Pigmentary dispersion syndrome and pigmentary glaucoma. A prospective study of the natural history

Lack of Association between LOXL1 Variants and Pigment Dispersion Syndrome/Pigmentary Glaucoma: A Meta-Analysis

The phenotypic similarities between exfoliation syndrome (XFS)/exfoliation glaucoma (XFG) and pigment dispersion syndrome (PDS)/pigmentary glaucoma (PG), particularly their association with material deposition in the eye's anterior segment, have prompted investigations into genetic commonalities. This study focuses on the LOXL1 gene, conducting a comprehensive meta-analysis of three candidate gene association studies. We analyzed three single nucleotide polymorphisms (SNPs) of LOXL1: rs1048661, rs3825942, and rs2165241. Our results reveal nominal significance for the exonic SNPs rs1048661 and rs3825942 (p ≤ 0.01), but show no significant association for the intronic SNP rs2165241 (p = 0.83) with PDS/PG. There was homogeneity across study cohorts (I2 = 0), and sensitivity analyses and funnel plots confirmed a lower likelihood of bias in our findings. The lack of a statistically significant association between LOXL1 variants and PDS/PG at p < 0.05 was attributable to the insufficient statistical power of the pooled data, which ranged from 5% to 37% for the three SNPs. This study suggests no association between LOXL1 variants and PDS/PG. Further validation and exploration of XFS/XFG-associated genes in larger and more diverse cohorts would be helpful to determine the genetic correlation or distinctiveness between these conditions.

Genetic Basis of Pigment Dispersion Syndrome and Pigmentary Glaucoma: An Update and Functional Insights

Pigment Dispersion Syndrome (PDS) and Pigmentary Glaucoma (PG) comprise a spectrum of ocular disorders characterized by iris pigment dispersion and trabecular meshwork changes, resulting in increased intraocular pressure and potential glaucomatous optic neuropathy. This review summarizes recent progress in PDS/PG genetics including rare pathogenic protein coding alterations (PMEL) and susceptibility loci identified from genome-wide association studies (GSAP and GRM5/TYR). Areas for future research are also identified, especially the development of efficient model systems. While substantial strides have been made in understanding the genetics of PDS/PG, our review identifies key gaps and outlines the future directions necessary for further advancing this important field of ocular genetics.

Secondary glaucoma: Toward interventions based on molecular underpinnings

Glaucoma is a heterogeneous group of progressive diseases that leads to irreversible blindness. Secondary glaucoma refers to glaucoma caused by a known underlying condition. Pseudoexfoliation and pigment dispersion syndromes are common causes of secondary glaucoma. Their respective deposits may obstruct the trabecular meshwork, leading to aqueous humor outflow resistance, ocular hypertension, and optic neuropathy. There are no disease-specific interventions available for either. Pseudoexfoliation syndrome is characterized by fibrillar deposits (pseudoexfoliative material) on anterior segment structures. Over a decade of multiomics analyses taken together with the current knowledge on pseudoexfoliative glaucoma warrant a re-think of mechanistic possibilities. We propose that the presence of nucleation centers (e.g., vitamin D binding protein), crosslinking enzymes (e.g., transglutaminase 2), aberrant extracellular matrix, flawed endocytosis, and abnormal aqueous-blood barrier contribute to the formation of proteolytically resistant pseudoexfoliative material. Pigment dispersion syndrome is characterized by abnormal iridolenticular contact that disrupts iris pigment epithelium and liberates melanin granules. Iris melanogenesis is aberrant in this condition. Cytotoxic melanogenesis intermediates leak out of melanosomes and cause iris melanocyte and pigment epithelium cell death. Targeting melanogenesis can likely decrease the risk of pigmentary glaucoma. Skin and melanoma research provides insights into potential therapeutics. We propose that specific prostanoid agonists and fenofibrates may reduce melanogenesis by inhibiting cholesterol internalization and de novo synthesis. Additionally, melatonin is a potent melanogenesis suppressor, antioxidant, and hypotensive agent, rendering it a valuable agent for pigmentary glaucoma. In pseudoexfoliative glaucoma, where environmental insults drive pseudoexfoliative material formation, melatonin's antioxidant and hypotensive properties may offer adjunct therapeutic benefits. This article is categorized under: Neurological Diseases > Molecular and Cellular Physiology.

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.

Histopathology of Pigment dispersion syndrome and glaucoma

Pigment dispersion syndrome (PDS) can have varied manifestations. Anterior and posterior segment involvement by dispersed pigments was documented in gross pathology and by staining under microscopy. Pigmentary changes in the sclera, cornea, anterior chamber, iris, trabecular meshwork, lens, and retinal pigment epithelium and optic nerve findings were consistent with PDS. External scleral and vitreous pigmentation has never been reported before in the scientific literature. Retinal pigment degeneration and granule dispersion were seen throughout the retina which could be a contributing factor in the etiology of PDS.

[Pigmentary glaucoma: yesterday, today, tomorrow]

Pigment dispersion syndrome (PDS) is a condition that mostly affects young men with myopic refraction. PDS is characterized by the presence of Krukenberg spindle, peripheral iris defects, significant trabecular meshwork pigmentation, as well as convex iris configuration. Such configuration can cause friction of iris's posterior pigment layer on its ligaments, which leads to the release of pigment and its accumulation mostly in the structures of the anterior chamber. Over time PDS can progress into pigmentary glaucoma (PG), which in turn can lead to permanent loss of vision. This review analyzes available data on diagnosis and treatment of PDS and PG.

