Central retinal vein occlusion in pseudoexfoliation of the lens capsule

Peripapillary and Macular Vessel Density in Unilateral Early Pseudoexfoliation Glaucoma

PRCIS

In early pseudoexfoliation glaucoma (PXG), radial peripapillary capillary vessel density (RPC-VD) was reduced nasally, while the retinal nerve fiber layer (RNFL) thinned from the nasal to temporal sectors. Nonglaucomatous fellow eyes demonstrated no RPC-VD or RNFL loss in comparison to the controls.

PURPOSE

To evaluate peripapillary and macular vessel density (VD) in unilateral early PXG and unaffected fellow eyes compared with healthy controls.

METHODS

This cross-sectional study included 28 eyes with PXG and 28 nonglaucomatous, pseudoexfoliation-free fellow eyes of 28 patients, and 28 eyes of 28 healthy participants. All subjects underwent optical coherence tomography angiography (OCTA) imaging. RPC-VD, macular VD, retinal nerve fiber layer (RNFL) thickness, and ganglion cell complex (GCC) thickness were compared among the groups.

RESULTS

The average RPC-VD and RNFL thickness were significantly reduced in PXG eyes compared with both fellow eyes and the control group ( P <0.001-0.002). In fellow eyes, neither RNFL thickness nor RPC-VD parameters differed from controls. In sector-based analysis, RPC-VD loss in the PXG eyes was significant in the nasal-superior, nasal-inferior, superonasal, and inferonasal sectors ( P =0.005-0.031), while RNFL thinning extended from the nasal sectors toward the superotemporal and temporal-superior sectors ( P <0.001-0.014). RPC-VD was strongly correlated with average and all sector RNFL thicknesses ( r =0.402-0.759, P <0.001-0.034). While perifoveal GCC differed from both fellow and control eyes ( P <0.001), there was no significant difference in macular VD parameters among the groups. RPC-VD and RNFL had comparable area under receiver operating curve (AUROC) values in the average and nasal sectors, while RPC-VD had no ability to distinguish PXG from controls in the superotemporal and inferotemporal sectors.

CONCLUSION

In the early stages of PXG, RNFL parameters mostly appear to have better diagnostic ability than RPC-VD parameters. Fellow eyes in the preclinical stage may not exhibit any RPC-VD and RNFL loss detectable by current OCTA technology.

[Secondary open-angle glaucoma: pseudoexfoliative glaucoma, pigmentary glaucoma and neovascular glaucoma]

Secondary open-angle glaucomas are a heterogeneous group of diseases in which a variety of pathophysiological mechanisms result in an elevation of intraocular pressure. This article is the first part of a review of the more common forms of secondary open-angle glaucomas. The pathogenesis, characteristic clinical findings and treatment of pseudoexfoliative glaucoma, pigmentary glaucoma and neovascular glaucoma are discussed. An emphasis is placed on the differences in treatment compared to primary open-angle glaucoma and prophylactic treatment approaches are explained where possible.

The Incidence of Retinal Vein Occlusion in Patients with Pseudoexfoliation Glaucoma: A Retrospective Cohort Study

PURPOSE

The aim of this study was to evaluate pseudoexfoliation (PXF) as an independent risk factor for the occurrence of retinal vein occlusion (RVO).

METHODS

This is a retrospective cohort study on the records of 300 PXF glaucoma patients (PXF group), 300 non-PXF glaucoma patients, and 599 nonglaucoma non-PXF (nGnP group) patients.

RESULTS

Multivariate analysis resulted in a significant probability for RVO in the PXF (p = 0.005; OR 2.29 [1.13-4.68]) and non-PXF glaucoma groups (p = 0.005; OR 3.03 [1.55-5.94]) compared to the nGnP group. There was a much higher probability for central RVO (CRVO) in the PXF (p = 0.013; OR 3.64 [1.39-9.49]) and non-PXF glaucoma groups (p = 0.013; OR 3.78 [1.48-9.65]) compared to the nGnP group. After matching and excluding neovascular glaucoma, no significant difference was found between the PXF and non-PXF glaucoma groups regarding RVO (p = 0.541), CRVO (p = 0.092), and branch RVO (p = 0.774).

CONCLUSIONS

PXF and other types of glaucoma are associated with RVOs, mainly CRVO. PXF was not found to be an independent risk factor for CRVO.

Comparison of Rotational Thromboelastography Findings in Pseudoexfoliation Syndrome Patients and Healthy Controls

PURPOSE

Rotational thromboelastography (ROTEM) is a useful test for studying the characteristics of fibrin clot formation. As patients with pseudoexfoliation (PEX) have an increased risk for thrombotic events, clot-forming dysfunction may play a role. The aim of this study is to compare ROTEM findings in PEX syndrome patients with age-matched and sex-matched healthy controls.

PATIENTS AND METHODS

A total of 21 patients with PEX syndrome and 22 age-matched and sex-matched healthy controls were included. All study participants underwent detailed ophthalmologic and systemic medical examination, including blood pressure measurement, hemoglobin-hematocrit levels, platelet count, coagulation parameters including prothrombin time, activated partial thromboplastin time, fibrinogen levels, and D-dimer levels. Peripheral blood samples were collected and analyzed with ROTEM Coagulation Analyzer.

