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

Associations of inner retinal layers with risk of incident dementia: An individual participant data analysis of four prospective cohort studies

INTRODUCTION

Our main objective was to investigate whether retinal neurodegeneration, estimated from lower thickness of inner retinal layers, was associated with incident all-cause dementia and Alzheimer's disease (AD).

METHODS

We performed an individual participant data meta-analysis using unpublished data from four prospective cohort studies with a total of 69,955 participants (n = 1087 cases of incident all-cause dementia; n = 520 cases incident AD; follow-up time median [interquartile range] 11.3 [8.8-11.5] years).

RESULTS

General baseline characteristics of the study population were mean (standard deviation) age, 58.1 (8.8) years; 47% women. After adjustment, lower baseline macular retinal nerve fiber layer thickness was significantly associated with a 10% and 11% higher incidence of all-cause dementia and AD, respectively. Lower baseline macular ganglion cell-inner plexiform layer thickness was not significantly associated with these outcomes.

DISCUSSION

These findings suggest that retinal neurodegeneration precedes the onset of clinical dementia. Retinal imaging tools may be informative biomarkers for the study of the early pathophysiology of dementia.

Intraocular Inflammation in Eyes Operated for Late In-the-bag intraOcular lens dislocatioN (LION): A Randomized Clinical Trial

PURPOSE

To compare the intraocular inflammation after 2 surgical approaches for late in-the-bag intraocular lens (IOL) dislocation.

DESIGN

Prospective, randomized, parallel-group clinical trial.

METHODS

We randomly assigned 100 patients (100 eyes) referred to Oslo University Hospital (tertiary referral center) with late in-the-bag IOL dislocation into IOL repositioning by scleral suturing (n=49) or IOL exchange with retropupillary fixation of an iris-claw lens (n=51). Patients were examined before surgery and 2 weeks, 6 weeks, and 6 months after surgery. The main outcome measure was anterior chamber laser flare, measured with a laser flare meter as photon counts per millisecond (pc/ms).

RESULTS

Two weeks following surgery, median flare values were 28.9 pc/ms (range, 7.9-140) in the repositioning group and 31.6 pc/ms (range, 9.8-92.3) in the exchange group (P = .83). Flare levels were still elevated after 6 weeks with no difference between the groups (P = .93), whereas it decreased to baseline levels after 6 months. Six weeks following surgery, the central retinal thickness was similar (P = .97); cystoid macular edema (CME) was found in 4 and 5 patients, respectively (P = .85); and the mean best corrected visual acuity was 0.17 (95% CI 0.09, 0.25) and 0.21 (95% CI 0.09, 0.32) logarithm of the minimum angle of resolution, respectively (P = .61).

CONCLUSIONS

This study revealed similar levels of intraocular inflammation following IOL repositioning and IOL exchange. There was no significant difference regarding risk of CME and visual outcome. The prolonged elevation in postoperative flare indicates a possible requirement for an extended anti-inflammatory treatment period after these operations.

Late in-the-bag intraocular lens dislocation

This review aimed to evaluate the cumulative incidence, patient characteristics, predisposing conditions, and treatment outcomes for late in-the-bag intraocular lens (IOL) dislocation. Literature searches in PubMed (MEDLINE), Embase, and Cochrane Library Central database identified 1 randomized clinical trial, 1 prospective case series, 2 prospective cohort studies, and 36 retrospective studies of this condition, which showed that the cumulative incidence was 0.5% to 3%, it occurred on average 6 to 12 years after cataract surgery, and mean patient age was 65 to 85 years. Pseudoexfoliation syndrome, myopia, and previous vitreoretinal surgery were the most common predisposing conditions. Studies indicated that IOL repositioning and IOL exchange provided similar visual outcomes and were equally safe. The long-term visual outcome seemed satisfactory. However, the quality of evidence regarding treatment was in general quite low. More studies of late in-the-bag IOL dislocation are needed, and in particular, different surgical techniques should be included in high-quality clinical trials.