Exome-based investigation of the genetic basis of human pigmentary glaucoma

Background

Glaucoma is a leading cause of visual disability and blindness. Release of iris pigment within the eye, pigment dispersion syndrome (PDS), can lead to one type of glaucoma known as pigmentary glaucoma. PDS has a genetic component, however, the genes involved with this condition are largely unknown. We sought to discover genes that cause PDS by testing cohorts of patients and controls for mutations using a tiered analysis of exome data.

Results

Our primary analysis evaluated melanosome-related genes that cause dispersion of iris pigment in mice (TYRP1, GPNMB, LYST, DCT, and MITF). We identified rare mutations, but they were not statistically enriched in PDS patients. Our secondary analyses examined PMEL (previously linked with PDS), MRAP, and 19 other genes. Four MRAP mutations were identified in PDS cases but not in controls (p = 0.016). Immunohistochemical analysis of human donor eyes revealed abundant MRAP protein in the iris, the source of pigment in PDS. However, analysis of MRAP in additional cohorts (415 cases and 1645 controls) did not support an association with PDS. We also did not confirm a link between PMEL and PDS in our cohorts due to lack of reported mutations and similar frequency of the variants in PDS patients as in control subjects.

Conclusions

We did not detect a statistical enrichment of mutations in melanosome-related genes in human PDS patients and we found conflicting data about the likely pathogenicity of MRAP mutations. PDS may have a complex genetic basis that is not easily unraveled with exome analyses.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-07782-0.

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.

Canaloplasty in Pigmentary Glaucoma: Long-Term Outcomes and Proposal of a New Hypothesis on Its Intraocular Pressure Lowering Mechanism

This study presents the long-term results on canaloplasty in a group of patients affected by pigmentary glaucoma, and studies the progression of the disease after surgery. Material and methods: Twenty-nine eyes of 25 patients with pigmentary glaucoma in maximum tolerated medical therapy with significant visual field damage progression underwent canaloplasty and were followed up to 11 years (mean 59.8 ± 30.1 months). All patients underwent a complete ophthalmic examination every 6 months. Results: The pre-operative mean intraocular pressure (IOP) was 31.8 mmHg ± 10.9 (range 21–70) with an average of 3.3 medications. After 1, 2, 3, and 4 years, the mean IOP was 15.9 ± 4.0, 14.4 ± 7.3, 14.1 ± 2.1, and 15.7 mmHg, respectively, with 0.4, 0.5, and 0.7 medications, respectively. Four patients underwent trabeculectomy after 3 to 30 months due to uncontrolled IOP. Gonioscopy showed a significant reduction of pigment in trabecular meshwork in all cases, starting from the sixth month. In some cases, the pigment was almost completely reabsorbed after two years, suggesting an accelerated transit and escape of the granules through the trabecular spaces. Conclusions: Canaloplasty seems to be a reasonable option in treating patients affected by progressive pigmentary glaucoma. The reabsorption of pigment granules from the trabecular meshwork could, at least in part, explain the relatively high success rate observed after this surgical procedure.

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.

Prevalence of Pigment Dispersion Syndrome in Patients Seeking Refractive Surgery

PURPOSE

To determine the prevalence of pigment dispersion syndrome (PDS) in patients presenting for vision correcting refractive surgery.

SETTING

Discover Vision Centers, Kansas City, MO.

DESIGN

This is a prospective case series.

MATERIALS AND METHODS

A total of 637 eyes of 319 serial patients who presented seeking refractive surgery were included in this prospective, observational study. Patients underwent routine ophthalmologic examination before refractive surgery. PDS was diagnosed by the presence of a deep anterior chamber, posterior bowing of the irides, Krukenberg spindles, and/or presence of mid-peripheral iris transillumination defects by the same experienced ophthalmologist. The prevalence of PDS and its associated ophthalmic and demographic characteristics were evaluated in those diagnosed.

RESULTS

Of the 637 eyes, 165 (25.9%) eyes were diagnosed with PDS. Krukenberg spindles were present in 53 (8.3%) of the total eyes and in 47 (28.5%) eyes that were diagnosed with PDS. Transillumination defects were present in 153 (95%) eyes diagnosed with PDS and 161 (25.2%) total eyes. There was equal distribution between sex in those diagnosed with PDS (male vs. female: 26 vs. 25.8%; P=0.942). Blue colored eyes were most likely to have PDS (35.8% of patients).

CONCLUSIONS

The prevalence of PDS within the population of patients seeking refractive surgery is likely greater than the general population as a whole. This is most likely the result of self-selection and high association between myopia and PDS. Given that not infrequent sequela can occur from untreated PDS, it is prudent that refractive surgeons be aware of this increased prevalence and perform thorough examinations to properly identify the condition.

Pathophysiology and management of glaucoma and ocular hypertension related to trauma

Ocular trauma is a significant cause of blindness worldwide, particularly if associated with glaucoma. Direct damage from blunt or penetrating trauma, bleeding, inflammation, lens-related problems, orbital and brain vascular pathologies related to trauma, and chemical injuries may increase intraocular pressure and lead to traumatic glaucoma. Treatment may be as simple as eliminating the underlying cause in some conditions or management can be challenging, depending on the mechanism of damage. If proper management is not undertaken, visual outcomes can be poor. We discuss a broad spectrum of trauma-related mechanisms of intraocular pressure elevation, as well as their management.

