Intraocular Pressure While Using Gonioscopy, SLT, and Laser Iridotomy Lenses: An Ex Vivo Study.

Purpose: The purpose of this study was to measure intraocular pressure (IOP) elevation while applying standard gonioscopy, selective laser trabeculoplasty (SLT), and laser iridotomy procedural lenses. Methods: Twelve cadaver eyes were mounted to a custom apparatus and cannulated with a pressure transducer which measured IOP. The apparatus was mounted to a load cell which measured the force on the eye. Six ophthalmologists performed simulated gonioscopy (Sussman 4 mirror lens), SLT (Latina lens), and laser iridotomy (Abraham lens) while a computer recorded IOP (mm Hg) and force (grams). The main outcome measures were IOP and force applied to the eye globe during ophthalmic diagnostics and procedures. Results: The average IOP's during gonioscopy, SLT, and laser iridotomy were 43.2 ± 16.9 mm Hg, 39.8 ± 9.9 mm Hg, and 42.7 ± 12.6 mm Hg, respectively. The mean force on the eye for the Sussman, Latina, and Abraham lens was 40.3 ± 26.4 grams, 66.7 ± 29.8 grams, and 65.5 ± 35.9 grams, respectively. The average force applied to the eye by the Sussman lens was significantly lower than both the Latina lens (P = 0.0008) and the Abraham lens (P = 0.001). During gonioscopy indentation, IOP elevated on average to 80.5 ± 22.6 mm Hg. During simulated laser iridotomy tamponade, IOP elevated on average to 82.3 ± 27.2 mm Hg. Conclusions: In cadaver eyes, the use of standard ophthalmic procedural lenses elevated IOP by approximately 20 mm Hg above baseline.

Treat the individual and not the angle.

BACKGROUND: Glaucoma, the silent thief of sight, is one of the most common vision-threatening conditions. Even though POAG (primary open angle glaucoma) is more common, PACG (primary angle closure glaucoma) is the dreaded variant. ISGEO (International Society for Geographical and Epidemiological Ophthalmology) has classified primary angle closure as PACS (primary angle closure suspect), PAC (primary angle closure), and PACG (primary angle closure glaucoma. The inconspicuous nature of PACS makes its diagnosis and treatment very tricky. PURPOSE: To determine which cases are best suited for laser peripheral iridotomy. SYNOPSIS: Laser peripheral iridotomy is the gold standard for acute primary angle closure glaucoma treatment. But there is a lot of confusion regarding its use in PACS as a prophylactic measure. We have tried to throw light on laser peripheral iridotomy, a much debatable topic. The video focuses on various trials regarding laser peripheral iridotomy, the indications, side effects, and contraindications. We have also discussed its use as a therapeutic and prophylactic procedure. HIGHLIGHTS: The video highlights that the approach of laser peripheral iridotomy should be on a case-by-case basis. VIDEO LINK: https://youtu.be/kiEYI9ct2Oo.

Clinical Presentation and Treatment Outcomes of Pupillary Block Glaucoma Following Vitreoretinal Surgery.

PURPOSE: To describe the clinical presentation and treatment outcomes of pupillary block glaucoma (PBG) following vitreoretinal surgery (VR surgery). MATERIAL AND METHODS: Retrospective observational study of 6941 patients, who underwent VR surgery at a tertiary eye care centre in South India between January 2015 and December 2019. Amongst them, clinical data of 61 patients who developed PBG were taken for statistical analysis. RESULTS: Mean (SD) age was 53.90 (13.4) years and the incidence of PBG was .87%. Median (IQR) time of onset of PBG following VR surgery was 3.33 (1.1-6.6) months and majority were pseudophakic (75%). PBG resolved with Nd:YAG laser peripheral iridotomy (LPI) alone in 50 (82%) patients, whereas 11(18%) patients required additional interventions like surgical iridectomy, trabeculectomy or diode laser cyclophotocoagulation (CPC) either as a stand-alone procedure or in combination with silicone oil removal (SOR). Mean (SD) intraocular pressure at the onset of PBG was 41.61 (14.5) mmHg, which reduced drastically following LPI to 24.28 (14.9) mmHg which further dropped significantly at 6 months follow up to 20.34 (13.9) mmHg. CONCLUSIONS: Incidence of secondary PBG after VR surgery was .87%, and we observed diabetes mellitus, combined cataract and VR surgery, use of 1000cs SO endotamponade, intraoperative endolaser and multiple VR surgical interventions as common associations. Majority of the patients with PBG after VR procedures resolved with LPI and medical management. Few individuals (18%) required additional laser or surgical intervention for IOP control.

