Pseudoexfoliation in the Reykjavik Eye Study: prevalence and related ophthalmological variables

The Prevalence of Exfoliation Syndrome in an Iranian Population Aged 45-69 Years

PURPOSE

To determine the prevalence of exfoliation syndrome (XFS) and some of its related factors in an Iranian population aged 45-69 years.

METHODS

In the first phase of the Shahroud Eye Cohort Study, 5190 people in 300 clusters from Shahroud city in the northeast of Iran participated in the study. The second phase of the study was conducted 5 years later in 2014. Vision testing, refraction, slit lamp examination, and fundus examination were performed for all participants. In this study, XFS was determined by an ophthalmologist using slit lamp biomicroscopy.

RESULTS

Of the 5190 first phase study participants, 4737 participated in the second phase (response rate 91.3%). In this study, the prevalence of XFS was 0.46% (95% confidence interval, CI, 0.24-0.68%) and the prevalence of bilateral XFS was 0.20% (95% CI 0.07-0.33%). XFS prevalence in men was 0.74% (95% CI 0.28-1.20%) and in women 0.26% (95% CI 0.07-0.45%). In a multivariable-adjusted logistic regression model, age, sex, diabetes, smoking status, dyslipidemia, and hypertension were entered into the model as covariables, where older age (odds ratio, OR, 1.18, 95% CI 1.08-1.28) was the only variable that remained significantly associated with XFS prevalence.

CONCLUSION

The prevalence of XFS in this study was very low. Similar to other studies, age was a factor associated with this syndrome.

Prevalence of Pseudoexfoliation Syndrome and Associated Factors in South Koreans: The Korean National Health and Nutrition Examination Survey

PURPOSE

To investigate the prevalence of pseudoexfoliation syndrome (PXS) and factors associated with PXS in South Koreans by analyzing data from the Korean National Health and Nutrition Examination Survey (KNHANES).

METHODS

Using the KNHANES database of 2009-2012, 13,223 participants aged 50 years or older were included. Participants underwent standardized interviews and systemic and ocular examinations. Systemic factors analyzed included age, sex, daily length of sun exposure, presence of Raynaud phenomenon or migraine, hypertension, diabetes mellitus, body mass index, serum lipid profile, duration and frequency of smoking, and alcohol consumption. Evaluated ocular factors were refractive error, presence of cataract and glaucoma, intraocular pressure, and peripheral anterior chamber depth. Logistic regression analysis was performed to identify factors associated with the presence of PXS.

RESULTS

PXS was found in 16 participants (0.12%). When compared with the non-PXS group, eyes with PXS showed a higher prevalence of cataract (p = 0.020). In logistic regression analysis, age (odds ratio, OR, 1.04, 95% confidence interval, CI, 0.99-1.09; p = 0.016) and the presence of cataract (OR 8.17, 95% CI 1.06-62.84; p = 0.044) were associated with the presence of PXS. Sun exposure for ≥5 hours/day was marginally associated with the presence of PXS (OR 2.76, 95% CI 0.96-7.95; p = 0.060).

CONCLUSION

The prevalence of PXS per 1000 persons was 1.10 in South Koreans aged ≥50 years. Participants with PXS had a higher prevalence of cataract, were older, and were more likely to be exposed to the sun for ≥5 hours/day than participants without PXS.

Deep Sclerectomy in Primary Open-Angle Glaucoma and Exfoliative Glaucoma

Purpose

To study the effect of deep sclerectomy (DS) in primary open-angle glaucoma (POAG) and exfoliative glaucoma (EXG).

Methods

We retrospectively analyzed the intraocular pressure (IOP)-lowering effect of DS in 235 consecutive eyes. Eyes were divided into 2 groups according to glaucoma subtype: POAG (127 eyes) and EXG (108 eyes). Postoperative IOP was the main outcome measurement. We recorded complete and qualified surgical success, need for YAG-laser goniopuncture, and need for postoperative glaucoma medication. We studied factors related to outcome of surgery in a Cox regression model.

Results

In the POAG group, the mean (SD) IOP decreased from 22.6 (5.1) mm Hg preoperatively to 16.8 (7.5) mm Hg, with qualified success achieved in 70% of eyes. Postoperatively, 57% were without medication. In the EXG group, IOP decreased from 25.5 (6.5) mm Hg preoperatively to 16.5 (7.8) mm Hg postoperatively, with qualified success achieved in 66% of eyes. Postoperatively, 50% were without medication. Decrease in IOP was statistically significant in both groups (p<0.001). In the POAG group, 12%, and in the EXG group, 24% needed a reoperation in the follow-up period (p = 0.037). In the Cox regression model, 1 week IOP between 2 and 14 mm Hg without medication lowered the hazard rate of losing complete success by 34% (p = 0.031) and the hazard rate of losing qualified success by 54% (p = 0.004).

Conclusions

The IOP 1 week postoperatively seems to be a prominent indicator of surgical success. Deep sclerectomy is effective in reducing IOP in POAG and EXG subgroups, with reoperations more common in EXG eyes.

The prevalence of exfoliation syndrome in Turkey

PURPOSE

To investigate the prevalence of the exfoliation syndrome and its relationship with ocular and cardiovascular diseases in the Central Anatolia region of Turkey.

METHODS

This cross-sectional and population-based study was conducted at the Sivas Province among the population aged 40 years and over. The diagnosis of XFS was made when exfoliative material was found on the anterior lens capsule or iris on slit-lamp examination. The subjects were divided into an XFS group and a non-XFS group according to the presence of exfoliative material, and the groups were compared for the presence of glaucoma, cataract, age-related macular degeneration, phacodonesis, hypertension, diabetes mellitus, coronary artery disease, smoking and alcohol-use frequency.

RESULTS

XFS was present in 63 subjects consisting of 42 males (8.0%) and 21 females (3.6%) for an overall rate of 5.7% (95% CI: 0.054-0.060). Once we adjusted the values for age, we found a statistically significant relationship of increased age and male gender with the presence of XFS (p = 0.001, p = 0.027, respectively). The relationship between XFS and glaucoma, cataract and phacodonesis was found to be statistically significant (p = 0.001). No relationship was found between exfoliation syndrome and hypertension, diabetes mellitus and coronary artery disease.

CONCLUSION

The prevalence of exfoliation syndrome was 5.7% in this population-based study. There was a statistically significant relationship between XFS and advancing age and male gender.

Hearing in older adults with exfoliation syndrome/exfoliation glaucoma or primary open-angle glaucoma

PURPOSE

To determine whether adults, aged 66-96 years, with exfoliation syndrome (XFS)/exfoliation glaucoma (XFG), or primary open-angle glaucoma (POAG) have poorer hearing than controls of similar age.

METHODS

Case (XFS/XFG and POAG) and control status was diagnosed in the Reykjavik Glaucoma Studies (RGS) using slit-lamp examination, visual field testing and optic disc photographs; the RGS data were merged with the Age, Gene/Environment Susceptibility-Reykjavik Study that collected hearing data using air-conduction, pure-tone thresholds obtained at 0.5, 1, 2, 3, 4, 6 and 8 kHz categorized by better ear and worse ear, based on pure-tone averages (PTAs) calculated separately for low and middle frequencies (PTA512 - mean of thresholds at 0.5, 1 and 2 kHz) and high frequencies (PTA3468 - mean of thresholds at 3, 4, 6 and 8 kHz). Multivariable linear regression was used to test for differences in PTAs between cases and controls.

RESULTS

The mean age for 158 XFS/XFG cases (30.4% male) was 77.4 years, 95 POAG cases (35.8% male) was 77.9 years, and 123 controls (46.3% male) was 76.8 years. Using multivariable linear regression analysis, there were no consistent, statistically significant differences in PTAs between the two case groups and controls in either the low- or high-frequency range, even when stratified by age group.