Non-Synonymous variants in premelanosome protein (PMEL) cause ocular pigment dispersion and pigmentary glaucoma

Pigmentary glaucoma (PG) is a common glaucoma subtype that results from release of pigment from the iris, called pigment dispersion syndrome (PDS), and its deposition throughout the anterior chamber of the eye. Although PG has a substantial heritable component, no causative genes have yet been identified. We used whole exome sequencing of two independent pedigrees to identify two premelanosome protein (PMEL) variants associated with heritable PDS/PG. PMEL encodes a key component of the melanosome, the organelle essential for melanin synthesis, storage and transport. Targeted screening of PMEL in three independent cohorts (n = 394) identified seven additional PDS/PG-associated non-synonymous variants. Five of the nine variants exhibited defective processing of the PMEL protein. In addition, analysis of PDS/PG-associated PMEL variants expressed in HeLa cells revealed structural changes to pseudomelanosomes indicating altered amyloid fibril formation in five of the nine variants. Introduction of 11-base pair deletions to the homologous pmela in zebrafish by the clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 method caused profound pigmentation defects and enlarged anterior segments in the eye, further supporting PMEL's role in ocular pigmentation and function. Taken together, these data support a model in which missense PMEL variants represent dominant negative mutations that impair the ability of PMEL to form functional amyloid fibrils. While PMEL mutations have previously been shown to cause pigmentation and ocular defects in animals, this research is the first report of mutations in PMEL causing human disease.

The Heritability of Pigment Dispersion Syndrome and Pigmentary Glaucoma

PURPOSE

Pigment dispersion syndrome (PDS) and pigmentary glaucoma (PG) are presumed to be inherited in an autosomal dominant manner. We examine relatives of patients with PDS and PG in order to determine the heritability of these diseases.

DESIGN

This was a prospective, cross-sectional study.

METHODS

One hundred and one patients with PDS were prospectively recruited over 11 months. Four of the patients had PDS without ocular hypertension or glaucoma, 6 had PDS and ocular hypertension, and 91 had PG. Criteria for PDS were 2 of 3 signs: Krukenberg spindle, midperipheral iris transillumination defects, and/or heavy trabecular meshwork pigmentation. Criteria for PG were PDS and 2 of 3 signs: intraocular pressure >21 mm Hg, glaucomatous optic nerve damage, and/or glaucomatous visual field loss. Ninety-nine first-degree relatives living within a 100-mile radius of Iowa City, Iowa were examined in the clinic to determine the probability of familial transmission.

RESULTS

A total of 10 of 99 (10.10%) first-degree relatives were diagnosed with PDS (1 with PDS alone, 2 with PDS and ocular hypertension, and 7 with PG). Seven families with ≥2 affected members were identified. The majority of affected family members (8/10) showed moderate to heavy trabecular meshwork pigmentation and either Krukenberg spindle or transillumination defects.

CONCLUSIONS

Most of the cases of PDS in our study were sporadic, and the risk to first-degree relatives is lower than previously reported. However, there are families with apparent autosomal dominant inheritance of PDS in which the risk to relatives may be high.

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.

Molecular Genetics of Pigment Dispersion Syndrome and Pigmentary Glaucoma: New Insights into Mechanisms

We explore the ideas and advances surrounding the genetic basis of pigment dispersion syndrome (PDS) and pigmentary glaucoma (PG). As PG is the leading cause of nontraumatic blindness in young adults and current tailored interventions have proven ineffective, a better understanding of the underlying causes of PDS, PG, and their relationship is essential. Despite PDS being a subclinical disease, a large proportion of patients progress to PG with associated vision loss. Decades of research have supported a genetic component both for PDS and conversion to PG. We review the body of evidence supporting a genetic basis in humans and animal models and reevaluate classical mechanisms of PDS/PG considering this new evidence.

A Severe Case of Pigmentary Glaucoma in a Child With a Family History of Pigment Dispersion Syndrome

PURPOSE

To report a case of severe pigmentary glaucoma (PG) in a 13-year-old boy of a family affected by pigment dispersion syndrome (PDS).

PATIENTS AND METHODS

A 13-year-old child was referred to our hospital for severe bilateral glaucoma. A complete ophthalmologic evaluation including refraction, intraocular pressure, central corneal thickness, slit-lamp biomicroscopy, gonioscopy, fundus examination, and ultrasound biomicroscopy was performed. Family members were also examined and a family pedigree was obtained.

RESULTS

Ophthalmologic examination revealed a severe bilateral PG with Krukenberg spindle and a widely open heavily pigmented iridocorneal angle. Ultrasound biomicroscopy showed a deep anterior chamber with pronounced iris concavity in both eyes. Within his family, his 15-year-old sister and 7-year-old brother were both affected by PDS diagnosed on gonioscopy findings.

CONCLUSIONS

We report for the first time a severe case of pediatric PG with a family history of PDS. This case demonstrates that accurate screening is necessary in cases of familial PDS and PG, even in the pediatric population.