Dysphotopsia and location of laser iridotomy: a systematic review.

This systematic review aimed to clarify the relationship between the location of laser peripheral iridotomy (LPI), a common procedure to prevent or treat angle-closure glaucoma, and the incidence of post-procedure visual disturbances known as dysphotopsias. Understanding this relationship is crucial due to the high frequency of LPIs performed and the significant impact dysphotopsia can have on vision and quality of life. Articles investigating the relationship between LPI location and dysphotopsia in at least five patients were identified via a literature search of OVID MEDLINE (1946-November 19, 2022) and EMBASE (1946-November 19, 2022). Non-comparative and non-English studies were excluded. Studies did not require a control group to be included. The Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system and Cochrane Risk of Bias 2 (RoB2) tool were used to appraise included studies. Our review included three studies encompassing 1756 eyes from 878 patients. The location of LPI was grouped into superior (604 patients, 889 eyes), inferior (150 patients, 150 eyes), and nasal/temporal (443 patients, 717 eyes). The analysis showed no significant difference in the incidence of any new dysphotopsia types among the location groups post-LPI. Overall, the incidence of lines, ghost images, and blurring significantly increased after LPI, while halos and glare significantly decreased. In conclusion, the current literature suggests that the location of LPI has no significant relationship to the types and rates of dysphotopsia experienced thereafter. While there is a 2-3% risk of linear dysphotopsia after LPI regardless of location, LPI may also resolve pre-existing halos and glare.

Cost-effectiveness analysis of prophylactic laser peripheral iridotomy for primary angle-closure suspect in Japan.

BACKGROUND/OBJECTIVES: This study aimed to compare the cost-effectiveness of prophylactic laser peripheral iridotomy (LPI) with that of observation for primary angle-closure suspect (PACS) in Japan. SUBJECTS/METHODS: A Markov model was developed to compare the costs and utilities of prophylactic LPI with those of observation of 40-year-old patients with PACS. In the model with a yearly cycle over a 20-year time horizon, the disease was postulated to irreversibly progress from PACS to primary angle closure, followed by primary angle-closure glaucoma, unilateral blindness, and bilateral blindness. The parameters were estimated mainly based on a recent randomised controlled trial and analyses of Japanese claims data. The incremental cost-effectiveness ratio was estimated from the healthcare payer's perspective and evaluated at the willingness-to-pay 5 million Japanese Yen per quality-adjusted life-year. The observation period and the age at entry into the cohort was changed to account for a variety of clinical courses in sensitivity analyses. We conducted one-way deterministic sensitivity analysis and probabilistic sensitivity analysis with Monte Carlo simulations with 10 000 iterations. RESULTS: The incremental cost-effectiveness ratio of LPI was 2,287,662 Japanese Yen (14,298 pounds sterling) per quality-adjusted life-year, which was below the willingness-to-pay threshold. The ratios were approximately 4 and 8 million in the 15-year and 10-year time horizons, respectively. Increasing the age at entry had little influence on the incremental cost-effectiveness ratio. The deterministic and probabilistic sensitivity analyses indicated that the results were robust. CONCLUSIONS: Our results indicate that prophylactic LPI for middle-aged patients with PACS is cost-effective in Japan.

Progressive Changes in the Anterior Segment and Their Impact on the Anterior Chamber Angle in Primary Angle Closure Disease.

PURPOSE: To investigate longitudinal changes in the anterior segment (AS) using serial optical coherence tomography (OCT) images and determine the impact of these changes on the anterior chamber angle (ACA) in eyes with primary angle closure disease (PACD) treated with laser peripheral iridotomy (LPI). DESIGN: Retrospective clinical cohort study. METHODS: This study included 103 patients with PACD who underwent LPI and were followed up by a mean 6.7 ± 1.7 AS-OCT examinations for a mean 6.5 ± 2.9 years. Temporal changes in AS-OCT parameters, including anterior chamber depth (ACD), angle opening distance (AOD750), angle recess area (ARA750), iris thickness (IT750), lens vault (LV), and pupil diameter (PD), were analyzed by multivariate linear mixed effects models (LMEMs). RESULTS: Multivariate LMEMs showed that decrease in AOD750 was not significant (-1.59 µm/y, P = .222); however, ARA750 decreased over time (-2.3 × 103 µm2/y, P = .033) and SSA showed marginal significance (-0.20°/y, P = .098), and LV increased significantly (11.6 µm/y, P < .001) after LPI. Mean LV change was negatively associated with AOD750, ARA750, and SSA, whereas PD was negatively associated with ARA750 (P < .001 each). PD decreased with aging (-13.7 µm/y, P = .036), accompanied by thinning of IT750 (-1.7 µm/y, P = .063). CONCLUSIONS: LV tends to increase with aging, which contributes to the shallowing of the anterior chamber and narrowing of ACA in PACD eyes treated with LPI. In the meantime, pupillary constriction and subsequent peripheral iris thinning associated with aging could possibly offset the effect of ACA narrowing.