CONCLUSION

Among the older individuals examined in this study hearing loss is highly prevalent and strongly associated with male gender and increasing age. As we did not find consistent statistically significant difference in hearing between cases and controls the diagnosis of XFS/XFG or POAG does not as such routinely call for audiological evaluation.

Effects of dorzolamide/timolol fixed combination on retrobulbar hemodynamics in pseudoexfoliative glaucoma

In our study we aimed to evaluate the short-term effects of dorzolamide/timolol on ocular perfusion pressure and retrobulbar blood flow in patients with pseudoexfoliative glaucoma (PXG). This prospective observational cross-sectional study enrolled 22 eyes of 22 newly-diagnosed patients with PXG in a single center. All of the patients received a fixed combination of dorzolamide/timolol. Besides routine ophthalmologic examination, the retrobulbar hemodynamic parameters in the ophthalmic artery, central retinal artery, and short posterior ciliary arteries were measured in all participants at baseline and the 3(rd) month using color Doppler imaging. The mean intraocular pressure (IOP) was 22.3 ± 2.1 mmHg at baseline and reduced to 17.4 ± 2.3 mmHg at the 3(rd) month (p < 0.05). None of the retrobulbar parameters, except peak systolic velocity and resistive index in temporal short posterior ciliary arteries, changed significantly on therapy with dorzolamide/timolol fixed combination when the results were analyzed at Month 3. The drug significantly decreased the peak systolic velocity (p = 0.044) and reduced the resistive index in 0.04 units, 95% confidence interval 0.03-0.05, (p < 0.001) in the temporal short posterior ciliary arteries. This study reports that the retrobulbar hemodynamics might be affected less than expected by dorzolamide/timolol fixed combination in patients with PXG although the reduction of IOP was statistically significant.

Characteristics of the Anterior Segment Biometry and Corneal Endothelium in Eyes with Pseudoexfoliation Syndrome and Senile Cataract

Objectives:

To evaluate the anterior segment biometric features and corneal endothelial changes in eyes with pseudoexfoliation (PEX) syndrome and senile cataract.

Materials and Methods:

The central corneal thickness, anterior chamber depth (ACD), pupil diameter, lens thickness, endothelial cell density (ECD), and percentages of polymegathism and pleomorphism of 52 subjects with PEX and cataract were compared with 51 age- and gender-matched control subjects with cataract using optical low-coherence reflectometry (OLCR, Lenstar LS 900; Haag Streit AG, Switzerland) and in-vivo confocal microscopy (Confo Scan 4, Nidek Co. Ltd, Osaka, Japan). Nineteen subjects with PEX syndrome had glaucoma and were using anti-glaucoma medications. Only one eye of the subjects was used in statistical analysis and a p value less than 0.05 was considered statistically significant.

Results:

None of the OLCR parameters reached statistically significant differences among the 3 groups (ANOVA p>0.05). The percentage of eyes with ACD <2.5 mm was 13.7% in the control group, 24.2% in PEX eyes without glaucoma and 21.1% in PEX eyes with glaucoma, with no statistically significant differences (p=0.45). There was a significant difference in mean ECD among the 3 groups (ANOVA p=0.02), whereas no differences could be found in respect to polymegathism and pleomorphism (p>0.05). Mean ECD was significantly lower in the PEX glaucoma group (2,199.5±176.8 cells/mm2) than the control group (2,363±229.3 cells/mm2) (p=0.02), whereas no difference was found in mean ECD of PEX eyes without glaucoma and the control group (p=0.42). ECD was less than 2,000 cells/mm2 in 15.8% of PEX subjects with glaucoma, 9.8% of control subjects and 6.1% of PEX eyes without glaucoma, with no statistically significant difference (p=0.52).

Conclusion:

As eyes with both PEX glaucoma and cataract seem to be associated with decreased endothelial cell number, specular or confocal microscopy screening should be done for the patients scheduled for intraocular surgery.

Ethnicity-Based Differences in the Association of LOXL1 Polymorphisms with Pseudoexfoliation/Pseudoexfoliative Glaucoma: A Meta-Analysis

Pseudoexfoliation (PEX) is an age-related disorder of the extracellular matrix; it is strongly associated with glaucoma, the leading cause of irreversible blindness worldwide. We conducted an ethnic-based meta-analysis of the association of LOXL1 polymorphisms with PEX/pseudoexfoliative glaucoma (PEXG). Association studies were retrieved systematically from PubMed, EMBASE, and Web of Knowledge. Allelic and genotype frequencies of rs3825942, rs1048661, and rs2165241 were compared between PEX/PEXG and controls. Odds ratios (OR) and 95% confidence intervals (CI) were calculated using a random effects model. Overall, 39 independent cohorts were included. Rs3825942 (G) was an at risk allele for PEX/PEXG in Caucasians, Japanese, Koreans, Chinese, South Asians, and Middle Easterners, but protective in Black South Africans (OR = 0.10, 95%CI:0.06-0.16). Rs1048661 (G) was an at risk allele for PEX/PEXG in Caucasians, South Asians, Middle Easterners and Black South Africans, but was protective in Japanese (OR = 0.03, 95%CI:0.02-0.06) and Koreans (OR = 0.10, 95%CI:0.05-0.22). These associations we-re confirmed for the genotypic recessive models. Rs2165241 (C) was a protective allele for PEX/PEXG in Caucasians, but was an at risk allele in Japanese (OR = 7.49, 95%CI:3.22-17.41) and Koreans (OR = 6.63, 95%CI:2.60-16.90). This was confirmed for the genotypic dominant model. Other genetic and/or environmental factors may modify the effect of LOXL1 polymorphisms in certain ethnic groups.

Pseudoexfoliation syndrome at a Singapore eye clinic

Background

The purpose of this study was to investigate the demographics of pseudoexfoliation syndrome (PXF) and pseudoexfoliative glaucoma (PXG) in a Singapore hospital eye outpatient clinic.

Methods

A retrospective study of 93 consecutive patients (146 eyes) with PXF was undertaken by a single ophthalmologist over a period of 37 months (July 1, 2006, to July 31, 2009).

Results

Ninety-three (2.8%) of 3,297 patients seen during the study period were diagnosed with PXF. Forty-three (46.2%) of the 93 PXF patients were male. Indians were 5.04 times more likely to develop PXF than Chinese (P<0.001, 95% confidence interval 3.05–8.33), while Malays were 2.22 times more likely to develop PXF as compared with Chinese (P=0.029, 95% CI 1.08–4.55). Twenty-two (23.7%) of the 93 PXF patients had PXG at the time of diagnosis. There was no statistically significant difference in mean age between PXF and PXG patients. There was a larger proportion of males with PXG than females (P<0.001).

Conclusion

PXF is not infrequent in elderly Singapore eye clinic patients, and is more likely to occur in Indians than in Chinese. In the Singapore eye clinic setting, males may be more likely to develop PXG, although larger studies will be required to confirm this.

Changes in intraocular pressure after descemet stripping automated endothelial keratoplasty: a retrospective analysis

PURPOSE

To analyze the occurrence of postoperative intraocular pressure (IOP) elevation and types of pressure-lowering treatment in patients after Descemet stripping automated endothelial keratoplasty (DSAEK) with and without previous diagnoses of glaucoma and/or pseudoexfoliation (PXF) syndrome.

METHODS

This retrospective assessment considered 211 consecutive DSAEK cases (176 patients) performed by 1 surgeon between January 2007 and November 2010 with at least 1-year follow-up. Salient patient characteristics, IOP, and type of antiglaucoma treatment registered in postoperative visits up to 36 months were extracted from medical records. IOP elevation and its association with glaucoma, PXF, and combination of the 2 were assessed using multivariate ordinal logit models.