Lhasa childhood eye study: the rationale, methodology, and baseline data of a 5 year follow-up of school-based cohort study in the Tibetan plateau region of Southwest China

Background

Tibetan Plateau is a highland area with special geographical location, time zone, and ethnic composition. We herein report the rationale, methodology and baseline data of the school-based childhood cohort study named Lhasa Childhood Eye Study (LCES), with the primary objective to pursue a comprehensive understanding on the longitudinal trends of refractive error as well as other ocular diseases and to address the differences between Tibetan Plateau and other parts of the world.

Methods

Grade one students from primary schools in Lhasa were cluster randomly selected. They were examined and would be conducted with follow-up annually for 5 years. The examination procedures for LCES consisted of standardized ocular, systematic examinations, and questionnaires, identical to the Anyang Childhood Eye Study (ACES) conducted in central China.

Results

One thousand nine hundred two Grade one students eligible for the LCES, 1856 (97.58%) participated in the study, with a mean age of 6.83 ± 0.46 years (range 5.89–10.32 years), and the proportions of male to be 53.02%. 1762 (94.93%) of the 1856 participants in the baseline exam were Tibetans. 1837 (98.98%) of the students examined had cycloplegic autorefraction performed. The numbers of hyperopia, emmetropia, myopia, and high myopia were 127 (6.91%), 1639 (89.22%), 71 (3.86%) and 3 (0.16%) respectively. Compared with ACES, students from LCES baseline had a younger age (p < 0.001), lower cycloplegic spherical equivalent (p < 0.001), similar myopia prevalence (p = 0.886), lower hyperopia prevalence (p < 0.001), and a higher emmetropia prevalence (p < 0.001).

Conclusions

LCES was a school-based cohort study in Tibetan Plateau with a high baseline response rate. A higher emmetropic trend was found in LCES compared with ACES. Continuous documentation of this cohort might potentially provide useful reference information for the areas of China which was previously not well studied.

Trial registration

The study has finished the clinical registration on Chinese Clinical Trial Registry. (ChiCTR1900026693).

Effect of age and refractive error on quick contrast sensitivity function in Chinese adults: a pilot study

PURPOSE

To evaluate the potential effect of age and refractive error on visual acuity (VA) performance and quick contrast sensitivity function (qCSF) in normal Chinese adults.

METHOD

Ninety-two subjects with normal best corrected distance VA (BCDVA) were enrolled in this pilot study. Measurements included BCDVA, best corrected near VA (BCNVA), unaided VA (UNVA), habitual spectacle-corrected near VA (SCNVA) and qCSF. For analyses, subjects were categorized into three age groups (20~40 years, 41~60 year and >60 years) and four refractive groups (hyperopia, emmetropia, myopia and high myopia). Relationships between age, refractive error, types of VA and qCSF were tested using simple and multiple linear regressions analyses.

RESULT

Mean age and refractive error of the study participants were 44.04 ± 12.68 years and -1.86 ± 2.91D, respectively. Among the stratified age groups, a hyperopic shift of refraction (-3.24 ± 2.88D vs. -1.24 ± 2.64D vs. 0.39 ± 1.42D, respectively; P < 0.001) and a reduction in BCNVA (P = 0.014), SCNVA (P < 0.001) and cut-off spatial frequency (SF) (P = 0.032) were found with increasing age. Among the four refractive groups, the SCNVA and cut-off SF of hyperopia were worse compared to the other refractive statuses (all P < 0.05). Age was significantly associated with cut-off SF (standardized β = -0.29, P = 0.005) after adjustment for SER, gender and all types of VA.

CONCLUSION

For normal Chinese adults with normal BCDVA, age was the main factor associated with CSF, which may be independent of refractive error.

Long-Term Outcomes after Surgery for Late In-The-Bag Intraocular Lens Dislocation: A Randomized Clinical Trial

PURPOSE

To compare the long-term efficacy and safety of 2 operation methods for late in-the-bag intraocular lens (IOL) dislocation.

DESIGN

Prospective, randomized, parallel group surgical clinical trial.

