• The 7-year cumulative incidence of cornea guttata and morphological changes in the corneal endothelium in the Reykjavik Eye Study.

      Zoega, Gunnar M; Arnarsson, Arsaell; Sasaki, Hiroshi; Söderberg, Per G; Jonasson, Fridbert; Uppsala Univ, Dept Neurosci, Gullstrand Lab, Uppsala, Sweden Univ Akureyri, Akureyri, Iceland Kanazawa Med Univ, Dept Ophthalmol, Uchinada, Ishikawa 92002, Japan Univ Iceland, Dept Ophthalmol, IS-101 Reykjavik, Iceland Landspitali Univ Hosp IS-101 Reykjavik, Iceland (Wiley-Blackwell, 2013-05)
      To examine the corneal endothelium and establish the 7-year cumulative incidence of cornea guttata (CG).
    • Actinomycotic canaliculitis: resolution following surgery and short topical antibiotic treatment

      Baldursdottir, Eyrun; Sigurdsson, Haraldur; Jonasson, Larus; Gottfredsson, Magnus; Department of Infectious Diseases, University of Iceland Medical School, Reykjavik, Iceland. (Wiley-Blackwell, 2010-05-01)
      Abstract. Purpose: This study aimed to study the incidence and clinical characteristics of patients diagnosed with actinomycotic canaliculitis in Iceland. Methods: We present a nationwide, retrospective case series for which cases were identified by searches of hospital diagnostic registries and pathology databases. Case histories were reviewed and histopathological analysis repeated to confirm the diagnosis. Results: Nine cases of actinomycotic canaliculitis were diagnosed in Iceland during 1988-2007. Subjects included six women and three men and represented 16% of all patients diagnosed with actinomycosis in the country. The incidence was 0.16 cases/100 000 inhabitants/year. Age-specific incidence rates were 0.59 cases/100 000 inhabitants/year for the 40-59-year-old age group and 1.37 cases/100 000 inhabitants/year for individuals aged 60-79 years. All patients underwent a three-way snip procedure and 1 week of topical antibacterial therapy. Conclusions: Actinomycotic canaliculitis is an uncommon condition which frequently eludes diagnosis. Topical antibiotics for 1 week may be sufficient following surgery, a finding which contrasts with previous reports.
    • Angiotensin Receptor Blockers in cyclodextrin nanoparticle eye drops: Ocular pharmacokinetics and pharmacologic effect on intraocular pressure.

      Lorenzo-Soler, Laura; Olafsdottir, Olof Birna; Garhöfer, Gerhard; Jansook, Phatsawee; Kristinsdottir, Iris Myrdal; Tan, Aimin; Loftsson, Thorsteinn; Stefansson, Einar; 1Faculty of Medicine, University of Iceland, Reykjavík, Iceland. 2Department of Ophthalmology, Landspitali University Hospital, Reykjavík, Iceland. 3Oculis ehf., Reykjavík, Iceland. 4Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria. 5Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, Thailand. 6Nucro-Technics, Toronto, ON, Canada. 7Faculty of Pharmacy, University of Iceland, Reykjavík, Iceland. (Wiley, 2020-11-16)
      Purpose: Orally administered angiotensin II receptor blockers (ARBs) decrease intraocular pressure (IOP). Topical administration may reduce systemic side effects and result in a useful glaucoma drug. The aim of this study is to test the ocular delivery and pharmacologic effect of nanoparticle eye drops containing ARBs (e.g. irbesartan and candesartan). Methods: 1.5% irbesartan and 0.15% candesartan eye drops were applied to rabbits. The pharmacokinetics in cornea and aqueous humour after single eye drop application were studied in 49 rabbits. The effect of the eye drops on IOP was studied in 10 rabbits using an iCare (® TonoVet Plus, iCare, Finland) tonometer and compared with 0.5% timolol eye drops. Results: Candesartan lowered IOP from 24.6 ± 5.1 mmHg at baseline to 19.0 ± 2.9 mmHg (mean ± SD, p = 0.030, n = 10) 4 hr after application. Irbesartan lowered IOP from 24.2 ± 1.7 mmHg to 20.2 ± 0.9 mmHg (p = 0.14, n = 10). Timolol decreased the IOP from 24.9 ± 4.2 mmHg to 20.4 ± 4.8 mmHg (mean ± SD, p = 0.036, n = 10). The pharmacokinetics data show that both formulations deliver effective amounts of drug into the intraocular tissues, with irbesartan and candesartan reaching concentrations of 121 ± 69 and 30.43 ± 13.93 ng/g (mean ± SD), respectively, in the aqueous humour 3 hr after a single-dose administration. Conclusions: Topical application of irbesartan and candesartan eye drops delivers effective drug concentrations to the anterior segment of the eye in rabbits, achieving drug concentrations 100 times above the IC50 for angiotensin II receptor and showing an IOP-lowering effect. Angiotensin receptor blocker (ARB) eye drops have potential as a new class of glaucoma drugs. Keywords: angiotensin receptor blockers; glaucoma; intraocular pressure; pharmacokinetics.
    • Body size at birth and age-related macular degeneration in old age.

