Assessment of conjunctival, episcleral and scleral thickness in healthy individuals using anterior segment optical coherence tomography

PURPOSE

To determine the thickness of the conjunctiva, episclera and sclera in healthy individuals using anterior segment optical coherence tomography (AS-OCT).

METHODS

We prospectively included 107 healthy individuals of different age groups (18-39 years, 40-54 years, 55-69 years and ≥70 years). For each eye, AS-OCT scans of four quadrants (temporal, nasal, superior and inferior) were acquired. The thickness of the conjunctiva, episclera and sclera was measured for each scan. In addition, the axial length of both eyes was measured, and general characteristics, including smoking, allergies and contact lens use, were collected.

RESULTS

The mean conjunctival thickness was significantly different between the nasal and superior quadrants (87 ± 30 μm vs. 77 ± 16 μm; p < 0.001), as well as the superior and inferior quadrants (77 ± 16 μm vs. 86 ± 19 μm; p = 0.001). The mean episcleral thickness was larger in the superior (174 ± 54 μm) and inferior (141 ± 43 μm) quadrants, compared to the nasal (83 ± 38 μm) and temporal quadrants (90 ± 44 μm). The mean scleral thickness of the inferior quadrant was the largest (596 ± 64 μm), followed by the nasal (567 ± 76 μm), temporal (516 ± 67 μm) and superior (467 ± 52 μm) quadrants (all p < 0.001). The averaged scleral thickness increased 0.96 μm per age year (0.41-1.47 μm, p < 0.001).

CONCLUSIONS

This study provides an assessment of the thickness of scleral and adjacent superficial layers in healthy individuals determined on AS-OCT, which could enable future research into the use of AS-OCT in diseases affecting the anterior eye wall.

Current insights in the pathogenesis of scleritis

Scleritis is a sight-threatening inflammation characterized by severe pain and redness of the eye. It can cause blindness by severe complications like scleral and corneal necrosis, keratitis, and uveitis. The pathogenesis of scleritis is largely unknown due to a combination of the rarity of the disease, the little available human tissue-based research material, and the lack of animal models. The immune system is assumed to play a crucial role in the pathogenesis of scleritis. Multiple clues indicate probable antigenic stimuli in scleritis, and the involvement of matrix metalloproteinases in the destruction of scleral tissue. In this article we review the current insights into the pathogenesis of scleritis, and we suggest new hypotheses by implementing knowledge of systemic autoimmune disease pathogenesis. Understanding the pathogenesis of scleritis is crucial to improve the clinical management, as well as to find novel treatment modalities.

Comparing the Effectiveness of Bevacizumab to Ranibizumab in Patients with Exudative Age-Related Macular Degeneration. The BRAMD Study

Purpose

To compare the effectiveness of bevacizumab and ranibizumab in the treatment of exudative age-related macular degeneration (AMD).

Design

Multicentre, randomized, controlled, double-masked clinical trial in 327 patients. The non-inferiority margin was 4 letters.

Patients

Patients ≥ 60 years of age with primary or recurrent sub- or juxtafoveal choroidal neovascularization (CNV) secondary to AMD with a total area of CNV < 12 disc areas and a best corrected visual acuity (BCVA) score between 20 and 78 letters on an EDTRS like chart in the study eye.

Methods

Monthly intravitreal injections with 1.25 mg bevacizumab or 0.5 mg ranibizumab were given during one year. Intention to treat with last observation carried forward analysis was performed.

Main Outcome Measures

Primary outcome was the change in BCVA in the study eye from baseline to 12 months.