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.

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.

Determining immune components necessary for progression of pigment dispersing disease to glaucoma in DBA/2J mice

Background

The molecular mechanisms causing pigment dispersion syndrome (PDS) and the pathway(s) by which it progresses to pigmentary glaucoma are not known. Mutations in two melanosomal protein genes (Tyrp1^b and Gpnmb^R150X) are responsible for pigment dispersing iris disease, which progresses to intraocular pressure (IOP) elevation and subsequent glaucoma in DBA/2J mice. Melanosomal defects along with ocular immune abnormalities play a role in the propagation of pigment dispersion and progression to IOP elevation. Here, we tested the role of specific immune components in the progression of the iris disease and high IOP.

Results

We tested the role of NK cells in disease etiology by genetically modifying the B6.D2-Gpnmb^R150XTyrp1^b strain, which develops the same iris disease as DBA/2J mice. Our findings demonstrate that neither diminishing NK mediated cytotoxic activity (Prf1 mutation) nor NK cell depletion (Il2rg mutation) has any influence on the severity or timing of Gpnmb^R150XTyrp1^b mediated iris disease. Since DBA/2J mice are deficient in CD94, an important immune modulator that often acts as an immune suppressor, we generated DBA/2J mice sufficient in CD94. Sufficiency of CD94 failed to alter either the iris disease or the subsequent IOP elevation. Additionally CD94 status had no detected effect on glaucomatous optic nerve damage.

Conclusion

Our previous data implicate immune components in the manifestation of pigment dispersion and/or IOP elevation in DBA/2J mice. The current study eliminates important immune components, specifically NK cells and CD94 deficiency, as critical in the progression of iris disease and glaucoma. This narrows the field of possible immune components responsible for disease progression.

Prevention of vision loss protects against age-related impairment in learning and memory performance in DBA/2J mice

The DBA/2J mouse is a model of pigmentary glaucoma in humans as it shows age-related increases in intraocular pressure (IOP), retinal ganglion cell death and visual impairment. Previously, we showed that visual ability declines from 9 to 12 months of age and visual impairment is correlated with poor learning and memory performance in visuo-spatial tasks but not in tasks that do not depend on visual cues. To test the “sensory impairment” hypothesis of aging, which postulates that sensory impaired individuals are disadvantaged in their performance on psychometric tests as a direct result of difficulties in sensory perception, we treated DBA/2J mice with a conventional glaucoma medication used in humans (Timoptic-XE, 0.00, 0.25, or 0.50%) daily from 9 weeks to 12 months of age to determine whether prevention of vision loss prevented the decline in visuo-spatial learning and memory performance. At all ages tested (3, 6, 9, and 12 months of age), mice treated with Timoptic-XE (0.25 and 0.50%) maintained a high level of performance, while 12 month old control mice (0.00%) exhibited impaired performance in visually-dependent, but not non-visual tasks. These results demonstrate that when sensory function is preserved, cognitive performance is normalized. Thus, as in many aging humans, DBA/2J mice show age-related decrements in performance on visually presented cognitive tests, not because of cognitive impairment but as a direct consequence of poor visual ability. Our results demonstrate that age-related impairment in performance in visuo-spatial tasks in DBA/2J mice can be prevented by the preservation of visual ability.

An Overlap Syndrome of Pigment Dispersion and Pigmentary Glaucoma accompanied by Marfan Syndrome: Case Report with Literature Review

‘Overlap syndrome' describes the situation in which two or more ‘independent' conditions are present, either one of which could cause a particular finding. This current presentation reports a case with bilateral pigment dispersion syndrome (PDS), advanced pigmentary glaucoma (PG), and the Marfan syndrome, with bilateral subluxation of the lenses, and large short-term and long-term fluctuations of intraocular pressure. It is interesting to consider whether the associated advanced glaucomatous nerve damage could be a manifestation of just the PDS, just the Marfan syndrome, or rather a combination of these two overlapping independent conditions.

How to cite this article: Chakravarti T, George S. An Overlap Syndrome of Pigment Dispersion and Pigmentary Glaucoma accompanied by Marfan Syndrome: Case Report with Literature Review. J Current Glau Prac 2013;7(2):91-95.

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.

The genetics of pigment dispersion syndrome and pigmentary glaucoma

We review the inheritance patterns and recent genetic advances in the study of pigment dispersion syndrome (PDS) and pigmentary glaucoma (PG). Both conditions may result from combinations of mutations in more than one gene or from common variants in many genes, each contributing small effects. We discuss the currently known genetic loci that may be related with PDS/PG in humans, the role of animal models in expanding our understanding of the genetic basis of PDS, the genetic factors underlying the risk for conversion from PDS to PG and the relationship between genetic and environmental--as well as anatomical--risk factors.

Pigment dispersion with elevation of intraocular pressure after bilateral phacoemulsification with implantation of acrylic intra-ocular lenses

The purpose is to report a case and management of secondary Pigment Dispersion (PD) with severe elevation of the Intraocular Pressure (IOP) after bilateral uncomplicated phacoemulsification with implantation "within the capsular bag" of hydrophobic acrylic intra-ocular lenses (HAIOLs). The patient, a 68-year-old Hispanic male, developed severe anterior segment PD in both eyes after uncomplicated bilateral cataract surgery with implantation within-the-capsular-bag of HAIOLs one week apart. This PD was accompanied by severe elevation of the IOPs in both eyes. After filtering surgery in the worse affected eye, and medical therapy for both, the IOPs stabilized and the patient retained good distance and near uncorrected visual acuity (UCVA). HAIOLs implantation may lead to PD and IOP elevation, even when correctly placed within the capsular bag. A separation of at least two weeks between surgeries would have prevented the occurrence of this rare complication in both eyes at the same time.

