Self-reported vs state-recorded motor vehicle collisions among older community dwelling individuals.

INTRODUCTION: Motor vehicle collisions (MVCs) continue to place an increased burden on both individuals and health care systems. Self-reported and state-recorded police reports are the most common methods for MVC evaluation in epidemiologic studies, with varying degrees of agreement of information when compared in previous studies. The objective of the current study is to address the differences in MVC reporting and provide a more robust measure of the agreement between self-reported and state-recorded MVCs in a community dwelling population of older adults. METHODS: A three-year prospective study was conducted in a population-based sample of 2000 licensed drivers aged 70 and older. At annual visits, participants were asked to self-report information on any MVC that occurred over the prior year where police were called to the scene. Information on police-reported MVCs was also ascertained from Alabama official state-recorded databases. The kappa coefficient was calculated to determine overall agreement between any self-reported and state-recorded crashes, as well as the raw number of crashes reported. In addition, agreement was stratified by demographics, health status, medication use, functional status (i.e. vision, cognition), and driving habits. RESULTS: 1747 participants who completed three years of follow up were involved in 225 state-recorded MVCs and 208 self-reported MVCs yielding overall substantial agreement between any self-report and state-recorded MVC (kappa=0.64). Cumulative number of self-reported and state-recorded MVCs was also compared, with agreement slightly reduced (kappa=0.55). The clinical characteristic resulting in the greatest variation in agreement with drivers was impaired contrast sensitivity showing better agreement between self-reported and state-recorded MVCs (kappa=0.9) than those with non-impaired contrast sensitivity (kappa=0.6). CONCLUSION: Study results showed substantial agreement between self-reported and state-recorded MVCs for any MVC involvement among the study population. When examining the reporting of the total number of MVCs over the three year period, agreement was reduced to a moderate level. There was consistency in agreement across MVC risk factors except among individuals with contrast sensitivity. These findings have implications for the design and analytic planning of epidemiologic and clinical research focused on MVCs.

Health-related quality of life and visual and cognitive impairment among nursing-home residents.

AIM: To examine whether the relationship between vision impairment and health-related quality of life (HRQoL) in nursing-home residents is impacted by coexisting cognitive impairment. METHODS: This cross-sectional study involved a total of 382 English-speaking older adults (>55 years of age) with > or =13 on the Mini Mental State Exam (MMSE) from seventeen nursing homes in Birmingham, Alabama. Assessments were taken of visual acuity (Lighthouse Near Visual Acuity Test), cognition (MMSE) and health-related quality of life (Nursing Home Vision-Targeted Health-Related Quality of Life Questionnaire, VF-14, and the SF-36). RESULTS: A greater portion of participants had both vision and cognitive impairments (38.5%) as compared with those with neither impairment (21.5%), vision impairment alone (13.4%), and cognitive impairment alone (26.7%). Cognitive impairment did not modify the impact of vision impairment on HRQoL. The reduction in HRQoL associated with vision impairment was similar for those with and without cognitive impairment. CONCLUSION: The deleterious impact of vision impairment on HRQoL in nursing-home residents was not exacerbated by the co-occurrence of cognitive impairment. Ageing-related visual impairment in nursing-home residents is often reversible through treatment leading to improved HRQoL, and thus it is clinically important to know that cognitive impairment is unlikely to interfere with this benefit.

Visual and medical risk factors for motor vehicle collision involvement among older drivers.

AIMS: To identify visual and medical risk factors for motor vehicle collisions (MVCs). METHODS: Data from four cohorts of older drivers from three states were pooled (n = 3158). Health information was collected at baseline, and MVC data were obtained prospectively. Cox proportional hazards regression was used to estimate rate ratios (RRs) and 95% CIs for associations between medical characteristics and MVCs. RESULTS: A total of 363 MVCs were observed during the study period (1990-1997), of which 145 were at fault, and 62 were injurious. Falls and impaired useful field of view (UFOV) were positively associated with overall MVCs. At-fault MVCs were also positively associated with falls and UFOV impairment, and inversely with cancer. Injurious MVCs were positively associated with arthritis and neurological disease, and inversely with hypertension. CONCLUSIONS: These findings show similarities and differences across the risk factors for all, at-fault and injurious MVCs, and point to the need for verification and possible interventions.

The association between thyroid problems and glaucoma.

AIMS: To evaluate the association between thyroid problems and glaucoma. METHODS: A population-based cross-sectional sample with 12,376 participants from the 2002 National Health Interview Survey. Odds ratios (OR) and 95% confidence intervals (CIs) were used to quantify the association between a self-reported diagnosis of glaucoma and a self-reported history of thyroid problems, controlling for demographic characteristics and smoking status. RESULTS: The overall prevalence of glaucoma was 4.6%; 11.9% reported a history of thyroid problems. The prevalence of glaucoma among those who did and did not report thyroid problems was 6.5% and 4.4%, respectively (p = 0.0003). Following adjustment for differences in age, gender, race and smoking status, the association between glaucoma and thyroid problems remained (OR 1.38, 95% CI 1.08 to 1.76). CONCLUSIONS: The results of this study lend support to the hypothesis that thyroid disorders may increase the risk of glaucoma. Research should continue evaluating potential mechanisms underlying this relationship and whether the treatment of thyroid problems reduces subsequent glaucoma risk.