RESULTS

The mean age of patients with PEX and controls was 66.5±8.3 and 65.9±9.5 years, respectively (P=0.7). The 2 groups did not differ with respect to age, sex, hemoglobin, hematocrit, platelet numbers, prothrombin time, activated partial thromboplastin time, fibrinogen levels, D-dimer levels, and glucose levels. When extrinsic thromboelastometry results were analyzed, PEX patients showed a significantly decreased clotting time when compared with healthy controls (79.8 vs. 98.0 s; P=0.01), indicating faster clot formation. Other ROTEM parameters did now show any difference between the 2 groups.

CONCLUSIONS

PEX patients showed faster clotting time when compared with healthy controls. This fibrin clot formation dysfunction may lead to vascular thrombotic events in these patients. Further studies are needed to elucidate the exact underlying mechanism of thrombosis seen in PEX patients.

Exfoliation syndrome: a disease with an environmental component

PURPOSE OF REVIEW

Exfoliation syndrome (XFS), the most common cause of secondary open angle glaucoma, is associated with significant ocular morbidity. Recent studies have pointed toward environmental components that may alter the risk of XFS development. This review focuses on the recent studies elucidating the role of environmental factors that play a role in the development of exfoliation syndrome.

RECENT FINDINGS

In XFS, aberrant microfibril formation emanating from the cell-extracellular matrix interface admixes with other macromolecules and is cross-linked by lysyl oxidase like 1 (LOXL1) activity. A common gene variant in the LOXL1 enzyme, an enzyme critical for enhancing the tensile strength of collagen and elastin in extracellular matrices, has been found in approximately 90% of XFS cases. However, approximately 80% of controls also have disease-associated LOXL1 gene variants. These findings point toward other nongenetic factors influencing the development of XFS. Increasing latitude, solar radiation, climatic variables and dietary factors such as high coffee consumption and low dietary folate intake are among the nongenetic factors associated with increased risk of XFS.

SUMMARY

A greater understanding of the environmental components associated with XFS may lead to lifestyle preventive strategies to ameliorate disease burden.

Relation between time spent outdoors and exfoliation glaucoma or exfoliation glaucoma suspect

PURPOSE

To evaluate the relation between time spent outdoors at various life periods and risk of exfoliation glaucoma or exfoliation glaucoma suspect.

DESIGN

Retrospective cohort study in the United States.

METHODS

Participants (49 033 women in the Nurses Health Study and 20 066 men in the Health Professionals Follow-up Study) were 60+ years old, were free of glaucoma and cataract, reported eye examinations, and completed questions about time spent outdoors in direct sunlight at midday at 3 life periods: high school to age 24 years, age 25-35 years, and age 36-59 years (asked in 2006 in women and 2008 in men). Participants were followed biennially with mailed questionnaires from 1980 women/1986 men to 2010. Incident cases (223 women and 38 men) were confirmed with medical records. Cohort-specific multivariable-adjusted rate ratios from Cox proportional hazards models were estimated and pooled with meta-analysis.

RESULTS

Although no association was observed with greater time spent outdoors in the ages of 25-35 or ages 36-59 years, the pooled multivariable-adjusted rate ratios for ≥11 hours per week spent outdoors in high school to age 24 years compared with ≤5 hours per week was 2.00 (95% confidence interval = 1.30, 3.08; P for linear trend = .001). In women, this association was stronger in those who resided in the southern geographic tier in young adulthood (P for interaction = .07).

CONCLUSIONS

Greater time spent outdoors in young adulthood was associated with risk of exfoliation glaucoma or exfoliation glaucoma suspect, supporting an etiologic role of early exposures to climatic factors.

Demographic and geographic features of exfoliation glaucoma in 2 United States-based prospective cohorts

PURPOSE

To examine prospectively the association between demographic and geographic factors in relation to exfoliation glaucoma (EG) or exfoliation glaucoma suspect (EGS).

DESIGN

Prospective cohort study.

PARTICIPANTS

Seventy-eight thousand nine hundred fifty-five women in the Nurses' Health Study and 41 191 men in the Health Professionals Follow-up Study.

METHODS

Female and male health professionals were followed prospectively from 1980 through 2008 and from 1986 through 2008, respectively. Eligible participants were 40 years of age or older, did not have EG or EGS at baseline, and reported undergoing eye examinations during follow-up. Information regarding demographic features, lifetime geographic residence, and potential confounders was collected. During follow-up, 348 EG or EGS cases were confirmed with medical record review. The relative risk of EG or EGS in each cohort was estimated separately and the results were pooled with meta-analysis.

MAIN OUTCOME MEASURES

Multivariate rate ratios (MVRRs) of EG or EGS and their 95% confidence intervals (CIs).

