YAG Laser Peripheral Iridotomy for the Prevention of Pigment Dispersion Glaucoma

Clinical risk stratification in glaucoma

Glaucoma is the leading cause of preventable sight loss in the United Kingdom and the provision of timely glaucoma care has been highlighted as a significant challenge in recent years. Following a recent high-profile investigation, The Healthcare Safety Investigation Branch recommended the validation of risk stratification models to safeguard the vision-related quality of life of glaucoma patients. There continues to be no nationally agreed evidence-based risk stratification model for glaucoma care across the United Kingdom. Some models have used simple measures of disease staging such as visual field mean deviation as surrogates for risk, but more refined, individualised risk stratification models should include factors related to both visual impairment and visual disability. Candidate tools should also incorporate both ocular and systemic co-morbidities, rate of disease progression, visual needs and driving status and undergo clinical refinement and validation to justify implementation. The disruption to routine glaucoma care caused by the COVID-19 pandemic has only highlighted the importance of such risk stratification models and has accelerated their development, application and evaluation. This review aims to critically appraise the available evidence underpinning current approaches for glaucoma risk stratification and to discuss how these may be applied to contemporary glaucoma care within the United Kingdom. Further research will be essential to justify and validate the utility of glaucoma risk stratification models in everyday clinical practice.

Pigment dispersion syndrome and pigmentary glaucoma: overview and racial disparities

Pigment dispersion syndrome (PDS) and pigmentary glaucoma (PG) are two stages within the same ophthalmic disease spectrum, which are known to be affected by race. The prevalence of PDS is underestimated, largely due to its minor clinical symptoms. Although the prevalence of PG is low, the visual impairment associated with PG is extremely severe. The prevalence of PDS-PG is four or more times higher in Caucasians than in Blacks or Asians, and the "classic" PDS in Caucasians has long been used as a benchmark diagnostic criterion. Following extensive research focused on African Americans and Asians, the standard for diagnosing PDS-PG was refined. At the same time, the pathogenesis of PDS is not the same in different races. Hence, the effectiveness of preventive treatment and the need for treatment may not be equivalent in different races. The rate of conversion of PDS to PG is nearly 1/3 in Caucasians and higher in blacks and Asians, requiring more aggressive treatment and monitoring. We systematically searched a PubMed database from inception to March 2022 to provide an overview of research progress in various aspects of PDS-PG. Specifically, this paper considers the effects of race on disease prevalence, clinical manifestation, diagnostic criteria, disease mechanism, hereditary traits, treatment, and prevention to provide an accurate and comprehensive guide for the diagnosis and treatment of PDS-PG in various races.

The Effectiveness of Laser Peripheral Iridotomy in Adolescent Eyes with Ocular Hypertension and Concave Configuration of the Peripheral Iris

Purpose

To evaluate the efficacy of laser peripheral iridotomy (LPI) in preventing deterioration in eyes with ocular hypertension (OHT) and concave configuration of the iris.

Materials and Methods

This was a retrospective study, which was carried out within a period of 3–5 years. Twenty-four patients with OHT and concave irises were treated with LPI and followed up periodically. IOP, central corneal thickness (CCT), anterior chamber depth (ACD), scleral spur angle (SSA), global neuroretinal rim (NRR) thickness, and global retinal nerve fiber layer (RNFL) were examined before and after LPI.

Results

The average age of the 24 patients was 14.21 ± 1.41 (13–17.5) years on admission. The initial IOP of the 48 eyes was 23.21 ± 1.56 mmHg in RE and 22.96 ± 2.1 mmHg in LE before LPI. All 48 eyes had concave irises in both eyes. All eyes treated with LPI have shown iris flattening, which has persisted during follow-up (mean 1.54 ± 0.9 years). At the last follow-up visit, the average IOP was 17.58 ± 2.63 (14–21) mmHg in RE and 17.58 ± 2.86 (14–21) mmHg in LE, which was statistically lower than that of the baseline (p < 0.001). There were significant changes in SSA in both eyes and global RNFL in RE after LPI.

Conclusions

In the current study, LPI resulted in an IOP-lowering effect and iris flattening in adolescent eyes with a concave configuration of the peripheral iris.

