Factors in the exfoliation syndrome

A Case-Cohort Study of Exfoliation Risk Factors and Literature Review

The purpose of the study is to evaluate the risk factors associated with exfoliation in a case-cohort setting and literature review. This single-center, prospective, case-cohort study was carried out from January 2010 to April 2020 on patients operated for cataract surgery by a single surgeon in Lebanon. Forty-nine consecutive patients with exfoliation syndrome (XFS) and 62 consecutive control patients were identified and further investigated for selected systemic (diabetes mellitus, systemic hypertension, asthma, or atopy) and ocular variables (baseline vision, severity of nuclear sclerosis, glaucoma, eye rubbing, history of dry eye, or allergic eye disease). The mean baseline Snellen visual acuity was 20/283 in XFS versus 20/145 in control cases (P = 0.012). XFS also demonstrated significantly denser nuclear sclerosis than controls (P = 0.00958). By univariate analysis, allergic conjunctivitis (15 [30.6%] vs. 2 [3.2%]; P < 0.001), dry eye (20 [40.8%] vs. 13 [21.0%]; P = 0.0133), and habitual rubbing of the eyes (33 [67.3%] vs. 19 [30.6%]; P < 0.001) were associated with the presence of XFS. Habitual ocular rubbing was closely associated with allergic conjunctivitis (odds ratio [OR] = 13.0; 95% confidence interval [CI]: 2.8–58.8; P = 0.032). After multivariable analysis, the following variables showed significant results: glaucoma (OR = 34.5; 95% CI: 4.4–250; P = 0.010), duration of surgery (OR = 5.6; 95% CI 2.43–12.9; P < 0.001), and habitual ocular rubbing (OR = 4.42; 95% CI: 1.97–9.90; P = 0.029). This study shows a novel potential correlation between eye rubbing and XFS in a Lebanese cohort. Chronic eye rubbing induces or may exacerbate preexistent zonular damage in subjects with XFS, hence the need to better manage concurrent ocular surface disorder in these patients.

Prevalence of Pseudoexfoliation Glaucoma Risk-associated Variants Within Lysyl Oxidase-like 1 in an Irish Population

PRECIS

High-risk alleles of risk-associated single-nucleotide polymorphisms (SNPs) within the lysyl oxidase-like 1 (LOXL1) gene are associated with pseudoexfoliation in patients recruited from an Irish population.

PURPOSE

SNPs within the LOXL1 gene have been identified as a major risk factor for pseudoexfoliation syndrome (PXF) and pseudoexfoliation glaucoma (PXFG), specifically SNPs within exon 1 and intron 1 regions of the gene. The common haplotype (G-G) of 2 SNPs within exon 1, rs1048661, and rs3825942, is the strongest associated risk factor for PXF in white populations, but is switched in some populations to act as protective or low risk. Herein, a study was undertaken to genotype an Irish population for PXF/PXFG risk-associated SNPs within LOXL1.

MATERIALS AND METHODS

Patient cohorts of PXFG, PXF, and controls were recruited and genotyped for risk-associated SNPs within exon 1 (rs1048661 and rs3825942), along with 3 SNPs within intron 1 (rs1550437, rs6495085, and rs6495086) of LOXL1.

RESULTS

The risk G alleles of rs1048661 and rs3825942 were most prevalent in PXFG patients, and a significant association was found between rs3825942 and pseudoexfoliation (P=0.04). Genotypes of several intron 1 SNPs were found to be present at higher frequencies within the pseudoexfoliation patient cohort (PXF/PXFG) compared with control patients, wherein rs6495085 showed statistical association (P=0.04). The G-G-G haplotype of rs1048661, rs3825942, and rs6495085 was the most prevalent in PXFG patients compared with control patients or patients with PXF alone. Patients with the G-G-G haplotype were more likely to need surgery, suggestive of a more severe form of disease.

CONCLUSION

Collectively, these results represent the first study to assess the association of LOXL1 SNPs with PXFG in an Irish population.