METHODS

During a 3-year period, 104 patients (104 eyes) were assigned one group for IOL repositioning by scleral suturing (n = 54) or one group for IOL exchange by retropupillary fixation of an iris claw IOL (n = 50). A single surgeon performed all operations using an anterior approach. Patients were examined before surgery and at 6 months and 1 and 2 years after surgery. The present study included the 66 patients (63%) who completed the 2-year follow-up, and the main outcaome measurement was corrected distance visual acuity (CDVA) 2 years after surgery.

RESULTS

After 2 years, the mean CDVA was 0.20 ± 0.29 logarithm of the minimum angle of resolution (logMAR) units (range, -0.18 to 1.10) in the repositioning group and 0.22 ± 0.30 logMAR (range, -0.10 to 1.22) in the exchange group (P = .69). A CDVA of 20/40 or better was achieved by 76% of all patients. Four eyes (12%) had cystoid macular edema in the repositioning group compared with 5 eyes (15%) in the exchange group. Two eyes underwent redislocation (1 in each group). There were no cases of endophthalmitis or retinal detachment.

CONCLUSIONS

There were no significant differences between the visual acuity using IOL repositioning and that using IOL exchange 2 years after surgery. The two methods were equally efficient and safe from a long-term perspective and are both considered acceptable treatments.

Evaluating refraction and visual acuity with the Nidek autorefractometer AR-360A in a randomized population-based screening study

PURPOSE

The evaluation of visual acuity (VA) and refraction in the Northern Finland Birth Cohort Eye study was performed using the Nidek AR-360A autorefractometer. The accuracy of the method for this population-based screening study was assessed.

METHODS

Measurements of the refractive error were obtained from the right eyes of 1238 subjects (mean age 47), first objectively with the AR-360A and then subjectively by an optometrist. Agreement with the subjective refraction was calculated for sphere, cylinder, mean spherical equivalent (MSE), cylindrical vectors J₄₅ and J₀ and presbyopic correction (add). Visual acuity (VA) was measured using an ETDRS chart and the autorefractometer.

RESULTS

The refractive error measured with the AR-360A was higher than the subjective refraction performed by the optometrist for sphere (0.007 D ± 0.24 D p = 0.30) and also for cylinder (-0.16 D ± 0.20 D p < 0.0005). The bias between the measurements of MSE, J₄₅ and J₀ was low: -0.07 D ± 0.22 D (p = 0.002), 0.01 D ± 0.43 D (p = 0.25) and -0.01 D ± 0.42 D (p = 0.43), respectively. The amount of add measured by the autorefractometer was higher than the subjective 0.35 D ± 0.29 D (p < 0.0005). There was a statistically significant correlation between VA (p < 0.0005) and the difference between the subjective and objective refraction. In 99.2% of the measurements, visual values were within one decimal line of each other.

CONCLUSION

The Nidek AR-360A autorefractometer is an accurate tool for determining the refraction and VA in a clinical screening trial.

The Decreasing Prevalence of Nonrefractive Visual Impairment in Older Europeans: A Meta-analysis of Published and Unpublished Data

TOPIC

To estimate the prevalence of nonrefractive visual impairment and blindness in European persons 55 years of age and older.

CLINICAL RELEVANCE

Few visual impairment and blindness prevalence estimates are available for the European population. In addition, many of the data collected in European population-based studies currently are unpublished and have not been included in previous estimates.

METHODS

Fourteen European population-based studies participating in the European Eye Epidemiology Consortium (n = 70 723) were included. Each study provided nonrefractive visual impairment and blindness prevalence estimates stratified by age (10-year strata) and gender. Nonrefractive visual impairment and blindness were defined as best-corrected visual acuity worse than 20/60 and 20/400 in the better eye, respectively. Using random effects meta-analysis, prevalence rates were estimated according to age, gender, geographical area, and period (1991-2006 and 2007-2012). Because no data were available for Central and Eastern Europe, population projections for numbers of affected people were estimated using Eurostat population estimates for European high-income countries in 2000 and 2010.