Short-term changes detected by corneal topography and optical coherence tomography after prophylactic laser iridotomy in primary angle closure suspect.

PURPOSE: To evaluate early changes in anterior segment parameters by Scheimpflug-Placido disc topography system and changes in retinal layers by optical coherence tomography in primary angle-closure suspects after laser peripheral iridotomy. METHODS: One eye of 26 patients with primary angle closure suspect and of 20 healthy subjects were included in this retrospective cross-sectional study. Anterior chamber depth/volume, iridocorneal angle and central corneal thickness were obtained by Scheimpflug-Placido disc topography system. Retinal thickness, retinal nerve fiber layer thickness and ganglion cell-inner plexiform layer thickness were acquired by optical coherence tomography. All the tests were repeated 1 week and 1 month after laser peripheral iridotomy. RESULTS: The mean ages of the patients and healthy controls were 64.8 ± 10.7 years and 64.5 ± 3.9 years, respectively (p = 0.990). Anterior chamber depth/volume and iridocorneal angle value were lower in the PACS group (p < 0.001, for all). Anterior chamber volume and iridocorneal angle increased significantly after laser peripheral iridotomy (p = 0.004, for both). While foveal thickness decreased significantly after laser peripheral iridotomy (p = 0.027), retinal nerve fiber layer thickness increased in superior and temporal quadrants (p = 0.038 and p = 0.016, respectively). CONCLUSION: Our results suggest that LPI in patients with PACS provides improved retinal thickness and RNFL thickness, as well as anterior chamber parameters.

Changes in Anterior Segment Parameters After Laser Peripheral Iridotomy in Caucasian Eyes With Different Primary Angle Closure Mechanisms.

PRCIS: Subgrouping of angle closure mechanisms based on the swept-source optical coherence tomography images may help to identify the predominant underlying anatomic mechanism, evaluate personal treatment, and improve the better outcomes. PURPOSE: The purpose of this study was to evaluate changes in anterior segment parameters in Caucasian eyes with different angle closure mechanisms before and after laser peripheral iridotomy (LPI). METHODS: Sixty-six subjects underwent swept-source optical coherence tomography (CASIA, Tomey Corporation) angle imaging in the dark before and 7 days after LPI. On the basis of the baseline swept-source optical coherence tomography images, the eyes were categorized into 4 angle closure mechanisms, namely pupillary block (PB), plateau iris configuration (PIC), thick peripheral iris (TPI), and large lens vault (LLV). Sixteen out of 128 cross-sectional images (11.25 degrees apart) per volume scan were selected for analysis. We used a generalized estimating equation to compare quantitative parameters among angle closure mechanisms and between before and after LPI after adjusting the intereye correlation. RESULTS: The mean age of subjects was 67.7±9.2 years, with the majority being female (82.2%). One hundred twenty-nine eyes (67 primary angle closure suspects, 34 primary angle closure, and 28 primary angle closure glaucoma) were categorized into PB (n=71, 55%), PIC (n=40, 31%), TPI (n=14, 10.9%), and LLV (n=4, 3.1%). Anterior chamber depth was the shallowest in the LLV, followed by TPI, PB, and PIC group at baseline. Widening of the angle and reduction of the iris curvature (IC) due to LPI were observed in all groups (all P <0.01). When compared to the PB group, the LPI-induced angle widening in the TPI group was significantly less even though the iris curvature reduction in the TPI group was greater (all P <0.05). CONCLUSIONS: In patients with angle closure, anterior segment morphology and LPI-induced angle widening were different among the various angle closure mechanisms.

[Predictors of the success of laser peripheral iridotomy and lensectomy in the early stages of primary angle closure disease]. / Prediktory uspekha perifericheskoi lazernoi iridotomii i lensektomii pri nachal'nykh stadiyakh zabolevaniya pervichnogo zakrytiya ugla perednei kamery.

