumference was sufficient to maintain physiological outflow. This model may help understand how outflow can be regulated in healthy, nonglaucomatous TM.