RESULTS

The age-standardized prevalence of nonrefractive visual impairment in people 55 years of age or older decreased from 2.22% (95% confidence interval [CI], 1.34-3.10) from 1991 through 2006 to 0.92% (95% CI, 0.42-1.42) from 2007 through 2012. It strongly increased with age in both periods (up to 15.69% and 4.39% in participants 85 years of age or older from 1991 through 2006 and from 2007 through 2012, respectively). Age-standardized prevalence of visual impairment tended to be higher in women than men from 1991 through 2006 (2.67% vs. 1.88%), but not from 2007 through 2012 (0.87% vs. 0.88%). No differences were observed between northern, western, and southern regions of Europe. The projected numbers of affected older inhabitants in European high-income countries decreased from 2.5 million affected individuals in 2000 to 1.2 million in 2010. Of those, 584 000 were blind in 2000, in comparison with 170 000 who were blind in 2010.

CONCLUSIONS

Despite the increase in the European older population, our study indicated that the number of visually impaired people has decreased in European high-income countries in the last 20 years. This may be the result of major improvements in eye care and prevention, the decreasing prevalence of eye diseases, or both.

Macular thickness in healthy eyes of adults (N = 4508) and relation to sex, age and refraction: the Tromsø Eye Study (2007-2008)

Purpose

To provide sex‐stratified normative data on retinal thickness and study the relationship with sex, age and refractive status.

Methods

Population‐based study including 2617 women and 1891 men, aged 38–87 (mean 61 ± 8) years, without diabetes, glaucoma and retinal diseases, and spherical equivalent refraction (SER) within ±6 dioptres. Retinal thickness was measured with optical coherence tomography (spectral domain Cirrus HD‐OCT).

Results

Women had thinner retina than men. Retinal thickness was significantly associated with refraction, where mean change in retinal thickness per 1 D increase in SER was −1.3 (0.2) μm in the fovea, 0.7 (0.1) μm in the pericentral ring and 1.4 (0.1) μm in the peripheral ring. In the fovea, there was a non‐monotonic curved relationship between retinal thickness and age in both sexes with a maximum at about 60 years (p < 0.001). In the pericentral ring, the mean reduction in retinal thickness per 10‐year increase was 2.7 (0.3) μm in women and 4.0 (0.4) μm in men and corresponding results in the peripheral ring were 2.3 (0.3) μm in women and 2.6 (0.4) μm in men. In both regions, there was evidence for a nonlinear pattern with an increased rate of change with higher age. There was a significant interaction between sex and age for retinal thickness of the pericentral ring (p = 0.041).

Conclusion

Women had thinner retina than men, and thickness varied with refractive status. Retinal thickness was associated with age in all macular regions, and the rate of change in retinal thickness varied at different ages.

Biometry and visual function of a healthy cohort in Leipzig, Germany

Background

Cross-sectional survey of ocular biometry and visual function in healthy eyes across the life span of a German population aged 20 to 69 years (n = 218). Subject number in percent per age category reflected the percentage within the respective age band of the population of Leipzig, Germany.

Methods

Measurements obtained: subjective and objective refraction, best-corrected visual acuity, accommodation, contrast sensitivity, topography and pachymetry with Scheimpflug camera, axial length with non-contact partial coherence interferometry, and spectral-domain optical coherence tomography of the retina. Pearson correlation coefficients with corresponding p-values were given to present interrelationships between stature, biometric and refractive parameters or their associations with age. Two-sample T-tests were used to calculate gender differences. The area under the logarithmic contrast sensitivity function (AULCSF) was calculated for the analysis of contrast sensitivity as a single figure across a range of spatial frequencies.