Iris development in vertebrates; genetic and molecular considerations

The iris plays a key role in visual function. It regulates the amount of light entering the eye and falling on the retina and also operates in focal adjustment of closer objects. The iris is involved in circulation of the aqueous humor and hence functions in regulation of intraocular pressure. Intriguingly, iris pigmented cells possess the ability to transdifferentiate into different ocular cell types of retinal pigmented epithelium, photoreceptors and lens cells. Thus, the iris is considered a potential source for cell-replacement therapies. During embryogenesis, the iris arises from both the optic cup and the periocular mesenchyme. Its interesting mode of development includes specification of the peripheral optic cup to a non-neuronal fate, migration of cells from the surrounding periocular mesenchyme and an atypical formation of smooth muscles from the neuroectoderm. This manner of development raises some interesting general topics concerning the early patterning of the neuroectoderm, the specification and differentiation of diverse cell types and the interactions between intrinsic and extrinsic factors in the process of organogenesis. In this review, we discuss iris anatomy and development, describe major pathologies of the iris and their molecular etiology and finally summarize the recent findings on genes and signaling pathways that are involved in iris development.

Infrared imaging technique may help demonstrate iris transillumination defects in blacks who show other pigment dispersion syndrome clinical signs

PURPOSE

Pigment dispersion syndrome (PDS) is considered to be rare among blacks, although the inability to detect iris transillumination defects (ITDs) among very darkly pigmented irides could diminish the clinician's commitment toward the PDS diagnosis due to uncertainty brought on by the lack of this clinical sign. The goal of this study was to investigate the potential utility of a new infrared (IR) imaging technique to demonstrate ITDs among a group of blacks whose initial PDS diagnosis had to be based on pigment dispersal signs other than iris transillumination.

METHODS

A previously described digital camera system, modified to detect visible and IR light, was used to image the irides of 10 blacks (20 eyes, 8 females, 2 males; age range=51 to 67 y) considered to have PDS on the basis of the clinical signs not including the presence of ITDs as detected with traditional slit lamp examination. Only 1 eye of 2 different subjects had ITDs that were detected with slit lamp examination, but these consisted of a very small, isolated ITD of questionable importance in each of the eyes. Normal control eyes that were matched according to age, race, sex, and refractive error were also photographed, and 2 glaucoma specialists independently reviewed PDS/control eye pairs in a masked fashion. They were instructed to select the eye more likely to be the PDS eye without the benefit of clinical information other than the digital transillumination characteristics.

RESULTS

Observer no. 1 correctly selected the PDS eye among 19 of 20 (95%) PDS-normal eye pairs, and observer no. 2 correctly selected the PDS eye among 15 of 20 (75%) matched pairs. On the basis of these results, it was unlikely that observer no. 1 (Fisher exact test, P<0.0001) or observer no. 2 (P=0.06) selected the PDS eye IR image due to chance alone. It was also unlikely that selection agreement between the 2 observers was due to chance alone (kappa coefficient=0.58).

CONCLUSIONS

Digital IR iris photography may help demonstrate abnormal ITDs among the darkly pigmented irides of blacks who have signs of pigment dispersal but who do not have detectable ITDs with traditional slit lamp examination. Infrared iris examination with newer methods should be studied further relative to blacks and others because useful clinical and/or research oriented information could be gained.

Genetic context determines susceptibility to intraocular pressure elevation in a mouse pigmentary glaucoma

BACKGROUND

DBA/2J (D2) mice develop an age-related form of glaucoma. Their eyes progressively develop iris pigment dispersion and iris atrophy followed by increased intraocular pressure (IOP) and glaucomatous optic nerve damage. Mutant alleles of the Gpnmb and Tyrp1 genes are necessary for the iris disease, but it is unknown whether alleles of other D2 gene(s) are necessary for the distinct later stages of disease. We initiated a study of congenic strains to further define the genetic requirements and disease mechanisms of the D2 glaucoma.

RESULTS

To further understand D2 glaucoma, we created congenic strains of mice on the C57BL/6J (B6) genetic background. B6 double-congenic mice carrying D2-derived Gpnmb and Tyrp1 mutations develop a D2-like iris disease. B6 single-congenics with only the Gpnmb and Tyrp1 mutations develop milder forms of iris disease. Genetic epistasis experiments introducing a B6 tyrosinase mutation into the congenic strains demonstrated that both the single and double-congenic iris diseases are rescued by interruption of melanin synthesis. Importantly, our experiments analyzing mice at ages up to 27 months indicate that the B6 double-congenic mice are much less prone to IOP elevation and glaucoma than are D2 mice.

