Neodymium-doped yttrium aluminum garnet (Nd: YAG) laser treatment in ophthalmology: a review of the most common procedures Capsulotomy and Iridotomy.

Nowadays, lasers are used in various medical fields. Ophthalmology was the first medical specialty to utilize lasers in patient treatment and still remains the leading medical field that uses laser energy for both therapeutic and diagnostic purposes. The neodymium: yttrium-aluminum-garnet (Nd: YAG) laser is one of the most common lasers used in ophthalmology. It is a solid-state laser with a wavelength of 1064 nm that works on the principle of photodisruption. Since its introduction in ophthalmology over 40 years ago, it has found various applications, mainly for procedures where cutting or disruption of ocular tissue is required. Compared to surgical alternatives, the use of Nd: YAG lasers on ocular tissue is minimally invasive. In this review, we focus on the two most common ophthalmic applications of Nd: YAG laser - laser peripheral iridotomy and posterior capsulotomy. The history of the techniques, current trends, potential complications, and the prognosis for future use is discussed.

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.

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.

Lensectomy as treatment for refractory or progressive retinopathy of prematurity narrow-angle glaucoma.

We present the case of a patient with a history of laser-treated retinopathy of prematurity (ROP) who developed narrow angles and intermittent angle closure. Despite laser peripheral iridotomy/iridoplasty, 1 year later, the patient had recurrent narrowing that resolved following clear lens extraction with intraocular lens placement. This case highlights the importance of continued monitoring for narrow angles in patients with ROP history.

Long-Term Efficacy of Selective Laser Trabeculoplasty in Primary Angle-Closure Disease After Laser Peripheral Iridotomy.

PURPOSE: To evaluate the long-term efficacy of selective laser trabeculoplasty (SLT) in eyes with primary angle-closure (PAC) and primary angle-closure glaucoma (PACG) following a laser peripheral iridotomy (LPI). METHOD: In this prospective cross-sectional study, 45 eyes of 34 patients with PAC/PACG diagnosis, uncontrolled intraocular pressure (IOP), and visible pigmented trabecular-meshwork (TM) at least 180° on gonioscopy following a LPI were recruited. Following a detailed baseline ophthalmic evaluation, all eligible eyes underwent SLT, and the patients were examined on day1, at 1 week, 1-, 3-, and 6-months, and 1-, 2-, 3-, 4-, and 5-year subsequently. The main outcomes measured were IOP, number of IOP-lowering agents, and complications. RESULTS: The mean age of the cohort was 57.80 ± 6.44 years, the male-female ratio was 8:26, and 17 eyes were PACG, and 28 were PAC. The baseline IOP was 23.81 ± 1.78 mm Hg, and was significantly declined at all follow-ups (p < .0001). The cumulative probability of overall success was 91% and 84% at 2-, and 5-year, respectively. At 5-year SLT provided drug-freedom in 80% of PAC and 23% of PACG eyes. Six eyes had IOP spike at 1-week and two patients underwent repeat SLT after 1-year. No other complications, such as pain/discomfort, inflammation, an increase in peripheral anterior synechiae and cystoid-macular-edema, were noted. CONCLUSIONS: SLT appears a safe and cost-effective procedure in PAC/mild- moderate PACG eyes with uncontrolled IOP after laser iridotomy. The long-term effectiveness of SLT as adjuvant treatment was good, but need large sized randomized studies for more validation.

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.

Outcome of combined cataract surgery and iris prosthesis implantation in iris melanoma patients previously treated with iridocyclectomy: A national retrospective non-comparative case series.

PURPOSE: To examine complications, visual outcomes, photic patient-reported symptoms, corneal morphology, IOL tilt, and intraocular pressure after implantation of an intraocular lens (IOL) and iris prosthesis (IP) following iridocyclectomy. METHODS: Patients with previous iridocyclectomy treated with an IOL and IP at the Copenhagen University Hospital Rigshospitalet between 2007 and 2018 were included in this national retrospective non-comparative case series. The assessment encompassed BCVA, PRO questionnaire, corneal topography, and anterior segment OCT. RESULTS: 45 patients were included. Eight of 45 patients were previously treated with ruthenium-106 brachytherapy in conjunction with iridocyclectomy. Six of 45 patients developed endothelial dysfunction four of whom had received ruthenium-106 brachytherapy. Five of 45 patients had subluxation of the IOL/IP complex due to incomplete zonula apparatus. BCVA improved for all patients after lens surgery. 26 patients participated in the invited follow-up examination. 19 of 26 (73%) reported none or mild photic symptoms after IP instalment. Five (19%) reported ongoing severe photic symptoms. The corneal astigmatism significantly increased after iridocyclectomy but did not change after lens surgery. CONCLUSIONS: Implantation of an IOL and IP is a safe procedure, alleviating photic symptoms in most patients. It comes with higher risk of complications due to a more demanding procedure and larger surgical traumas from previous treatments. Ruthenium-106 brachytherapy increases the complication risk. Corneal astigmatism is induced by iridocyclectomy but does not change after lens surgery.