The article reviews literature data on the search for predictors of the success of laser peripheral iridotomy (LPI) and lensectomy in the early stages of primary angle closure disease (PACD) and presents a trend analysis of the studies conducted on individuals identified as primary angle closure suspects (PACs) and those with primary angle closure (PAC). The concept of the review was determined by the ambiguous choice of treatment for patients at the stage of PAC onset. Determining the success predictors of LPI or lensectomy plays a key role in optimizing the treatment of PACD. The results of literature analysis are contradictory, which indicates the need for further research taking into account modern methods of visualization of the eye structures such as optical coherence tomography (OCT), Swept Source OCT (SS-OCT), and the use of uniform criteria for evaluating the effectiveness of treatment.

Efficacy and safety of laser peripheral iridoplasty with different energy levels and locations in the treatment of primary angle closure disease assessed by swept-source anterior segment optical coherence tomography.

BACKGROUND: To explore the efficacy and safety of laser peripheral iridoplasty (LPIp) with different energy levels and locations in the treatment of primary angle closure disease (PACD) assessed by swept-source anterior segment optical coherence tomography (AS-OCT). METHODS: We enrolled patients with PACD following best-corrected visual acuity (BCVA), intraocular pressure (IOP), anterior chamber gonioscopy, ultrasound biomicroscopy(UBM), optic disc OCT, and visual field examinations. After Pentacam and AS-OCT measurements, the patients were randomly divided into four treatment groups for LPIp with two different energy levels (high vs. low energy) and two locations (far from the periphery vs. near the periphery) and combined with laser peripheral iridotomy. BCVA, IOP, pupil diameter, central anterior chamber depth, anterior chamber volume, anterior opening distance (AOD)500, AOD750, trabecular iris angle (TIA)500, and TIA750 in four quadrants before and after laser treatment were compared. RESULTS: We followed up 32 patients (64 eyes; average age, 61.80 ± 9.79 years; 8 patients/16 eyes per group) for up to 2 years. The IOP of all enrolled patients was decreased after surgery compared to that before (t = 3.297, P = 0.002), the volume of the anterior chamber was increased (t=-2.047, P = 0.047), and AOD500, AOD750, TIA500, and TIA750 were increased (all P < 0.05). Within-group comparisons showed that BCVA in the low-energy/far-periphery group was improved after surgery (P < 0.05). After surgery, the IOP was decreased in the two high-energy groups, whereas the volume of the anterior chamber, AOD500, AOD750, TIA500, and TIA750 were increased in all groups (all P < 0.05). However, when comparing every two groups, the high-energy/far-periphery group showed a stronger effect on pupil dilation than the low-energy/near-periphery group (P = 0.045). The anterior chamber volume in the high-energy/near-periphery group was larger than that in the high-energy/far-periphery group (P = 0.038). The change in TIA500 was for 6 points smaller in the low-energy/near-periphery group than in the low-energy/far-periphery group (P = 0.038). Other parameters showed no significant group differences. CONCLUSION: LPIp combined with iridotomy can effectively reduce IOP, increase anterior chamber volume, increase chamber angle opening distance, and widen the trabecular iris angle. Intraoperatively, high-energy laser spots positioned one spot diameter from the scleral spur can obtain the best effect and safety. Swept-source AS-OCT can safely and effectively quantify the anterior chamber angle.

Fourteen-Year Outcome of Angle-Closure Prevention with Laser Iridotomy in the Zhongshan Angle-Closure Prevention Study: Extended Follow-up of a Randomized Controlled Trial.

