ABSTRACT.Purpose: To establish a population profile of central corneal thickness (CCT), radius of the corneal curvature (CC) and intraocular pressure (IOP) and the relationships between them using non-contact techniques. Methods: We used a population-based random sample of 415 male and 510 female Caucasians aged 50 years and older. CCT and the radius of CC were measured with Scheimpflug anterior segment photography. IOP was measured with air-puff tonometry. Results: The mean IOP of right eyes was 15.1 mmHg (SD 3.3) among men and 15.8 mmHg among women (SD 3.1), which is a statistically significant difference. The mean radius of CC for male right eyes was 7.78 (SD 0.60) and for females 7.62 (SD 0.58) which is also statistically significant. Mean CCT for male right eyes was 0.528 mm (SD 0.041) and for females 0.526 mm (SD 0.037), which is not a significant difference. Linear regression analysis shows no relationship between the radius of CC and IOP or between age and radius of CC. Linear regression analysis of the relationship between CCT and IOP suggests higher IOP measurements with thicker corneas. There was no significant correlation between age and CCT. Conclusion: IOP was found to be independent of age and significantly higher in females than in males. Radius of CC was found to be age-independent and significantly steeper in females than in males. CCT appears to be independent of age and gender. Greater CCT is associated with higher mean IOP.Key words: population based study ª intra ocular pressure ª central corneal thickness ª corneal curvature ª Scheimpflug photography.

. Purpose:  To examine the age and sex‐specific prevalence of pseudoexfoliation syndrome (PEX) and its relationship with some ophthalmological variables. Methods:  We carried out a population‐based study using a random sample taken from the national population census for citizens of Reykjavik, aged ≥ 50 years. A total of 1045 individuals participated in all parts of the study. Pseudoexfoliation was established by slit‐lamp examination with a maximally dilated pupil carried out by two experienced ophthalmologists, who were masked to one another’s results except in cases of disagreement where they had to reach a consensus. Results:  In all, 108 (10.7%) persons were found to have PEX in at least one eye. Prevalence increased from 2.5% in those aged 50–59 years to 40.6% in those aged ≥ 80 years. Women were more frequently affected than men (12.3% versus 8.7%). This difference remained statistically significant after controlling for the effect of age (p < 0.001). Eyes with PEX were found to have higher intraocular pressure (IOP) than eyes without PEX (p < 0.05). However, PEX was not found to be related to central corneal thickness, anterior chamber depth, lens thickness, nuclear lens opacifications or optic disc morphology in a multivariate model. Conclusions:  Pseudoexfoliation is an age‐related phenomenon commonly found in Iceland. It is more commonly found in women than in men and is associated with elevated IOP.

Purpose To establish the age-and sex-specific prevalence of open-angle glaucoma (OAG) subsuming pseudoexfoliation (PEX) in the city of Reykjavik. Methods Participants 50 years of age and older who were part of the Reykjavik Eye Study and classified as having glaucoma were divided into three categories: Category 1: two or more of the following based on optic nerve stereophotograph reading: vertical cup to disc ratio (VCDR) 97.5th percentile (40.7), focal glaucomatous disc change, C/D asymmetry of 97.5th percentile difference between eyes (40.2) as well as glaucomatous visual field defect (GVFD). Category 2: 99.5th percentile of VCDR (40.8) and 99.5% percentile difference between eyes (Z0.3), without a GVFD. Category 3: VAo3/60 and IOP499.5th percentile or VAo3/60 and evidence of filtering surgery. For a glaucoma suspect, one of the following was present: VCDR499.5th percentile (40.8), focal glaucomatous disc change, C/D asymmetry of 99.5th percentile (Z0.3), GVFD only, IOPZ23 mmHg (97.5 percentile). PEX was diagnosed by the presence of a central shield and/or a peripheral band on the anterior lens capsule. Results Of 42 persons (22 males and 20 females) with OAG, 13 (31.0%) had PEX. The minimum prevalence of OAG was 4.0% (42/1045) (95% CI 2.8-5.2) for those 50 years and older and 10.3% (95% CI 8.5-12.2) for PEX. The prevalence of OAG increases with age (OR ¼ 1.10/year, 95% CI 1.07-1.13, P ¼ 0.000) and the same applies for the prevalence of PEX, OR ¼ 1.10 (95% CI 1.07-1.12, P ¼ 0.000). Conclusion There is a 10% annual increase for both OAG and PEX in persons 50 years and older.

Pseudoexfoliation (PEX) syndrome is the commonest identifiable cause of open-angle glaucoma worldwide. PEX is characterized clinically by small whitish deposits of fibrillar-granular material in the anterior segment of the eye. Despite its prevalence and potential for ophthalmic morbidity, surprisingly little is known about the etiology and pathogenesis of PEX. This article reviews the literature and presents evidence regarding genetic and nongenetic arguments for the etiology of pseudoexfoliation. Lines of evidence that support a genetic basis for PEX include transmission in two-generation families, twin studies, an increased risk of PEX in relatives of affected patients, and HLA studies. Nearly all pedigrees in the literature, and our own experience with PEX families in Iceland and Canada, suggest maternal transmission, raising the possibilities of mitochondrial inheritance, X-linked inheritance, and autosomal inheritance with genomic imprinting. A number of nongenetic factors have also been evaluated for their possible implication in the development of PEX. These include ultraviolet light, autoimmunity, slow virus infection, and trauma. It is possible that a combination of genetic and nongenetic factors may be involved in the etiology and pathogenesis of PEX, i.e. it may be a multifactorial disorder. Further studies with larger numbers of patients are needed to delineate more clearly the contribution of genetic (nuclear DNA, mitochondrial DNA or both) and nongenetic factors to the development of pseudoexfoliation syndrome and pseudoexfoliation glaucoma.

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