Changes of trabecular meshwork pigmentation in patients with pigment dispersion syndrome: A 15-year study

To report the changes of trabecular meshwork (TM) pigmentation and clinical outcomes of patients with pigment dispersion syndrome (PDS) after resolution of reverse pupillary block.Twenty one eyes of 11 PDS patients were followed up periodically for 15 years after resolution of reverse pupillary block with either Nd: YAG laser peripheral iridotomy (LPI) or trabeculectomy. Visual acuity (VA), best-corrected visual acuity (BCVA), slit lamp examination, intraocular pressure (IOP), Humphrey visual field analysis (VFA), gonioscopy and stereoscopic funduscopy were performed on admission and every 6 months postoperatively. TM pigmentation was quantitatively evaluated and graded every 5 years after the treatment, in which the circumference of anterior chamber angle was divided into 4 quadrants: superior, inferior, nasal and temporal. Postoperative IOP, VA, BCVA, VFA, TM pigmentation and adjunctive anti-glaucoma medications were main outcome measurements and compared with baseline.Eleven patients (9 males, 2 females) were identified as PDS according to the diagnostic criteria, with average age of 38.25 ± 6.93 years (range, 31-55 years) at initial diagnosis. The mean IOP level was 33.1 ± 9.8 mmHg (range, 22-56 mmHg) at diagnosis. Ten PDS eyes received LPI, and the other eleven eyes underwent uneventful trabeculectomy. The median TM pigmentation score of the 21 PDS eyes was 16 (interquartile range [IQR], 15-16) on admission, which changed to 14 (IQR, 13-15), 13 (IQR, 12-14), 12(IQR, 10.5-12) at 5-, 10-, 15-year follow-up visits respectively. The decrease rate of TM pigmentation was 37% in inferior quadrant, while in nasal, temporal, and superior quadrant the reduction rate was 28%, 23%, and 18%, respectively, at the last follow-up visit. Majority of these enrolled eyes (19/21) had stable VA and BCVA with average endpoint IOP of 15.1 ± 3.4 mmHg.TM pigmentation in PDS patients attenuates with time after reverse pupillary block was resolved, in which the inferior quadrant seems faster than the other quadrants.

Pigment dispersion syndrome and its implications for glaucoma

Pigment dispersion syndrome (PDS) represents a clinical spectrum of a relatively common and usually underdiagnosed phenomenon produced by spontaneous pigment dispersion from the iris into the anterior segment. PDS is often bilateral, has no gender predisposition, and presents at a young age, particularly in myopes. Although most patients experiencing an episode of pigment dispersion are asymptomatic, extreme photophobia, ocular pain, redness, and blurred vision may occur. Other characteristic signs are iridolenticular contact, concave iris configuration, 360° peripheral iris transillumination, and pigment deposition on the anterior chamber angle or the corneal endothelium (Krukenberg spindle). Early PDS diagnosis is crucial to detect patients with pigment-related ocular hypertension (POHT) that can eventually lead to pigmentary glaucoma (PG). The latter represents a sight-threatening condition in which mechanical, environmental, and genetic factors contribute to optic nerve damage. In this review, we update the pathogenic mechanisms involved in the clinical spectrum of the disease. We describe its clinical presentation, ophthalmologic manifestations, and complications, including the factors influencing the development of POHT and PG. Because PDS has variable clinical presentations that lead to misdiagnoses, we emphasize the differential diagnosis and the actual therapeutic strategies according to disease status.

Effects of Nd-YAG Laser iridotomy on anterior segment measurements in pigment dispersion syndrome and ocular hypertension

PURPOSE

To compare the anterior segment optical coherence tomography (AS-OCT) measurements of eyes with pigment dispersion syndrome (PDS) and ocular hypertension (OHT) before and after neodymium:yttrium-aluminum-garnet (Nd:YAG) laser peripheral iridotomy (LPI).

METHODS

A total of 23 eyes of 23 patients with PDS and OHT with features of PDS were included in this retrospective study. All of the eyes with PDS and OHT were examined by AS-OCT before and after Nd:YAG LPI. Anterior chamber depth, angle opening distance 500, angle opening distance 750, trabecular iris space 500, trabecular iris space 750 and scleral spur angle, iris bowing and iris shape were measured with AS-OCT by the same examiner.

RESULTS

The differences in all parameters before and after Nd:YAG LPI were statistically significant. Iris configuration was concave in all eyes prior to iridotomy. After Nd:YAG laser iridotomy, the iris configuration became convex in 7 eyes, flat in 9 eyes and remained concave in 7 eyes.

