Changing views on open-angle glaucoma: definitions and prevalences--The Rotterdam Study

PURPOSE

To create a quantitative basis for diagnostic criteria for open-angle glaucoma (OAG), to propose an epidemiologic definition for OAG based on these, and to determine the prevalence of OAG in a general white population.

METHODS

Of the 7983 subjects 55 years of age or older participating in the population-based Rotterdam Study, 6756 subjects participated in the ophthalmic part of this study (6281 subjects living independently and 475 in nursing homes). The criteria for the diagnosis of OAG were based on ophthalmoscopic and semiautomated Imagenet estimations of the optic disc such as vertical cup-to-disc ratio (VCDR), minimal width of neural rim, or asymmetry in VCDR between both eyes, and visual field testing with kinetic Goldmann perimetry. All criteria for the diagnosis of OAG were assessed in a masked way independently of each other.

RESULTS

Mean VCDR on ophthalmoscopy was 0.3 and with Imagenet 0.49, and the 97.5th percentile for both was 0.7. The prevalence of glaucomatous visual field defects was 1.5%. Overall prevalence of definite OAG in the independently living subjects was 0.8% (95% confidence interval [CI] 0.6, 1.0; 50 cases). Prevalence of OAG in men was double that in women (odds ratio 2.1; 95% CI 1.2, 3.6). Different commonly used criteria for diagnosis of OAG resulted in prevalence figures ranging from 0.1% to 1.2%.

CONCLUSIONS

The overall prevalence of OAG in the present study was comparable to most population-based studies. However, prevalence figures differed by a factor of 12 when their criteria for OAG were applied to this population. A definition for definite OAG is proposed: a glaucomatous optic neuropathy in eyes with open angles in the absence of history or signs of secondary glaucoma characterized by glaucomatous changes based on the 97.5 percentile for this population together with glaucomatous visual field loss. In the absence of the latter or of a visual field test, it is proposed to speak of probable OAG based on the 99.5th or possible OAG based on the 97.5th percentiles of glaucomatous disc changes for a population under study.

Polypoidal choroidal vasculopathy in exudative and haemorrhagic pigment epithelial detachments

AIMS

To determine the prevalence of polypoidal choroidopathy in consecutive patients presenting with large haemorrhagic and exudative neurosensory retinal and retinal pigment epithelial detachments (PEDs) of over 2 mm in diameter in the absence of drusen.

METHODS

40 patients were identified over a 5 month period of which 29 had haemorrhagic detachments, and 11 had purely exudative detachments. All had indocyanine green (ICG) angiography, and the presence was sought of large blood vessels in the choroid associated with localised dilated terminals that filled slowly and leaked ICG.

RESULTS

In 34 cases (85%) there was an appearance consistent with previous descriptions of idiopathic polypoidal choroidal vasculopathy. Of the six without polypoidal lesions the disorder was attributed to choroidal neovascularisation in four, chorioretinitis in one, and a fibrovascular PED in one. Of those with polypoidal lesions 20 (65%) were female, the mean age was 65.4 years (range 44-88), and 25 (74%) were white, seven (20%) black, and two (6%) east Asian. Eight had a history of hypertension. Visual acuity varied from 6/6 to counting fingers in the involved eye (mean 6/24). Bilateral polypoidal choroidal lesions were demonstrated in 16 patients (47%). The predominant location for these lesions was the macular region in 23 patients (68%). Polypoidal vasculopathy was found in 16 patients (47%) who had a previous diagnosis of age related macular disease (AMD). No patients had evidence of intraocular inflammation.

CONCLUSIONS

In a largely white patient population a high proportion of patients with haemorrhagic and exudative PEDs has evidence of polypoidal lesions on ICG angiography.

A randomized controlled clinical trial on the efficacy of radiation therapy in the control of subfoveal choroidal neovascularization in age-related macular degeneration: radiation versus observation

BACKGROUND

The results of several pilot studies concerning radiation therapy for age-related subfoveal choroidal neovascularization (CNV) have been published recently. Although positive treatment results have been described, it is not known whether this therapy alters the natural course of eyes with neovascular age-related macular degeneration (AMD). A randomized controlled clinical trial was conducted in which radiation therapy was compared with observation in patients with subfoveal neovascular AMD.