RESULTS

Of 211 eyes, 97 eyes (45%) showed at least 1 increase in IOP >25 mm Hg after DSAEK. Of these 97 eyes, 17 eyes (17.5%) had a history of glaucoma alone, another 17 eyes (17.5%) had a history of glaucoma combined with PXF, 10 eyes (9.7%) had PXF alone, and 53 eyes (54.6%) were steroid responders only. To control IOP elevation, steroid reduction alone was performed in 6 eyes (6.2%) and IOP-lowering medication as the only measure was performed in 26 eyes (26.8%). In 46 eyes (47.4%), steroids were reduced in combination with IOP-lowering medication and 16 eyes (16.5%) required surgery. In 3 eyes (3.1%), no action was required. Presence of PXF (odds ratio, 1.71; 95% confidence interval, 0.62-2.81; P = 0.002) and PXF glaucoma (1.14; 95% confidence interval, 0.06-2.21; P = 0.038) required a more intensive IOP-lowering management than patients without PXF with IOP problems.

CONCLUSIONS

Increased IOP is common after DSAEK, and a significant number of patients need IOP-lowering treatment. PXF syndrome and PXF glaucoma are risk factors for significant IOP elevation after DSAEK. In most cases, IOP remains controlled with conservative management, but some patients require glaucoma surgery.

Evaluation of Optical Low Coherence Reflectometry Parameters in Patients with Exfoliation Syndrome

Purpose. To evaluate optical low coherence reflectometry (OLCR) parameters in patients with exfoliation syndrome (EXS) undergoing cataract surgery. Methods. Forty-seven eyes of 47 patients with EXS (Group 1), and 55 eyes of 55 healthy subjects (Group 2) were included in the study. Anterior chamber depth (ACD), lens thickness (LT), axial length (AL), central corneal thickness (CCT), horizontal corneal length (HCL), and pupil diameter (PD) parameters were measured by OLCR (Lenstar LS 900, Haag-Streit) and compared between groups. Shapiro-Wilk test and Mann Whitney U tests were used for statistical analyses. Results. The mean ACD, HCL, and PD values were significantly lower in EXS group than in healthy subjects (P = 0.01, P = 0.04, and P < 0.001, resp.). The mean LT was significantly higher in EXS group than in healthy subjects (P = 0.007). There was no significant difference between groups in means of AXL and CCT. Conclusions. According to OLCR measures, eyes with EXS have shallower ACD, smaller PD, thicker LT, shorter HCL, and no significantly different CCT levels.

Update on pseudoexfoliation syndrome pathogenesis and associations with intraocular pressure, glaucoma and systemic diseases

PURPOSE OF REVIEW

Pseudoexfoliation (PEX) syndrome is a common age-related disorder affecting intraocular and extraocular tissues. This review focuses on recent publications related with the pathogenesis and associations of PEX syndrome with intraocular pressure (IOP), glaucoma and systemic diseases.

RECENT FINDINGS

In PEX tissues, expression of lysyl oxidase-like 1 (LOXL1) was found to be markedly dysregulated. This may adversely affect elastin metabolism and lead to elastotic alteration in tissues such as lamina cribrosa. There is increasing evidence that cellular stress conditions and low-grade chronic inflammatory processes are involved in the pathogenesis of PEX. Although there is an increased risk for glaucoma development in patients with PEX and ocular hypertension as compared with non-PEX patients with ocular hypertension, LOXL1 single nucleotide polymorphisms were not associated with intraocular pressure (IOP) differences. Lack of association of PEX with all-cause mortality or dementia has been reported recently. The association with vascular diseases is not consistent among different studies.

SUMMARY

Despite the high prevalence of the LOXL1 variants in the general population, a much lower proportion of the population develops PEX, suggesting that in addition to LOXL1, other genetic, epigenetic and environmental factors may contribute to the development of PEX. Also, LOXL1 cannot help to identify those with PEX at increased risk for glaucoma development. Increased risk for glaucoma development in PEX patients who present with increased IOP may be related to other factors beyond IOP, contributing to increased vulnerability of the optic nerve to glaucoma development in the presence of PEX.

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.

Comparison of primary open-angle glaucoma and exfoliation glaucoma at diagnosis

PURPOSE

To compare ocular findings in eyes with primary open-angle glaucoma (POAG) and exfoliation glaucoma (EG) at the time of diagnosis when identical diagnostic criteria for glaucoma were applied.

METHODS

We conducted a study on records of 519 consecutive, unselected patients with chronic glaucoma filing for cost-free medication from the Finnish National Social Insurance Institute (FSII). Fourteen cases were excluded for having other types of glaucoma. The documents were provided by eye hospitals or by licensed ophthalmologists. The criteria for glaucoma were set by the Parliament of Finland and applied by FSII. A total of 329 patients had POAG and 176 had EG. The main outcome measures were best-corrected visual acuity (BCVA), intraocular pressure (IOP), cup-to-disc ratio of the optic nerve head (C/D), and glaucomatous changes of the visual fields (VF).

RESULTS

As regards sex, the 2 groups were comparable: 66% female with POAG and 68% with EG. The EG patients were older (mean ± SD 74 ± 8.6 years) vs POAG (68 ± 11.4 years). The EG eyes had slightly lower BCVA. The POAG eyes had mean intraocular pressure (IOP) 24 ± 5.4 mm Hg. A total of 12% in this group had highest IOP of less than 18 mm Hg (low-tension glaucoma [LTG]) but there were none of EG. All EG eyes had a mean IOP 28.3 ± 9.3 mm Hg. Among EG patients, 26% had unilateral disease, with a mean IOP of 33.7 ± 8.7 mm Hg, while the opposite eyes had a mean of 19 ± 3 mm Hg. There was not much difference in the C/D ratios of POAG and EG eyes and the VF profiles were similar.

CONCLUSIONS

At diagnosis, patients with EG were older than those with POAG and had higher mean IOP values. Among patients with POAG, there were 12% with LTG, but none among EG. A total of 26% among EG had unilateral disease with marked IOP asymmetry. The C/D and VF profiles were similar because the patients had been seen early in the disease course. Early recognition and lifelong most effective therapy of EG are strongly advocated.

Choroidal thickness changes in patients with pseudoexfoliation syndrome

To evaluate the choroidal thickness using spectral-domain optical coherence tomography (OCT) in patients with pseudoexfoliation syndrome (PXS) and to compare them with healthy controls. This observational comparative study consisted of 35 PXS patients and 35 age- and sex-matched control cases. The control cases had neither systemic nor ocular disease. All 70 patients underwent a complete ophthalmic examination as well as choroidal thickness measurement using a high speed and high resolution SD-OCT device (Topcon 3D OCT-2000, Japan). There was no significant difference with respect to mean refractive error and intraocular pressure measurement between patients with PXS and controls (p = 0.237 and 0.433, respectively). The mean choroidal thickness was found as 206.6 ± 37.6 µm in the PXS group and 215.9 ± 47.3 µm in controls, respectively. The mean choroidal thickness was not significant between the PXS patients and the control cases (p = 0.362). Although PXS patients had lower mean choroidal thickness than controls, our results did not reach any statistical significance.

Role of an extracellular chaperone, Clusterin in the pathogenesis of Pseudoexfoliation Syndrome and Pseudoexfoliation Glaucoma

Pseudoexfoliation (PEX), an age related disorder is a prominent contributor to secondary glaucoma. Earlier studies have suggested involvement of clusterin in the development of PEX. We designed a case-control study to understand the role of clusterin single nucleotide polymorphisms (SNPs) in PEX and analyzed the role of risk alleles in the disease. Genotyping of SNPs in 136 PEX patients and 89 controls of Indian origin revealed a genetic association between rs2279590 and PEX in Indian population with a p-value of 0.004. The high risk allele "G" at rs2279590 has an effect on clusterin mRNA expression. There was a twofold higher clusterin mRNA level in "GG" genotyped individuals in comparison to "AA" genotyped individuals (p = 0.039). Western blot and immunohistochemistry studies showed an upregulation of Clusterin protein in pseudoexfoliation glaucoma (PXG) affected individuals in both aqueous humor and lens capsules respectively. Together, our results reveal that rs2279590 was found to be associated with PEX in Indian population and the risk allele mediates an allele specific upregulation of the clusterin mRNA. Moreover, upregulation of Clusterin protein in PXG individuals augments further protein deposition.