PURPOSE: This study aimed to evaluate the efficacy of laser peripheral iridotomy (LPI) prophylaxis for patients with primary angle-closure suspect (PACS) after 14 years and to identify risk factors for the conversion from PACS to primary angle closure (PAC). DESIGN: Extended follow-up of the Zhongshan Angle-Closure Prevention Study. PARTICIPANTS: Eight hundred eighty-nine Chinese patients 50 to 70 years of age with bilateral PACS. METHODS: Each patient received LPI in 1 randomly selected eye, with the fellow untreated eye serving as a control. Because the risk of glaucoma was low and acute angle closure (AAC) occurred only rarely, the follow-up was extended to 14 years despite substantial benefits of LPI reported after the 6-year visit. MAIN OUTCOME MEASURES: Incidence of PAC, a composite end point including peripheral anterior synechiae, intraocular pressure (IOP) of > 24 mmHg, or AAC. RESULTS: During the 14 years, 390 LPI-treated eyes and 388 control eyes were lost to follow-up. A total of 33 LPI-treated eyes and 105 control eyes reached primary end points (P < 0.01). Within them, 1 LPI-treated eye and 5 control eyes progressed to AAC. Primary angle-closure glaucoma was found in 2 LPI-treated eyes and 4 control eyes. The hazard ratio for progression to PAC was 0.31 (95% confidence interval, 0.21-0.46) in LPI-treated eyes compared with control eyes. At the 14-year visit, LPI-treated eyes showed more severe nuclear cataract, higher IOP, and larger angle width and limbal anterior chamber depth (LACD) than control eyes. Higher IOP, shallower LACD, and greater central anterior chamber depth (CACD) were associated with an increased risk of end points developing in control eyes. In the treated group, eyes with higher IOP, shallower LACD, or less IOP elevation after the darkroom prone provocative test (DRPPT) were more likely to demonstrate PAC after LPI. CONCLUIONS: Despite a two-third decrease in PAC occurrence after LPI, the cumulative risk of progression was relatively low in the community-based PACS population over 14 years. Apart from IOP, IOP elevation after DRPPT, CACD, and LACD, more risk factors are needed to achieve precise prediction of PAC occurrence and to guide clinical practice. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Comparison of Lens Extraction Versus Laser Iridotomy on Anterior Segment, Choroid, and Intraocular Pressure in Primary Angle Closure Using Machine Learning.

PRCIS: Treatment strategy of primary angle closure (PAC) is not clear due to the large number of clinical and anatomic-topographic parameters in PAC, influencing the treatment algorithm. Using the machine learning method DD-SIMCA, we justify the expediency of early lens extraction (LE) in PAC. PURPOSE: To compare the anatomic and functional efficacy of LE and laser peripheral iridotomy (LPI) in patients with PAC using Machine Learning. MATERIALS AND METHODS: This prospective study included 120 patients aged 41-80 years: 60 eyes with PAC, 30 with PAC suspects, and 30 with healthy eyes (control). Thirty PAC eyes with intraocular pressure (IOP) up to 30 mm Hg were treated using LE with intraocular lens implantation and 30 eyes with LPI. All subjects underwent Swept Source optical coherence tomography. We analyzed 35 parameters of each eye including the lens vault, the choroidal thickness, the anterior chamber angle, and iris specifications such as iris curvature. Considering the correlations between them, the machine learning method DD-SIMCA 1-class classification was applied: the proximity of each sample to the target class (control) was characterized by the total distance to it. RESULTS: After LE, IOP was significantly lower than after LPI ( P =0). Every third eye with PAC after LE reached the target class: specificity according to DD-SIMCA equals 0.67. This was not observed for the eyes after LPI: specificity equals 1.0. After LE, all parameters of the anterior chamber angle did not differ from the control (all P >0.05). After LPI, there was an increase in anterior chamber depth ( P =0) and a decrease in lens vault ( P =0), but results comparable to the control were achieved only for iris curvature ( P =1.000). CONCLUSION: The efficacy of LE in PAC is higher than LPI due to the better postoperative anterior chamber topography and lower IOP. This study lends further clinical and anatomic support to the emerging notion of LE as an effective treatment for PAC.

Effect of Topical Pilocarpine Instilled Before Laser Peripheral Iridotomy on Regional Iris Thickness in Primary Angle Closure Disease: A Swept-Source Anterior Segment Optical Coherence Tomography Pilot Study.

PURPOSE: To determine whether the temporal-superior or the nasal-superior iris area becomes thinner (more optimal) for laser peripheral iridotomy (LPI) after pilocarpine instillation in primary angle closure disease (PACD); and to identify an angle for optimal penetration of the laser beam. PATIENTS AND METHODS: Iris thickness at 2 mm from the iris root in the preset scanning axes was measured using swept-source anterior segment optical coherence tomography before and 60 minutes after the instillation of pilocarpine 2% in one eye of 30 consecutive Japanese PACD patients with thick, dark brown iris. Iris thickness at 1:30 and 10:30 clock hour positions were evaluated in sagittal and oblique directions, resulting sagittal iris thickness (SIT) and minimum iris thickness (MIT) parameters, respectively. RESULTS: Compared to the baseline values, iris thickness decreased significantly (P < .001) in both locations after pilocarpine instillation. Both before and after pilocarpine instillation the temporal-superior iris thickness was significantly smaller than the nasal-superior thickness (P ≤ .001). After pilocarpine instillation, the temporal-superior iris was significantly thinner in an approximately 13° angle direction temporal to the sagittal direction than in the sagittal direction (MIT: 0.322 mm; SIT: 0.346 mm, P < .001). CONCLUSIONS: After pilocarpine instillation, the temporal-superior iris and an approximately 13° angle temporal to the sagittal direction may provide an optimal location and laser beam angle for LPI in PACD eyes.

