Thordur Sverrisson

Chronic open-angle glaucoma and associated ophthalmic findings in monozygotic twins and their spouses in Iceland

PURPOSE To determine the concordance of glaucoma and ocular parameters in monozygotic twins and their spouses. METHODS This was a prospective study that included 50 twin pairs 55 years of age or older and 47 of their spouses. Zygosity was determined by genetic laboratory testing. RESULTS The concordance of open-angle glaucoma in monozygotic twin pairs was 98.0%, which significantly exceeded that of twin/spouse pairs (70.2%). There was a significant association in mean intraocular pressure (IOP), mean axial length, anterior chamber depth, and refractive error in the twin pairs. However, there was no association between the twins and their spouses for these ocular parameters. Eight twin pairs were found to have pseudoexfoliation syndrome (PXFS), five of which were concordant. There was no association between glaucoma and mean axial length or glaucoma and refractive error in the twin pairs studied. CONCLUSION The statistically significant higher concordance of glaucoma--and the high correlation of mean IOP, mean axial length, anterior chamber depth, and refractive error--in twin pairs and the lack of association of these factors in twin/spouse pairs strongly suggests the importance of genetic factors for these ocular parameters.

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.

Exfoliation syndrome in the Reykjavik Eye Study: risk factors for baseline prevalence and 5-year incidence.

Aim To examine the age- and gender-specific prevalent and 5-year incident risk of developing exfoliation syndrome (XFS). Methods and participants In a population-based random sample of citizens 50 years and older, 1045 persons had baseline examination in 1996; 846 of the 958 survivors (88.2%) had a follow-up examination in 2001. Following maximum dilatation of pupils, a diagnosis of exfoliation was established on slit-lamp examination. An extensive questionnaire was administered at baseline and follow-up. Prevalent and incident risk was then calculated using a multivariate analysis. Results The following variables were found to correlate significantly with prevalence risk of XFS at baseline: age, female gender, increased iris pigmentation, moderate use of alcohol and self-reported asthma. We also found that, compared with those who consumed dietary fibre-rich vegetables, green or yellow vegetables, and fruit less than once a month in their 20s and 40s, those consuming the same food items once or twice every 2 weeks were found to be less likely to have XFS. The same applied to those consuming dietary fibre rich once or twice every 2 weeks in their 40s and 60s. Conclusion Food items that are possibly surrogates for antioxidative effect may correlate with decreased risk of XFS and increased iris pigmentation may correlate with increased risk. Given the large number of comparisons, these findings require validation through additional clinical studies. Increased age and female gender increase the likelihood of XFS.