METHODS

Seventy-four patients with a recent drop in central vision due to subfoveal age-related CNV were randomized to either radiation treatment or observation. Patients with either classic, occult or mixed type CNV were included. Eyes in the treatment group received a radiation dose of 24 Gy in four fractions of 6 Gy. Evaluation of data concerning visual acuity (VA) and fluorescein angiography occurred at 3, 6 and 12 months after inclusion.

RESULTS

At 12 months of follow-up 52.2% of the observation group versus 32.0% of the irradiation group had lost 3 or more lines of VA (P = 0.03, log rank test). More severe visual decline, 6 lines or more, was observed in 40.9% of the observation versus 8.8% in the irradiation group (P = 0.002 using log rank test). At 12 months 39.6% of the observation group and 20.0% of the treatment group had VA of less than 0.1 (P = 0.08, log rank test). The size of the CNV membrane doubled in 25.2% of eyes in the observation group versus 20.0% in the treatment group at least 12 months (P = 0.5, log rank test). No side effects were observed.

CONCLUSION

Preservation of VA was significantly better in the treatment group compared with the control group at 12 months. Nevertheless we noted a drop in central vision of 3 or more lines in a substantial proportion of the treatment group. Radiation therapy does not prevent visual loss in all patients with age-related subfoveal CNV, and whether the treatment benefit at 12 months will persist has to be awaited.

Age-specific prevalence and causes of blindness and visual impairment in an older population: the Rotterdam Study

OBJECTIVE

To study the prevalence and causes of blindness and visual impairment in various age categories of a large population-based study.

METHODS

For the study, 6775 subjects aged 55 years or older underwent an extensive ophthalmologic screening examination, including measurements of visual acuity and the visual field and fundus photography. The causes of blindness or visual impairment were determined using all screening information and medical records.

RESULTS

The prevalence of blindness, according to World Health Organization criteria, ranged from 0.1% in subjects aged 55 to 64 years to 3.9% in subjects aged 85 years or older; the prevalence of visual impairment ranged from 0.1% to 11.8%. For persons younger than 75 years, myopic degeneration and optic neuropathy were the most important causes of impaired vision. For persons aged 75 years or older, age-related macular degeneration was the major cause of the increased prevalence of blindness, whereas age-related cataract predominantly caused the increased prevalence of visual impairment.

CONCLUSIONS

The hierarchy of causes of blindness and visual impairment is highly determined by age. As yet, little can be done to reduce the exponential increase of blindness; however, adequate implementation of surgery to treat cataract could reduce visual impairment by one third. Underuse of ophthalmologic care is a prominent cause of the high frequency of untreated cataracts among the elderly.

Distribution of central corneal thickness and its association with intraocular pressure: The Rotterdam Study

PURPOSE

To perform a cross-sectional study on the distribution of central corneal thickness and its association with intraocular pressure in an elderly population.

METHODS

We measured central corneal thickness and intraocular pressure in 395 subjects (352 control subjects, 13 patients with ocular hypertension, and 30 patients with primary open-angle glaucoma) aged 55 years or more.

RESULTS

Mean central corneal thickness in the 352 control subjects was 537.4 microm (95% confidence interval [CI], 533.8 to 540.9 microm; range, 427 to 620 microm), with a maximal difference between eyes of 42 microm. There were no differences between sexes and no significant association with age. Linear regression analysis showed an increase of 0.19 mm Hg in intraocular pressure with each 10-microm increase in central corneal thickness (95% CI, 0.09 to 0.28 mm Hg). This association was similar in both eyes and in both sexes. The 13 patients with ocular hypertension had corneas a mean of 16.0 microm thicker (95% CI, -2.6 to +34.6 microm) compared with control subjects (P = .093); the 30 patients with primary open-angle glaucoma had corneas a mean of 21.5 microm thinner (95% CI, 8.8 to 34.1 microm) compared with control subjects (P = .001).