      Haapanen, Markus J; von Bonsdorff, Mikaela B; Fisher, Diana; Jonasson, Fridbert; Eiriksdottir, Gudny; Gudnason, Vilmundur; Cotch, Mary Frances; 1Department of General Practice and Primary Health Care, University of Helsinki and Helsinki University Hospital, Helsinki, Finland. 2Folkhälsan Research Center, Helsinki, Finland. 3Gerontology Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland. 4Division of Epidemiology and Clinical Applications, Intramural Research Program, National Eye Institute, National Institutes of Health, Bethesda, Maryland, USA. 5Faculty of Medicine, University of Iceland, Reykjavik, Iceland. 6Department of Ophthalmology, Landspitali, The National University Hospital of Iceland, Reykjavik, Iceland. 7Icelandic Heart Association, Kópavogur, Iceland. (Wiley, 2019-12-29)
      Purpose To study associations between body size at birth and age‐related macular degeneration (AMD) in old age. Methods The study sample consists of 1497 community‐dwelling individuals (56.1% women) aged 67–89 years with birth data and retinal data collected twice in old age 5 years apart. Birth data (weight, length, birth order) were extracted from original birth records. Digital retinal photographs were graded to determine AMD status. Data on covariates were collected at the baseline physical examination in old age. Multivariable regression analyses were used to study the association between birth data and AMD adjusting for known confounding factors, including birth year cohort effects. Results The prevalence and 5‐year incidence of any AMD were 33.1% and 17.0%, respectively. Men and women born in 1930–1936 were significantly leaner and slightly longer at birth compared to those in earlier birth cohorts. There were no consistent associations between weight, length or ponderal index (PI) at birth and AMD in old age even when stratified by birth cohort. Age‐related macular degeneration (AMD) prevalence (39.8%) and 5‐year incidence (28.6%) were highest in individuals who were in the highest quartile of PI at birth and who were obese in old age. Conclusion Body size at birth was not consistently associated with AMD in old age, suggesting that intrauterine growth might have little direct importance in the development of AMD in old age. It is possible that some yet unknown factors related to larger size at birth and obesity in old age may explain differences in the prevalence and incidence of AMD in the ageing population.
    • Can postoperative dexamethasone nanoparticle eye drops replace mitomycin C in trabeculectomy?