Evaluation of tear and aqueous humor level, and genetic variants of connective tissue growth factor as biomarkers for early detection of pseudoexfoliation syndrome/glaucoma

Pseudoexfoliation syndrome (PEX) may lead to the development of pseudoexfoliative glaucoma (PEG), a potential cause of irreversible blindness, if left untreated. This type of glaucoma often presents with much higher intraocular pressure (IOP) values than observed in primary open angle glaucoma, and patients are often unaware of their condition. Therefore, early diagnosis is of utmost importance in PEX and PEG. Unfortunately, no valid objective biomarkers are available that can be used for this purpose. The excessive synthesis and deposition of elastic microfibrillar pseudoexfoliation material is observed in the pathophysiology of PEX, therefore, growth factors may play roles in this pathology. Thus, in this study, we sought to determine the roles of phenotypes and genotypes of connective tissue growth factor (CTGF) as objective biomarkers for early diagnosis of PEX and PEG. Thus, we investigated possible associations involving tear and aqueous humor CTGF concentrations and four single nucleotide polymorphisms (SNPs) of the CTGF gene in PEX and PEG. The study was designed as a 2-year case-control study in the Turkish population. Study population was composed of 214 patients with PEG, 214 patients with PEX, and 214 age-matched controls for CTGF SNP analysis. Tear fluid study group consisted of 78 patients with PEG, 77 patients with PEX, and 78 controls. Aqueous humor analysis included 8 patients with PEG, 17 patients with PEX, and 23 controls. Tear fluid was collected using Schirmer strips, and aqueous humor samples were taken during cataract surgery. CTGF concentration was determined by ELISA, and total protein concentration was determined by Bradford assay in tear and aqueous humor samples. PCR followed by restriction fragment length polymorphism analysis was used for genotyping of rs6918698 G/C and rs9399005 C/T, while real-time PCR was used for rs9402373 C/G and rs12526196 T/C. Intraocular pressure, visual field score, mean deviation, and pattern standard deviation parameters were also evaluated. CTGF concentration in tear fluid was significantly higher in PEG patients compared with controls (P = 0.001), while it was lower in PEX patients. Similarly, total protein concentration in tear fluid was significantly increased in PEG patients relative to PEX patients (P = 0.026) and controls (P = 0.004). CTGF concentration in aqueous humor did not differ markedly between the groups, whereas total protein was significantly higher in the PEG group compared with the PEX group (P = 0.012) and controls (P = 0.003). Receiver operating characteristic analysis revealed that total protein in aqueous humor was a robust classifier for evaluating the presence of PEG against controls (Area under the curve = 0.897, P = 0.001). The genotypes of the studied SNPs were not significantly correlated with CTGF concentration in aqueous humor or tear fluid, and did not exhibit significant association with PEG or PEX. In conclusion, this was the first study to investigate tear fluid CTGF concentration in PEX and PEG, which came out not to be a good classifier for PEG or PEX. Total protein level in tear fluid and CTGF SNPs also did not predict PEG or PEX status successfully.

Epidemiology of Exfoliation Syndrome

BACKGROUND

From a historical standpoint the epidemiology of exfoliation syndrome (XFS) is one of the most controversial subjects in ophthalmic literature. Current literature abounds with studies on the prevalence of XFS in various ethnic populations and clearly XFS is a common condition, but its true prevalence is difficult to ascertain. Overall, XFS is considered to be the most common identifiable cause of glaucoma worldwide.

PURPOSE

This review critically examines the published literature documenting the epidemiological features of XFS and attempts to provide a unified concept concerning existing controversy.

METHODS

A critical review of selected literature pertaining to the epidemiology of XFS.

RESULTS

It is well established that XFS and the ensuing exfoliative glaucoma have a worldwide prevalence and a progressively increasing age-related incidence. The prevalence of the condition is significantly underestimated. Many past studies have proposed clear geographic variations within and between ethnic groups. In contrast, there has also been some epidemiological evidence suggesting that the prevalence of XFS is similar within various ethnic groups. Published literature fails to address the potential role and impact of suspected exfoliation cases in the reported prevalence figures of the condition. Incidence figures for the condition are limited and vary extensively. Cumulative data have indicated that several, as yet partly understood genetic, ethnic, and environmental factors contribute to the varied prevalence of this condition.

CONCLUSIONS

Further understanding on XFS epidemiology is needed. Only a future large prospective study conducted by the same investigators, using similar methodologies for different ethnic populations will prove beyond doubt the hypothesis that significant geographic variations exist. Since patients with exfoliative glaucoma are at significant risk of losing vision it is vital to elucidate the causes and the risk of developing XFS. To reach this goal, it is important to better delineate the early changes of XFS and to focus research efforts on modifiable factors for XFS development.