CONCLUSION

Mean central corneal thickness was similar to that found in clinical studies, was slightly higher in patients with ocular hypertension, and was significantly lower in patients with primary open-angle glaucoma. Intraocular pressure was positively related with central corneal thickness. Central corneal thickness may influence the division between normal and increased intraocular pressure at a simple cutoff point of 21 mm Hg.

Age-related macular degeneration and smoking. The Rotterdam Study

OBJECTIVE

To assess the relation between cigarette smoking and age-related macular degeneration (AMD) in a population of elderly persons.

DESIGN

A cross-sectional, community-based study.

SETTING

City district of Rotterdam, the Netherlands.

PARTICIPANTS

A total of 6174 persons 55 years and older who participated in the Rotterdam Study. In 36 persons atrophic AMD and in 65 persons neovascular AMD were diagnosed.

MAIN OUTCOME MEASURES

Age-related macular degeneration was diagnosed by evaluating fundus transparencies, smoking behavior was identified by interviewing subjects, and the presence of atherosclerosis was assessed by the ankle-arm systolic blood pressure index. Relative risks and 95% confidence intervals (CIs) were calculated using multivariate logistic regression analysis.

RESULTS

In subjects younger than 85 years, current smokers had a 6.6-fold increased risk of neovascular AMD vs those who had never smoked (95% CI, 2.8-15.9). Former smokers had a 3.2-fold increased risk of neovascular AMD vs nonsmokers in this age group (95% CI, 1.4-7.4). These associations were not observed in subjects 85 years or older. Smoking was not associated with atrophic AMD. A strong increased risk of neovascular AMD was present in those who had smoked more than 10 pack-years (relative risk, 6.5; 95% CI, 2.9-14.8). Adjusting the results for atherosclerosis did not change the association. Persons who had quit smoking 20 or more years before the eye examination had no increased risk.

CONCLUSIONS

The results provide evidence for a dose-response relationship between smoking and AMD, particularly in persons with the neovascular form of the disease.

Primary open-angle glaucoma, intraocular pressure, and diabetes mellitus in the general elderly population. The Rotterdam Study

PURPOSE

To investigate the association of primary open-angle glaucoma and intraocular pressure (IOP) with newly diagnosed diabetes mellitus.

METHODS

Subjects participating in the Rotterdam Study (n = 4178; ages, 55 years and older) were examined according to standard protocols, including a medical history interview, perimetry, applanation tonometry, funduscopy, and a nonfasting glucose tolerance test. Glaucoma was defined by the presence of a glaucomatous visual field defect. A distinction was made between high-tension glaucoma and normal-tension glaucoma. The relation of glaucoma and IOP with newly diagnosed diabetes mellitus and blood glucose was analyzed using regression analysis.

RESULTS

The presence of diabetes mellitus was associated with an overall rise in mean IOP of both eyes of 0.31 mmHg (95% confidence interval, 0.12-0.50), and with a threefold increased presence of high-tension glaucoma (odds ratio, 3.11; 95% confidence interval, 1.12-8.66). A 10-mmol/l higher random serum glucose level was borderline significantly associated with a mean IOP that was, on average, 0.41 mmHg (95% confidence interval, -0.02-0.84) higher and with an odds ratio of 2.82 (95% confidence interval, 0.92-8.58) for high-tension glaucoma. A 10-mmol/l rise in serum glucose on a glucose tolerance test was associated with an overall rise of mean IOP of 0.59 mmHg (95% confidence interval, 0.26-0.92) and with an odds ratio of 1.88 (95% confidence interval, 0.81-4.32) for high-tension glaucoma.

CONCLUSION

Newly diagnosed diabetes mellitus and high levels of blood glucose are associated with elevated IOP and high-tension glaucoma.