CONCLUSION

Nd:YAG laser peripheral iridotomy is an effective method for reversing the iris concavity and iris bowing in pigment dispersion syndrome.

[The trabecular meshwork: Structure, function and clinical implications. A review of the littérature (French translation of the article)]

Glaucoma is a blinding optic neuropathy, the main risk factor for which is increased intraocular pressure (IOP). The trabecular meshwork, located within the iridocorneal angle, is the main pathway for drainage of aqueous humor (AH) out of the eye, and its dysfunction is responsible for the IOP elevation. The trabecular meshwork is a complex, fenestrated, three-dimensional structure composed of trabecular meshwork cells (TMC) interdigitated into a multilayered organization within the extracellular matrix (ECM). The purpose of this literature review is to provide an overview of current understanding of the trabecular meshwork and its pathophysiology in glaucoma. Thus, we will present the main anatomical and cellular bases for the regulation of aqueous humor outflow resistance, the pathophysiological mechanisms involved in trabecular dysfunction in the various types of glaucoma, as well as current and future therapeutic strategies targeting the trabecular meshwork.

Efficacy and Safety of Trabeculectomy Versus Nonpenetrating Surgeries in Open-angle Glaucoma: A Meta-analysis

PURPOSE

The purpose of this study was to conduct a meta-analysis on the efficacy and safety of trabeculectomy (TE) and nonpenetrating glaucoma surgery (NPGS) techniques in patients with primary open-angle glaucoma, pseudoexfoliation glaucoma, pigmentary glaucoma, and normal-tension glaucoma.

METHODS

All studies were identified by searching electronic sources (PubMed, Medline, Scopus, and Embase) until February 5, 2018. Primary outcome was mean intraocular pressure (IOP) reduction at 6, 12, and 24 months. Complications, number of antiglaucomatous medications, and visual outcomes were also evaluated.

RESULTS

Twenty-one studies were included. Ten studies compared TE with deep sclerectomy (DS), 5 with viscocanalostomy (VC), 1 study with both DS and VC, and 5 with canaloplasty (CP). TE was superior to DS, VC, and CP in reducing IOP at 6 and 12 months, and to DS at 24 months. When comparing TE to VC and to CP at 24 months, there was no significant difference in IOP reduction. Hypotony, choroidals, anterior chamber shallowing or flattening, and cataract formation or progression were more associated with TE than with NPGSs. TE was more effective in reducing antiglaucomatous medications than VC and CP.

CONCLUSIONS

TE is more effective in reducing IOP. TE presents a higher risk of complications as compared with NPGS, except for hyphema.

The trabecular meshwork: Structure, function and clinical implications. A review of the literature

Glaucoma is a blinding optic neuropathy, the main risk factor for which is increased intraocular pressure (IOP). The trabecular meshwork, located within the iridocorneal angle, is the main pathway for drainage of aqueous humor (AH) out of the eye, and its dysfunction is responsible for the IOP elevation. The trabecular meshwork is a complex, fenestrated, three-dimensional structure composed of trabecular meshwork cells (TMC) interdigitated into a multilayered organization within the extracellular matrix (ECM). The purpose of this literature review is to provide an overview of current understanding of the trabecular meshwork and its pathophysiology in glaucoma. Thus, we will present the main anatomical and cellular bases for the regulation of aqueous humor outflow resistance, the pathophysiological mechanisms involved in trabecular dysfunction in the various types of glaucoma, as well as current and future therapeutic strategies targeting the trabecular meshwork.

Pigment dispersion syndrome and response to laser peripheral iridotomies in a child with Marfan syndrome

Pigment dispersion syndrome (PDS) and pigmentary glaucoma have rarely been reported in Marfan syndrome and have never been reported in a child with Marfan syndrome. We report the clinical and ultrasound biomicroscopic findings of PDS in a 14-year-old girl with Marfan syndrome and its favorable response to bilateral laser peripheral iridotomy.

Pigment dispersion syndrome and pigmentary glaucoma: a review and update

INTRODUCTION

Pigment dispersion syndrome (PDS) is a condition where anomalous iridozonular contact leads to pigment dispersion throughout the anterior segment and the released pigment is abnormally deposited on various ocular structures.