      Jóhannesson, Gauti; Gottfredsdóttir, María Soffía; Ásgrimsdóttir, Guðrún Marta; Loftsson, Thorsteinn; Stefánsson, Einar; 1Department of Clinical Sciences, Ophthalmology, Umeå University, Umeå, Sweden. 2Wallenberg Centre for Molecular Medicine, Umeå University, Umeå, Sweden. 3Department of Ophthalmology, Faculty of Medicine, National University Hospital, University of Iceland, Reykjavik, Iceland. 4Oculis ehf., Reykjavik, Iceland. 5Faculty of Pharmaceutical Science, University of Iceland, Reykjavik, Iceland. (Wiley, 2020-02-17)
      Purpose: Compare (a) nonmitomycin C (MMC) trabeculectomy and 1.5% dexamethasone nanoparticle (DexNP) eye drops postoperatively with (b) trabeculectomy with MMC and Maxidex® eye drops postoperatively. Methods: Randomized prospective single masked clinical trial with 20 patients with primary open-angle glaucoma undergoing primary trabeculectomy. The study group consisted of 10 patients without MMC intraoperatively and postoperative DexNP eye drops, and the control group consisted of 10 patients treated with MMC intraoperatively and postoperative Maxidex® . The drops were tapered out over 8 weeks. The main outcome measures were as follows: rates of complete success, that is intraocular pressure (IOP) within target pressures at different time-points without IOP-lowering medication, or reoperation. Secondary outcome measures included the following: relative success rate (with IOP-lowering medications), number of glaucoma medications and reoperations. Patients were followed for 36 months. Results: Both groups showed similar postoperative course and IOP reduction. Intraocular pressures (IOPs) in the DexNP group and in the control group were 25.6 and 24.4 mmHg, respectively, at baseline. Intraocular pressures (IOPs) were reduced to 13.2 and 14.5 mmHg at 12 months, 11.7 and 12.6 mmHg at 24 months and 11.7 and 12.1 mmHg at 36 months, respectively. There were no statistically significant differences between the groups in absolute (p = 0.36) or relative (p = 1.0) success rates, number of medications (p = 0.71) or reoperations (p = 1.0) between the groups at any time-point. Conclusions: DexNP eye drops are effective postoperative treatment following trabeculectomy. The potent anti-inflammatory and antifibrotic effect of DexNP may offer an alternative to mitomycin C in glaucoma surgery.
    • Diabetic eye screening with variable screening intervals based on individual risk factors is safe and effective in ophthalmic practice.

      Estil, Svein; Steinarsson, AEgir Þór; Einarsson, Stefan; Aspelund, Thor; Stefánsson, Einar; 1Robrygga Eye, Namsos Medical Center, Namsos, Norway. 2Risk ehf, Reykjavík, Iceland. 3Landspitali University Hospital, University of Iceland, Reykjavik, Iceland. (Wiley, 2020-03-25)
      Purpose: To test in a 'real world' diabetic eye-screening programme, a computer-based personal risk evaluation for progression to sight-threatening diabetic retinopathy. Screening intervals were individualized, and clinical outcomes, safety and cost-effectiveness documented. Methods: The RETINARISK algorithm was used in an ophthalmology clinic in Norway. The diabetes cohort was divided on voluntary basis into two groups: one with variable screening intervals based on their personal risk profile and the other group with conventional fixed interval diabetic eye screening. Compliance, clinical outcomes, safety and health economics were evaluated. A total of 843 diabetic patients participated in the program 2014-2019. A total of 63 had type 1 and 780 type 2 diabetes. A total of 671 patients had no diabetic retinopathy at baseline and 171 had retinopathy. Results: A total of 444 (53%) diabetic patients were included in the personal risk profile program and 399 in the fixed interval group. The RETINARISK algorithm calculated 563 screening intervals for the variable interval group, which was 23 ± 16 months (mean ± SD), compared to 14 ± 5 months for the group with fixed screening intervals. Due to selection bias, the two groups could not be directly compared. We did not experience any delay in detecting diabetic retinal changes when using the personal risk profile program. Conclusion: The RETINARISK algorithm was safe and effective in a diabetic screening program in an ophthalmology clinic over 5 years. The use of the program reduces the mean frequency of screening visits and liberates valuable time in ophthalmic practice to be used on high-risk diabetic patients or other patient groups.
    • Early detection of type 2 diabetes mellitus and screening for retinopathy are associated with reduced prevalence and severity of retinopathy.

      Olafsdottir, Eydis; Andersson, Dan K G; Dedorsson, Inger; Svärdsudd, Kurt; Jansson, Stefan P O; Stefánsson, Einar; [ 1 ] Natl Univ Hosp Reykjavik, Dept Ophthalmol, Reykjavik, Iceland   Organization-Enhanced Name(s)      Landspitali National University Hospital [ 2 ] Univ Iceland, Reykjavik, Iceland [ 3 ] Orebro Univ Hosp, Dept Ophthalmol, S-70116 Orebro, Sweden [ 4 ] Uppsala Univ, Dept Publ Hlth & Caring Sci, Family Med & Prevent Med Sect, Uppsala, Sweden [ 5 ] Univ Orebro, Sch Hlth & Med Sci, Orebro Cty Council, Family Med Res Ctr, S-31705 Orebro, Sweden (Wiley-Blackwell, 2016-05)
      To explore whether the prevalence and severity of retinopathy differ in diabetes cohorts diagnosed through screening as compared with conventional health care.
    • Effects of retrobulbar bupivacaine on post-operative pain and nausea in retinal detachment surgery