Evaluation of the endothelial cell density and the central corneal thickness in pseudoexfoliation syndrome and pseudoexfoliation glaucoma

Purpose. Evaluation of central corneal thickness (CCT) and endothelial cell density (ECD) in patients with senile cataract and coexisting pseudoexfoliation (PEX) syndrome with glaucoma (PEXG) and without glaucoma using specular microscopy. Participants and Methods. The study included 122 patients (217 eyes). In this group of patients we identified 133 eyes with PEX syndrome (65 with glaucoma, 68 without glaucoma) and 84 eyes without PEX syndrome. ECD and CCT were measured in each eye by specular microscopy. Results. ECD in eyes with PEX syndrome without glaucoma (2297 ± 359 cell/mm²) and in eyes with PEXG (2241 ± 363 cell/mm²) was lower than in the control group (2503 ± 262 cell/mm²) (P < 0.001). CCT in eyes with PEXG (508.2 ± 32.6 μm) was thinner than in eyes with PEX syndrome without glaucoma (529.7 ± 30.3 μm) and control group (527.7 ± 29.4 μm) (P < 0.001). Conclusions. This research shows that in eyes with PEX syndrome, both with and without glaucoma, ECD was statistically significantly lower than in the control group. In patients with PEXG, CCT was statistically significantly thinner than in the PEX syndrome and control group.

Cardiovascular repercussions of the pseudoexfoliation syndrome

Pseudoexfoliation syndrome is a primarily ophthalmological disorder caused by deposition of whitish-gray protein on the lens, iris, and multiple other eye tissues. There is increasing evidence over the previous years that pseudoexfoliation syndrome is a systemic disorder with various extraocular manifestations and has recently been linked to several cardiovascular disorders. The present article aims to summarize the current knowledge on cardiovascular implications of this well-described clinical entity.

Pseudoexfoliation: normative data and associations. The Central India Eye and Medical Study

Purpose

To assess the prevalence of pseudoexfoliation (PEX) and its associations in a population-based setting.

Design

Population-based, cross-sectional study.

Methods

The Central India Eye and Medical Study included 4711 individuals. All study participants underwent a detailed ophthalmological examination. After medical pupil dilation, PEX was assessed by an experienced ophthalmologist using slit-lamp based biomicroscopy.

Results

Slit lamp examination results were available for 4646 (98.6%) study participants with a mean age of 49.3±13.3 years (range: 30–100 years). PEX was detected in 87 eyes (prevalence: 0.95±0.10% (95%CI: 0.75, 1.15) of 69 subjects (prevalence: 1.49±0.18% (95%CI: 1.14, 1.83). PEX prevalence increased significantly (P<0.001) from 0% in the age group of 30–39 years, to 2.85±0.56% in the age group of 60–69 years, to 6.60±1.21% in the age group of 70–79 years, and to 12.3±4.11% in the age group of 80+ years. In multivariate analysis, PEX prevalence was associated with higher age (P<0.001; regression coefficient B:0.11; odds ratio (OR): 1.11 (95%CI: 1.09, 1.13)), lower body mass index (P = 0.001; B: −0.12; OR: 0.88 (95CI: 0.82, 0.95)) and higher diastolic blood pressure (P = 0.002; B: 0.02; OR: 1.03 (95%CI: 1.01, 1.04)). In the multivariate analysis, PEX was not associated with retinal nerve fiber layer cross section area (P = 0.76) and presence of open-angle glaucoma (P = 0.15).

Conclusions

In a rural Central Indian population aged 30+ years, PEX prevalence (mean: 1.49±0.18%) was significantly associated with older age, lower body mass index and higher diastolic blood pressure. It was not significantly associated with optic nerve head measurements, refractive error, any ocular biometric parameter, nuclear cataract, early age-related macular degeneration and retinal vein occlusion, diabetes mellitus, smoking, and dyslipidemia.

Pseudoexfoliation: normative data and associations: the Beijing eye study 2011

OBJECTIVE

To assess the prevalence of pseudoexfoliation syndrome (PEX) and its associations in a population-based setting.

DESIGN

Population-based, cross-sectional cohort study.

PARTICIPANTS

Of 4403 eligible subjects with an age of ≥ 50 years, 3468 individuals (78.8%) participated in the Beijing Eye Study 2011 (mean age, 64.6 ± 9.8 years; range, 50-93 years).

METHODS

All study participants underwent a detailed ophthalmologic examination. After medical pupil dilation, PEX was assessed by an experienced ophthalmologist using slit-lamp-based biomicroscopy.

MAIN OUTCOME MEASURES

Prevalence and associations of PEX.

RESULTS

Slit-lamp examination results were available for 3022 study participants (87.1%). Definite pseudoexfoliation was observed in 72 of the 3022 subjects, with a prevalence of 2.38% (95% confidence interval [CI], 1.84-2.93). Suspected PEX was detected in 104 of the subjects (3.44%; 95% CI, 2.8-4.1). The overall prevalence of PEX (definite and suspected) was 176 of 3022 or 5.82% (95% CI, 4.99-6.66). In 80 subjects (45.5%), PEX was detected in both eyes, whereas it was detected only in the right eye in 42 subjects (23.9%) and only in the left eye in 54 (30.7%). The prevalence of PEX increased from 1.1% in among those 50 to 54 years old, to 3.5%, 5.7%, and 11.8% among those 60 to 64 years, 70 to 74 years, and ≥ 80 years, respectively. In multivariate analysis, presence of PEX was significantly associated with older age (P<0.001; odds ratio [OR], 1.08; 95% CI, 1.04-1.10), shorter axial length (P = 0.03; OR, 0.82; 95% CI, 0.68,0.98), and shallower anterior chamber (P = 0.03; OR, 0.59; 95% CI, 0.36-0.95). We found that PEX was not associated (all P>0.05) with sex, diabetes mellitus, blood pressure, psychological depression, smoking, dyslipidemia, body mass index, central corneal thickness, corneal diameter, optic nerve head measurements, choroidal thickness, retinal vessel diameters, early age-related macular degeneration, or retinal vein occlusion.

CONCLUSIONS

In a North Chinese population aged ≥ 50 years, the prevalence of definite PEX was 2.38% (95% CI, 1.84-2.93), suspect PEX was 3.4% (95% CI, 2.8-4.1) and overall PEX was 5.82% (95% CI, 4.99-6.66). We found PEX to be associated with older age, shorter axial length, and shallower anterior chamber. The relationship between PEX and glaucomatous optic neuropathy remained inconclusive among our population.

FINANCIAL DISCLOSURE(S)

The authors have no proprietary or commercial interest in any materials discussed in this article.

Twelve-year Incidence of Exfoliation Syndrome in the Reykjavik Eye Study

PURPOSE

To examine the 12-year incidence of exfoliation syndrome (XFS) in persons aged 50-79 years at baseline and also to monitor changes in related ophthalmologic variables, to identify possible risk factors for incidence and to estimate the reliability of our diagnostic criteria.

METHODS

Baseline examination was performed in 1996 on a random sample of 1045 participants from the population of Reykjavik, 50 years and older. Five years later, in 2001, 88.2% of survivors returned for a follow-up. In 2008, 12 years after the baseline examination, a total of 573 participants returned for the third examination (71.5% of survivors). On all three occasions, the participants underwent a thorough eye examination including slitlamp examination specifically looking for XFS and answered a comprehensive questionnaire.

RESULTS

A total of 8.0% of participants developed XFS during the follow-up period in at least one eye, with women being more commonly affected than men, 9.2% versus 6.6%. The overall 12-year incidence for either eye increased with increasing age, from 6.5% in those participants aged 50-59 years at baseline to 10.6% in those that were 70-79 years at baseline; 71% of clinically unilateral cases had converted to bilateral over 12 years.