Long-Term Risk and Prediction of Progression in Primary Angle Closure Suspect.

Importance: Identifying primary angle closure suspect (PACS) eyes at risk of angle closure is crucial for its management. However, the risk of progression and its prediction are still understudied in long-term longitudinal studies about PACS. Objective: To explore baseline predictors and develop prediction models for the 14-year risk of progression from PACS to primary angle closure (PAC). Design, Setting, and Participants: This cohort study involved participants from the Zhongshan Angle Closure Prevention trial who had untreated eyes with PACS. Baseline examinations included tonometry, ultrasound A-scan biometry, and anterior segment optical coherence tomography (AS-OCT) under both light and dark conditions. Primary angle closure was defined as peripheral anterior synechiae in 1 or more clock hours, intraocular pressure (IOP) greater than 24 mm Hg, or acute angle closure. Based on baseline covariates, logistic regression models were built to predict the risk of progression from PACS to PAC during 14 years of follow-up. Results: The analysis included 377 eyes from 377 patients (mean [SD] patient age at baseline, 58.28 [4.71] years; 317 females [84%]). By the 14-year follow-up visit, 93 eyes (25%) had progressed from PACS to PAC. In multivariable models, higher IOP (odds ratio [OR], 1.14 [95% CI, 1.04-1.25] per 1-mm Hg increase), shallower central anterior chamber depth (ACD; OR, 0.81 [95% CI, 0.67-0.97] per 0.1-mm increase), and shallower limbal ACD (OR, 0.96 [95% CI, 0.93-0.99] per 0.01 increase in peripheral corneal thickness) at baseline were associated with an increased 14-year risk of progression from PACS to PAC. As for AS-OCT measurements, smaller light-room trabecular-iris space area (TISA) at 500 µm from the scleral spur (OR, 0.86 [95% CI, 0.77-0.96] per 0.01-mm2 increase), smaller light-room angle recess area (ARA) at 750 µm from the scleral spur (OR, 0.93 [95% CI, 0.88-0.98] per 0.01-mm2 increase), and smaller dark-room TISA at 500 µm (OR, 0.89 [95% CI, 0.80-0.98] per 0.01-mm2 increase) at baseline were identified as predictors for the 14-year risk of progression. The prediction models based on IOP and central and limbal ACDs showed moderate performance (area under the receiver operating characteristic curve, 0.69; 95% CI, 0.63-0.75) in predicting progression from PACS to PAC, and inclusion of AS-OCT metrics did not improve the model's performance. Conclusions and Relevance: This cohort study suggests that higher IOP, shallower central and limbal ACDs, and smaller TISA at 500 µm and light-room ARA at 750 µm may serve as baseline predictors for progression to PAC in PACS eyes. Evaluating these factors can aid in customizing PACS management.

Practice Patterns and Sociodemographic Disparities in the Clinical Care of Anatomical Narrow Angles in the United States.

PURPOSE: To assess treatment and visit patterns among patients with newly diagnosed anatomical narrow angle (ANA) and identify sociodemographic factors associated with disparities in care. DESIGN: Retrospective practice pattern evaluation study. METHODS: A total of 263,422 patients diagnosed with ANA between 2007 and 2019 were identified in the Optum Clinformatics Data Mart. Inclusion was limited to newly diagnosed ANA, defined as (1) continuous enrollment during a 2-year lookback period and 1-year study period from first diagnosis; (2) diagnosis by an ophthalmologist or optometrist; and (3) no history of pseudophakia, ANA treatments, or prior primary angle closure glaucoma diagnosis. Outcome measures were treatment with laser peripheral iridotomy (LPI), cataract surgery, or intraocular pressure-lowering medications and number of eye care visits. Logistic and Poisson regression were performed to assess factors associated with treatment and eye care visits, respectively. RESULTS: Among 52,405 eligible cases, 27.7% received LPI, 13.9% received drops, and 15.1% received cataract surgery. Odds of LPI were higher in Asians and Hispanics (odds ratio [OR] ≥ 1.16, P < .001). Non-Whites had higher odds of drops (OR ≥ 1.19, P < .001), but Hispanics had lower odds of cataract surgery (OR = 0.79, P < .001). The mean number of eye care visits was 2.6±2.1 including the day of diagnosis. Older age and treatment were associated with higher rates of eye care visits (rate ratio > 1.15, P < .001). CONCLUSION: More than a quarter of patients with newly diagnosed ANA receive treatment with LPI. Racial minorities are more likely to receive ANA-specific treatments but less likely to receive cataract surgery. These differences may reflect racial differences in disease severity and the need for clearer practice guidelines in ANA care.