Pseudoexfoliation Syndrome and Pseudoexfoliation Glaucoma: A Review of the Literature with Updates on Surgical Management

Pseudoexfoliation syndrome (PES) is a systemic disorder caused by progressive accumulation of extracellular material over various tissues. PES usually determines increased intraocular pressure, changes in the anatomical aspects of the optic nerve, and visual field alterations leading to the diagnosis of pseudoexfoliation glaucoma (PEG). Use of topical medical treatment usually leads to poor results in terms of long-term follow-up but many surgical techniques, such as Argon Laser or Selective Laser Trabeculoplasty, have been proposed for the management of PEG affected patients. The present paper is a review on the pseudoexfoliation syndrome and pseudoexfoliation glaucoma with an update on surgical management.

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.

Prevalence and Prognosis of Pseudoexfoliation Glaucoma in Western India

PURPOSE

To investigate the prevalence and reconnoiter treatment modalities for Pseudoexfoliation Glaucoma (PXG) in subjects with Pseudoexfoliation Syndrome (PXF) in a rural scenario of western India.

DESIGN

A prospective prevalence study.

METHODS

Occurrence of PXG in 250 subjects with PXF was studied in the Department of Glaucoma, Shri Ganapati Netralaya, Jalna, India, from 2009 to 2011. The subject pool presented with PXF, having intraocular pressure (IOP) ≥ 20 mm of Hg, and evidencing optic nerve damage and abnormal visual fields were judiciously selected as PXG cohorts. A decision table is formulated to assist the physician in rendering medical or surgical treatment options.

RESULTS

The prevalence of PXG increased with increasing age at 30% (95% CI: 28.56-33.72) in the 60-year-old and older population. It was predominantly higher in cohorts involved in outdoor physical activities at 46% (95% CI: 41.24-52.38). The eminence and prevalence of nuclear cataract in subjects with PXG was 72 % (95% CI: 65.72-76.34). Visual impairment was highly prevalent in 75% (95% CI: 73.43-78.29) and 10% (95% CI: 6.87-13.21) cohorts with PXG and PXF respectively. In general, linear modelling IOP was 26.37±1.64 in subjects with PXG, which was managed to 16.50±1.32 after rendering our adapted treatment protocols.

CONCLUSIONS

Increased IOP, occludable angles, and glaucomatous optic neuropathy occur more frequently in the population with PXF. It is inferred that that treatment protocol of combined cataract and glaucoma surgery gives maximum reduction in IOP.

Tonography assessment using quantitative and qualitative analysis of the aqueous humor outflow mechanism

PURPOSE

To perform qualitative evaluation of the aqueous humor (AH) outflow mechanism in glaucoma and nonglaucoma patients by means of tonography assessment and mathematical analysis.

METHODS

Sixty-two primary open angle and 58 pseudoexfoliation glaucoma patients were recruited in a non-interventional, observational study between 2004 and 2007. Qualitative and quantitative outflow assessment was acquired by means of a digital tonographer and mathematical analysis. Qualitative results were represented using slope analysis of the change of the AH outflow rate over the tonography study. The results were compared to the control group (CG; n=100) as well as to a pseudoexfoliation group (PEX; n=46).

RESULTS

Regarding quantitative analysis, glaucoma groups exhibited significantly lower outflow facility compared to nonglaucoma ones (p<0.001). Outflow facility value was significantly correlated to cup to disc ratio (Pearson correlation r=-0.3, p<0.001). Regarding qualitative analysis, the primary open-angle glaucoma (POAG) group presented a significant profile variation at the beginning of the tonography, expressed as an increased resistance of the AH outflow. Both glaucoma groups exhibited profile stabilization at the end of the measurement, suggesting that the outflow rate remained constant, while nonglaucoma groups followed a continuous reduction of the AH outflow rate throughout the study.

CONCLUSIONS

The POAG, PXG, PEX, and CG groups demonstrated both qualitative and quantitative tonographic profile differences. The observed differences in the glaucoma groups suggest a distinct pathomechanism between POAG and PXG. It is suggested that POAG patients have a temporary disruption of the AH flow pathway, while PXG patients have a generalized increased flow resistance.