      Gottfredsdottir, M S; Gislason, I; Stefansson, E; Sigurjonsdottir, S; Nielsen, N C; Department of Ophthalmology, University of Iceland, Landakotsspítalis, Reykjavík. (Scriptor Publishers Aps, 1993-08)
      A prospective double-masked clinical trial was conducted to determine whether retrobulbar bupivacaine block had an effect on post-operative pain, nausea and intra- and post-operative use of analgesics in retinal detachment surgery performed under general anaesthesia. Thirty-two patients were randomized to have general anaesthesia with or without retrobulbar bupivacaine. Pain score was documented as 0-10 (0 = no pain. 10 = worst pain ever felt). Post-operative pain score was significantly lower in the retrobulbar block group during the first post-operative hours than in the control group. Men complained more about post-operative pain than did women. The patients in the retrobulbar group complained less about nausea. Significantly fewer patients in the retrobulbar group required parenteral pain relief during operation and the first 48 h after.
    • Enalaprilat and enalapril maleate eyedrops lower intraocular pressure in rabbits.

      Loftsson, Thorsteinn; Thorisdottir, Sigridur; Fridriksdottir, Hafrun; Stefansson, Einar; University of Iceland, Reykjavik, Iceland. thorstlo@hi.is <thorstlo@hi.is> (2010-05-01)
      PURPOSE: This study aimed to develop low-viscosity aqueous eyedrops containing enalaprilat and its prodrug enalapril maleate in solution, and to evaluate the eyedrops in rabbits. METHODS: Aqueous eyedrops with hydroxypropyl-beta-cyclodextrin containing 0.01-2.9% (w/v) enalaprilat, 1.0% (w/v) enalapril maleate with cyclodextrin or 0.5% (w/v) timolol were prepared. The eyedrops were administered to rabbits and intraocular pressure (IOP) was measured at various time intervals after the administration and the results (mean of 10 experiments +/- standard error of the mean) are expressed as the change from baseline (24.7 +/- 3.3 mmHg). RESULTS: Enalaprilat possessed sufficient stability to be formulated as an aqueous eyedrop solution with a shelf-life of several years at room temperature. The maximum decline in IOP after topical administration of one drop of 2.9% enalaprilat solution was 6.2 +/- 0.7 mmHg at 4 hours after administration. Duration of activity exceeded 10 hours. A 1% enalaprilat solution lowered IOP by 4.4 +/- 0.8 mmHg at 4 hours after administration and had similar duration, and was more potent than 0.5% timolol. The enalapril maleate eyedrops resulted in delayed action, showing maximum potency at 10-22 hours after administration and duration of up to 32 hours. CONCLUSIONS: Enalaprilat eyedrops lower IOP in rabbits. The decline in IOP is proportional to the concentration of dissolved enalaprilat in low-viscosity aqueous eyedrop formulations.
    • Enucleation in Iceland 1992-2004: study in a defined population.

      Geirsdottir, Asbjorg; Agnarsson, Bjarni A; Helgadottir, Gudleif; Sigurdsson, Haraldur; Landspitali, Dept Ophthalmol, IS-101 Reykjavik, Iceland, Univ Iceland, Sch Med, Reykjavik, Iceland, Landspitali, Dept Pathol, IS-101 Reykjavik, Iceland (Wiley-Blackwell, 2014-03)
      To determine the incidence rate as well as causative diagnoses and surgical indications of enucleation in Iceland during the years 1992-2004.
    • From epidemiology to lysyl oxidase like one (LOXL1) polymorphisms discovery: phenotyping and genotyping exfoliation syndrome and exfoliation glaucoma in Iceland

      Jonasson, Fridbert; University of Iceland, Landspitali, Reykjavik, Iceland. fridbert@landspitali.is (Wiley-Blackwell, 2009-08-01)
      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.
    • Geographic atrophy and choroidal melanoma located 3 mm apart

      Geirsdottir, Asbjorg; Hungerford, John; Stefansson, Einar; Jonasson, Fridbert; Helgadottir, Gudleif; Sigurdsson, Haraldur (Blackwell Munksgaard, 2008-08-01)
      [No abstract]
    • Kinetics of γ-cyclodextrin nanoparticle suspension eye drops in tear fluid.