CONCLUSION

As demonstrated here, the Gpnmb and Tyrp1 iris phenotypes are both individually dependent on tyrosinase function. These results support involvement of abnormal melanosomal events in the diseases caused by each gene. In the context of the inbred D2 mouse strain, the glaucoma phenotype is clearly influenced by more genes than just Gpnmb and Tyrp1. Despite the outward similarity of pigment-dispersing iris disease between D2 and the B6 double-congenic mice, the congenic mice are much less susceptible to developing high IOP and glaucoma. These new congenic strains provide a valuable new resource for further studying the genetic and mechanistic complexity of this form of glaucoma.

Histologic Findings in Pigment Dispersion Syndrome and Pigmentary Glaucoma

PURPOSE

To investigate the morphologic changes in the trabecular meshwork in a case series of eyes with pigment dispersion syndrome and pigmentary glaucoma, and surgical trabeculectomy specimens from eyes with pigmentary glaucoma.

MATERIALS AND METHODS

Trabecular meshworks from 6 whole eyes from 3 donors and 7 trabeculectomy specimens were studied by light and electron microscopy. Axonal counts from the whole eyes were correlated with qualitative and quantitative data of meshwork changes.

RESULTS

Changes in the meshwork varied around the circumference of the eyes, but in all 6 eyes in most regions of the circumference there were numerous pigment granules within trabecular cells; pigment was not found within intertrabecular or cribriform spaces. In some regions of the circumference there was trabecular cell loss, loss of intertrabecular spaces, fusion of lamellae, and an increase in extracellular material under the inner wall of the canal. Separation of the normal tendinous connection to the canal wall cells was noted in some regions of all eyes. This change could be associated with regions of pathologic separation of the inner wall from the cribriform region, associated with partial obliteration of the lumen of the canal with cells and cell processes. In eyes with pronounced axon loss, meshworks showed most pronounced loss of trabecular cells and increased extracellular material. Trabeculectomy specimens had similar changes and, in addition, showed damaged trabecular cells and collapse of intertrabecular spaces without fusion of lamellae, consistent with artifacts from manipulation during surgery.

CONCLUSIONS

Loss of trabecular cells, fusion of trabecular lamellae with collapse of intertrabecular spaces, increase in extracellular material, and obliteration of the canal were found in various amounts around the circumference of eyes with pigment dispersion syndrome and elevated intraocular pressure, and pigmentary glaucoma. These probably all contribute to the development of increased intraocular pressure. Meshworks from trabeculectomy specimens showed these findings and also showed artifactual damage of cells and loss of intertrabecular spaces. This suggests that handling during surgery may cause single trabeculectomy specimens to give only an incomplete picture of the pathophysiology of pigmentary glaucoma.

A Cross-Sectional Study of Krukenberg Spindles and Pigmented Lens Striae in a Predominately Black Population

PURPOSE

To investigate the relationship of Krukenberg spindles (KS) and pigmented lens striae (PLS), clinical signs related to iris pigment dispersal and possibly glaucoma.

METHODS

During a 31-month period, 5 practitioners in an urban, primary eye care setting examined consecutive patients for KS and PLS. Multiple logistic regression was used to evaluate relationships among KS, PLS, and other variables.

RESULTS

Krukenberg spindles were present in 65 patients (52 females), comprised of 57 of 2647 (2.2%) blacks, 5 of 303 (1.7%) whites, 2 of 121 (1.7%) Hispanics, and 1 of 55 (1.8%) Asians. PLS were present in 64 subjects (56 females), comprised of 59 (2.2%) blacks, 3 (1.0%) whites, and 2 (3.6%) Asians. KS and PLS were coexistent in 27 subjects. Mean age +/- SD (range) of the KS and PLS subjects was 63.1 +/- 15.0 years (24-88 years) and 67.0 +/- 10.4 years (33-88 years), respectively. Mean refractive error +/- SD (range) of KS and PLS right eyes was +0.55 +/- 2.32D (-6.50 to +5.50D) and +1.34 +/- 2.18D (-6.50 to +7.25D), respectively. Controlling for other variables, PLS were highly predictive (OR = 30.2, P < 0.0001) of KS, and KS were highly predictive (OR = 29.5, P < 0.0001) of PLS. Ignoring presence or absence of PLS, increasing age (in decades) (OR = 1.60, P < 0.0001) was strongly associated with KS. Ignoring presence or absence of KS, age (OR = 1.74, P < 0.0001), female gender (OR = 2.96, P = 0.009), and increasing hyperopic refractive error (OR = 1.30, P < 0.0001) were strongly associated with PLS.

CONCLUSIONS

Krukenberg spindles and PLS were strongly associated in our patient population, and the likelihood of both increased with increasing age. Female gender and increasing hyperopic refractive error were highly significant predictors of PLS.

Pigmented striae of the anterior lens capsule and age-associated pigment dispersion of variable degree in a group of older African-Americans: an age, race, and gender matched study

PURPOSE

To investigate pigmented striae of the anterior lens capsule in African-Americans, a potential indicator of significant anterior segment pigment dispersion.

METHODS

A group of 40 African-American subjects who exhibited pigmented lens striae (PLS) were identified from a non-referred, primary eye care population in Chicago, IL, USA. These subjects were then compared to an age, race, and gender matched control group relative to refractive error and the presence or absence of diabetes and hypertension.