Results

The mean gain in BCVA was 5.1 (±14.1) letters in the bevacizumab group (n = 161) and 6.4 (±12.2) letters in the ranibizumab group (n = 166) (p = 0.37). The lower limit of the 95% confidence interval of the difference in BCVA gain was 3.72. The response to bevacizumab was more varied; 24% of patients showed a gain of ≥15 letters, 11% a loss of ≥15 letters and 65% a gain or loss < 15 letters compared to 19%, 5% and 76% respectively for ranibizumab (p = 0.038). No significant differences in absolute CRT and CRT change (p = 0.13) or in the presence of subretinal or intraretinal fluid (p = 0.14 and 0.10, respectively) were observed. However, the presence of any fluid on SD-OCT (subretinal and/or intraretinal) differed significantly (p = 0.020), with definite fluid on SD-OCT in 45% of the patients for bevacizumab versus 31% for ranibizumab. The occurrence of serious adverse events and adverse events was similar, with 34 SAEs and 256 AEs in the bevacizumab group and 37 SAEs and 299 AEs in the ranibizumab group (p = 0.87 and p = 0.48, respectively).

Conclusions

Bevacizumab was not inferior to ranibizumab. The response to bevacizumab was more varied with higher percentages of both gainers and losers and more frequently observed retinal fluid on SD-OCT at 12 months when compared to the ranibizumab group.

Trial Registration

Trialregister.nl NTR1704

Comparing the effectiveness and costs of Bevacizumab to Ranibizumab in patients with Diabetic Macular Edema: a randomized clinical trial (the BRDME study)

Background

The effectiveness of ranibizumab in the treatment of diabetic macular edema has been proven with large clinical trials. For bevacizumab only two clinical trials have been published and a head-to-head comparison is lacking to date. However, if proved non-inferior to ranibizumab, use of the off-label bevacizumab could reduce costs enormously without a loss in visual acuity. A cost-effectiveness study has been designed to substantiate this hypothesis.

Aim

To compare the effectiveness and costs of 1.25 mg of bevacizumab to 0.5 mg ranibizumab given as monthly intravitreal injections during 6 months in patients with diabetic macular edema. It is hypothesized that bevacizumab is non-inferior to ranibizumab regarding its effectiveness.

Design

This is a randomized, controlled, double masked, clinical trial in 246 patients in seven academic trial centres in The Netherlands.

Outcomes

The primary outcome measure is the change in best-corrected visual acuity (BCVA) in the study eye from baseline to month 6. Secondary outcomes are the proportions of patients with a gain or loss of 15 letters or more or a BCVA of 20/40 or more at 6 months, the change in leakage on fluorescein angiography and the change in foveal thickness by optical coherence tomography at 6 months, the number of adverse events in 6 months, and the costs per quality adjusted life-year of the two treatments.

Retinal vascular caliber and metabolic syndrome in a Chinese population

BACKGROUND

Microvascular changes have been associated with the metabolic syndrome.

METHODS

We included 869 participants aged ≥ 40 years from the High-risk for Diabetes Changfeng Study, who had gradable fundus photographs. On digital photographs sum retinal arteriolar and venular calibers were measured with a semi-automated system. Metabolic syndrome was defined according to the International Diabetes Federation consensus.

RESULTS

A total of 286 (32.9%) participants was diagnosed with metabolic syndrome. Participants with narrower retinal arteriolar caliber were more often diagnosed with metabolic syndrome (odds ratio 1.78, 95% confidence interval 1.02 – 3.10; lowest vs highest quintile). Additionally adjusting for age, gender, education, smoking and weekly activity, and adding arteriolar and venular caliber simultaneously in the same models did not alter these associations. In the component analyses, participants with narrower retinal arteriolar caliber were more likely to have central obesity, dyslipidaemia or raised blood pressure, and less likely to have raised fasting plasma glucose. The association between wider venular caliber and metabolic syndrome was less pronounced and non-significant (odds ratio 1.34; 95% confidence interval 0.79 – 2.38; highest vs lowest quintile).

CONCLUSION

Retinal arteriolar narrowing and, to a lesser extent, retinal venular dilatation were associated with metabolic syndrome in this Chinese population. These vascular changes, although small in magnitude, may still be important in the pathophysiological mechanisms involved in the metabolic syndrome.

Retinal vascular caliber and risk of dementia: the Rotterdam study

BACKGROUND

Retinal vessels provide a unique opportunity to study both systemic and cerebrovascular disease. Smaller retinal arteriolar calibers are strongly related to hypertension, whereas larger retinal venular calibers are more related to inflammation, cerebral hypoperfusion, and cerebrovascular disease. Whether retinal vessel calibers are related to dementia remains unclear.