      Jóhannesson, Gauti; Moya-Ortega, Maria D; Ásgrímsdóttir, Gudrún Marta; Lund, Sigrún H; Thorsteinsdóttir, Margrét; Loftsson, Thorsteinn; Stefánsson, Einar; Department of Ophthalmology, Faculty of Medicine, National University Hospital, University of Iceland, Reykjavik, Iceland; Department of Clinical Science, Ophthalmology, Umeå University, Umeå, Sweden (Wiley, 2014-09)
      We have developed nanoparticle γ-cyclodextrin dexamethasone (DexNP) and dorzolamide (DorzNP) eye drops that provide sustained high drug concentrations on the eye surface. To test these characteristics, we measured dexamethasone and dorzolamide levels in tear fluid in humans following eye drop administration.
    • Non-invasive structural and metabolic retinal markers of disease activity in non-proliferative diabetic retinopathy.

      Weisner, Gwen; Blindbaek, Søren Leer; Tang, Fang Yao; Cheung, Carol Y; Henriksen, Jan Erik; Stefánsson, Einar; Peto, Tunde; Grauslund, Jakob; 1Department of Ophthalmology, Odense University Hospital, Odense, Denmark. 2Department of Clinical Research, University of Southern Denmark, Odense, Denmark. 3Centre for Public Health, Queen's University Belfast, Belfast, UK. 4OPEN, Open Patient data Explorative Network, Odense University Hospital, Odense, Denmark. 5Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China. 6Steno Diabetes Center Odense, Odense University Hospital, Odense, Denmark. 7University of Iceland, Reykjavik, Iceland. 8Landspitali University Hospital, Reykjavik, Iceland. (Wiley, 2021-01-08)
      Purpose: Metabolic and structural microvascular retinal alterations are essential components in diabetic retinopathy (DR). The present study aimed to measure changes at different stages of non-proliferative DR (NPDR) and to explore interactions of imaging-based metrics. Methods: This cross-sectional, cohort study included 139 eyes from 80 diabetic patients. Each patient underwent dilated fundal examinations including colour fundus photography, retinal oximetry and optical coherence tomography angiography (OCTA), analysed by semi-automated and automated software. Diabetic retinopathy (DR) severity was classified according to the International Clinical Diabetic Retinopathy (ICDR) Severity Scale, ranging from no DR to severe NPDR (level 0-3). Retinal metabolism was evaluated by oximetry as retinal arteriolar (raSatO2 ) and venular oxygen saturation (rvSatO2 ), and macular microvascular structure was measured by OCTA as the area of foveal avascular zone (FAZ), vessel density (VD), vessel diameter index (VDI), FAZ circularity and fractal dimension (FD) in the superficial and deep retinal capillary plexus. Results: A trend for increasing rvSatO2 was found with increasing DR severity (51.3%, 53.3%, 54.2%, 59.8%, p = 0.02). Increasing severity of DR associated with decreasing FD in the superficial and deep plexus (p < 0.001 and p = 0.014), and in the superficial plexus decreasing VD (p < 0.001), increasing VDI (p = 0.003) and decreasing FAZ circularity (p = 0.006). A few interactions were identified between raSatO2 , rvSatO2 and VDI, but only in the deep capillary plexus (p < 0.01 and p < 0.01). Conclusion: Alterations of the venular retinal vascular oxygen saturation and microvascular structural abnormities were found continuously throughout the DR-spectrum. Given the sparse correlations between metabolic and structural abnormalities, it seems that these occur independently in DR. Keywords: diabetes; diabetic retinopathy; non-proliferative diabetic retinopathy; optical coherence tomography angiography; retinal oximetry.
    • Oximetry in glaucoma: correlation of metabolic change with structural and functional damage.