Age-related macular degeneration is associated with atherosclerosis. The Rotterdam Study

Age-related macular degeneration is the most frequent cause of blindness in the elderly. A vascular basis of the disease has been suggested, but not confirmed. The association between atherosclerosis and this type of macular degeneration was investigated in 104 subjects with and 1,324 subjects without macular degeneration as part of the population-based Rotterdam Study. The study was performed between March 1990 and July 1993 in a suburb of Rotterdam, the Netherlands. Macular degeneration was assessed on fundus photographs. Carotid atherosclerosis was ultrasonographically evaluated by measurement of the common carotid intima-media thickness and by assessment of the presence of atherosclerotic plaques. Atherosclerosis in arteries of the lower extremities was studied by determination of the ankle-arm systolic blood pressure ratio. In subjects younger than age 85 years, plaques in the carotid bifurcation were associated with a 4.7 times increased prevalence odds of macular degeneration (95% confidence interval (CI) 1.8-12.2); those with plaques in the common carotid artery showed an increased prevalence odds of 2.5 (95% CI 1.4-4.5). The intima-media thickness of the common carotid arteries was not significantly different. Lower extremity arterial disease (ankle-arm index less than 0.90 on at least one side) was associated with a 2.5 times increased prevalence odds (95% CI 1.4-4.5). These findings suggest that atherosclerosis may be involved in the etiology of age-related macular degeneration.

The prevalence of age-related maculopathy in the Rotterdam Study

PURPOSE

To determine the prevalence of age-related maculopathy in an elderly population in The Netherlands.

METHODS

Fundus photographs of 6251 participants of the Rotterdam Study, a single-center prospective follow-up study in persons 55 to 98 years of age, were reviewed for the presence of drusen, pigmentary abnormalities, and atrophic or neovascular age-related macular degeneration.

RESULTS

The prevalence of at least one drusen of 63 microns or larger increased from 40.8% in persons 55 to 64 years of age to 52.6% in those 85 years of age or older. Similarly, the prevalence of the following abnormalities increased significantly in these age categories: drusen of 125 microns or larger from 4.8% to 17.5%, retinal pigment epithelial hypopigmentations from 3.5% to 9.0%, and increased retinal pigment from 3.7% to 15.3%. Atrophic or neovascular age-related macular degeneration was present in 1.7% of the total population. Atrophic age-related macular degeneration increased from 0.1% in persons 55 to 64 years of age to 3.7% in those 85 years of age or older. Neovascular age-related macular degeneration increased from 0.1% to 7.4% in these age groups. No sex differences were observed for these lesions.

CONCLUSIONS

The prevalence of atrophic or neovascular age-related macular degeneration is 1.7%. In those 55 years of age or older, the prevalence increases strongly with age and it is similar in men and women. Neovascular age-related macular degeneration was twice as common as atrophic age-related macular degeneration. These findings suggest that age-related maculopathy may be less common in this European population than in similar populations in the United States.

Primary open-angle glaucoma, intraocular pressure, and systemic blood pressure in the general elderly population. The Rotterdam Study

PURPOSE

The purpose of this study is to investigate the association of primary open-angle glaucoma (POAG), intraocular pressure (IOP), and systemic blood pressure.

METHODS

Subjects participating in the Rotterdam Study (n = 4187, 55 years of age and older) were examined according to standard protocols, including a medical history interview, IOP measurement, perimetry, funduscopy, and blood pressure measurement. Primary open-angle glaucoma was defined by the presence of a glaucomatous visual field defect. Additionally, the distinction was made between high-tension glaucoma, defined as POAG with an IOP of more than 21 mmHg, and normal-tension glaucoma, defined as POAG with an IOP of 21 mmHg or less. The relation between blood pressure and hypertension with IOP, POAG, high-tension glaucoma, and normal-tension glaucoma was studied by means of regression analysis.

RESULTS

A systolic blood pressure or diastolic blood pressure that was 10 mmHg higher was associated with an IOP that was, on average, 0.23 mmHg (95% confidence interval [CI], 0.19-0.27) or 0.24 mmHg (95% CI, 0.16-0.32) higher, respectively. The presence of hypertension was associated with a higher mean IOP of 0.66 mmHg (95% CI, 0.39-0.93). A higher systolic blood pressure of 10 mmHg was associated with an odds ratio of 1.22 (95% CI, 1.03-1.46) for high-tension glaucoma and 0.90 (95% CI, 0.72-1.12) for normal-tension glaucoma. Hypertension was associated with an odds ratio of 2.33 (95% CI, 0.99-5.47) for high-tension glaucoma and 0.77 (95% CI, 0.22-2.72) for normal-tension glaucoma.

