Computer-assisted retinal vessel measurement in an older population: correlation between right and left eyes

This study assessed the correlation between computer-assisted retinal vessel measurements of right and left eyes, from subjects in a defined, community-based older population. Retinal photographs from participants in the Blue Mountains Eye Study were digitized. All retinal arterioles and venules located 0.5-1.0 disc diameters from the optic disc margin were identified and a computer program measured their diameters. Pearson correlation (R2) statistic was used to assess the correlation in a random subsample of 1546 images. Substantial correlation between right and left eye measurements was found for summary indices of retinal arterioles (R2 = 0.70) and venules (R2 = 0.77). Higher correlation was found for intragrader (R2 0.75-079) than for intergrader assessment (R2 0.67-0.72). Moderate correlation was found in arteriole-to-venule ratio assessed by the same (R2 = 0.57) or different (R2 = 0.52) graders. Measurements from one eye can thus adequately represent the retinal vessel diameters of a person.     

Refractive errors and incident cataracts: the Beaver Dam Eye Study

PURPOSE: To describe the relation between refractive errors and incident age-related cataracts in a predominantly white US population. METHODS: All persons aged 43 to 84 years of age in Beaver Dam, Wisconsin, were invited for a baseline examination from 1988 through 1990 and a follow-up examination 5 years later from 1993 through 1995. At both examinations, participants had refraction and photographic assessment of cataract, according to a standardized protocol. Myopia was defined as a spherical equivalent of -1.0 diopters (D) or less, hyperopia as +1.0 D or more. The relations between refractive errors at baseline and cataract at baseline (prevalent cataract), 5-year incident cataract, and incident cataract surgery were analyzed by using generalized estimating equations. RESULTS: When age and gender were controlled for, myopia was related to prevalent nuclear cataract (odds ratio [OR], 1.67; 95% confidence interval [CI], 1.23-2.27), but not to cortical and posterior subcapsular cataracts. Myopia was not related to 5-year incident nuclear, cortical, and posterior subcapsular cataracts, but was related to incident cataract surgery (OR 1.89; CI 1.18-3.04). Hyperopia was related to incident nuclear (OR 1.56; CI 1.25-1.95) and possibly cortical (OR 1.25; CI 0.96-1.63) cataracts, but not to posterior subcapsular cataract or cataract surgery. After further adjustment for diabetes, smoking, and education, the association between myopia and incident cataract surgery was attenuated (OR 1.60; CI 0.96-2.64), but the associations between hyperopia and incident nuclear and cortical cataracts were unchanged. CONCLUSIONS: These data support the cross-sectional association between myopia and nuclear cataract seen in other population-based studies, but provide no evidence of a relationship between myopia and 5-year incident cataract. Hyperopia may be related weakly to incident nuclear and cortical cataract.     

Changes in refractive error over a 5-year interval in the Beaver Dam Eye Study.

PURPOSE: To examine changes in spherical equivalent over a 5-year period in persons 43 to 84 years of age. METHODS: All people 43 to 84 years of age and living in Beaver Dam, Wisconsin, in 1988 were invited for a baseline examination (1988-1990) and a 5-year follow-up examination (1993-1995). Refractions were determined according to the same protocol at both examinations. Aphakic and pseudophakic eyes were excluded as well as eyes with best corrected Snellen visual acuity of 20/40 and worse. After exclusions, refraction was obtained on 3007 right eyes and 3012 left eyes of the 3684 people participating in both examinations. RESULTS: Right and left eyes behaved similarly. Spherical equivalent became more positive in the youngest subjects and more negative in older subjects. After adjusting for other factors, the 5-year change in spherical equivalent of those 45, 55, 65, and 75 years of age was +0.15, +0.18, +0.10, and -0.07D, respectively. Severity of nuclear sclerosis was related to the amount of change. Those with mild nuclear sclerosis at baseline had a change of +0.2 D, whereas those with severe nuclear sclerosis had a change of -0.5 D. The amount of change was also related to gender, diabetes, and age at onset of myopia. It was unrelated to education and baseline spherical equivalent. CONCLUSIONS: Changes in spherical equivalent over a 5-year period were small. Before the age of 70, people became more hyperopic. After the age of 70, people became more myopic. Much of the myopic change may be related to increasing nuclear sclerosis.     