Exfoliation syndrome in various ethnic populations

This introductory lecture to the epidemiological session in the Workshop on the Exfoliation Syndrome (ES) gathers together figures for the prevalence of ES around the world. Prevalence figures from published reports are shown in the text separately for each country. Four ways of comparing the prevalences are used. 1) Prevalences in people over 60 years of age, 2) Percentages of glaucoma in persons with ES, 3) Percentages of ES in patients with glaucoma or ocular hypertension, with separate statistics for the proportion of capsular glaucoma in patients treated with laser trabeculoplasty (LTP), 4) Prevalence of ES in patients with cataract. The major differences in prevalence can partly be explained by the different techniques used in the investigations. Very few authors have studied people in different countries, which is the best way of obtaining comparable results. The author has personally studied Finns, Lapps, Eskimos in Greenland, Canada and Alaska, Icelanders, populations in Tunis, India and Peru and four populations in the USSR by the same technique. The prevalences vary from 0% in Eskimos to 21% in Finns over 60 years of age, and are at the same high level in Lapps, Finns, Russians in Novosibirsk and Icelanders, but significantly lower in all the others. The results support the opinion that ES is not uniformly distributed in all countries, and this is confirmed by many reports from different countries in this workshop.

Exfoliation syndrome prevalence in the glaucoma population of South Louisiana

A prospective study was performed to determine the prevalence of exfoliation syndrome in a glaucoma population of South Louisiana. Five hundred consecutive open angle glaucoma patients over 50 years of age (median age 70.6 years) from both indigent clinic and private referral sources were examined for the presence of exfoliation material on the lens capsule. The prevalence in caucasian patients was 2.7%, blacks 0.4%, combined 1.4%. This compares with a reported prevalence of exfoliation syndrome among patients with open angle glaucoma in the United States of 3% to 28%, Denmark of 26%, Ireland of 66%, and Sweden of 75%. This low prevalence may be a reflection of the ethnic origin of the population, but other explanations are considered.

Genetics of pseudoexfoliation syndrome

PURPOSE OF REVIEW

Pseudoexfoliation syndrome (XFS) is a late-onset and complex disorder that is strongly associated with the development of glaucoma. The purpose of this review is to discuss the inheritance patterns and recent genetic advances in the study of this disorder.

RECENT FINDINGS

XFS has a strong familial association and recently, the lysyl oxidase-like 1 gene has been strongly associated with this disorder. This gene is involved in the synthesis and maintenance of elastic fibers and therefore has a strong biological rationale for being involved in this disorder. However, the exact relationship between lysyl oxidase-like 1 polymorphisms and the development of XFS has not been elucidated. Also, the value of genetic testing for this disorder has not been validated.

SUMMARY

XFS is an important risk factor for glaucoma and lysyl oxidase-like 1 polymorphisms are strongly associated with XFS. The mechanisms behind glaucoma development and the value of genetic testing are not clear and further study is needed.

Correlation of Capsular Pseudoexfoliation Material and Iridocorneal Angle Pigment With the Severity of Pseudoexfoliation Glaucoma

PURPOSE

To evaluate the correlation between the amount of pseudoexfoliation (PXF) material on the anterior lens capsule, pigment in the iridocorneal angle, presenting intraocular pressure (IOP) and severity of glaucoma in patients with PXF glaucoma/syndrome.

PATIENTS AND METHODS

Anterior lens capsule PXF material and iridocorneal pigment of 98 untreated patients with PXF syndrome/glaucoma were graded from photographs and correlated with untreated IOP and indices of glaucoma severity (cup to disc ratio, and visual field mean deviation, and pattern standard deviation).

RESULTS

There was a positive statistically significant correlation between the iridocorneal angle pigmentation and IOP (P=0.047, R2=0.2), but not the indices of glaucoma severity (P>0.13). There was no significant correlation between the anterior lens capsule PXF material and IOP or the indices of glaucoma severity (P>0.42). The grade of angle pigmentation, but not lens PXF, in eyes with IOP >21 mm Hg was significantly higher than in eyes with IOP < or =21 mm Hg (P=0.04).

CONCLUSIONS

In patients with PXF syndrome/glaucoma, gonioscopically identified iridocorneal angle pigmentation correlates more strongly with presenting IOP than the amount of PXF material on the anterior lens capsule.