      Vandewalle, Evelien; Abegão Pinto, L; Olafsdottir, Olof B; De Clerck, Eline; Stalmans, Peter; Van Calster, Joachim; Zeyen, Thierry; Stefánsson, Einar; Stalmans, Ingeborg; KULeuven, Lab Ophthalmol, Leuven, Belgium Univ Hosp Leuven, Dept Ophthalmol, B-3000 Leuven, Belgium Univ Lisbon, Fac Med, Dept Pharmacol & Neurosci, P-1699 Lisbon, Portugal Ctr Hosp Lisboa Cent, Dept Ophthalmol, Lisbon, Portugal Univ Iceland, Dept Ophthalmol, Reykjavik, Iceland (Wiley-Blackwell, 2014-03)
      To determine whether retinal vessel oxygen saturation in patients with glaucoma is associated with structural optic disc and retinal nerve fibre layer (RNFL) changes and visual field (VF) defects.
    • Oxygen saturation in branch retinal vein occlusion.

      Hardarson, Sveinn Hakon; Stefánsson, Einar; Department of Ophthalmology, University of Iceland/ Landspítali - The National University Hospital of Iceland, Reykjavik, Iceland. (2012-08)
      The aim of this study was to test whether oxygen saturation in retinal blood vessels is affected by branch retinal vein occlusion (BRVO). The spectrophotometric retinal oximeter is based on a fundus camera. It simultaneously captures images of the retina at 586 and 605 nm and calculates optical density (absorbance) of retinal vessels at both wavelengths. The ratio of the two optical densities is approximately linearly related to haemoglobin oxygen saturation. Relative oxygen saturation was measured in retinal blood vessels in 24 patients with BRVO. Friedman's test and Dunn's post test were used for statistical analyses. Results:  Oxygen saturation in occluded venules ranged from 12% to 93%. The median oxygen saturation was 59% (range 12-93%, n = 22) in affected retinal venules, 63% (23-80%) in unaffected venules in the BRVO eye and 55% (39-80%) in venules in the fellow eye (p = 0.66). Corresponding values for arterioles were 101% (89-115%, n = 18), 95% (85-104%) (p < 0.05) and 98% (84-109%). Venular saturation in BRVO is highly variable between patients. Hypoxia is seen in some eyes but not in others. This may reflect variable severity of disease, degree of occlusion, recanalization, collateral circulation, tissue atrophy, arteriovenous diffusion or vitreal transport of oxygen.
    • The oxygen saturation in retinal vessels from diabetic patients depends on the severity and type of vision-threatening retinopathy.

      Jørgensen, Christina M; Hardarson, Sveinn H; Bek, Toke; Aarhus Univ Hosp, Dept Ophthalmol, DK-8000 Aarhus C, Denmark, Univ Iceland, Dept Ophthalmol, Reykjavik, Iceland (Wiley-Blackwell, 2014-02)
      Diabetic retinopathy is characterized by morphological lesions in the retina secondary to disturbances in retinal blood flow which may influence the supply of oxygen to the retinal metabolism. Using retinal oximetry, it has been shown that the oxygen saturation is increased in retinal arterioles and venules from diabetic patients with retinopathy, but oxygenation before the development of retinopathy and possible differences in retinal oxygenation between diabetic maculopathy and proliferative diabetic retinopathy patients have not been evaluated.
    • Prevalence and causes of visual impairment and blindness in Icelanders aged 50 years and older: the Reykjavik Eye Study.