The relationship of optic disk cupping to retinal vein occlusion: the Beaver Dam Eye Study

PURPOSE: To examine the association between optic disk cupping and retinal vein occlusion (RVO). DESIGN: Prospective epidemiologic study. METHODS: setting: Population-based prospective study in Beaver Dam, Wisconsin. study population: Adults aged 43 to 86 years at baseline (n = 4926). observation procedures: Optic disk cupping and RVO were determined from retinal photographs. A standardized medical examination and questionnaire were administered. main outcome measure: Ten-year cumulative incidence of RVO. RESULTS: There were 58 persons who developed incident RVO at 5 (n = 31) or 10 (n = 27) years after the baseline examination. Those sustaining RVO were older, had higher intraocular pressure (IOP), and were more likely to have definite or probable glaucoma at the baseline examination. The odds of having an incident RVO increased with increasing cup-to-disk ratio at baseline (odds ratio [OR] = 1.29/0.1 increase in cup-to-disk ratio, 95% confidence interval 1.07, 1.56), while controlling for age, systolic blood pressure, current smoking, diabetes status, and IOP. A similar OR was found after excluding those with glaucoma. Excluding persons with central (as opposed to branch) vein occlusion did not have a significant effect on the OR. CONCLUSION: Cup-to-disk ratio is a significant predictor of risk of incident RVO.     

Frailty and age-related macular degeneration: the Beaver Dam Eye Study

PURPOSE: To investigate the associations of measures of frailty to prevalent age-related maculopathy (ARM). DESIGN: Cross-sectional population-based study. METHODS: Time to walk a measured course (gait-time), handgrip strength, peak expiratory flow rate, ability to stand from a sitting position without using arms, self-reported co-morbidities, and ARM were assessed at the third examination of the Beaver Dam Eye Study (n = 2,962). ARM was determined by grading stereoscopic color fundus photographs. RESULTS: While controlling for age, smoking, and the number of co-morbid conditions, weaker handgrip strength was associated with early ARM (odds ratio [OR]/10 kg decrease 1.28, confidence interval [CI] 1.08, 1.52, P = .004) and late ARM (OR 1.55, 95% CI 1.02, 2.36) in men but not women. Other measures of frailty were not related to ARM. CONCLUSIONS: A weak cross-sectional association of handgrip strength with ARM (in men) was found after controlling for co-morbid conditions. These data suggest that ARM is due to a specific disease process, albeit age-related, rather than to biologic aging, as reflected by measures of frailty.     

Assessment of cataracts from photographs in the Beaver Dam Eye Study

Presence and severity of age-related cataract was determined in adults 43 to 84 years of age in Beaver Dam, Wisconsin. Duplicate photograph gradings for nuclear sclerosis (n = 1160), cortical opacities (n = 1159), and posterior subcapsular cataract (n = 1137) were performed. There are five levels of nuclear sclerosis. Exact agreement occurred in 64.7% of the cases; agreement within one category in 99.8%. For cortical opacities, graders estimate involved area in nine segments of the lens. When the continuous scale is divided into 12 categories of severity, exact agreement varied between 73.5 and 82.4%; for agreement within one category, rates varied between 84.6 and 89.9%. For posterior subcapsular cataracts, exact agreement for involvement of the central circle occurred in 95.0% and agreement within one category occurred in 97.7%. Intraobserver comparisons disclosed similar concordance. These grading schemes are semiquantitative, reproducible, and can be performed for the large numbers of photographs from population-based studies.     

Associations of selected medications and visual function: the Beaver Dam Eye Study

AIM: To investigate association of drug use and visual function. METHODS: A cross sectional population based study was carried out on participants in the 1993-5 examination phase of the Beaver Dam Eye Study. All drugs in current use by study participants were recorded. Performance based and self assessed visual functions were obtained at the time of the study evaluation. The main outcome measure was the relation of levels of visual functions by use of specific drugs. RESULTS: Many classes of drugs were associated with decreases in at least two performance based visual functions. For example, high blood pressure drugs were significantly associated with poorer best corrected visual acuity, poorer near vision, and poorer contrast sensitivity (p<0.001 for all). Patterns of association for self assessed visual functions were not as strong. However, use of glaucoma drops and benzodiazepines were associated with poorer self assessed visual functions in most circumstances cited. CONCLUSIONS: Many commonly used medications are inversely associated with visual functions in a middle and older aged population. This may influence the ability to perform complex tasks and quality of life.     