CLINICAL PRESENTATION

The clinical presentation of PDS is defined by the presence of pigmented cells on the corneal endothelium, an increase of pigmentation of the trabecular meshwork, and mid-periphery transillumination defects of the iris. This syndrome, more common in myopes, is usually bilateral and can be associated with ocular hypertension or glaucoma. Secondary open-angle pigmentary glaucoma (PG) can develop due to reduction of the outflow of aqueous humour and consequent increase in intraocular pressure leading to glaucomatous optic neuropathy. Diagnosis of PG is commonly between 40 and 50 years of age, occurring more frequently in men. The advent of ultrasound biomicroscopy and anterior segment optical coherence tomography has contributed to enhancing our knowledge on the condition. Typical alterations of the anterior segment are the posterior insertion of the iris and iris concavity. Treatment of PG should be initiated early to hinder disease progression, glaucomatous damage, and vision loss. Management is based on medical therapy, laser iridotomy, selective laser trabeculoplasty, and filtration procedures.

CONCLUSIONS

The differential diagnosis of PDS with other disorders can be challenging and awareness of the condition together with meticulous ophthalmologic examination allows early diagnosis followed by appropriate management strategies. The present review is a comprehensive report on the clinical characteristics, pathogenesis, current management, and status quo of PDS and PG.

[Role of laser peripheral iridotomy in pigmentary glaucoma and pigment dispersion syndrome: A review of the literature [French version]]

PURPOSE

Pigment dispersion syndrome (PSD) is characterized by a structural abnormality of the posterior surface of the iris causing contact with the zonular fibers. It can lead to an open-angle glaucoma secondary to pigment dispersion into the trabecular meshwork. Laser peripheral iridotomy (PI) has been proposed as a treatment for pigmentary glaucoma (PG) and pigment dispersion syndrome (PDS) by reducing the dispersion of pigment. The goal of this review was to assess the effects of PI for PSD and PG.

METHODS

We included six randomized controlled trials and two cohort studies (286 eyes of 218 participants). Four trials included participants with PG, and 4 trials enrolled participants with PSD with or without elevated intraocular pressure (IOP).

RESULTS

Among patients with PG, at an average of 9 months of follow-up, the mean difference in IOP between groups was 2.69mmHg less in the PI group (95 % CI: -6.05 to 0.67; 14 eyes). In patients with PDS, the average IOP was statistically lower after PI as compared to baseline (Student test, t=11.49, P<0.01). With regard to visual field progression in participants with GP, after an average follow-up of 28 months, the risk of progression was not influenced by PI (RR 1.00 95 %: CI 0.16 to 6.25; 32 eyes). No trials that enrolled patients with PSD showed a diminution of the risk of glaucoma conversion at mid- and long-term.

CONCLUSION

PI decreases the biomechanical factor causing contact between the iris and zonular fibers and may lower IOP over the long-term. Nevertheless, the effects of PI on visual field changes or progression have not been established in PG and PDS. There is no scientific evidence as of yet to advocate PI as a treatment for PDS or PG.

Reverse pupillary block after implantation of a scleral-sutured posterior chamber intraocular lens: a retrospective, open study

BACKGROUND

To report the clinical features of patients with reverse pupillary block (RPB) after scleral-sutured posterior chamber intraocular lens (PC IOL) implantation and biometric changes after laser peripheral iridotomy (LPI).

METHODS

Eight patients attending our hospital's ophthalmology outpatient clinic, who developed RPB after implantation of a scleral-sutured PC IOL due to subluxation of the crystalline lens or IOL, were investigated in this retrospective, observational study.

RESULTS

Preoperative evaluations showed angle pigmentation in all cases and iridodonesis in 2 cases. Two subjects had used an α1A-adrenoceptor antagonist for benign prostatic hyperplasia. Pars plana or anterior partial vitrectomy was performed in all cases. All eyes showed an extremely deep anterior chamber, a concave iris configuration, and contact between the IOL optic and the iris at the pupillary margin. Pupil capture was detected in 2 cases. The mean (± SD) anterior chamber angle (ACA) was 89.91 ± 10.06°, and the anterior chamber depth (ACD) was 4.42 ± 0.16 mm before LPI. After LPI, the iris immediately became flat with a decreased ACA (51.70 ± 2.59°; P = 0.018) and ACD (4.14 ± 0.15 mm; P = 0.012). After LPI, the intraocular pressure decreased from 19.75 ± 3.77 mmHg to 15.63 ± 4.30 mmHg (P = 0.011), and the spherical equivalent decreased from -0.643 ± 0.385 D to - 0.875 ± 0.505 D (P = 0.016).