Results

The results of axial length (AL), anterior chamber depth (ACD) and anterior chamber volume (ACV) differed as a function of the age of the participants (rho (p value): AL −0.19 (0.006), ACD −0.56 (< 0.001), ACV-0.52 (< 0.001)). Longer eyes had deeper ACD (AL:ACD 0.62 (< 0.001), greater ACV (AL:ACV 0.65 (< 0.001) and steeper corneal radii (AL:R1ant; R2ant; R1post; R2post 0.40; 0.35; 0.36; 0.36 (all with (< 0.001)). Spherical equivalent was associated with age (towards hyperopia: 0.34 (< 0.001)), AL (−0.66 (< 0.001)), ACD (−0.52 (< 0.001)) and ACV (−0.46 (< 0.001)). Accommodation was found lower for older subjects (negative association with age, r = −0.82 (< 0.001)) and contrast sensitivity presented with smaller values for older ages (AULCSF −0.38, (< 0.001)), no change of retinal thickness with age. 58 % of the study cohort presented with a change of refractive correction above ±0.50 D in one or both eyes (64 % of these were habitual spectacle wearers), need for improvement was present in the young age-group and for older subjects with increasing age.

Conclusion

Biometrical data of healthy German eyes, stratified by age, gender and refractive status, enabled cross-comparison of all parameters, providing an important reference database for future patient-based research and specific in-depth investigations of biometric data in epidemiological research.

Trial registration

ClinicalTrials.gov # NCT01173614 July 28, 2010

Danish Rural Eye Study: Epidemiology of Adult Visual Impairment

PURPOSE

To examine the frequency and causes of visual impairment (VI) in a select population of Danish adults.

METHODS

A total of 3843 adults aged 20-94 years from the Danish General Suburban Population Study (GESUS) were included in the population-based, cross-sectional ophthalmological study, Danish Rural Eye Study (DRES). All DRES participants received a comprehensive general health examination preceding their eye examination, including measurement of best-corrected visual acuity (BCVA) for each eye, bilateral 45° retinal fundus photographs and further ophthalmological examination where indicated.

RESULTS

Overall, 3826 of 3843 participants (99.6%) had bilateral visual acuity measurements. The overall frequency of VI (BCVA <20/40 in the better-seeing eye) was 0.4% (95% confidence interval, CI, 0.2-0.7%; n = 15) among all DRES participants, 0.6% (95% CI 0.3-1.0%; n = 15) among participants >50 years and 3.7% (95% CI 2.1-6.5%; n = 11) in participants >80 years. The primary causes of VI in the better-seeing eye were age-related macular degeneration (AMD) in 46.7% (7/15) and cataract in 26.7% (4/15). A total of 43.3% (n = 115) of participants >80 years were pseudophakic in one or both eyes. The frequency of diabetes (HbA1c ≥ 48 mmol/mol or self-reported diagnosis) was 5.9% (n = 227), including 1.3% (n = 51) newly diagnosed in the GESUS. Of participants determined to have VI due to exudative AMD, 50% had received anti-vascular endothelial growth factor (VEGF) treatment.

CONCLUSION

We report a relatively low frequency of VI among Danish adults over 59 years of age compared with that observed 10-15 years ago, which is both consistent with other recent Scandinavian studies and reflective of our relatively healthy and mobile population sample.

Estimated and Measured GFR Associate Differently with Retinal Vasculopathy in the General Population

BACKGROUND/AIMS

Estimated glomerular filtration rate (eGFR) is used extensively in epidemiological research. Validations of eGFR have demonstrated acceptable performance, but the dependence of creatinine and cystatin C on non-GFR factors could confound associations with disease. Few studies have investigated this issue in direct comparison with measured GFR (mGFR). We compared the associations between eGFR and mGFR and retinal vasculopathy, a marker of systemic microvasculopathy.

METHODS

Iohexol clearance and retinal photography were examined in the Renal Iohexol Clearance Survey in Tromsø 6, which consists of a representative sample of middle-aged persons from the general population. A total of 1,553 persons without self-reported kidney disease, cardiovascular disease or diabetes were investigated. Three eGFR equations based on creatinine and/or cystatin C from the Chronic Kidney Disease Epidemiology Collaboration were studied. Differences between eGFR and mGFR were analyzed with seemingly unrelated regression methods.