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.

Retrospective Study of Preoperative Laser Peripheral Iridotomy Versus Intraoperative Surgical Peripheral Iridectomy in Descemet Membrane Endothelial Keratoplasty.

PURPOSE: The aim of this study was to examine the outcomes of laser peripheral iridotomy (LPI) and surgical peripheral iridectomy (SPI) for Descemet membrane endothelial keratoplasty (DMEK) and DMEK with cataract extraction (triple DMEK). METHODS: This retrospective interventional study included 135 eyes of 135 patients who underwent DMEK alone or triple DMEK. Primary outcomes were graft detachments necessitating rebubbling, repeat grafts, and pupillary block. The secondary outcomes included rejection, cystoid macular edema, uveitis, intraoperative hyphema, visual disturbances, and surgical time. RESULTS: Thirty-one eyes in the LPI group and 104 eyes in the SPI group were included. Fifty-six eyes had DMEK alone, and 79 had triple DMEK. Visually significant graft detachments occurred in 7 of 31 eyes in the LPI group versus 19 of 104 eyes in the SPI group ( P = 0.61). No statistical significance in DMEK alone versus triple DMEK groups ( P = 0.61 vs. P > 0.99). Two patients in the LPI group and 5 in the SPI group required regraft ( P = 0.66). One (3.2%) experienced pupillary block compared with 5 (4.8%) ( P = 0.99) in the LPI and SPI groups, respectively. Secondary outcomes were similar in both groups ranging from 0% to 3% ( P > 0.99). None had visual disturbances. In DMEK alone, duration of surgery was significantly shorter in the LPI versus SPI group (32.8 vs. 44.1 minutes, P = 0.02). CONCLUSIONS: This study demonstrated similar outcomes between LPI and SPI, although the LPI group had a shorter duration of surgery when DMEK was performed alone. The remainder of the outcomes demonstrated no statistically significant differences.

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.

Bilateral angle closure glaucoma with retinitis pigmentosa in young patients: case series.

BACKGROUND: To report the ocular characteristics and management of three cases of retinitis pigmentosa (RP) concurrent primary angle closure glaucoma (PACG). CASE PRESENTATION: Three middle-aged patients presenting with diminished vision, high intraocular pressure (IOP), and typical fundus manifestations of RP were clinically evaluated. The individualized treatment was based on the ocular conditions of each case. A novel genetic alteration in ZNF408 was identified in one patient. Two patients with short-axial eyes received unilateral combined trabeculectomy, cataract surgery, and Irido-zonulo-hyaloid-vitrectomy. One of them had a subluxated lens, managed with a capsular tension ring implantation. Their contralateral eyes, respectively, underwent laser peripheral iridotomy (LPI) and transscleral cyclophotocoagulation. The third patient underwent bilaterally combined laser peripheral iridoplasty, LPI, and medication. Ultimately, all patients achieved the target IOP during a two-year follow-up. CONCLUSION: Young patients with RP may have a risk of developing angle closure glaucoma, and conversely, patients with angle closure glaucoma at younger age should be aware of the presence of RP. Therefore, routine gonioscopy and IOP monitoring are required for RP patients, and detailed fundus examinations are warranted for young PACG patients.

Twenty-Four-Hour Intraocular Pressure in Chronic Primary Angle-Closure Disease.