CONCLUSIONS

Twelve-year incidence of XFS is higher in women than in men and higher in older age groups than in younger ones. Most persons deemed on the slitlamp to be unilaterally affected have converted to bilateral over 12 years. Eyes with XFS at baseline were 3-4 times more likely to have cataract surgery during the 12 years. Our definition of definite XFS generally holds, while our definition of probable XFS is of no prognostic value over 12 years.

Central corneal thickness and corneal curvature in pseudoexfoliation syndrome with and without glaucoma

PURPOSE

To determine the central corneal thickness (CCT) and corneal curvature (CC) in pseudoexfoliative (PE) eyes with and without glaucoma.

METHODS

Charts of 551 consecutive patients undergoing preoperative examinations for cataract surgery between April 2006 and May 2009 in our clinic were reviewed retrospectively. Fourty-eight PE patients (48 eyes; 19 with glaucoma, 29 without glaucoma) and 48 age-matched and sex-matched control patients were enrolled in the study. The CCT, CC, intraocular pressure, and axial length were measured by ultrasonic pachymeter, autorefractokeratometer, Goldmann applanation tonometry, and ultrasound biometry, respectively. The independent samples t test and paired samples t test was used for the comparisons of the groups.

RESULTS

Mean CCT was significantly thinner in all PE and nonglaucomatous PE (Pseudoexfoliation syndrome "PES") eyes than in control eyes (P=0.004 and P=0.005, respectively). There was no difference in CCT between PE glaucoma (PEG) and control eyes (P=0.089). There was no difference in mean keratometry (K) and axial length in the study and control groups. In 22 unilateral PE eyes, mean CCT and K readings were insignificant between the PE eyes and fellow non-PE eyes.

CONCLUSIONS

CCT was significantly thinner in eyes with PES compared with control eyes; however, difference between the PEG and control eyes was insignificant. In addition, mean K readings were not different in study and control eyes. Thinner CCT in eyes with PES, both as it is an independent risk factor and as a result of artificially lower intraocular pressure readings, may be an illuminating cause for development and rapid progression of glaucoma in the patients with PES.

Corneal biomechanical properties of patients with pseudoexfoliation syndrome

PURPOSE

To assess the corneal biomechanical properties of patients with pseudoexfoliation syndrome (PEX syndrome).

METHODS

Fifty-two eyes of 52 patients (27 unilateral and 25 bilateral) and 42 eyes of 42 age-matched control subjects were enrolled in the study. Metrics of corneal biomechanical properties, including corneal hysteresis (CH) and corneal resistance factor (CRF), were measured with the ocular response analyzer (ORA). The ORA also determined the values of Goldmann-correlated intraocular pressure and corneal-compensated intraocular pressure. Central corneal thickness (CCT) was measured by the ORA integrated handheld ultrasonic pachymeter. The values recorded by the ORA were compared between eyes with PEX syndrome and those without PEX syndrome. Eyes with unilateral PEX syndrome and fellow eyes without PEX syndrome were also compared.

RESULTS

The mean CH and CRF of all eyes with PEX syndrome were significantly lower than those of control eyes (P < 0.05). Neither corneal-compensated intraocular pressure nor Goldmann-correlated intraocular pressure showed a statistically significant difference in both the groups. Mean CCT values also did not show significant difference. Comparison of the unilateral eyes with PEX syndrome with the apparently normal fellow eyes revealed no significant difference between the mean CCT, mean CH, and mean CRF values (P > 0.05). However, the mean corneal-compensated intraocular pressure and Goldmann-correlated intraocular pressure were relatively higher in the PEX syndrome eye (P < 0.05). There was no significant difference between the mean CCT values of these groups (P > 0.05).

CONCLUSIONS

The CH and CRF decrease in both unilateral and bilateral PEX syndrome suggested that PEX syndrome has a weakening effect on corneal biomechanical properties. Moreover, in subjects with clinically unilateral PEX syndrome, these properties were closer to eyes with PEX syndrome than to normal control eyes.

Pseudoexfoliation syndrome in Congolese patients

PURPOSE

To determine the frequency of pseudoexfoliation syndrome (PEX) in Congolese patients and its association with cataract and glaucoma.

METHODS

We performed a cross-sectional and descriptive analysis of the data from patients diagnosed with PEX. Data were collected between February 2005 and June 2008 in a general practice of ophthalmology in Kinshasa. Patients aged 50 or above who attended the general practice of ophthalmology were included in the study. Each patient underwent complete ophthalmic evaluation, including visual acuity testing, slit-lamp biomicroscopy, applanation tonometry, gonioscopy, and ophthalmoscopy. The diagnosis of PEX was based on presence of typical pseudoexfoliation material on the anterior lens surface and/or the pupillary margin in either or both eyes.

RESULTS

Of 2142 patients seen during the study period, 37 (59 eyes) had PEX in either eye, for a frequency of 1.73%. The mean (±SD) age of the patients with PEX was 70.40 years±8 (range: 57-87 years). The frequency of PEX had a tendency to increase with age: 0.50% of patients aged 50-59 years had PEX, whereas 7.29% of those aged more or equal to 80 years were affected (P<0.0001), with a female predominance (2.18% of women versus 1.22% of men, P=0.035). PEX was bilateral in 22 (59.46%) of 37 patients (74.58% of eyes). Bilateral PEX was found more often in females (16 patients over 22, 72.72%) than in males (six patients over 15, 40%) (P=0.05). PEX was significantly associated with cataract (P=0.002) and glaucoma (P<0.001).

CONCLUSION

Despite the limitations inherent in a clinic-based study, this investigation provides an indication of the frequency of PEX in Central Africa. This shows that Congolese patients have a low frequency of PEX (1.73%), inferior to that of black people in South Africa (12.1-16%). This study confirms that PEX is an age-related condition and is associated with cataract and glaucoma, as in other races.

Geographic and climatic factors associated with exfoliation syndrome

OBJECTIVE

To identify geographic and climatic risk factors associated with exfoliation syndrome (ES).

METHODS

A retrospective study of 626 901 eye care recipients, dating from 2001 to 2007 from 47 US states in a managed care network. Incident ES cases-patients (N = 3367) were identified by using billing codes. We assessed the risk of ES by geographic latitude tier in the continental United States and assigned state-level climatic data (eg, ambient temperature, elevation, and sun exposure) according to patients' residential location. The hazard of ES was calculated by using multivariable-adjusted Cox proportional hazards regression models.

RESULTS

Compared with middle-tier residence, northern-tier residence (above 42°N) was associated with an increased hazard of ES (adjusted hazard ratio [HR], 2.14; 95% confidence interval [CI], 1.94-2.35). Southern-tier (below 37°N) was associated with a reduced hazard of ES (HR, 0.83; 95% CI, 0.75-0.93). Excluding whites did not change these associations. After adjustment for joint environmental effects, for every 1° increase in July high temperature, the hazard of ES decreased by 9% (HR, 0.91; 95% CI, 0.89-0.93); for every 1° increase in January low temperature, the hazard decreased 3% (0.97; 0.96-0.98). For each additional sunny day annually, the hazard increased by 1.5% (HR, 1.02; 95% CI, 1.01-1.02) in locations with average levels of other climatic factors.

CONCLUSION

Ambient temperature and sun exposure may be important environmental triggers of ES.

Risk factors for primary open-angle glaucoma and pseudoexfoliative glaucoma in the Thessaloniki eye study

PURPOSE

To investigate risk factors for primary open-angle glaucoma (POAG) and pseudoexfoliative glaucoma (PEXG) in the Thessaloniki Eye Study.

DESIGN

Cross-sectional, population-based study.