RESULTS

Exfoliation glaucoma or EGS was strongly age related with subjects 75 years of age or older at 46.22-fold (95% CI, 22.77-93.80) increased risk compared with those between 40 and 55 years of age. Although men were 68% less likely to develop EG or EGS than women (MVRR, 0.32; 95% CI, 0.23-0.46), no predisposition to EG or EGS by ancestry, particularly Scandinavian ancestry, emerged. Compared with a lifetime of living in the northern tier of the continental United States, lifetime residence in the middle geographic tier (MVRR, 0.53; 95% CI, 0.40-0.71) and in the southern geographic tier (MVRR, 0.25; 95% CI, 0.09-0.71) was associated with markedly reduced risks of EG or EGS.

CONCLUSIONS

In this mainly white cohort from the United States, increasing age and female gender were significant risk factors for EG or EGS; however, Scandinavian heritage was not. Living in the middle or southern regions of the United States relative to living in the northern region was associated with a reduced risk of EG or EGS.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Association of exfoliation syndrome and central retinal vein occlusion: an ultrastructural analysis

PURPOSE

To evaluate prospectively the frequency with which exfoliation syndrome (XFS) occurs in patients with central retinal vein occlusion (CRVO) by clinical examination and ultrastructural examination of conjunctival biopsy specimens.

METHODS

Prospective observational case series. Thirty-six eyes of 36 consecutive patients with CRVO were investigated for XFS by slit-lamp examination and conjunctival biopsy when XFS was not clinically visible on examination.

RESULTS

A clinical diagnosis of XFS or a positive biopsy result for exfoliation material (XFM) was present in 22 of the 36 patients (61%; 95% confidence interval 45-75%). Twelve of these 22 patients (54%) had a clinical diagnosis of XFS. Aggregates of XFM were identified ultrastructurally in the biopsy specimens in 10 of 24 patients with no clinical signs of XFS (42%). Patients with and without XFS had similar distribution of age, gender, race and prevalence of systemic disorders. Twelve of the 22 (54%) XFS patients had neither glaucoma nor ocular hypertension prior to the CRVO.

CONCLUSION

In accordance with previous retrospective and histological studies, this prospective, in vivo study suggests that CRVO is commonly associated with XFS.

Ocular and systemic pseudoexfoliation syndrome

PURPOSE

To provide an update on most recent developments regarding ocular and systemic manifestations and complications, clinical diagnosis and management, and molecular pathophysiology of pseudoexfoliation (PEX) syndrome, and to discuss future tasks and challenges in this field.

DESIGN

Perspective.

METHODS

Review of recent literature and authors' own clinical and laboratory studies.

RESULTS

PEX syndrome is a common age-related generalized fibrotic matrix process of worldwide significance, which may not only cause severe chronic open-angle glaucoma and cataract, but also a spectrum of other serious spontaneous and surgical intraocular complications. Recent progress and advances have led to (1) improvements in clinical management by understanding the effects of the PEX process on ocular tissues, by refining diagnostic criteria, by applying new treatment regimes, and by developing preventive strategies to reduce surgical complications; (2) increasing evidence for systemic associations of PEX with cardiovascular and cerebrovascular morbidity; and (3) new insights into the molecular pathophysiology by analyzing the composition of PEX material, the differential gene expression of affected tissues, and key factors involved in pathogenesis. The current pathogenetic concept describes PEX syndrome as an elastic microfibrillopathy involving transforming growth factor-beta1, oxidative stress, and impaired cellular protection mechanisms as key pathogenetic factors.

CONCLUSIONS

Future tasks and challenges comprise epidemiologic prevalence and genetic studies of PEX syndrome, prospective randomized clinical and histopathological screening studies on its systemic manifestations and associations, and intensified basic research on differential protein and gene expression, animal and in vitro models, as well as potential biomarkers for PEX syndrome and its associated glaucoma.

Pseudoexfoliation syndrome: pathological manifestations of relevance to intraocular surgery

Pseudoexfoliation syndrome (PEX) is a common ocular condition often associated with the need for intraocular surgery. Although results of cataract and glaucoma filtering surgery in eyes with PEX in the early stages of the disease may be comparable to those in eyes without PEX, in the later stages morbidity is significantly increased due to periocular surgical complications and the outcome is worse. Surgical and postoperative difficulties are often multifactorial and are directly related to the pathological changes of PEX on intraocular structures. Recent years have seen a large increase in the understanding of the effects of PEX on the various ocular tissues. Although the visible areas of the anterior capsule are most obviously involved, this is only a small part of the picture and of least significance. Biomicroscopically invisible changes of the zonules and their attachments are of greatest consequence. There is also distinct, often active, involvement of almost all tissues of the anterior segment of the eye, many of which have important implications for the anterior segment surgeon including iridopathy, iris vasculopathy (including persistent breakdown of the blood-aqueous barrier and anterior segment hypoxia), ciliary body involvement and keratopathy. Trabecular dysfunction is evident by the deposition of PEX material derived from both in situ and extra-trabecular production as well as protein and melanin deposition. These changes should be kept in mind by all intraocular surgeons as a source of potential difficulties in the perioperative period. Additionally, in light of these changes, patients need to be given realistic expectations regarding the increased risk of complications and more prolonged expected recovery time. In this short review, current reports relating to PEX pathological changes of practical interest to the intraocular surgeon are summarized.