CONCLUSION

Systemic blood pressure and hypertension are associated with IOP and high-tension glaucoma. No association was found between blood pressure or hypertension and normal-tension glaucoma.

Retinopathy, glucose, and insulin in an elderly population. The Rotterdam Study

We studied the association between retinopathy and glucose metabolism in a population-based study of elderly men and women. Glucose metabolism was assessed by serum fructosamine and a nonfasting oral glucose tolerance test, and retinopathy was evaluated by fundus photography. Retinopathy was present in 296 of 6,191 subjects examined (4.8%; 120 men and 176 women). Serum glucose and fructosamine levels were higher in subjects with retinopathy compared with those without (8.4 vs. 6.8 mmol/l and 329.8 vs. 308.5 mumol/l, respectively, P < 0.001). Two-hour postload insulin levels and insulin resistance, assessed by the ratio of postload insulin over postload glucose level, did not differ between the two groups. These associations were similar in men and women and in subjects with and without diabetes and did not change after adjustment for body mass index or systolic blood pressure. Within the group of subjects who had retinopathy, serum glucose was significantly associated with the number of hemorrhages. These findings suggest that the presence and severity of retinopathy are associated with higher serum glucose levels, both in subjects with and without diabetes.

The prevalence of primary open-angle glaucoma in a population-based study in The Netherlands. The Rotterdam Study

PURPOSE

The objective of this study is to assess the prevalence of primary open-angle glaucoma (POAG) in a defined population in Rotterdam, The Netherlands.

METHODS

The Rotterdam Study is a single-center prospective cohort study of a total population of more than 10,000 people, 55 years of age or older. For the current analysis, the first 3062 consecutive, unselected, noninstitutionalized participants were examined according to standard protocols, including perimetry. The diagnosis of POAG was based on the presence of a glaucomatous visual field defect combined with either a vertical cup: disc ratio of 0.5 or more or a cup:disc ratio asymmetry of 0.2 or more, or an intraocular pressure (IOP) more than 21 mmHg, with open and normal anterior chamber angles.

RESULTS

The overall prevalence of POAG in the current study was 1.10% (95% confidence interval [CI]: 1.09, 1.11). Age-specific prevalence figures increased from 0.2% (95% CI: 0.16, 0.24) in the age group of 55 to 59 years to 3.3% (95% CI: 2.57, 4.04) in the age group of 85 to 89 years. Men had a more than three times higher risk of having POAG than women (odds ratio, 3.6). In 52.9% of the patients, POAG had not been diagnosed previously. Of these patients, 38.9% had IOPs of 21 mmHg or lower. In 8.8% of the eyes (2.9% of patients), visual acuity was 20/200 or less due to POAG.

CONCLUSION

The overall prevalence of POAG in the current study was 1.1%. The prevalence of POAG was higher in men than in women. Of the untreated patients, 38.9% had IOPs of 21 mmHg or lower.

Reliability of intraocular pressure measurement with the Goldmann applanation tonometer in epidemiological studies

The reproducibility of intraocular pressure (IOP) measurement with the Goldmann applanation tonometer was investigated as part of a population-based epidemiological study. Sixty-two subjects were examined in a first measurement session. The IOP was measured three times consecutively in both eyes according to a fixed protocol. The mean standard deviation (SD) of these measurements was 0.8 mmHg. The mean intraobserver variation for the first measurement was 1.64 (SD 2.07) mmHg. For the median of the three measurements the intra-observer variation was 1.50 (SD 1.96) mmHg. The mean inter-observer values were 1.79 (SD 2.41) mmHg for the first measurement and 1.60 (SD 2.15) mmHg for the median measurement. The correlation coefficient between the median values of the three measurements of both observers was 0.81. No systematic differences were found between the two observers. Using the median value of three consecutive measurements reduced the inter-observer variation by 11% and the intra-observer variation by 9% compared with a single measurement.