METHODS

We investigated whether retinal arteriolar and venular calibers are associated with risk of dementia, and its subtypes Alzheimer disease (AD) and vascular dementia, in the prospective population-based Rotterdam Study. Digitized retinal images were available in 5,553 participants aged 55 years or over and dementia-free at baseline (1990-1993). Participants were re-examined in 1993-1994, 1997-1999, and 2002-2004 and were continuously monitored for development of dementia.

RESULTS

During a mean follow-up of 11.6 years, 655 participants developed dementia. AD was diagnosed in 519 and vascular dementia in 73 participants. Larger venular calibers were associated with an increased risk of dementia, in particular vascular dementia (age- and sex-adjusted hazard ratio per SD increase: 1.31; 95% confidence interval 1.06-1.64), but not AD. The association remained significant after adjustment for stroke and cardiovascular risk factors. Smaller arteriolar calibers were also associated with an increased risk of vascular dementia, yet only when adjusted for venular calibers.

CONCLUSIONS

Retinal venular widening is associated with an increased risk of vascular dementia. Our findings are in line with previous observations in stroke and cerebral small-vessel disease and suggest that the association between larger retinal venular calibers and dementia may reflect cerebral hypoperfusion and subsequent ischemia.

Effects of blood pressure lowering and intensive glucose control on the incidence and progression of retinopathy in patients with type 2 diabetes mellitus: a randomised controlled trial

AIMS/HYPOTHESIS

The aim of the present study was to investigate the effect of blood pressure lowering and intensive glucose control on the incidence and progression of retinopathy in type 2 diabetic patients.

METHODS

The Action in Diabetes and Vascular Disease: Preterax and Diamicron MR Controlled Evaluation (ADVANCE) Retinal Measurements study, a substudy of ADVANCE, is a randomised (using a central, computer-based procedure) controlled 2 x 2 factorial trial comprising a double-blind comparison of blood pressure lowering with perindopril-indapamide vs placebo, and an open comparison of standard vs intensive glucose control targeting a HbA(1c) of < or = 6.5% in 1,602 diabetic patients from ADVANCE centres with access to retinal cameras conducted from 2001 to 2008. At baseline and the final visit, seven-field stereoscopic retinal photographs were taken and graded by blinded readers (gradeable baseline and final photographs from 1,241 patients). Progression of > or =2 steps in the Early Treatment of Diabetic Retinopathy Study classification (using the eye with worst grading) was the primary outcome.

RESULTS

Retinopathy progressed in 59 (4.8%) patients and developed in 128 (10.3%) patients over 4.1 years. Fewer patients on blood pressure-lowering treatment (n = 623) experienced incidence or progression of retinopathy compared with patients on placebo (n = 618), but the difference was not significant (OR 0.78; 95% CI 0.57-1.06; p = 0.12). Blood pressure-lowering treatment reduced the occurrence of macular oedema (OR 0.50; 95% CI 0.29-0.88; p = 0.016) and arteriovenous nicking compared with placebo (OR 0.60; 95% CI 0.38-0.94; p = 0.025). Compared with standard glucose control (n = 611), intensive glucose control (n = 630) did not reduce (p = 0.27) the incidence and progression of retinopathy (OR 0.84; 95% CI 0.61-1.15). Lower, borderline significant risks of microaneurysms, hard exudates and macular oedema were observed with intensive glucose control, adjusted for baseline retinal haemorrhages. These effects of the two treatments were independent and additive. Adverse events in the ADVANCE study are reported elsewhere.

CONCLUSIONS/INTERPRETATION

Blood pressure lowering or intensive glucose control did not significantly reduce the incidence and progression of retinopathy, although consistent trends towards a benefit were observed, with significant reductions in some lesions observed with both interventions.

TRIAL REGISTRATION

ClinicalTrials.gov ID no. NCT00145925.