METHODS

Randomly selected subjects 60 years of age and older (n=2554) participated in the Thessaloniki Eye Study. Glaucomatous damage and presence of pseudoexfoliation (PEX) were defined according to specific criteria. Open-angle glaucoma (OAG) subjects were compared with nonglaucoma subjects (controls), POAG subjects were compared with controls without PEX, and PEXG subjects were compared with controls with PEX for demographic, lifestyle, ophthalmic, and systemic factors. Factors with P < .2 in the univariate analysis were retained for multivariate analyses.

RESULTS

In multivariate analysis restricted to persons who participated in clinic visits and who had at least 1 phakic eye (n=2078), intraocular pressure (odds ratio [OR], 1.21 per 1 mm Hg; P<.001), PEX (OR, 2.81; P<.001), history of coronary artery bypass or vascular surgery (OR, 1.95; P=.017), and moderate-to-high myopia (≥ -3 diopters; OR, 2.40; P=.009) were associated with higher odds for OAG. In analysis including all clinic visits (n=2261), age became significantly associated (OR, 1.05; P=.004). In multivariate analysis for POAG (n=1840), associations were found for age (OR, 1.04 per year; P=.048), IOP (OR, 1.19 per 1 mm Hg; P<.001), history of coronary artery bypass or vascular surgery (OR, 2.09; P=.01), and history of diabetes treated with insulin (OR, 3.05; P=.045). In multivariate analysis for PEXG (n=238), the latter was associated with increased IOP (OR, 1.25 per 1 mm Hg; P<.001).

CONCLUSIONS

IOP was the only factor associated with both POAG and PEXG, whereas moderate-to-high myopia showed borderline significance in both. Vascular systemic diseases and their treatment were associated only with POAG. The implications of these differences for the pathogenesis between the 2 common types of OAG should be explored further.

Review: The role of LOXL1 in exfoliation syndrome/glaucoma

Exfoliation syndrome is a common cause of open-angle glaucoma. It is characterized by microscopic flakes of protein-rich material being deposited in both ocular and non-ocular tissues. While its mechanism is poorly understood, family- and population-based studies have established that the disorder has a strong genetic component. A further understanding of the relevant gene variants might help reveal the molecular mechanism behind exfoliation. The most-strongly associated genetic variants are found in the lysyl oxidase-like 1 (LOXL1) gene. However, two major risk alleles in the LOXL1 coding region are reversed between ethnic groups. It now appears the strong association between LOXL1 and XFS is due to non-coding variants that have not yet been identified. Such variants might alter LOXL1 expression, which is decreased in the late stages of exfoliation syndrome/glaucoma. Here we discuss LOXL1 as a risk gene for exfoliation syndrome and glaucoma.

LOXL1 promoter haplotypes are associated with exfoliation syndrome in a U.S. Caucasian population

PURPOSE

LOXL1 is a major genetic risk factor for exfoliation syndrome (ES) and exfoliation glaucoma (EG). Recent evidence documenting reversal of risk alleles for the disease-associated missense variants R141L and G153D suggests that these variants are not causative and that they may be proxies for other unknown functional LOXL1 variants. The purpose of this study was to investigate the disease association of LOXL1 variants spanning the gene region, including the 5' and 3' regulatory regions, in a U.S. Caucasian case-control sample.

METHODS

Twenty-five LOXL1 single-nucleotide polymorphisms (SNPs), distributed throughout the gene, were genotyped in 196 Caucasian patients with ES/EG and 201 matched controls. Genotype data were analyzed for single SNP associations, SNP interactions, and haplotype associations.

RESULTS

Promoter region haplotypes that included the risk alleles for rs12914489, a SNP located in the distal promoter region and independently associated with ES, and rs16958477, a SNP previously shown to affect gene transcription, were associated with increased disease risk (P=0.0008; odds ratio [OR], 2.34; 95% confidence interval [CI], 1.42-3.85) and with protective effects (P=2.3 × 10(-6); OR, 0.38; 95% CI, 0.25-0.57). Haplotypes containing rs12914489 and rs16958477 risk and protective alleles also significantly influenced the disease risk associated with missense alleles R141L and G153D.

CONCLUSIONS

LOXL1 promoter haplotypes were identified that are significantly associated with ES/EG in a U.S. Caucasian population. These results suggest that promoter region SNPs can influence LOXL1 gene expression, potentially causing a reduction of enzyme activity that may predispose to disease.

The frequency of pseudoexfoliation syndrome in the middle Black Sea region of Turkey

PURPOSE

To assess the frequency of pseudoexfoliation syndrome (PEX) and evaluate its association with specific ocular diseases in patients attending the Department of Ophthalmology at Gaziosmanpasa University Hospital.

METHODS

A prospective study was conducted at the Gaziosmanpasa University Hospital between December 2007 and December 2008. A total of 831 subjects aged 45 or above attending the general ophthalmic clinics were recruited for this study. Each patient underwent complete ophthalmic assessment, including ocular history, visual acuity testing, slit-lamp examination, applanation tonometry, gonioscopy, and fundus examination.

RESULTS

Of the 831 subjects, 12.2% had PEX. Pseudoexfoliation was bilateral in 74.2% of cases, significantly associated with cataract, glaucoma, age-related macular degeneration (AMD), and phacodenesis. Of the patients with PEX, 43.6% had cataract, 6.9% had glaucoma, 7.9% had AMD, and 0.9% had phacodenesis. In addition, 9.8% had cataract + glaucoma, 13.7% had cataract + phacodenesis, and 17.8% had all of them. The prevalence of PEX had a tendency to increase with age but had no sex predilection.

CONCLUSIONS

The study findings enhance our knowledge of PEX in Anatolia, particularly in the Middle Black Sea region.

Lack of association of polymorphisms in elastin with pseudoexfoliation syndrome and glaucoma

PURPOSE

To evaluate the elastin gene (ELN) as a secondary risk factor for pseudoexfoliation syndrome (PXFS) and the associated glaucoma pseudoexfoliation glaucoma (PXFG).

METHODS

One hundred seventy-eight unrelated patients with PXFS, including 132 patients with PXFG, and 113 unrelated controls were recruited from the Massachusetts Eye and Ear Infirmary. All the patients and controls were white of European ancestry. Three tag SNPs (rs2071307, rs3823879, and rs3757587) that capture the majority of alleles in ELN were genotyped. Single-SNP association was analyzed using Fisher exact test. Haplotype analysis and the set-based test were used to assess the association for the whole gene. Interaction analysis was done between the ELN SNP rs2071307 and LOXL1 SNP rs2165241 using logistic regression. Multiple comparisons were corrected using the Bonferroni method.

RESULTS

All 3 ELN tag SNPs were not significantly associated with PXFS and PXFG (P>0.20). The minor allele frequencies in PXFS, PXFG, and controls were 40.7%, 39.8%, and 45.6%, respectively for rs2071307, 6.7%, 6.3%, and 5.4% for rs3823879, and 14.8%, 16.2%, and 13.6% for rs3757587. Haplotype analysis and the set-based test did not find significant association of ELN with PXFS (P=0.94 and 0.99, respectively). No significant interaction effects on PXFS were identified between the ELN and LOXL1 SNPs (P=0.55).

CONCLUSIONS

Our results suggest that common polymorphisms of ELN are not associated with PXFS and PXFG in white populations. Further studies are required to identify secondary genetic factors that contribute to PXFS.

Scanning laser ophthalmoscopic parameters of eyes with exfoliation syndrome

PURPOSE

To evaluate optic nerve head (ONH) characteristics in patients with exfoliation syndrome (EXS).

METHODS

This was a cross-sectional, observational study in which 73 eyes from 73 patients with EXS and 93 eyes from 93 age-matched healthy subjects who met the inclusion criteria were included. Topographic measurements of the ONH and peripapillary retinal nerve fiber layer (RNFL) thickness were performed by confocal scanning laser ophthalmoscopy, using a Heidelberg retina tomograph. Outcomes of interest were studied by Student t test and chi-squared test.