Cataract progression after Nd:YAG laser iridotomy in primary angle-closure suspect eyes.

BACKGROUND/AIMS: Prophylactic laser peripheral iridotomy (LPI) is performed in primary angle-closure suspect (PACS) eyes to prevent acute angle-closure attacks. However, accelerated cataractogenesis is a potential risk of the procedure that may result in decreased visual acuity. We aimed to assess the long-term impact of LPI on cataract formation in Chinese PACS. METHODS: In the Zhongshan Angle Closure Prevention Trial, eligible bilateral PACS participants received LPI in one randomly selected eye, while the fellow eye remained untreated. Cataract was graded using the Lens Opacity Classification System III, and progression was defined as an increase in grade by at least two units in any category or cataract surgery. RESULTS: In total, 889 participants were randomly assigned to LPI in one eye only (mean age 59±5 years, 83% female). At 72 months, treated eyes had slightly higher average nuclear grades (p<0.001). However, there were no differences between eyes for predefined cataract progression (cumulative probability at 72 months: 21.2% in LPI vs 19.4% in control, p=0.401) or cataract surgery (1% for both). While LPI-treated eyes had a 10% higher risk of progression over 6 years (HR=1.10 (95% CI 0.88 to 1.36)), this was not statistically significant. Visual acuity at 72 months was similar in treated and untreated eyes (p=0.43). CONCLUSION: Although lenses were graded on average as slightly more opaque in laser-treated eyes, prophylactic neodymium:yttrium-aluminum-garnet LPI did not cause significant cataract progression. Our results suggest that LPI treatment of asymptomatic narrow angles does not increase the risk of developing clinically meaningful cataract worsening over time. TRIAL REGISTRATION NUMBER: ISRCTN45213099.

Predictors of long-term intraocular pressure control after lens extraction in primary angle closure glaucoma: results from the EAGLE trial.

BACKGROUND/AIMS: To assess baseline ocular parameters in the prediction of long-term intraocular pressure (IOP) control after clear lens extraction (CLE) or laser peripheral iridotomy (LPI) in patients with primary angle closure (PAC) disease using data from the Effectiveness of Early Lens Extraction for the treatment of primary angle-closure glaucoma (EAGLE) tria. METHODS: This study is a secondary analysis of EAGLE data where we define the primary outcome of 'good responders' as those with IOP<21 mm Hg without requiring additional surgery and 'optimal responders' as those who in addition were medication free, at 36-month follow-up. Primary analysis was conducted using a multivariate logistic regression model to assess how randomised interventions and ocular parameters predict treatment response. RESULTS: A total of 369 patients (182 in CLE arm and 187 in LPI arm) completed the 36-month follow-up examination. After CLE, 90% met our predefined 'good response' criterion compared with 67% in the LPI arm, and 66% met 'optimal response' criterion compared with 18% in the LPI arm, with significantly longer drops/surgery-free survival time (p<0.05 for all). Patients randomised to CLE (OR=10.1 (6.1 to 16.8)), Chinese (OR=2.3 (1.3 to 3.9)), and those who had not previously used glaucoma drops (OR=2.8 (1.6 to 4.8)) were more likely to maintain long-term optimal IOP response over 36 months. CONCLUSION: Patients with primary angle closure glaucoma/PAC are 10 times more likely to maintain drop-free good IOP control with initial CLE surgery than LPI. Non-Chinese ethnicity, higher baseline IOP and using glaucoma drops prior to randomisation are predictors of worse long-term IOP response.

Clinical implication of recent randomized control trial in primary angle-closure disease management.