FUNDING

Grants from Servier and the National Health and Medical Research Council of Australia.

Association of diabetes with age-related macular degeneration in the EUREYE study

OBJECTIVE

To examine the association between self-reported diabetes history and early or late age-related macular degeneration (AMD) in the European population.

METHODS

Participants aged 65 years and over in the cross-sectional population-based EUREYE study underwent an eye examination including digital retinal photography. The images were graded at a single centre. A structured questionnaire was administered by trained field workers for putative risk factors for AMD including history of diabetes mellitus. Logistic regression models were used to examine the association between diabetes and stages of AMD, taking account of potential demographic, behavioural, dietary and medical (history of cardiovascular disease) confounders.

MAIN OUTCOME MEASURES

Photographic images were graded according to the modified International Classification System for AMD and stratified into five exclusive stages from no signs of AMD (AMD stage 0), early AMD (Stages 1-3) and late AMD (Stage 4). Late AMD was subdivided in neovascular AMD (NV-AMD) or geographic atrophy (GA).

RESULTS

Data on diabetes history and potential confounders were available in 2117 control subjects without AMD, 2182 with early AMD, 49 with GA and 101 with NV-AMD. Of all participants, 13.1% reported a history of diabetes. After adjusting for potential confounders, subjects with neovascular AMD compared with controls had increased odds for diabetes (odds ratio 1.81; 95% confidence interval, 1.10 to 2.98, p = 0.02). Subjects with AMD grades 1 to 3 or GA had no increased odds for diabetes compared with those without AMD.

CONCLUSIONS

In the EUREYE study, after multiple adjustments, positive association of diabetes mellitus with neovascular AMD was found. The hypothesis that diabetes is associated with neovascular AMD but not with geographic atrophy may suggest a different pathogenesis of the two advanced forms of the disease and needs to be further evaluated.

Cigarette smoking and age-related macular degeneration in the EUREYE Study

OBJECTIVE

To examine the association between cigarette smoking and age-related maculopathy (ARM) including age-related macular degeneration (AMD) in the European population.

DESIGN

Cross-sectional study.

PARTICIPANTS

Four thousand seven hundred fifty randomly sampled > or =65-year-olds from 7 study centers across Europe (Norway, Estonia, United Kingdom, France, Italy, Greece, and Spain).

METHODS

Participants underwent an eye examination and digital retinal photography. The images were graded at a single center. Smoking history was ascertained by a structured questionnaire administered by trained fieldworkers. Multinomial and binary logistic regressions were used to examine the association between smoking history and ARM grade and type of AMD, taking account of potential confounders and the multicenter study design.

MAIN OUTCOME MEASURES

Photographic images were graded according to the International Classification System for ARM and stratified using the Rotterdam staging system into 5 exclusive stages (ARM 0-3 and ARM 4, also known as AMD). Age-related macular degeneration also was classified as neovascular AMD or geographic atrophy (GA).

RESULTS

One hundred fifty-eight cases were categorized as AMD (109 neovascular AMD and 49 GA); 2260 had no signs of ARM (ARM 0). Current smokers had increased odds of neovascular AMD (odds ratio [OR], 2.6; 95% confidence interval [CI], 1.4-4.8) or GA (OR, 4.8; 95% CI, 2.1-11.1), whereas for ex-smokers the odds were around 1.7. Compared with people with unilateral AMD, those with bilateral AMD were more likely to have a history of heavy smoking in the previous 25 years (OR, 5.1; 95% CI, 1.3-20.0). The attributable fraction for AMD due to smoking was 27% (95% CI, 19%-33%). There was no consistent association with ARM grades 1 to 3 and smoking.

CONCLUSIONS

These findings highlight the need for increasing public awareness of the risks associated with smoking and the benefit of quitting smoking. Patients with unilateral disease who are current smokers should be advised of the risk of second-eye disease.

Retinal vessel diameters and risk of stroke: The Rotterdam Study

BACKGROUND

Retinal vessels may provide information on cerebral vascular pathology, because they share many features with cerebral vessels. A smaller ratio of the retinal arteriolar-to-venular diameters reportedly predicts the risk of stroke. It is unclear if this is due to arteriolar narrowing or venular dilation.