PRCIS: Primary angle closure and primary angle closure glaucoma may exhibit normal intraocular pressure. Twenty-four-hour intraocular pressure fluctuation is highest in primary angle closure glaucoma. The degree of peripheral anterior synechiae was associated with a 24-hour intraocular pressure pattern in primary angle-closure disease without laser iridotomy. PURPOSE: The purpose of this study was to study 24-hour intraocular pressure (IOP) patterns in eyes with chronic primary angle-closure disease and evaluate associations between peripheral anterior synechiae (PAS) and 24-hour IOP pattern. PATIENTS AND METHODS: In this prospective cohort study, 59 eyes of 35 Asian patients with chronic primary angle-closure disease underwent complete ocular examinations at Ramathibodi Hospital, Mahidol University. Twenty-four-hour IOP records were obtained using Goldmann applanation tonometry at 2-hour intervals. Peak, mean, and trough 24-hour IOP values and 24-hour IOP fluctuation (difference between peak and trough values) were compared among groups. None of the participants received any treatment before complete data collection. RESULTS: Even univariable analysis demonstrated a significant difference in peak, mean, and trough IOP and 24-hour IOP fluctuation between the 3 groups; the magnitude of trough IOP was not higher than 21 mmHg in all groups. In multivariable analysis, PAC and PACG eyes showed significantly higher peak IOP ( P =0.020 and 0.006, respectively) and 24-hour IOP fluctuation ( P =0.048 and 0.001, respectively) compared with PACS eyes. In comparison between combined PACS and PAC eyes versus PACG eyes, PACG eyes revealed significantly higher 24-hour IOP fluctuation. The degree of PAS was associated with peak and mean IOP values and with 24-hour IOP fluctuation in PAC and PACG eyes. CONCLUSIONS: Twenty-four-hour IOP fluctuation was highest in PACG eyes. Although PAC and PACG eyes showed higher peak IOP and 24-hour IOP fluctuation values, compared with PACS eyes, trough IOP in PAC and PACG eyes were mostly below 21 mmHg. In addition, the degree of PAS was associated with a 24-hour IOP pattern in either PAC or PACG eyes.

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.

Chronic Antioxidant Capacity Loss in Anterior Chamber Environment After Iridectomy.

Purpose: To compare the ascorbic acid concentration and total antioxidant capacity in the aqueous humor of pigmented Rex rabbits after sham operation (control), iridectomy, and trabeculectomy. Methods: Pigmented Rex rabbits were divided into control, iridectomy, and trabeculectomy groups and followed up for 12 months after surgery. Ascorbic acid concentration and total antioxidant capacity in the aqueous humor, intraocular pressure, and the occurrence of cataracts were examined in each group. Results: The ascorbic acid concentration and total antioxidant capacity after iridectomy and trabeculectomy were significantly lower at one week and at one, six, and 12 months after operation than those in the control group (P ≤ 0.03). Ascorbic acid concentration was positively and significantly correlated with total antioxidant capacity in the aqueous humor (P < 0.01). Compared to the control and the iridectomy groups, intraocular pressure in the trabeculectomy group was significantly lower at one week and at one and six months after surgery (one week: P < 0.01 and P < 0.01, respectively; one month: P < 0.01 and P = 0.03, respectively; six months: P = 0.03). Histological findings in the iridectomy and trabeculectomy groups included the appearance of vacuoles in the lens at six and 12 months after surgery. Conclusions: Iridectomy causes a sustained decrease in ascorbic acid concentration, followed by a long-term decrease in the total antioxidant capacity within the aqueous humor. Translational Relevance: The animal model possibly predicts the vulnerability focusing on the antioxidant level in the anterior chamber environment after trabeculectomy and iridectomy per se in clinical settings.

Cost-effectiveness of Prophylactic Laser Peripheral Iridotomy in Primary Angle-Closure Suspects.

PURPOSE: To investigate the cost-effectiveness (CE) of prophylactic laser peripheral iridotomy (LPI) in primary angle-closure (PAC) suspects (PACSs). DESIGN: Cost-effectiveness analysis utilizing Markov models. SUBJECTS: Patients with narrow angles (PACSs). METHODS: Progression from PACSs through 4 states (PAC, PAC glaucoma, blindness, and death) was simulated using Markov cycles. The cohort entered at 50 years and received either LPI or no treatment. Transition probabilities were calculated from published models, and risk reduction of LPI was calculated from the Zhongshan Angle Closure Prevention trial. We estimated costs of Medicare rates, and previously published utility values were used to calculate quality-adjusted life year (QALY). Incremental CE ratios (ICER) were evaluated at $50 000. Probabilistic sensitivity analyses (PSAs) addressed uncertainty. MAIN OUTCOME MEASURES: Total cost, QALY, and ICER. RESULTS: Over 2 years, the ICER for the LPI cohort was > $50 000. At 6 years, the LPI cohort was less expensive with more accrued QALY. In PSA, the LPI arm was cost-effective in 24.65% of iterations over 2 years and 92.69% over 6 years. The most sensitive parameters were probability of progressing to PAC and cost and number of annual office visits. CONCLUSIONS: By 6 years, prophylactic LPI was cost-effective. The rate of progressing to PAC and differing practice patterns most impacted CE. With uncertainty of management of narrow angles, cost may be a decision management tool for providers. FINANCIAL DISCLOSURE(S): The authors have no proprietary or commercial interest in any materials discussed in this article.