RESULTS

mGFR in the lowest quartile was associated with an increased multivariable-adjusted odds ratio of retinopathy (OR 1.86, 95% CI 1.16-2.97), but not with retinal artery or vein diameters. eGFR based on cystatin C (eGFRcys) was consistently biased relative to mGFR in its associations with retinal vessel diameters across different models. eGFR based on creatinine (eGFRcrea) and eGFR based on both creatinine and cystatin C were also biased in several of these models (p < 0.05). For retinopathy, the differences between the 3 eGFR and mGFR measurements were not statistically significant.

CONCLUSIONS

Low mGFR is associated with retinopathy in the general population. eGFR based on creatinine and/or cystatin C are not valid substitutes for mGFR in studies of the relationship between the retina and kidney function in healthy persons.

Cycloplegic refraction is the gold standard for epidemiological studies

Many studies on children have shown that lack of cycloplegia is associated with slight overestimation of myopia and marked errors in estimates of the prevalence of emmetropia and hyperopia. Non-cycloplegic refraction is particularly problematic for studies of associations with risk factors. The consensus around the importance of cycloplegia in children left undefined at what age, if any, cycloplegia became unnecessary. It was often implicitly assumed that cycloplegia is not necessary beyond childhood or early adulthood, and thus, the protocol for the classical studies of refraction in older adults did not include cycloplegia. Now that population studies of refractive error are beginning to fill the gap between schoolchildren and older adults, whether cycloplegia is required for measuring refractive error in this age range, needs to be defined. Data from the Tehran Eye Study show that, without cycloplegia, there are errors in the estimation of myopia, emmetropia and hyperopia in the age range 20-50, just as in children. Similar results have been reported in an analysis of data from the Beaver Dam Offspring Eye Study. If the only important outcome measure of a particular study is the prevalence of myopia, then cycloplegia may not be crucial in some cases. But, without cycloplegia, measurements of other refractive categories as well as spherical equivalent are unreliable. In summary, the current evidence suggests that cycloplegic refraction should be considered as the gold standard for epidemiological studies of refraction, not only in children, but in adults up to the age of 50.

Suitability of UK Biobank Retinal Images for Automatic Analysis of Morphometric Properties of the Vasculature

Purpose

To assess the suitability of retinal images held in the UK Biobank - the largest retinal data repository in a prospective population-based cohort - for computer assisted vascular morphometry, generating measures that are commonly investigated as candidate biomarkers of systemic disease.

Methods

Non-mydriatic fundus images from both eyes of 2,690 participants - people with a self-reported history of myocardial infarction (n=1,345) and a matched control group (n=1,345) - were analysed using VAMPIRE software. These images were drawn from those of 68,554 UK Biobank participants who underwent retinal imaging at recruitment. Four operators were trained in the use of the software to measure retinal vascular tortuosity and bifurcation geometry.

Results

Total operator time was approximately 360 hours (4 minutes per image). 2,252 (84%) of participants had at least one image of sufficient quality for the software to process, i.e. there was sufficient detection of retinal vessels in the image by the software to attempt the measurement of the target parameters. 1,604 (60%) of participants had an image of at least one eye that was adequately analysed by the software, i.e. the measurement protocol was successfully completed. Increasing age was associated with a reduced proportion of images that could be processed (p=0.0004) and analysed (p<0.0001). Cases exhibited more acute arteriolar branching angles (p=0.02) as well as lower arteriolar and venular tortuosity (p<0.0001).

Conclusions

A proportion of the retinal images in UK Biobank are of insufficient quality for automated analysis. However, the large size of the UK Biobank means that tens of thousands of images are available and suitable for computational analysis. Parametric information measured from the retinas of participants with suspected cardiovascular disease was significantly different to that measured from a matched control group.

The ophthalmic branch of the Gutenberg Health Study: study design, cohort profile and self-reported diseases

Purpose

This paper describes the study design, methodology, cohort profile and self-reported diseases in the ophthalmological branch of the Gutenberg Health Study (GHS).