      Gunnlaugsdottir, Elin; Arnarsson, Arsaell; Jonasson, Fridbert; Department of Ophthalmology, University of Iceland, Reykjavik, Iceland. (Blackwell Munksgaard, 2008-11-01)
      PURPOSE: This study aimed to study the prevalences and causes of visual impairment and blindness in an Icelandic adult population. METHODS: The Reykjavik Eye Study includes a random sample of citizens of Reykjavik aged > or = 50 years, with an equal proportion (6.4%) for each year of birth and each sex. A total of 1045 persons were examined, representing a response rate of 75.8%. All participants underwent an extensive ophthalmological examination using a standard protocol. We used World Health Organization (WHO) definitions for bilateral visual impairment (best corrected visual acuity [VA] < 6/18 or visual field of > or = 5 degrees and < 10 degrees around the fixation point in the better eye) and blindness (VA < 3/60 or visual field < 5 degrees in the better eye). We also used US criteria, which define bilateral visual impairment as present if VA is < 6/12 and blindness as present if VA is < or = 6/60 (both in the better eye). The causes of visual loss were determined for all participants found to be visually impaired in one or both eyes. RESULTS: The prevalences of bilateral visual impairment and blindness were 0.96% (95% confidence interval [CI] 0.37-1.55) and 0.57% (95% CI 0.12-1.03), respectively, using the WHO criteria, and 2.01% (95% CI 1.16-2.86) and 0.77% (95% CI 0.24-1.29), respectively, using the US criteria. The prevalence rates were 4.40% and 5.45% for unilateral visual impairment and 1.72% and 3.06% for unilateral blindness, using the WHO and US criteria, respectively. Age-related macular degeneration (AMD) was the major cause of bilateral visual loss, whereas the most common causes of unilateral visual loss were, in this order, amblyopia, cataract and glaucoma. CONCLUSIONS: Prevalence of visual loss increases with age. The leading cause of bilateral visual impairment and blindness was AMD, accounting for more than half of all cases, and cases of geographic atrophy outnumbered those of exudative AMD by two to one.
    • The prevalence of cataract in a population with and without type 2 diabetes mellitus.

      Olafsdottir, Eydis; Andersson, Dan K G; Stefánsson, Einar; Department of Ophthalmology, The National University Hospital, Reykjavik, Iceland. (Wiley-Blackwell, 2012-06)
      To evaluate the prevalence and risk factors of lens opacities in a geographically defined population of subjects with type 2 diabetes mellitus compared with a control population. Subjects in the community of Laxå with a diagnosis of type 2 diabetes mellitus (n = 275) and a control group (n = 256) participated in the study. Lens opacities were graded with Lens Opacities Classification System II in all participants. Lens Opacities Classification System score ≥ 2 was considered as significant lens opacity. Anthropometric and blood chemistry data were collected for all participants in connection with the eye examination. For the diabetic population, yearly updated information on glucose control, blood pressure and body mass index was available through medical records from diabetes diagnosis until the time of the eye examination. The prevalence of significant cortical, posterior subcapsular and nuclear cataract was 65.5%, 42.5% and 48.0%, respectively, in the type 2 diabetes population in Laxå. In logistic regression analyses, all types of lens opacities were strongly associated with age (p < 0.0001). Cortical lens opacity was also associated with a diagnosis of diabetes (p < 0.0001), posterior subcapsular lens opacity with HbA1c (p < 0.0001) and nuclear lens opacity with female gender and higher heart rate (both p = 0.0004). In the diabetic population, all types of cataract were likewise strongly associated with age (p < 0.0001), posterior subcapsular cataract with HbA1c (p = 0.0032), nuclear cataract with female gender (p = 0.0002) and higher heart rate (p = 0.0008). Conclusions:  Our study shows that cortical cataract is associated with diabetes mellitus, not necessarily defined by glucose control, whereas posterior subcapsular cataract is associated with glucose levels. Nuclear cataract is not associated with diabetes mellitus, but is more frequent in women and is also associated with higher heart rate.
    • The prevalence of retinopathy in subjects with and without type 2 diabetes mellitus.

      Olafsdottir, Eydis; Andersson, Dan K G; Dedorsson, Inger; Stefánsson, Einar; Natl Univ Hosp Reykjavik, Dept Ophthalmol, Reykjavik, Iceland, Univ Iceland, Reykjavik, Iceland, Orebro Univ Hosp, Dept Ophthalmol, S-70185 Orebro, Sweden, Uppsala Univ, Dept Publ Hlth & Caring Sci, Family Med & Clin Epidemiol Sect, Uppsala, Sweden (Wiley-Blackwell, 2014-03)
      To evaluate the prevalence of and risk factors for, retinopathy in a geographically defined population with type 2 diabetes mellitus compared with a control group of subjects without diabetes, matched by age, sex and residence in order to find the retinopathy attributable to type 2 diabetes.