RESULTS

EXS patients and age-matched controls did not differ in ONH parameters. Nevertheless, the mean cup depth and height variation contour values were higher in the normal subjects (P = 0.07, P = 0.056, respectively). Mean RNFL thickness was 0.22 +/- 0.06 mm in the EXS group and 0.26 +/- 0.06 mm in the control group, (P = 0.001). Likewise, the RNFL cross-sectional area was significantly lower in exfoliative eyes (1.16 +/- 0.35 mm(2)) than in those of the control group (1.31 +/- 0.33 mm(2)) (P = 0.006).

CONCLUSIONS

No significant differences in ONH parameters between EXS patients and age-matched healthy subjects were observed; however, RNFL measurements in eyes with EXS showed lower values.

Prevalence of major eye diseases and causes of visual impairment in the adult Finnish population: a nationwide population-based survey

PURPOSE

To estimate the prevalence of cataract, glaucoma, age-related maculopathy (ARM) and diabetic retinopathy (DR) in the adult Finnish population.

METHODS

A representative cross-sectional sample of the Finnish population aged 30 years and older. Of the 7979 eligible people, 7413 (93%) were interviewed and/or examined. The interview included self-reported doctor-made diagnoses of cataract, glaucoma, degenerative fundus changes (mainly ARM) or DR. Information on self-reported eye diseases was complemented with data from national registers, and case records were gathered for non-participants and persons with visual acuity (VA) < 0.5 or reporting difficulties in vision or eye diseases without assessed VA.

RESULTS

Based on self-reported and/or register-based data the estimated total prevalences of cataract, glaucoma, ARM and DR in the study population were 10%, 5%, 4% and 1%, respectively. All these chronic eye diseases increased with age (p < 0.001). The corresponding prevalences for persons aged 65 and older were 34%, 13%, 12% and 2%, respectively. Cataract and glaucoma were more common in women than in men [odds ratio (OR) 1.55, 95% confidence interval (CI) 1.26-1.91; OR 1.57, 95% CI 1.24-1.98, respectively]. The most prevalent eye diseases in people with visual impairment (VA < or = 0.25) were ARM (37%), unoperated cataract (27%), glaucoma (22%) and DR (7%).

CONCLUSION

The high prevalence of these mainly age-related eye diseases, together with increasing life expectancy, mean that continuous efforts are needed to identify and treat eye diseases in order to maintain patients' quality of life and to alleviate the social and economic burden of serious eye diseases.

Prevalence of pseudoexfoliation syndrome among adult Spanish in the Salnés eye Study

PURPOSE

To estimate the prevalence of Pseudoexfoliation syndrome (PXF) and to investigate its relationship with systemic and ocular diseases and lifestyle factors in a general adult population in north-western Spain.

METHODS

An age-stratified random sample of 1155 subjects was drawn from the population aged 40 years and over of O Salnés (Spain). From 937 eligible subjects, 619 (66.1%) participated (mean age (Standard Deviation [SD]): 63.4 (14.5) years, range: 40-96, 37.0% males). An interview to collect past history of ocular and systemic diseases and lifestyle details, and a comprehensive ophthalmic evaluation were performed. Study subjects with typical pseudoexfoliative material on the anterior capsule or in the pupil margin were labelled as having PXF. A design based analysis was performed and all calculations were weighted to give unbiased estimates.

RESULTS

The prevalence of PXF was 6.5% (95% confidence interval [CI]:4.9-8.1). PXF rates increased significantly with age (P = 0.000). No cases of PXF were detected in subjects between 40 and 60 years. Prevalence of PXF was 8.0% (95% C I5.4-11.6) in men and 5.4% (95% CI 3.8-7.6) in women (P = ns). The prevalence of glaucoma in subjects with PXF was 19.6% (95% CI 8.2-40.0). After controlling for age and sex, glaucoma, cataract surgery, rose bengal staining and diabetes were associated with PXF but only glaucoma and rose bengal staining associations remained significant in a multivariate model.

CONCLUSIONS

PXF is common among older individuals in north-western Spain. Subjects with pseudoexfoliation have a significantly higher prevalence of glaucoma than subjects without. An abnormal ocular surface detected by rose bengal staining is highly prevalent among subjects with pseudoexfoliation.

Epidemiology of exfoliation syndrome in the Reykjavik Eye Study

Exfoliation syndrome (XFS) is a major risk factor for glaucoma. It is characterized by a pathological accumulation of polymorphic fibrillar material in the anterior segment of the eye. It is likely that the increase in intraocular pressure (IOP) seen in XFS patients is at least in part because of flakes of material clogging up the trabecular meshwork, and thereby increasing the resistance to outflow and increasing IOP. XFS glaucoma progresses more rapidly, is more resistant to medical treatment and has worse prognosis than other glaucomas. The prevalence of XFS has been found to vary greatly between different studies, raising the possibility of racial and/or environmental modulators. XFS has also been linked to other changes in ophthalmological structures such as; changes in central corneal thickness (CCT), steeper corneal curvature (CC) and nuclear lens opacifications. Some studies have found XFS to be associated with systemic diseases, mostly cardiovascular and cerebrovascular. Exposure to ultra-violet (UV) light has also been investigated as a possible culprit, along with several other plausible factors. The aim of the present study was to determine the prevalence and 5-year incidence of XFS, to establish possible risk factors and/or concomitant symptoms and finally to investigate the relationship between XFS and glaucomatous changes. The Reykjavík Eye Study (RES) is a prospective study based on a random sample from the Icelandic national population sample. The baseline examination was performed in the autumn of 1996, when 1045 persons older than 50 years participated. Of these, 846 (88.2% of survivors) participated in a follow-up 5 years later. All participants went through a standard examination protocol, and answered a comprehensive questionnaire on health and life style. In the prevalence study, XFS was found in 10.7% of subjects, more frequently in women and older persons. Five years later, a further 5.2% of those that participated in the follow-up study and had no signs of XFS at baseline were diagnosed having XFS. We found a strong correlation between IOP and XFS. No difference was found in the anterior segment parameters measured, but there was a significant loss of neural tissue in the XFS as demonstrated by measurements of cup/disk ratio. In conclusion, we find XFS to be frequent among Icelanders, increasing with age and more in women. Our diagnostic criteria are reliable over time. We have also identified possible risk factors that point to a role of antioxidants in the development of XFS. We find changes in corneal curvature and thickness more related to age than XFS.

Central corneal thickness in subjects with glaucoma and in normal individuals (with or without pseudoexfoliation syndrome)

Objective:

The evaluation of central corneal thickness (CCT) in subjects with pesudoexfoliation glaucoma (PEXG), primary open-angle glaucoma (POAG), and in normotensive individuals with or without pseudoexfoliation syndrome (PXS).

Study design/patients and methods:

CCT was evaluated with ultrasound pachymetry in a total of 179 individuals: 32 had bilateral PEXG, 55 had bilateral POAG, 35 had PXS, and 57 were healthy individuals without PXS.

Results:

CCT in PEXG eyes (526.00 ± 34.30 μm) was significantly thinner compared to POAG eyes (549.36 ± 39.3 μm) (P = 0.027) and normal control eyes with (550.64 ± 39.0 μm) or without PXS (547.36 ± 33.1 μm), (P = 0.039 and 0.048 respectively). No statistically significant difference was found comparing CCT values of POAG eyes to control group eyes.

Conclusion:

The evaluation of CCT is necessary in all patients with glaucoma and especially in those with PEXG due to the thinner cornea and the risk of underestimation of intraocular pressure.

Increased likelihood of glaucoma at the same screening intraocular pressure in subjects with pseudoexfoliation: the Thessaloniki Eye Study

PURPOSE

To compare the clinical characteristics of primary open-angle glaucoma (POAG) and pseudoexfoliative glaucoma (PEXG) identified in the Thessaloniki Eye Study and to evaluate the proportion of subjects with and without pseudoexfoliation (PEX) who have glaucoma by screening intraocular pressure (IOP).