Blindness due to primary angle-closure glaucoma (PACG) can be reduced significantly if the ongoing angle-closure process is arrested at an early stage. Various treatments such as laser peripheral iridotomy (LPI), iridoplasty, and clear lens extraction (CLE) have been advocated as first-line therapy for primary angle-closure (PAC), PACG, and high-risk cases of primary angle-closure suspect (PACS). EAGLE study, propagated the effectiveness of CLE over LPI for the management of primary angle closure and have sparked controversy regarding the role of LPI as a first line procedure. Randomized controlled trials (RCT), systematic reviews, and meta-analyses of RCTs done on the same question provide us with a solid base for creating guidelines/modules for our day-to-day clinical practice. A systematic review was conducted, searching several databases, including PubMed, Cochrane Library, EMBASE, and ClinicalTrials.gov, for the last 16 years (January 2005-December 2021) for RCTs with data published related to primary angle-closure disease (PACD). The search strategy included the following terms: "Primary Angle Closure disease," "Primary Angle Closure Glaucoma," "Primary Angle Closure," "Primary Angle Closure Suspect," "clear lens extraction," "laser iridotomy," "laser peripheral iridotomy," "argon laser peripheral iridoplasty," "selective laser trabeculoplasty," "trabeculectomy," "randomized control trial," and "meta-analysis of randomized control trial." In this review, we will discuss recently published RCTs (within the last 16 years) for the management of PACD and their clinical implications in day-to-day practice.

Efficacy and safety of trabeculectomy versus peripheral iridectomy plus goniotomy in advanced primary angle-closure glaucoma: study protocol for a multicentre, non-inferiority, randomised controlled trial (the TVG study).

INTRODUCTION: Primary angle-closure glaucoma (PACG) is a major subtype of glaucoma that accounts for most bilateral glaucoma-related blindness globally. Filtering surgery is a conventional strategy for PACG, yet it has a long learning curve and undesirable disastrous complications. Minimally invasive glaucoma surgery (MIGS) plays an increasing role in the management of glaucoma due to its safer and faster recovery profile; cataract surgery-based MIGS is the most commonly performed such procedure in PACG. However, for patients with a transparent lens or no indications for cataract extraction, incorporation of MIGS into PACG treatment has not yet been reported. Therefore, this multicentre, non-inferiority, randomised controlled clinical trial aims to compare the efficacy and safety of trabeculectomy versus peripheral iridectomy plus an ab interno goniotomy in advanced PACG with no or mild cataracts. METHODS AND ANALYSIS: This non-inferiority, multicentre, randomised controlled trial will be conducted at seven ophthalmic departments and institutes across China. Eighty-eight patients with no or mild cataracts and advanced PACG will be enrolled and randomised to undergo trabeculectomy or peripheral iridectomy plus ab interno goniotomy. Enrolled patients will undergo comprehensive ophthalmic examinations before and after surgery. The primary outcome is intraocular pressure (IOP) at 12 months postoperatively. The secondary outcomes are cumulative success rate of surgery, surgery-related complications and number of IOP-lowering medications. Participants will be followed up for 36 months postoperatively. ETHICS AND DISSEMINATION: The study protocol was approved by the ethical committees of the Zhongshan Ophthalmic Center, Sun Yat-sen University, China (ID: 2021KYPJ191) and of all subcentres. All participants will be required to provide written informed consent. The results will be published in peer-reviewed journals and disseminated in international academic meetings. TRIAL REGISTRATION NUMBER: NCT05163951.

Biometric indicators of anterior segment parameters before and after laser peripheral iridotomy by swept-source optical coherent tomography.

BACKGROUND: Primary angle closure glaucoma (PACG) is the most common type of glaucoma in China. Laser peripheral iridotomy (LPI) is the primary choice to treat PAC: We aim to evaluate the changes of biometric parameters of anterior segment and to find possible biometric predictors of the effect of laser peripheral iridotomy (LPI) in primary angle closure (PAC) eyes using swept-source optical coherent tomography (OCT). METHODS: LPI was performed in 52 PAC eyes of 28 participants. The change of intraocular pressure and anterior segment parameters, including angle opening distance (AOD500), AOD500 area, trabecular iris space area (TISA500), TISA500 volume, trabecular iris angle (TIA500), iridotrabecular contact (ITC) index, ITC area, anterior chamber volume (ACV), anterior chamber depth (ACD), lens vault (LV) and lens thickness (LT) before and 1 week after LPI were measured by Tomey CASIA2 anterior segment OCT. We also estimate and analyze potential associated factors possibly affecting the change of anterior chamber parameters. RESULTS: No post-laser complications were found. The ACD, LV and LT did not change significantly 1 week after LPI. AOD500, AOD500 area, TISA500, TISA500 volume, TIA500, ACV increased significantly after LPI. There was significant decrease in ITC index and ITC area. LT was positively correlated to the change of ITC index (ß = 0.239, *p = 0.045). CONCLUSIONS: The anterior segment architecture significantly changed after LPI in PAC spectrum eyes. Crystalline lens measurements remained unchanged before and after LPI. AS-OCT can be used to follow anterior chamber parameter changes in PAC spectrum eyes. LT may play a role in the therapeutic effect of LPI.