CONCLUSION

Concomitant vitrectomy, angle pigmentation, and iridodonesis may be risk factors for RPB after scleral-sutured PC IOL implantation. LPI is effective for relieving the RPB.

Update on pigment dispersion syndrome and pigmentary glaucoma

PURPOSE OF REVIEW

The present article reviews the clinical features and pathogenesis of pigment dispersion syndrome and pigmentary glaucoma and provides an update regarding their diagnosis and management.

RECENT FINDINGS

Newer imaging modalities including ultrasound biomicroscopy and anterior segment optical coherence tomography facilitate visualization of the iris concavity characteristic of eyes with pigment dispersion syndrome and pigmentary glaucoma. Patients with pigmentary glaucoma may be distinguished from those with other glaucoma types by the presence of typical symptoms, personality type, and patterns of diurnal intraocular pressure fluctuation. Although laser iridotomy has been shown to alter iris anatomy in pigmentary glaucoma, it is not proven to slow visual field progression. Multiple trials have validated the safety and efficacy of filtering surgery in treating pigmentary glaucoma, with fewer studies published on the role of micro-invasive glaucoma surgery.

SUMMARY

Literature from the review period has further defined the unique clinical characteristics of pigment dispersion syndrome and pigmentary glaucoma. Laser surgery has a limited role in the management of these entities, whereas trabeculectomy remains an acceptable first-line surgical treatment. Further studies are needed to define the potential application of the newer micro-invasive glaucoma procedures in pigmentary glaucoma.

Laser iridotomy to treat uveitis-glaucoma-hyphema syndrome secondary to reverse pupillary block in sulcus-placed intraocular lenses: Case series

PURPOSE

To present cases of uveitis-glaucoma-hyphema (UGH) syndrome due to reverse pupillary block in sulcus-placed posterior chamber intraocular lenses (PC IOLs) that were managed with laser peripheral iridotomy (LPI).

SETTING

Community-based subspecialty clinics.

DESIGN

Retrospective interventional case series.

METHODS

A chart review of patients with a sulcus-placed PC IOLs presenting with UGH syndrome and reverse pupillary block with posterior iris bowing as diagnosed by gonioscopy and anterior segment optical coherence tomography was carried out. Laser peripheral iridotomy was performed in the eyes included in the study. The main outcome measure was clinical resolution of UGH syndrome.

RESULTS

The study included 6 eyes of 6 patients with a mean age of 59.8 years (range 43.0 to 66.0 years) who presented with unilateral UGH syndrome a mean of 28.7 months (range 0.3 to 84.0 months) after PC IOL implantation. All patients were previously myopic, with 5 (83.3%) having a history of vitrectomy. The mean axial length was 27.0 mm ± 1.4 (SD). An LPI was used to treat the reverse pupillary block with resultant improvement in iris profile and resolution of UGH syndrome in all eyes. The mean intraocular pressure decreased from 30.5 ± 10.0 mm Hg on 0.5 ± 0.8 glaucoma medications to 15.5 ± 3.2 mm Hg postoperatively on 0.7 ± 1.2 medications.

CONCLUSIONS

The UGH syndrome due to reverse pupillary block occurred after sulcus-placed PC IOLs in susceptible patients, those with axial myopia, and post-vitrectomized eyes. The cases were managed with LPIs.

FINANCIAL DISCLOSURE

Dr. Ahmed is a consultant to Alcon Laboratories, Inc. and Abbott Medical Optics, Inc. No author has a financial or proprietary interest in any material or method mentioned.

Peripheral iridotomy for pigmentary glaucoma

BACKGROUND

Glaucoma is a chronic optic neuropathy characterized by retinal ganglion cell death resulting in damage to the optic nerve head and the retinal nerve fiber layer. Pigment dispersion syndrome is characterized by a structural disturbance in the iris pigment epithelium (the densely pigmented posterior surface of the iris) that leads to dispersion of the pigment and its deposition on various structures within the eye. Pigmentary glaucoma is a specific form of open-angle glaucoma found in patients with pigment dispersion syndrome.Topcial medical therapy is usually the first-line treatment; however, peripheral laser iridotomy has been proposed as an alternate treatment. Peripheral laser iridotomy involves creating an opening in the iris tissue to allow drainage of fluid from the posterior chamber to the anterior chamber and vice versa. Equalizing the pressure within the eye may help to alleviate the friction that leads to pigment dispersion and prevent visual field deterioration. However, the effectiveness of peripheral laser iridotomy in reducing the development or progression of pigmentary glaucoma is unknown.

