| 1. |
- Jóhannesson, Gauti, 1979-, et al.
(author)
-
Can the prevalence of open-angle glaucoma be estimated from a retrospective clinical material? A study on the west coast of Iceland.
- 2005
-
In: Acta Ophthalmologica Scandinavica. - : Wiley. - 1395-3907 .- 1600-0420. ; 83:5, s. 549-553
-
Journal article (peer-reviewed)abstract
- PURPOSE: To explore the possibility of estimating the prevalence of open-angle glaucoma (OAG) on the west coast of Iceland using a clinical retrospective material, and to compare that estimate with the results from a recent prospective Icelandic study. METHODS: The compulsory ophthalmological examination for the prescription of eye glasses in combination with information obtained from Statistics Iceland were used to establish the prevalence of glaucoma in Akranes and to estimate the minimum prevalence for the greater west coast area. A recent prospective study from Iceland was used as reference. RESULTS: In all, 79% of 1443 Akranes inhabitants aged 50 years or more had visited the eye clinic at least once between 1996 and 2001. The prevalence of OAG was 4.8% (95% CI 3.6-6.1). The minimum prevalence for the west coast was 3.8% (95% CI 3.2-4.4). The prevalence increased with age (p < 0.001). The overall prevalence was similar to that of recently published prospective data but the prevalence of normal tension glaucoma (NTG) was lower. CONCLUSION: The results from the two studies are similar in many respects, which indicates that retrospective data may supply meaningful information on glaucoma prevalence. Important sources of error are the selection and attendance of patients, screening methods and diagnostic criteria. If routine examination does not include fundus photography and/or perimetry, the prevalence of NTG will be underestimated.
|
|
| 2. |
- Jóhannesson, Gauti, 1979-, et al.
(author)
-
Pascal, ICare and Goldmann applanation tonometry : a comparative study
- 2008
-
In: Acta ophthalmologica. - : Wiley. - 1755-3768 .- 1755-375X. ; 86:6, s. 614-621
-
Journal article (peer-reviewed)abstract
- PURPOSE: To compare intraocular pressure (IOP) measurements by Pascal, ICare and Goldmann applanation tonometry (GAT), to evaluate the effects of central corneal thickness (CCT) and curvature on IOP measurement and to estimate the intra-observer variability.METHODS: A prospective, single-centre study of 150 eyes with a wide range of pressures. Six masked IOP measurements/method; corneal thickness and curvature were studied for each eye. GAT was the reference.RESULTS: IOPPascal and IOPICare correlated with IOPGAT (r = 0.91, 0.89). Mean ICare measurement exceeded GAT by 2 mmHg. Pascal measured higher than GAT at low IOPs and lower at high IOPs. For every 10 mmHg increase in IOP above 31 mmHg, Pascal measured 2 mmHg lower than GAT and vice versa. CCT was correlated significantly with IOPGAT (r = 0.23) and IOPICare (r = 0.43) but not with IOPPascal (P = 0.12). CCT was correlated with age. In a subgroup (>50 years), ICare and the difference between IOPGAT and IOPPascal were affected significantly by the CCT, whereas IOPGAT and IOPPascal were not. Corneal curvature was correlated significantly with IOPGAT (r = -0.27) and IOPPascal (r = -0.26) but not with IOPICare (P = 0.60). Intra-observer variability within each set of six measurements was approximately 2 mmHg, irrespective of method.CONCLUSION: This study showed a reasonable overall correlation and concordance between the IOP obtained with the three instruments. None of the methods were completely independent of the biomechanical properties of the cornea. ICare showed a significant dependency upon CCT, whereas GAT and Pascal showed a significant dependency on corneal curvature. All methods showed intra-observer variability, which leaves room for further improvement of methods.
|
|