Methods

The GHS is an ongoing, prospective, interdisciplinary, single-center, population-based cohort study in Germany. The main goals of the ophthalmological section are to assess the prevalence and incidence of ocular diseases and to explore risk factors, genetic determinants and associations with systemic diseases and conditions. The eye examination at baseline included a medical history, self-reported eye diseases, visual acuity, refractive errors, intraocular pressure, visual field, pachymetry, keratometry, fundus photography and tear sampling. The 5-year follow-up visit additionally encompassed optical coherence tomography, anterior segment imaging and optical biometry. The general examination included anthropometry; blood pressure measurement; carotid artery ultrasound; electrocardiogram; echocardiography; spirometry; cognitive tests; questionnaires; assessment of mental conditions; and DNA, RNA, blood and urine sampling.

Results

Of 15,010 participants (aged 35-74 years at the time of inclusion), ocular data are available for 14,700 subjects (97.9%). The mean visual acuity (standard deviation), mean spherical equivalent, median decimal visual acuity, and mean intraocular pressure were 0.08 (0.17) logMar, -0.42 (2.43) diopters, 0.9 and 14.24 (2.79) mm Hg, respectively. The frequencies of self-reported strabismus, glaucoma, surgery for retinal detachment and retinal vascular occlusions were 2.7%, 2.3%, 0.2% and 0.4%, respectively.

Conclusions

The GHS is the most extensive dataset of ophthalmic diseases and conditions and their risk factors in Germany and one of the largest cohorts worldwide. This dataset will provide new insight in the epidemiology of ophthalmic diseases and related medical specialties.

Cardiovascular risk factors associated with age-related macular degeneration: the Tromsø Study

PURPOSE

To examine associations between cardiovascular risk factors and age-related macular degeneration (AMD).

METHODS

A population-based, cross-sectional study of Caucasians aged 65-87 years was conducted in Norway in 2007/2008. Retinal photographs were graded for AMD. Multivariable logistic regression analyses were performed based on questionnaires addressing habits of smoking, alcohol consumption, physical activity, health and medication; and physical examination comprising anthropometric measurements, blood pressure and blood sampling. Cardiovascular disease status was obtained from a validated end-point registry.

RESULTS

Gradable photographs were available for 2631 participants, of whom 92 (3.5%) subjects had late AMD. In the multivariable analysis of late AMD, significant interactions were found between sex and the variables age, triglyceride level, use of lipid-lowering drugs and physical exercise. Current daily smoking was significantly related to late AMD in both sexes (odds ratio (OR) 4.06, 95% confidence interval (CI) 1.69-9.76 and OR 3.59, 95% CI 1.17-11.04, women and men, respectively) compared with never smokers. Higher number of pack years was associated with the presence of large drusen (>125 μm) (OR 1.04, 95% CI 1.01-1.09 per 5 years). Higher systolic blood pressure (OR 1.06, 95% CI 1.01-1.12 per 5 mmHg), overweight (OR 2.87, 95% CI 1.13-7.29) and obesity (OR 2.92, 95% CI 1.06-8.03), physical exercise duration (OR 0.41, 95% 0.18-0.96 for 30 min or more compared with less) and frequency (OR 0.46, 95% CI 0.23-0.92 for weekly or more often compared to less) were associated with late AMD in women only.

CONCLUSIONS

Smoking was strongly associated with AMD, in line with results from other populations. Also, late AMD was related to higher systolic blood pressure, physical inactivity, overweight and obesity in women.

Retinal vascular calibre and response to light exposure and serial imaging

Purpose

To investigate whether retinal vessel calibre measurements on optical retinal photography are affected by light and dark exposure prior to photography and whether the vessel calibre changes during an imaging sequence of several images.

Methods

Digital optical retinal photographs were obtained from 32 healthy adults in two separate image sequences of six images during 1 min; one sequence with 10 min of dark exposure and one with 10 min of light exposure prior to imaging. Retinal arteriolar and venular calibres were measured computer-assisted and summarized as central retinal artery and vein equivalents (CRAE and CRVE). Outcome measures were difference in calibres after prior light versus prior dark exposure and difference in calibre during each of the two imaging sequences.