DESIGN

Cross-sectional, population-based study.

METHODS

Randomly selected subjects > or =60 years (n = 2,554) participated in the Thessaloniki Eye Study. Subjects were classified as having POAG or PEXG according to specific criteria. POAG and PEXG cases were compared for various clinical characteristics. The proportion with glaucoma among subjects with PEX and the proportion with glaucoma among subjects without PEX were estimated by IOP levels.

RESULTS

Among the clinic-visit participants (n = 2,261), 94 subjects (4.2%) had POAG and 41 (1.8%) had PEXG. The prevalence of glaucoma among subjects with PEX was 15.2% and the prevalence of glaucoma among subjects without PEX was 4.7%. In subjects without treatment, the mean IOPs were 19.8 mm Hg and 24.3 mm Hg for POAG and PEXG, respectively. For IOP level >20 mm Hg, the proportion with glaucoma among subjects with PEX was higher than that for glaucoma among subjects without PEX (37% vs 15%; P = .004), while no statistically significant difference was found for IOP level < or =20 mm Hg (2.1% vs 2.1%; P = .999), Fisher exact test.

CONCLUSIONS

In the Thessaloniki Eye Study, for screening IOP </=20 mm Hg the proportion with glaucoma was similar in subjects with and without PEX. For IOP level >20 mm Hg, the proportion with glaucoma increased highly in subjects both with and without PEX, while it was much higher among those with PEX at the same screening IOP.

From epidemiology to lysyl oxidase like one (LOXL1) polymorphisms discovery: phenotyping and genotyping exfoliation syndrome and exfoliation glaucoma in Iceland

The first Icelandic articles on exfoliation syndrome (XFS) and exfoliation glaucoma (XFG) appeared some 35 years ago in 1974. Articles since then have included epidemiology, pedigree-based and twin-studies as well as investigations into XFG response to medical therapy and XFS/XFG genetics. All studies found XFS/XFG to be common in Iceland and to be age-related. The Reykjavik Eye Study (RES), a population-based epidemiological study, was first conducted in 1996. The RES found that XFS and XFG prevalence in patients aged 50 years and older was 11% and that XFS/XFG was more common in women than in men. These results were confirmed in 5- and 12-year incidence studies that also suggested that detailed characterization of the phenotype is important, including pupil dilation. In the RES, eyes with XFS were found to be clinically unilateral in about half of cases and to have higher mean intraocular pressure (IOP) than non-XFS eyes. However, XFS was not found to be associated with central corneal thickness, corneal curvature, anterior chamber depth, lens thickness, lens opacification or optic disc morphology. About 15% of persons with XFS had XFG, and XFG eyes had higher risk of developing visual impairment and blindness than eyes with primary open-angle glaucoma. The first genetic studies on Icelanders, conducted about 12 years ago, were linkage studies and were unsuccessful in discovering the genetics behind XFS/XFG. However, in 2007 a genome-wide association study in Iceland using more than 300 000 markers [single nucleotide polymorphisms (SNPs)] on a relatively small number of patients did discover that lysyl oxidase like 1 (LOXL1) on chromosome 15q24 is a major gene for XFS/XFG. These results have now largely been replicated world-wide.

Pseudoexfoliation in the reykjavik eye study: five-year incidence and changes in related ophthalmologic variables

PURPOSE

To examine the 5-year incidence of pseudoexfoliation (PEX) and monitor changes in related ophthalmologic variables.

DESIGN

Population-based, prospective cohort study.

METHODS

A random sample from the Reykjavik Population Census for persons 50 years and older was used. At baseline 1,045 participants were examined for signs of PEX including peripheral band and/or central shield of exfoliative material on the anterior lens capsule. Five years later, 846 (88.2%) of survivors returned for a follow-up visit.

RESULTS

The 5-year incidence of PEX was 3.5% in right eyes only, and 5.2% in either eye. Age increased the risk of 5-year incidence by 5% when looking at 10-year age groups (P = .02); the incidence was higher in female subjects (P = .05) than in male. A total of 27% of clinically asymmetric cases converted to clinically bilateral disease over 5 years. Intraocular pressure increased in the group that developed PEX during the 5 years, but the size of the optic cup increased most in eyes that already had PEX at baseline.

CONCLUSION

This incidence study from Iceland confirms findings from previous prevalence studies that PEX is increasingly common with older age in this population. Earliest changes related to PEX may be subtle and difficult to detect, which may lead to some misclassification. Further study is needed to identify clinical features that can reliably detect patients at risk for developing PEX.

Identification of LOXL1 protein and Apolipoprotein E as components of surgically isolated pseudoexfoliation material by direct mass spectrometry

Pseudoexfoliation (PEX) syndrome is the commonest cause of secondary glaucoma. Many extracellular matrix proteins and elastic fibre structure components are present in the pathological PEX deposits in the anterior segment of the eye including the anterior lens capsule. Common coding variants in the lysyl oxidase-like 1 (LOXL1) gene, involved in cross-linking elastin, have been reported to be strongly associated with PEX syndrome in various human populations. The mechanism by which the LOXL1 protein contributes to the formation of PEX material is unknown. A comprehensive map of the component proteins of PEX deposits can aid the understanding of disease pathogenesis. The purpose of this study was to identify additional protein constituents of pathological PEX deposits. We employed a novel proteomics approach by performing mass spectrometry on "isolated" PEX material surgically removed from the anterior lens capsule of affected eyes. This approach led to the identification of LOXL1 protein and Apolipoprotein E (ApoE) in PEX material. Previously identified protein constituents, latent-transforming growth factor beta-binding protein-2, complement 3 and clusterin were also detected. Immunohistochemical analysis of lens capsules from affected eyes confirmed the presence of both LOXL1 and ApoE in pathological PEX deposits. ApoE is a novel component of these deposits. This is the first report where a direct analytical approach has led to the identification of LOXL1 in PEX deposits and is consistent with its detection in these deposits by immunolabelling in another recent report. LOXL1 is both genetically associated with PEX syndrome and present in pathological PEX deposits. Hence it clearly has an important and direct role in pathophysiology of the disease. In conclusion, additional as yet unknown components are present in pathological PEX deposits and mass spectrometry of "isolated" PEX material is an effective strategy for their identification.

Is exfoliation syndrome a sign of systemic vascular disease?

Exfoliation syndrome (ES) is an age-related disorder in which greyish-white flakes accumulate in different tissues in the anterior eye. Its pathogenesis is not completely known, but it results in electron-dense microfibrils. The finding that these can be seen outside the eye in many visceral organs inspired the theory that ES might be a part of a generalized disorder. It was postulated that ES might contribute to increased morbidity, mainly of systemic vascular diseases. This review is a summary of the existing knowledge. The prevalence of arterial hypertension (AHT) in elderly populations is > 30%. No differences have been found in the frequency of AHT among patients with ES or exfoliative glaucoma (EG) compared with those with primary open-angle glaucoma (POAG) or no ES. There are conflicting reports of frequencies of ischaemic heart disease (IHD). A recent registry-based study that used uniform criteria for IHD found no difference in the rate of IHD between patients with EG and those with POAG. However, findings of elevated homocysteine levels in the plasma and aqueous humour of patients with ES or EG suggest an increased vascular risk. No studies have yet been conducted to assess possible links between ES and systemic vascular diseases. In a single-blind study, ES was associated with abdominal aortic aneurysm, but this was not found in a large, cross-sectional investigation. The frequency of ES in patients with diabetes mellitus (DM) is only about half of that when compared in patients with no ES or with POAG. This finding warrants further studies. Molecular genetics research has found no common denominator for ES and the vascular diseases. There is no evidence that ES or EG are related to increased mortality for cardiovascular diseases. Further large-scale, randomized clinical studies are required. At present there are no known medical indications that infer an increased systemic vascular risk or imply a need for the complete internal medical examination of a symptom-free patient with newly diagnosed ES in the eye.