OBJECTIVES

The objective of this review was to assess the effects of peripheral laser iridotomy compared with other interventions, including medication, trabeculoplasty, and trabeculectomy, or no treatment, for pigment dispersion syndrome and pigmentary glaucoma.

SEARCH METHODS

We searched a number of electronic databases including CENTRAL, MEDLINE and EMBASE and clinical trials websites such as (mRCT) and ClinicalTrials.gov. We last searched the electronic databases on 2 November 2015.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that had compared peripheral laser iridotomy versus no treatment or other treatments for pigment dispersion syndrome and pigmentary glaucoma.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures for systematic reviews. Two review authors independently screened articles for eligibility, extracted data, and assessed included trials for risk of bias. We did not perform a meta-analysis because of variability in reporting and follow-up intervals for primary and secondary outcomes of interest.

MAIN RESULTS

We included five RCTs (260 eyes of 195 participants) comparing yttrium-aluminum-garnet (YAG) laser iridotomy versus no laser iridotomy. Three trials included participants with pigmentary glaucoma at baseline, and two trials enrolled participants with pigment dispersion syndrome. Only two trials reported the country of enrollment: one - Italy, the other - United Kingdom. Overall, we assessed trials as having high or unclear risk of bias owing to incomplete or missing data and selective outcome reporting.Data on visual fields were available for one of three trials that included participants with pigmentary glaucoma at baseline. At an average follow-up of 28 months, the risk of progression of visual field damage was uncertain when comparing laser iridotomy with no iridotomy (risk ratio (RR) 1.00, 95% confidence interval (95% CI) 0.16 to 6.25; 32 eyes; very low-quality evidence). The two trials that enrolled participants with pigment dispersion syndrome at baseline reported the proportion of participants with onset of glaucomatous visual field changes during the study period. At three-year follow-up, one trial reported that the risk ratio for conversion to glaucoma was 2.72 (95% CI 0.76 to 9.68; 42 eyes; very low-quality evidence). At 10-year follow-up, the other trial reported that no eye showed visual field progression.One trial reported the mean change in intraocular pressure (IOP) in eyes with pigmentary glaucoma: At an average of nine months of follow-up, the mean difference in IOP between groups was 2.69 mmHg less in the laser iridotomy group than in the control group (95% CI -6.05 to 0.67; 14 eyes; very low-quality evidence). This trial also reported the mean change in anterior chamber depth at an average of nine months of follow-up and reported no meaningful differences between groups (mean difference 0.04 mm, 95% CI -0.07 to 0.15; 14 eyes; very low-quality evidence). No other trial reported mean change in anterior chamber depth. Two trials reported greater flattening of iris configuration in the laser iridotomy group than in the control group among eyes with pigmentary glaucoma; however, investigators provided insufficient data for analysis. No trial reported data related to mean visual acuity, aqueous melanin granules, costs, or quality of life outcomes.Two trials assessed the need for additional treatment for control of IOP. One trial that enrolled participants with pigmentary glaucoma reported that more eyes in the laser iridotomy group required additional treatment between six and 23 months of follow-up than eyes in the control group (RR 1.73, 95% CI 1.08 to 2.75; 46 eyes); however, the other trial enrolled participants with pigment dispersion syndrome and indicated that the difference between groups at three-year follow-up was uncertain (RR 0.91, 95% CI 0.38 to 2.17; 105 eyes). We graded the certainty of evidence for this outcome as very low.Two trials reported that no serious adverse events were observed in either group among eyes with pigment dispersion syndrome. Mild adverse events included postoperative inflammation; two participants required cataract surgery (at 18 and 34 months after baseline), and two participants required a repeat iridotomy.

AUTHORS' CONCLUSIONS

We found insufficient evidence of high quality on the effectiveness of peripheral iridotomy for pigmentary glaucoma or pigment dispersion syndrome. Although adverse events associated with peripheral iridotomy may be minimal, the long-term effects on visual function and other patient-important outcomes have not been established. Future research on this topic should focus on outcomes that are important to patients and the optimal timing of treatment in the disease process (eg, pigment dispersion syndrome with normal IOP, pigment dispersion syndrome with established ocular hypertension, pigmentary glaucoma).