Elevated aqueous humour tissue inhibitor of matrix metalloproteinase-1 and connective tissue growth factor in pseudoexfoliation syndrome

BACKGROUND/AIMS

Pseudoexfoliation syndrome (PXF) was recently found to be associated with increased expression of transforming growth factor beta(1) (TGFbeta(1)) in the aqueous humour. As concern has been raised regarding anti-TGFbeta therapy, which can potentially disrupt the maintenance of anterior chamber associated immune deviation, the authors explored the levels of tissue inhibitor of matrix metalloproteinase-1 (TIMP-1), matrix metalloproteinase-9 (MMP-9), and connective tissue growth factor (CTGF) in aqueous humour to determine if these may represent alternative therapeutic targets.

METHODS

Aqueous humour samples were collected from patients who underwent routine cataract surgery. All patients were categorised into three main groups-PXF, uveitis, and control. The PXF group was further subcategorised into three grades based on the density of the exfoliative material observed on biomicroscopy, as well as the presence or absence of glaucoma. TIMP-1, MMP-9, and CTGF levels were measured using specific enzyme immunoassays (ELISA).

RESULTS

Eyes with PXF had significantly higher aqueous humour TIMP-1 concentration (n = 56, mean (SE), 9.76 (1.10) ng/ml) compared with controls (n = 112, 5.73 (0.43) ng/ml, p<0.01). Similarly, the CTGF level in PXF eyes (n = 36, 4.38 (0.65) ng/ml) was higher than controls (n = 29, 2.35 (0.46) ng/ml, p<0.05). Further, the CTGF concentration in the PXF glaucoma group is significantly higher compared with PXF eyes without glaucoma (6.03 (1.09) ng/ml v 2.73 (0.45) ng/ml, p<0.01). The MMP-9 levels were low and below detection limit in all PXF and control samples with no statistical difference between groups.

CONCLUSION

A raised TIMP-1 level and a low MMP-9 level in aqueous humour of PXF eyes may imply a downregulation in proteolytic activity. The increased CTGF concentration supports the proposed fibrotic pathology of PXF. Regulation of MMP/TIMP expression and anti-CTGF therapy may offer potential therapeutic avenues for controlling PXF associated ocular morbidity.

Exfoliation syndrome as a risk factor for cataract development: five-year follow-up of lens opacities in exfoliation syndrome

PURPOSE

To ascertain whether the exfoliation syndrome (EXS) is a risk factor for cataract development.

SETTING

Helsinki University Eye Hospital, Helsinki, Finland.

METHODS

This prospective study examined the development of lens opacities using the Lens Opacity Meter. Visual acuity and refraction were measured in both eyes of 63 nonglaucomatous patients with clinically unilateral EXS. After 5 years, 46 patients were available for follow-up. Case histories of 14 patients were recorded.

RESULTS

During the 5 year study, the rate of conversion to bilateral disease was 22% and to exfoliative glaucoma, 30%. At the beginning of the study, the mean lens opacity was 23.5 opacity units (OU) +/- 6.7 (SD) in EXS eyes and 22.9 +/- 7.2 OU in fellow, initially nonexfoliative (NE) eyes; the difference was not significant. After 5 years, the mean opacity was 30.0 +/- 8.8 OU in EXS eyes and 26.9 +/- 8.3 OU in NE eyes (P <.001). In patients who remained unilaterally affected, the EXS eye had a higher opacity value than the NE eyes at the start of the study (23.6 +/- 7.3 OU and 22.7 +/- 7.2 OU, respectively) (P <.05) and after 5 years (29.9 +/- 9.0 OU and 27.0 +/- 8.5 OU) (P <.01). There was a significant myopic change in refraction over time in both groups. The mean refraction in EXS eyes was +1.02 +/- 2.48 diopters (D) at the start and + 0.11 +/- 3.06 D after 5 years (P =.0001) and in NE eyes, +0.99 +/- 2.25 D and +0.43 +/- 2.55 D, respectively (P <.01). At the start of the study, the mean difference in refraction between fellow eyes (refraction in NE eye - refraction in EXS eye) was -0.27 +/- 1.00 D. After 5 years, it was +0.32 +/- 1.44 D (P =.016), showing a greater myopic change in EXS eyes.

CONCLUSION

The results show that EXS is a risk factor for lens opacification.