Six-Year Incidence and Risk Factors for Primary Angle-Closure Disease: The Singapore Epidemiology of Eye Diseases Study.

PURPOSE: To determine the incidence and risk factors of primary angle-closure disease (PACD) over 6 years in a multi-ethnic Asian population. DESIGN: Population-based, longitudinal study. PARTICIPANTS: The Singapore Epidemiology of Eye Diseases study is a population-based cohort study conducted among adults aged 40 years or more. The baseline examination was conducted between 2004 and 2010, and the 6-year follow-up visit was conducted between 2011 and 2017. Of 6762 participants who attended the follow-up examination, 5298 at risk for primary angle-closure glaucoma (PACG) and 5060 at risk for PACD were included for analyses. METHODS: Standardized examinations including slit-lamp biomicroscopy, indentation gonioscopy, intraocular pressure (IOP) measurement, and static automated perimetry were performed. In this study, PACD includes primary angle-closure suspect (PACS), primary angle-closure (PAC), and PACG. MAIN OUTCOME MEASURES: The 6-year PACD incidence was evaluated among an at-risk population excluding adults with baseline glaucoma, PACS, PAC, pseudophakia at baseline or follow-up, or laser peripheral iridotomy or iridectomy at baseline visit. Logistic regression analysis adjusting for age, gender, and ethnicity was performed to evaluate associations between PACD development and demographic or ocular characteristics. Forward selection based on the Quasi-likelihood Information Criterion was used in multivariable analysis to reduce potential multicollinearity. RESULTS: The 6-year age-adjusted PACD incidence was 3.50% (95% confidence interval [CI], 2.94-4.16). In multivariable analysis, increasing age per decade (odds ratio [OR], 1.35; 95% CI, 1.15-1.59), higher IOP (OR, 1.04; 95% CI, 1.00-1.08), and shallower anterior chamber depth (OR, 1.11; 95% CI, 1.08-1.14) at baseline were associated with higher odds of PACD, whereas late posterior subcapsular cataract (PSC) (OR, 0.60; 95% CI, 0.48-0.76) was associated with lower odds of PACD. The 6-year age-adjusted incidences of PACG, PAC, and PACS were 0.29% (95% CI, 0.14-0.55), 0.46% (95% CI, 0.29-0.75), and 2.54% (95% CI, 2.07-3.12), respectively. CONCLUSIONS: Our study showed that the 6-year incidence of PACD was 3.50%. Increasing age, higher IOP, and shallower anterior chamber were associated with a higher risk of incident PACD, whereas late PSC was associated with a lower odds of PACD. These findings can aid in future projections and formulation of health care policies for screening of at-risk individuals for timely intervention.

Optical coherence tomography analysis of anterior segment parameters before and after laser peripheral iridotomy in primary angle-closure suspects by using CASIA2.

BACKGROUND: Laser peripheral iridotomy (LPI) is effective in primary angle-closure suspects (PACS); however, predictors for anterior segment alterations after LPI are limited. We aimed to evaluate the anterior segment biometric parameters before and after LPI in PACS using the recently developed, CASIA 2 device of anterior segment optical coherence tomography (AS-OCT). METHODS: We performed LPI in 52 PACS. Anterior segment parameters, including anterior chamber depth (ACD), anterior chamber width (ACW), anterior chamber volume (ACV), iris curvature (ICURVE), iridotrabecular contact (ITC), lens vault (LV), lens thickness (LT), radius of the lens, angle opening distance (AOD), angle recess area (ARA), trabecular iris space area (TISA), and trabecular iris angle (TIA) at different distances (i.e., 500 µm from the sclera spur), were evaluated before and after LPI using CASIA 2. RESULTS: Eyes of PACS after LPI had a greater ACV, AOD, ARA, TISA, and TIA, and a lower ITC and ICURVE (all p < 0.001) than those before LPI. On a 360° scan, the anterior chamber angle in the superior quadrant increased the most after the LPI. A higher baseline LT was significantly associated with a greater postoperative increase in AOD 500, ARA 500, TISA 500, and TIA 500 (p = 0.001, p = 0.010, p = 0.004, and p < 0.001, respectively). CONCLUSIONS: We found that LPI widens the anterior chamber angle in the PACS, especially, in the superior quadrant around the iridotomy hole. Eyes with a thicker lens are more likely to experience angle opening because of the LPI.