Age-related macular degeneration and optic disk cupping: the Beaver Dam Eye Study

PURPOSE: To examine the association between presence, severity, and extent of lesions of age-related macular degeneration (AMD) and optic disk and cup diameters in a general population. DESIGN: Cross-sectional study. METHODS: setting: Population-based. study population: Adults aged 43 to 86 years participating in the Beaver Dam Eye Study. observation procedures: Fundus photographs were graded for lesions of AMD using standard protocols. The photographs were obtained during the baseline examination of the Beaver Dam Eye Study. main outcome measure: Optic disk cupping as related to presence, severity, and extent of lesions of AMD. RESULTS: There were no significant differences in the vertical optic disk and cup measurements or in the vertical cup to disk ratios by severity of lesions of AMD (P values all greater than .10). In those eyes with late lesions of AMD, there was no association of the size of the lesions or their distribution in the fundus and the extent of cupping. CONCLUSIONS: From a population perspective, there is no relationship of the presence or severity of AMD and optic disk cupping.     

The Tromsø Eye Study: study design,methodology and results on visual acuity and refractive errors

Purpose: To describe the study design and methodology of the Tromsø Eye Study (TES), and to describe visual acuity and refractive error in the study population. Methods: The Tromsø Eye Study is a sub‐study of the Tromsø Study, a population‐based multipurpose longitudinal study in the municipality of Tromsø, Norway. The Tromsø Eye Study was a part of the sixth survey of the Tromsø Study, conducted from October 2007 through December 2008. The eye examination included information on self‐reported eye diseases, assessment of visual acuity and refractive errors, retinal photography and optical coherence tomography. Retinal images were graded for diabetic retinopathy and age‐related macular degeneration, and with computer‐assisted measurements of arteriolar and venular diameters. In addition, TES researchers have access to the large comprehensive Tromsø Study database including physical examination results, carotid artery ultrasound, electrocardiogram, bone densitometry, cognitive tests, questionnaires, DNA, blood and urine samples and more from the present and the five previous surveys. Results: Visual acuity was assessed in 6459 subjects and refraction in 6566 subjects aged 38–87 years. Snellen visual acuity <20/60 was found in 1.2% (95% CI 0.95–1.5) of the participants and there was no gender difference. Visual impairment increased with age, and in the age group 80–87 years, the overall visual acuity <20/60 was 7.3% (95% CI 3.3–11.2). Spherical equivalent showed an increasing trend with age and there was no clinically relevant difference between men and women. Retinal photography was performed in 6540 subjects. Conclusion: Prevalence of visual impairment was low but increased with age. There was a trend towards hyperopia with age and no clinically relevant difference in refraction between the sexes. TES aims to provide epidemiological research on several eye and eye‐related diseases. Owing to a comprehensive data collection, it has the opportunity to explore issues related to environmental factors, cognition and their interaction with diseases in this community.     

Right and left correlation of retinal vessel caliber measurements in anisometropic children: effect of refractive error

Purpose. Previous studies have reported high right-left eye correlation in retinal vessel caliber. We test the hypothesis that right-left correlation in retinal vessel caliber would be reduced in anisometropic compared with emmetropic children. Methods. Retinal arteriolar and venular calibers were measured in 12-year-old children. Three groups were selected: group 1, both eyes emmetropic (n = 214); group 2, right-left spherical equivalent refraction (SER) difference ≥1.00 but <2.00 diopter (D) (n = 35); and group 3, right-left SER difference ≥2.00 D (n = 32). Pearson's correlations between the two eyes were compared between group 1 and group 2 or 3. Associations between right-left difference in refractive error and right-left difference in caliber measurements were assessed using linear regression models. Results. Right-left correlation in group 1 was 0.57 for central retinal arteriolar equivalent (CRAE) and 0.70 for central retinal venular equivalent (CRVE) compared with 0.60 and 0.82 for CRAE and CRVE, respectively, in group 2 (P = 0.42 and P = 0.08), and 0.36 and 0.52, respectively, in group 3 (P = 0.08 and P = 0.07, referenced to group 1). Each 1.00-D increase in right-left SER difference was associated with a 0.74-μm increase in mean CRAE difference (P = 0.02) and a 1.23-μm increase in mean CRVE difference between the two eyes (P = 0.002). Each 0.1-mm increase in right-left difference in axial length was associated with a 0.21-μm increase in the mean difference in CRAE (P = 0.01) and a 0.42-μm increase in the mean difference in CRVE (P < 0.0001) between the two eyes. Conclusions. Refractive error ≥2.00 D may contribute to variation in measurements of retinal vessel caliber.