Exfoliation syndrome

Exfoliation syndrome (XFS) is an age-related disease in which abnormal fibrillar extracellular material is produced and accumulates in many ocular tissues. Its ocular manifestations involve all of the structures of the anterior segment, as well as conjunctiva and orbital structures. Glaucoma occurs more commonly in eyes with XFS than in those without it; in fact, XFS has recently been recognized as the most common identifiable cause of glaucoma. Patients with XFS are also predisposed to develop angle-closure glaucoma, and glaucoma in XFS has a more serious clinical course and worse prognosis than primary open-angle glaucoma. There is increasing evidence for an etiological association of XFS with cataract formation, and possibly with retinal vein occlusion. XFS is now suspected to be a systemic disorder and has been associated preliminarily with transient ischemic attacks, stroke, systemic hypertension, and myocardial infarction. Further ramifications await discovery. Deposits of white material on the anterior lens surface are the most consistent and important diagnostic feature of XFS. The classic pattern consists of three distinct zones that become visible when the pupil is fully dilated. Whereas the classic picture of manifest XFS has been often described, the early stages of beginning exfoliation have not been well defined. Next to the lens, exfoliation material is most prominent at the pupillary border. Pigment loss from the iris sphincter region and its deposition on anterior chamber structures is a hallmark of XFS. Despite extensive research, the exact chemical composition of exfoliation material (XFM) remains unknown. An overproduction and abnormal metabolism of glycosaminoglycans have been suggested as one of the key changes in XFS. The protein components of XFM include both noncollagenous basement membrane components and epitopes of the elastic fiber system such as fibrillium. Regardless of etiology, typical exfoliation fibers have been demonstrated electron microscopically in close association with the pre-equatorial lens epithelium, the nonpigmented ciliary epithelium, the iris pigment epithelium, the corneal endothelium, the trabecular endothelium, and with almost all cell types of the iris stroma, such as fibrocytes, melanocytes, vascular endothelial cells, pericytes, and smooth muscle cells. The presence of XFS should alert the physician to the increased risks of intraocular surgery, most commonly zonular dehiscence, capsular rupture, and vitreous loss during cataract extraction. Heightened awareness of this condition and its associated clinical signs are important in the detection and management of glaucoma, and preoperative determination of those patients at increased risk for surgical complications.

Epidemiology of pseudoexfoliation in the island of Crete (Greece)

PURPOSE

To evaluate the pseudoexfoliation (PEX) prevalence in the island of Crete (Greece).

METHOD

Organized visits to various villages, to examine a predetermined number of people born and living in these villages, in collaboration with the local birth register offices.

RESULTS

PEX prevalence in Crete, in people aged 40 years and more, was found to be 16.1% (men: 21.3%, women: 12.6% - Prefecture of: Heraklion 11.5%, Chania 13.4%, Lasithi 16.9%, Rethymnon 27%). 28.8% of PEX-patients presented IOP > 21 mmHg. In unilateral PEX-patients, mean IOP of PEX-eyes was found to be 17.82 mmHg versus 15.6 mmHg in fellow eyes.

CONCLUSION

PEX prevalence was higher in men than in women and increases with age, as does bilaterality. A correlation between increased PEX prevalence and high altitude may exist. PEX is a risk factor for the development of IOP disturbances which seem to appear earlier in women.

Frequency of exfoliation syndrome in Greek cataract patients

The frequency of exfoliation syndrome (EXS) was investigated in a group of Greek patients undergoing extracapsular cataract surgery. Five hundred and nine (509) consecutive cataract patients without any other manifest ocular abnormality were prospectively examined for the presence of EXS. Patients were clinically divided into 3 groups: group I (EXS group) consisted of patients in whom exfoliation material deposition could be seen; Group II (possible EXS group) comprised patients who demonstrated a number of pigmentary signs and group III (normal subjects) comprised patients with senile cataract and no sign of EXS. EXS was found in 140 (28%) of our patients, possible EXS in 119 (23%) and the rest (49%) had no evidence of EXS. Patients with EXS were older (mean age 73.8) when compared to the possible EXS group (70 years) and the control group (64.7 years). The IOP was significantly higher in patients with EXS (mean 15.5 mmHg versus 14.3 mmHg in the other two groups). Blue irides were significantly more common in patients with EXS (19%) than in the possible EXS group (14%) and the controls (4%). EXS is common in Greek cataract patients and this study has identified a large group of patients who may be at an early stage of development of the condition. EXS may predispose to the development of cataract in Greek patients.

Association of HLA type with pseudoexfoliation of the lens capsule

AIMS/BACKGROUND

To identify an HLA association with pseudoexfoliation of the lens capsule to support the hypothesis that there is a genetic predisposition to pseudoexfoliation. A randomised trial would be ideal for establishing a relation but is more costly and time consuming to conduct. Case-control studies provide an alternative method of establishing a relation.