Pigment Dispersion Syndrome Progression to Pigmentary Glaucoma in a Latin American Population

Objective: To determine the progression of pigment dispersion syndrome (PDS) into pigmentary glaucoma (PG) in a population at the Central Military Hospital in Bogotá, Colombia.

Materials and methods: A retrospective study was conducted, based on a review of medical records of patients with PDS evaluated in the Glaucoma Clinic. Data were collected in a database in excel and subsequently analyzed with the software Statistical Package for the Social Sciences (SPSS), performing Chi-square test analysis and Spearman’s rho test.

Results: Forty-eight eyes of 24 patients were included. Forty-two percent were women and 58% were men. Pigmentation of the trabecular meshwork was the most frequent clinical sign (100%), followed by Krukenberg’s spindle (91.7%), the least frequent were the iris concavity and iris heterochromia (4.2%), the average of the spherical equivalent was of - 1.33 (SD 2.07).

The rate of conversion of PDS to PG was 37.5%, after an average follow-up of 50.7 months. Having an intraocular pressure (IOP) greater than 21 mm Hg was statistically the only significant risk factor for conversion.

Conclusion: We found several differences in frequency and clinical signs in these patients in contrast to previous data, probably due to different racial characteristics.

The rate of progression is similar to previous reports despite of heterogeneity of these. Having IOP > 21 mm Hg was the only risk factor associated with progression in this sample.

How to cite this article: Gomez Goyeneche HF, Hernandez-Mendieta DP, Rodriguez DA, Sepulveda AI, Toledo JD. Pigment Dispersion Syndrome Progression to Pigmentary Glaucoma in a Latin American Population. J Curr Glaucoma Pract 2015;9(3):69-72.

Anterior-segment morphology and corneal biomechanical characteristics in pigmentary glaucoma

Purpose

The aim of the study reported here was to evaluate characteristics of the anterior-segment via anterior-segment optical coherence tomography (AS-OCT) and corneal biomechanical properties using an ocular response analyzer and their changes by peripheral laser iridotomy (PI) in patients with pigmentary glaucoma (PG).

Materials and methods

Seventeen eyes with PG were included consecutively. AS-OCT and ocular response analyzer measurements were taken before and 3 months after PI. Baseline morphology and change in morphology were analyzed by correlation and multiple linear regression analysis. The main parameters assessed were anterior-chamber (AC) angles and volume as well as corneal hysteresis (CH) and corneal resistance factor.

Results

AC angles were found to have decreased significantly in each quadrant after PI (P<0.001), with the highest effect seen in the temporal quadrant, which decreased from 57.0°±9.6° to 44.1°±5.2° (± standard deviation). Mean AC volume decreased significantly from 213.1±36.4 to 187.0±23.4 mm³ (P<0.001). CH and corneal resistance factor did not change after PI. CH was found to correlate with the preoperative superior and inferior angle width (Spearman’s rho 0.553 and 0.615, respectively, P<0.05). Biomechanical parameters showed no predictive value on the change of AC angles or volume.

Conclusion

PI in eyes with PG results in a highly significant reduction in the AC angles and volume as visualized by AS-OCT, with the largest effect seen in the temporal quadrant. CH is strongly positively correlated with the superior and inferior preoperative AC angles, emphasizing the importance of the biomechanical properties of the cornea for glaucoma pathogenesis in PG, but corneal biomechanical properties cannot predict PI-related AC changes.

Iris coloboma in one eye and pigment dispersion syndrome in the fellow eye

We report a case of a 43-year-old patient with coloboma of the iris, zonule, ciliary body, choroid and retina in the right eye and pigment dispersion syndrome in the left eye. Considering the hypothesis of the pigment dispersion syndrome pathogenesis in which a difference of pressures in the anterior and posterior chambers creates a posterior convexity of the iris leading to reverse pupillary block, iris touch and consequently causing pigment dispersion, we suggest that the presence of an iris coloboma, by equalising the pressures in the two chambers, prevented the onset of syndrome in that eye.