Results

CRVE was wider with prior light exposure (2.7%, p = 0.0001), comparing the first image in each image sequence. Within each sequence, there was a venular dilatation from first to last image, both with prior light exposure (1.7%, p = 0.0003) and prior dark exposure (3.1%, p < 0.0001), with the change less pronounced with prior light exposure (p = 0.0164). CRAE showed no significant change in either outcome.

Conclusions

Retinal venular calibre was wider with light exposure prior to imaging and increased slightly during the imaging sequences, less pronounced after prior light than dark exposure. Measurement error due to these effects will probably be reduced by avoiding dark prior to imaging, and a possible bias effect of endothelial dysfunction may possibly be reduced by measuring calibre on an image taken early in the image sequence.

Longitudinal increase in anisometropia in older adults

PURPOSE

Anisometropia shows an exponential increase in prevalence with increasing age based on cross-sectional studies. The purpose of this study was to evaluate longitudinal changes in anisometropia in all refractive components in older observers and to assess the influence of early cataract development.

METHODS

Refractive error was assessed at two time points separated by approximately 12 years in 118 older observers (aged 67.1 and 79.3 years at the two test times). Anisometropia defined as greater than or equal to 1.00 D was calculated for all refractive components. The subjects had intact ocular lenses in both eyes throughout the study. Lens evaluations were performed at the second test using the Lens Opacities Classification System III.

RESULTS

All refractive components approximately doubled in prevalence of anisometropia. Spherical equivalent anisometropia changed from 16.1 to 32.2%. Similar changes were found for spherical error (17 to 38.1%), primary astigmatism (7.6 to 17.8%), and oblique astigmatism (14.4 to 29.7%). Many who did not have anisometropia at the first visit subsequently developed anisometropia (e.g., 26.3% for spherical error and 22.9% for oblique cylinder). The onset of anisometropia occurred at all ages within the studied age range, with no particular preference for any one age. A small number lost anisometropia over time. Individual comparisons of refractive error changes in the two eyes in combination with nuclear lens changes showed that early changes in nuclear sclerosis in the two eyes could account for a large proportion of anisometropia (~40%), but unequal hyperopic shift in the spherical component in the two eyes was the primary cause of the anisometropia.

CONCLUSIONS

Anisometropia is at least 10 times more common in the elderly than in children, and anisometropia develops in all refractive components in the oldest observers. Clinicians need to be aware of this common condition that could lead to binocular vision problems and potentially cause falls in the elderly.

Cognitive function, drusen, and age-related macular degeneration: a cross-sectional study

PURPOSE

To examine the cross-sectional relationship between drusen, late age-related macular degeneration (AMD), and cognitive function. METHODS; We included 2149 stroke-free participants from the population-based Tromsø Study in Norway. Retinal photographs were graded for presence of drusen and AMD. Cognitive function was assessed using the verbal memory test (short verbal memory), digit-symbol coding test (processing speed), and the tapping test (psychomotor tempo). We assessed the relationship between drusen, late AMD, and cognitive test scores, adjusted for potential confounders.

RESULTS

Late AMD was associated with decreased performance in the verbal memory test (standardized β=-0.23, 95% confidence interval (CI): -0.51 to -0.01). Intermediate and large drusen were associated with decreased performance in the digit-symbol coding test (standardized β=-0.14 and -0.19, 95% CIs: -0.23 to -0.05 and -0.29 to -0.09, respectively). Participants with large drusen were more likely to have test scores in the lowest quartile of the digit-symbol coding test (odds ratio (OR)=1.9, 95% CI: 1.1-3.5) and the tapping test (OR=1.6, 95% CI: 1.0-2.6), but not in the verbal memory test (OR=1.0, 95% CI: 0.6-1.6).

CONCLUSIONS

The findings suggest a relationship between drusen deposition and reduced cognitive function. Although the relationships between drusen, late AMD, and the cognitive test results varied in strength and significance across the types of cognitive test, and may partly have been caused by residual confounding, it is not unlikely that a genuine but weaker relationship exists between drusen deposition and cognitive decline.