RESULTS

The PLS subjects (mean age = 65.4 +/- 8.8 years, range = 50-87 years) consisted of 36 females and 4 males. PLS were bilateral in 36 (85%) of the 40 subjects. Among the eyes with PLS, 21 (55%) of 38 right eyes and 22 (61%) of 36 left eyes also had significant corneal endothelial pigment dusting, commonly in the shape of a Krukenberg's spindle. Ten (25%) of the PLS subjects had either glaucoma or ocular hypertension (7 bilateral, 3 unilateral). The presence of trabecular meshwork pigment varied from minimal to heavy. The mean +/- SD (range) refractive error of the PLS right eyes was +1.61 +/- 1.43D (-1.50 to +5.00D) and +1.77 +/- 1.37D (-1.00 to +5.00D) for the left eyes. Based on these data, the PLS right eyes were +1.63D (Student's t, p = 0.0001; 95% CI = +0.82 to +2.44D) more hyperopic on average than the control right eyes, and the PLS left eyes were +1.77D (p = 0.0001; 95% CI = +0.92 to +2.63D) more hyperopic on average than the control left eyes. Trend analysis showed a gradually increasing likelihood of PLS with increasing magnitude of hyperopia in both eyes (Mantel-Haenszel chi-square, p = 0.001). Among PLS subjects, 24 (60%) of 40 were hypertensive and 9 (23%) of 40 were diabetic. However, these proportions were not significantly different (two-tailed Fisher's exact test; hypertension: p = 0.30; diabetes: p = 0.70) from the randomly selected controls.

CONCLUSIONS

Among our African-American group, which consisted predominately of females >50 years of age, the likelihood of PLS increased with increasing hyperopic refractive error. This finding is consistent with the possibility that PLS may, in some circumstances, indicate a significant pigment dispersal process due to iris-lens rubbing that may be associated with crowding of anterior segment structures. Additional study is warranted to further assess the nature of PLS, their precise relationship with an age-related pigment dispersal process, and their true significance as a risk factor for development of glaucoma.

What is the risk of developing pigmentary glaucoma from pigment dispersion syndrome?

PURPOSE

To determine the probability of converting from pigment dispersion syndrome to pigmentary glaucoma.

DESIGN

Retrospective community-based study of all newly diagnosed cases of pigment dispersion syndrome or pigmentary glaucoma.

METHOD

Subjects were patients newly diagnosed with pigment dispersion syndrome or pigmentary glaucoma from 1976 to 1999 in Olmsted County, Minnesota. Criteria for pigment dispersion syndrome were two of three signs: midperipheral, radial iris transillumination defects; Krukenberg spindle; heavy trabecular meshwork pigmentation. Criteria for pigmentary glaucoma were pigment dispersion syndrome and two of three findings: intraocular pressure (IOP) greater than 21 mm, optic nerve damage, or visual field loss. Kaplan-Meier survival curves were used to determine the probability of conversion to pigmentary glaucoma.

RESULTS

A total of 113 patients were newly diagnosed with pigment dispersion syndrome over the 24-year period. Of these, 9 persons developed pigmentary glaucoma or elevated IOP requiring therapy. The probability of converting to pigmentary glaucoma was 10% at 5 years and 15% at 15 years. An additional 23 patients were found to have pigmentary glaucoma at their initial examination. The mean age at diagnosis of pigmentary glaucoma was 42 +/- 12 years; 78% of patients were male, whereas 58% of patients with pigmentary dispersion syndrome glaucoma were male. The most significant risk factor for conversion to pigmentary glaucoma was an IOP greater than 21 mm Hg at initial examination, whereas age, refractive error, and family history of glaucoma were not correlated with conversion.

CONCLUSIONS

The risk of developing pigmentary glaucoma from pigment dispersion syndrome was 10% at 5 years and 15% at 15 years. Young, myopic men were most likely to have pigmentary glaucoma. An IOP greater than 21 mm Hg at initial examination was associated with an increased risk of conversion.

By altering ocular immune privilege, bone marrow-derived cells pathogenically contribute to DBA/2J pigmentary glaucoma

Pigment dispersion syndrome causes iris pigment release and often progresses to elevated intraocular pressure and pigmentary glaucoma (PG). Because melanin pigment can have adjuvant like properties and because the Gpnmb gene, which contributes to pigment dispersion in DBA/2J (D2) mice, is expressed in dendritic cells, we tested the hypothesis that ocular immune abnormalities participate in PG phenotypes. Strikingly, we show that D2 eyes exhibit defects of the normally immunosuppressive ocular microenvironment including inability of aqueous humor to inhibit T cell activation, failure to support anterior chamber (AC)-associated immune deviation, and loss of ocular immune privilege. Histologic analysis demonstrates infiltration of inflammatory leukocytes into the AC and their accumulation within the iris, whereas clinical indications of inflammation are typically very mild to undetectable. Importantly, some of these abnormalities precede clinical indications of pigment dispersal, suggesting an early role in disease etiology. Using bone marrow chimeras, we show that lymphohematopoietic cell lineages largely dictate the progression of pigment dispersion, the ability of the eye to support induction of AC-associated immune deviation, and the integrity of the blood/ocular barrier. These results suggest previously unsuspected roles for bone marrow-derived cells and ocular immune privilege in the pathogenesis of PG.