METHODS

The study group comprised 128 subjects who presented to a major eye centre with pseudoexfoliation. Data from blood donors representative of the population of Ireland were used to form a control group.

RESULTS

An HLA association with pseudoexfoliation is identified for 14 antigens. Eleven antigens (HLA A1, A33, B8, B47, B51, B53, B57, B62, DR3, DR12, and DR13) are significantly more common in the pseudoexfoliation group while three antigens (HLA B12, B17, and DR2) are significantly less common. Four HLA antigens are strongly associated, with odds ratios of over 7.5.

CONCLUSION

The strength of this HLA association is supportive evidence for a genetic component to the development of pseudoexfoliation of the lens capsule.

The amount of lens exfoliation and chamber-angle pigmentation in exfoliation syndrome with or without glaucoma

Correlations of the amount of chamber-angle pigmentation and exfoliation material with IOP and with image analysis of the optic discs are reported in the paired eyes of 63 persons with unilateral exfoliation syndrome, and 35 patients with unilateral capsular glaucoma. The effect on IOP of phenylephrine-induced pigmentary dispersion is examined. Chamber-angle pigmentation was more pronounced in capsular glaucoma than in the nonglaucomatous exfoliation eyes (p < 0.01), although the amount of lens exfoliation was the same. In nonglaucomatous exfoliative eyes IOP correlated significantly with the amount of chamber-angle pigmentation (p < 0.01) and exfoliation material (p < 0.05). The nonglaucomatous exfoliative eyes with grade > or = 2 trabecular pigmentation and those with reduction of IOP on phenylephrine provocation had smaller rim areas and rim/disc area ratios than the fellow eyes (p < 0.05). Rather than the amount of exfoliation, the main risk factor for glaucoma seems to be the degree of chamber-angle pigmentation.

Exfoliation syndrome and occludable angles

Images

Prevalence, diagnostic features, and response to trabeculectomy in exfoliation glaucoma

BACKGROUND

The "true" prevalence and clinical attributes of exfoliation glaucoma remain controversial. The authors studied these characteristics in glaucoma patients requiring trabeculectomy.

METHODS

One hundred consecutive patients undergoing trabeculectomy for open-angle glaucoma were investigated by clinical examination (biomicroscopy and gonioscopy) and classified into three categories: exfoliation glaucoma, possible exfoliation glaucoma, and primary open-angle glaucoma (POAG). A definitive diagnosis of exfoliation glaucoma was provided by pathologic examination of iris tissue.

RESULTS

All 22 patients with clinical evidence of exfoliation glaucoma and 4 of 18 patients with possible exfoliation glaucoma on clinical examination had ultrastructural evidence of exfoliation material. The prevalence of exfoliation glaucoma, therefore, was 26%. The clinical examination for the diagnosis of exfoliation glaucoma had an 85% sensitivity rate and a 100% specificity rate. In comparison with POAG, patients with exfoliation glaucoma had higher untreated intraocular pressure (IOP), higher IOP with medical therapy, and shorter duration of medical therapy. They were more often operated on for unacceptably high IOP. Exfoliation glaucoma patients exhibited significantly lower IOP after surgery.

CONCLUSION

Exfoliation glaucoma is common in patients requiring trabeculectomy for open-angle glaucoma. This condition differs from POAG by a poorer response to medical therapy and a better response to trabeculectomy.

Clinical features of capsular glaucoma in comparison with primary open-angle glaucoma in Japan

Clinical features of capsular glaucoma during a recent 15-year period were compared with those of primary open-angle glaucoma (POAG). Out of 1623 new glaucoma patients, 263 patients (16.2%) were capsular glaucoma and 268 (16.5%) were POAG. The patients with capsular glaucoma were older than the patients with POAG. The former had higher intraocular pressure, lower visual acuity, more advanced visual field change and heavier trabecular pigmentation than POAG patients at the time of initial examination. These findings suggest that capsular glaucoma is more difficult to manage than POAG and that the prognosis is poorer than for POAG. Pseudoexfoliative material was found on the pupillary border in 98.3%, on the central lens surface in 46.1%, and on the peripheral lens surface in 72.3%. Though 190 of 263 patients with capsular glaucoma (73.9%) were unilateral cases, 38.9% of the fellow eyes had some abnormalities related to glaucoma. Phakodonesis was found in 10% of patients with capsular glaucoma. This finding suggests that the presence of capsular glaucoma might be a risk factor in cataract surgery.