OBJECTIVE

To investigate whether smaller arteriolar or larger venular diameters are related to the risk of stroke and cerebral infarction.

METHODS

This study was based on the prospective population-based Rotterdam Study and included 5,540 participants of 55 years or over, who had gradable fundus transparencies and were free of stroke at baseline (1990 to 1993). For each participant, retinal arteriolar and venular diameters were measured on digitized images of one eye. Follow-up for first-ever stroke was complete until January 1, 2002.

RESULTS

After a mean follow-up of 8.5 years, 411 participants had a stroke, of whom 259 had cerebral infarction. Larger venular diameters were associated with an increased risk of stroke (hazard ratio [HR] adjusted for age and sex per SD increase: 1.12 [95% CI: 1.02 to 1.24]) and cerebral infarction (HR: 1.15 [95% CI: 1.02 to 1.29]). Smaller arteriolar diameters were neither related to the risk of stroke (HR per SD decrease: 1.02 [95% CI: 0.93 to 1.13]) nor to the risk of cerebral infarction (HR: 1.02 [95% CI: 0.90 to 1.15]). After additional adjustment for other cardiovascular risk factors, the results did not change.

CONCLUSIONS

Larger retinal venular diameters are associated with an increased risk of stroke and cerebral infarction. The role of venules in cerebrovascular disease warrants further exploration.

Incidence and progression rates of age-related maculopathy: the Rotterdam Study

PURPOSE

To describe the incidence rate of age-related macular degeneration (AMD) and the progression rates of early stages of age-related maculopathy (ARM), and to study the hierarchy of fundus features that determine progression.

METHODS

A group of 4953 subjects aged 55 years and older living in Rotterdam, The Netherlands, was studied at baseline and at 2-year follow-up to determine the incidence of neovascular and atrophic AMD. A subgroup of 1244 subjects was studied for progression of early stages of ARM. Fundus transparencies were graded for features of ARM using the International Classification System. ARM was stratified in four exclusive stages, according to type of drusen and presence of pigmentary irregularities.

RESULTS

The overall 2-year cumulative incidence of AMD was 0.2%, increasing to 1.8% in subjects of 85 years and older. Of those in the early stages, one fourth showed progression to a more severe stage. The most important predictors for progression were more than 10% of macular area covered by drusen (odds ratio [OR] 5.7, 95% confidence interval [CI] 2.9-11.3), presence of depigmentation (OR 4.0, 95% CI 2.5-6.4), and hyperpigmentation (OR 3.4, 95% CI 2.1-5.4).

CONCLUSIONS

The incidence of AMD appears to be lower in The Netherlands than in the United States. Progression of early ARM stages occurs in a distinct pattern at a stable rate, with a large area of drusen and presence of pigmentary changes as the most important predictors.

Is open-angle glaucoma associated with early menopause? The Rotterdam Study

The authors examined the association between age at menopause and open-angle glaucoma among women aged > or = 55 years in the population-based Rotterdam Study (1990--1993). Information on age and type of menopause was obtained by interview. Subjects (n = 3,078) were stratified into three categories according to age at menopause: <45 years, 45--49 years, and > or = 50 years, with the last group serving as the reference group. Diagnosis of open-angle glaucoma was based on the presence of a glaucomatous visual field defect and glaucomatous optic neuropathy. Open-angle glaucoma was diagnosed in 78 women with a natural menopause and 15 women with an artificial menopause. In the category of natural menopause, women who went through menopause before reaching the age of 45 years had a higher risk of open-angle glaucoma than the reference group (odds ratio = 2.6; 95% confidence interval: 1.5, 4.8), after adjustment for age and use of hormone replacement therapy. Among women who went through menopause between the ages of 45 and 49 years, the odds ratio was 1.1 (95% confidence interval: 0.7, 2.0). These findings suggest that early menopause is associated with a higher risk of open-angle glaucoma.

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.