The evaluation of retinal nerve fiber layer in pigment dispersion syndrome and pigmentary glaucoma using scanning laser polarimetry

PURPOSE

To measure the retinal nerve fiber layer thickness in patients with pigment dispersion syndrome (PDS) using scanning laser polarimetry and to compare these measurements with those of normal subjects and patients with pigmentary glaucoma (PG).

METHODS

Age-, sex-, and refractive error-matched subjects--18 patients with PDS, 18 patients with PG, and 20 healthy subjects--were evaluated by scanning laser polarimetry (Nerve Fiber Analyzer [NFA] GDx). The NFA did not have a compensator for corneal polarization. One randomly selected eye from each patient was included in the statistical analysis. The NFA measurements of patients with PDS and PG and healthy subjects were compared statistically using analysis of variance, Tukey multiple comparisons, chi-square, and independent t-tests.

RESULTS

The mean values for average thickness, superior and inferior maximum, superior and inferior average, ellipse average thickness, and superior integral were found to be lower in the patients with PDS (p < 0.02) and PG (p < 0.005) compared to the normal subjects. The mean values for maximum modulation, superior ratio, inferior ratio, and superior/nasal ratio in PDS were in between those of the PG and control groups (p > 0.05). The ellipse modulation was significantly lower in the PG group when compared to the other two groups (p < 0.03).

CONCLUSIONS

Retinal nerve fiber loss is present to some extent in patients with PDS and this loss is not age or sex dependent. Parameters of modulation might be more representative of significant damage of the nerve fiber layer.

Prevalence of pigmented lens striae in a black population: a potential indicator of age-related pigment dispersal in the anterior segment

PURPOSE

To determine the prevalence of pigmented striae of the anterior lens capsule, with or without associated glaucoma, in a black primary eye care population.

METHODS

Over a 16-month period, five practitioners searched for pigmented lens striae (PLS) among consecutive patients who underwent pupillary dilation during routine eye care provided within the primary care service of an urban eye clinic in Chicago, Illinois.

RESULTS

Meeting the inclusion criteria were 1608 blacks (mean age +/- SD, 40.9 +/- 23.7 years; range, 5 to 100; 1056 females, 552 males). Among the group, 29 (1.8%) subjects had PLS (mean age, 66.5 +/- 11.3 years; range, 33 to 88; 25 females, 4 males). PLS were bilateral 89% of the time. Sixteen of the 29 (55%) blacks had central corneal endothelial pigment dusting (14 bilateral), frequently creating a well-formed Krukenberg's spindle. Trabecular pigmentation varied among the PLS subjects from mild to heavy. Using multiple logistic regression, age (in years) (odds ratio, 1.05; 95% confidence interval, 1.02 to 1.07; p = 0.0003), female gender (odds ratio, 4.46; 95% confidence interval; 1.03 to 19.19; p = 0.045), and hyperopic refractive error (in diopters) (odds ratio, 1.35; 95% confidence interval; 1.09 to 1.67; p = 0.006) were significant predictors of PLS.

CONCLUSIONS

PLS were present in about 1.8% (2.4% females, 0.7% males) of our black population, and they were frequently associated with other signs of intraocular pigment dispersion. Age, female gender, and refractive error were significant predictors for PLS. This is new information that is helpful for understanding a clinical sign that may be an indicator of age-related pigment dispersal within the anterior segment.

Anterior chamber angle anomalies associated with signs of pigment dispersion in a group of black probands and their first-degree relatives

PURPOSE

To evaluate the presence of iridocorneal angle anomalies associated with signs of pigment dispersion among a group of black probands and their first-degree relatives.

METHODS

Eleven blacks who exhibited pigment dispersion syndrome (PDS) signs, including Krukenberg's spindles, moderate-to-heavy trabecular meshwork pigmentation, and peripheral lenticular/zonular pigmentation, received a complete eye examination that included gonioscopy. Overt iridocorneal angle abnormalities other than pigment deposition were photo-documented. Twenty-two first-degree relatives (6 siblings, 15 children, and 1 parent) of these probands underwent similar examination.

RESULTS

Among the subjects, 5 of 11 probands (age range 13 to 59 years) and 4 of 22 relatives (age range 14 to 51 years) exhibited definite angle anomalies. The nine subjects with angle anomalies belonged to 7 of 11 separate families. The four relatives with angle anomalies did not have PDS according to our criteria, but two other relatives from two additional families did have signs consistent with clinical PDS. Types of angle anomalies included (1) peripheral anterior synechia-like lesions; (2) a prominent concavity of the peripheral iris at the 6-o'clock meridian; (3) a whitish, thread-like band of tissue near the iris base; (4) a prominent, externally-visible Schwalbe's line at the 6-o'clock meridian; and (5) a prominent, web-like confluence of exaggerated iris processes 360 degrees along the angle wall. Iris processes and prominent Schwalbe's lines were not considered abnormal or anomalous unless they were clearly atypical.

CONCLUSIONS

Iridocorneal angle anomalies, other than pigment deposition, were common among our black group who exhibited signs of pigment dispersion as well as among their first-degree relatives. Further consideration should be given to the possibility that among some patient groups, overt goniodysgenesis could be part of a constellation of signs indicative of a pigment dispersion syndrome. Potentially, clinically detectable goniodysgenesis could prove to be a useful marker to identify certain subjects who carry PDS genetic traits but who have not expressed complete phenotypical disease.