Lens capsule and epithelium in age-related cataract

On the basis of preoperative assessment of patient characteristics, intraoperative obtainment of a lens-capsule and epithelium specimen, histopathologic investigation of lens capsule and epithelium, and biochemical analysis of glutathione reductase in lens epithelium, age-related cataract was studied in 50 adult patients who underwent consecutive extracapsular cataract-posterior chamber lens implant surgery. Patients (25 men and 25 women; age range, 41 to 91 years; mean age, 75 years) had a wide range of systemic and ocular disease; 17 of 50 (34%) patients had a history of severe vision-impairing cataract in a first-degree relative. Anterior lens-capsule thickness ranged from 10 to 22 microns, with a mean of 17 microns. Statistical analysis of lens-epithelium ultrastructure in 41 of 50 specimens documented mixing of normal and abnormal cells, verified a gradation in the degree of abnormal ultrastructural features, and demonstrated a statistically significant decrease in epithelial cytologic activity with advancing age (P = .038). Biochemical analysis documented a severe glutathione reductase deficiency in nine of 39 (23%) lens-epithelium specimens, possibly reflecting a dietary deficiency of riboflavin.

Pigmentation of the anterior chamber angle in normal and pseudoexfoliative eyes

Anterior chamber angle pigmentation was gonioscopically graded in 833 persons recruited for the KEYS (Kuopio Eye Survey) during 1989. Pseudoexfoliation was observed in 8.5% in either eye from those born in 1924, the figure being 13.2% for those born in 1914. Anterior chamber angle pigmentation was found to be significantly heavier in eyes with pseudoexfoliation.

Pseudoexfoliation glaucoma in Greece

Pseudoexfoliation glaucoma is commonly seen in Greece, however there is little data concerning the prevalence and characteristics of this disorder. Patients undergoing trabeculectomy for open angle glaucoma were investigated both by the appraisal of the case notes and by re-examination. The prevalence of pseudoexfoliation glaucoma in this population was found to be 87.8%. The characteristics of this disease process in the population studied are discussed. These findings indicate that pseudoexfoliation is a major contributor to severe glaucoma in the population of Northern Greece.

Anterior chamber angle in the exfoliation syndrome

The gonioscopic findings of 76 patients with the exfoliation syndrome were reviewed. A high frequency of narrowness of the anterior chamber (AC) angle was found (32%). 18% had angles considered occludable, and 14% had obvious angle-closure glaucoma as shown by the presence of peripheral anterior synechias (PAS). Increased pigmentation of the posterior trabecular meshwork (PTM) was noted in all cases. When this pigmentation was markedly asymmetrical, unilateral exfoliation with glaucoma was common in the more pigmented eye. In addition heavy angle pigmentation in the absence of exfoliation was noted in the fellow eye of patients with characteristic exfoliated material in the other eye. Increased pigmentation of the PTM may be the earliest detectable sign of the exfoliation syndrome (ES). The clinical significance of our estimating PTM pigmentation at the 12 o'clock position is discussed. In view of the accelerated optic nerve damage associated with the development of glaucoma secondary to ES, routine estimation of the pigmentation of the PTM at 12 o'clock is recommended in the hope of early detection of cases of otherwise inapparent ES.

Some factors affecting the intraocular pressure reduction after argon laser trabeculoplasty in open-angle glaucoma

One hundred and thirty-five eyes in 120 patients with open-angle glaucoma were treated with argon laser trabeculoplasty and followed up for 6 months. The mean reduction in intraocular pressure in the whole material was 10.9 mmHg. 13.1 in eyes with capsular glaucoma and 7.2 in eyes with simple glaucoma. The possible influence of the degree of trabecular pigmentation, the pre-treatment intraocular pressure level and the presence of exfoliative material on the amount of pressure reduction was analysed. The presence of some trabecular pigmentation was a prerequisite for the effect of ALT, but the degree of pigmentation did not influence the pressure-reducing capacity of argon laser trabeculoplasty. The pressure reduction was found to be correlated to the pre-treatment intraocular pressure level without influence of the presence of exfoliative material. Eyes with capsular glaucoma had higher pre-treatment intraocular pressures and seldom had non-pigmented trabecular meshwork, which may explain the greater pressure reduction in this group.