Secondary pigmentary glaucoma in patients with underlying primary pigment dispersion syndrome

Primary pigment dispersion syndrome (PPDS) is a bilateral condition that occurs in anatomically predisposed individuals. PPDS may evolve into pigmentary glaucoma, but it is difficult to predict which patients will progress. Secondary pigment dispersion is more often unilateral and acquired as a result of surgery, trauma, or intraocular tumor, but can likewise lead to pigmentary glaucoma. We report two cases of patients with bilateral PPDS who developed secondary pigment dispersion and pigmentary glaucoma in one eye. Patients with PPDS who acquire a secondary mechanism of pigment dispersion may be at an increased risk of progression to pigmentary glaucoma, presumably due to an increased burden of liberated pigment. In addition to regular surveillance for progression to glaucoma from PPDS, secondary causes of pigmentary dispersion in these eyes should be considered when patients present with grossly asymmetric findings. When secondary pigment dispersion is identified in eyes with PPDS, we recommend prompt intervention to alleviate the cause of secondary pigment dispersion and/or aggressive control of intraocular pressure to limit glaucomatous damage.

[Is prophylactic YAG iridotomy useful in pigment dispersion syndrome?]

Despite theoretical considerations concerning the advantage of iridotomy in eyes with pigment dispersion syndrome or early pigment glaucoma, there is a lack of clinical evidence that this procedure has a long-term effect in preventing glaucoma damage under these circumstances. However, several factors may contribute to this lack of evidence, e.g. the statistical problem of a low conversion rate from pigment dispersion syndrome to pigment glaucoma or the inclusion criteria in the studies treating patients older than 40 years or genetic dispositions in pigment glaucoma that are not yet fully clear. On the basis of current data the decision for YAG iridotomy should only be taken in patients younger than 40 years, if the midperipheral iris shows an inverse bowing and the intraocular pressure is normal or slightly increased with no progressive signs of optic nerve damage. In cases of insufficient intraocular pressure and visual defects due to glaucomatous optic nerve damage, incisional glaucoma surgery is usually necessary especially in younger patients with a long life expectancy.

Marfan syndrome caused by a novel FBN1 mutation with associated pigmentary glaucoma

Mutations in fibrillin-1 (FBN1) cause a wide spectrum of disorders, including Marfan syndrome, which have in common defects in fibrillin-1 microfibrils. Ectopia lentis and myopia are frequently observed ocular manifestations of Marfan syndrome. Glaucoma is also associated with Marfan syndrome, though the form of glaucoma has not been well-characterized. In this report, ocular examination of a patient diagnosed with Marfan syndrome based on family history and aortic dilatation was performed, including measurement of facility of aqueous humor outflow by tonography. The patient did not have ectopia lentis at the age of 42 years. Based on optic nerve appearance, reduced outflow facility, elevated IOP with open angles and clear signs of pigment dispersion, the patient was diagnosed with pigmentary glaucoma. The patient was heterozygous for a novel truncating mutation in FBN1, p.Leu72Ter. Histology of normal human eyes revealed abundant expression of elastic fibers and fibrillin-1 in aqueous humor outflow structures. This is the first report of a patient with Marfan syndrome that is caused by a confirmed FBN1 mutation with associated pigmentary glaucoma. In addition to identifying a novel mutation of FBN1 and broadening the spectrum of associated ocular phenotypes in Marfan syndrome, our findings suggest that pigmentary glaucoma may involve defects in fibrillin-1 microfibrils. © 2013 Wiley Periodicals, Inc.

Two Japanese cases of pigmentary glaucoma followed for 15 and 16 years following laser peripheral iridotomy

PURPOSE

To report two Japanese cases of pigmentary glaucoma (PG) treated with laser peripheral iridotomy (LPI) that were followed for 15 and 16 years, respectively.

METHODS

The medical records of two patients with PG who were successfully treated with LPI were reviewed. Changes in the intraocular pressure (IOP) were followed.

RESULTS

Case 1 was that of a 35-year-old man with LPI who underwent argon laser trabeculoplasty twice. He required ocular hypotensive drugs to maintain the IOP at normal levels. Case 2 involved a 36-year-old man with LPI who required ocular hypotensive drugs to maintain his IOP at the low-teen level. The IOP of both patients was unstable during the first 6-8 years following the LPI, but showed a decrease at each annual follow-up examination up to the age of 50 years.

CONCLUSIONS

Although only two cases were followed, we conclude that the long-term effects of LPI may play a role, at least partly, in stabilizing the IOP at the low-teen level. Both patients were relatively young at the time of the LPI, and age may have been a factor in the stabilization process. Our findings confirm similar findings in Western countries.