Development of a nursing home vision-targeted health-related quality of life questionnaire for older adults.

PURPOSE: To develop a questionnaire assessing vision-targeted health-related quality of life in older adults residing in nursing homes. METHODS: Using content previously identified through structured interviews with nursing home residents, the 57-item Nursing Home Vision-Targeted Health-Related Quality of Life questionnaire (NHVQoL) was drafted with nine subscales - general vision, reading, ocular symptoms, mobility, psychological distress, activities of daily living, activities/hobbies, adaptation/coping and social interaction. Construct validity and internal consistency and test-retest reliability of subscales were evaluated in a sample of adults >or=60 years old residing in nursing homes in Birmingham, Alabama, who had Mini Mental State Exam (MMSE) scores of >or=13. RESULTS: Participants (n=189) had a mean age of 82 years (SD=7.7), were 84% women and 16% men, 24% African-American and 76% Caucasian and had resided in a nursing home for two years on average. All NHVQoL subscales were correlated with subscales from other vision-targeted and generic health-related quality of life instruments (ADVS, 0.43 to 0.85; VF-14, 0.46 to 0.84; SF-36, 0.19 to 0.43). Lower scores were associated with increased depressive symptomatology by the Geriatric Depression Scale (-0.23 to -0.59), increased mobility problems (-0.17 to -0.54), worse distance and near acuity (-0.21 to -0.51) and worse contrast sensitivity (0.20 to 0.50). All subscales had Cronbach alpha>0.95. Test-retest reliability (two-week period) for subscales ranged from 0.57 to 0.84. Subscale scores did not differ as a function of MMSE scores. CONCLUSIONS: The NHVQoL has subscales with good internal consistency reliability and validity. Test-retest reliability is comparable to other questionnaires designed for the nursing home population. This questionnaire may ultimately be useful in understanding the personal burden of visual impairment and eye disease on quality of life and mental health in older nursing home residents and for evaluating the impact of psychosocial and eye care interventions on health-related quality of life in this population.

Plasma apolipoproteins and risk for age related maculopathy.

AIM: To determine if elevated plasma levels of atherogenic and/or anti-atherogenic lipoproteins are risk factors for developing age related maculopathy (ARM). METHODS: In a cross sectional study in a university clinic setting, 129 patients (72 women and 57 men) underwent colour fundus photography, acuity and contrast sensitivity assessment, and electroimmunoassays of plasma apolipoproteins B (apoB) and A-I (apoA-I), the principal proteins of low density and high density lipoproteins, respectively. Maculopathy stage was assigned using the AREDS grading system. RESULTS: Levels of apoB in no ARM, mild, intermediate, and advanced ARM groups were 93.3, 91.8, 95.2, and 98.2 mg/dl, respectively. Levels of apoA-I were 147.4, 148.6, 141.0, and 144.9 mg/dl in the same groups. There was no significant association between these measures, typical for age, and maculopathy stage. CONCLUSION: Although drusen associated with ARM and ageing contain cholesterol and apoB, like the lipid rich core of an atherosclerotic plaque, the results of this study and our previous work in toto make the prospects of a plasma origin for these lesion constituents increasingly untenable. This conclusion is consistent with an emerging hypothesis that a large lipoprotein of intraocular origin is an important pathway for constituent retinal lipid processing and the biogenesis of drusen.

Is there an association between pre-existing sleep apnoea and the development of glaucoma?

AIM: To determine if sleep apnoea is associated with an increased risk of developing glaucoma. METHODS: This was a nested case-control study. Patients seen at the Veterans Affairs Medical Center (BVAMC) in Birmingham, Alabama, with newly diagnosed glaucoma (cases) between 1997 through 2001 were selected (n = 667) and age matched with non-glaucomatous controls (n = 6667). Patient information was extracted from the BVAMC data files containing demographic, clinical, and medication information. An index date was assigned to the glaucoma subjects corresponding to the time of diagnosis. Patients who had a glaucoma diagnosis before the observation period of the study were excluded. 10 controls were randomly selected for each case and matched on age (plus or minus 1 year) and an encounter on or before the index date of the matched case. Ihe main outcome measures were crude and adjusted relative risks for the association between the previous diagnosis of sleep apnoea and the development glaucoma. Adjustment was performed for the associations of diabetes, lipid metabolism disorders, hypertension, cardiovascular disease, cerebrovascular disease, arterial disease, and migraines. RESULTS: Individuals who developed glaucoma were more likely to have a previous sleep apnoea diagnosis relative to control subjects. However, this finding was of borderline significance at an alpha of 0.05 (p value = 0.06, odds ratio = 2.20, 95% confidence intervals 0.967 to 5.004). Following adjustment for other potential risk factors, no significant difference was seen (p value = 0.18, odds ratio = 1.80, 95% confidence interval 0.76 to 4.23). CONCLUSIONS: This nested case-control study does not support a large impact of sleep apnoea on the eventual development of glaucoma relative to other putative risk factors.

Non-arteritic anterior ischaemic optic neuropathy and the treatment of erectile dysfunction.

AIM: To determine the association between Viagra (sildenafil) and Cialis (tadalafil) and non-arteritic anterior ischaemic optic neuropathy (NAION). METHODS: A retrospective matched case-control study was conducted. 38 cases of NAION in males were identified from an academic ophthalmology practice in Birmingham, Alabama, and matched (on age) to 38 controls without a history of NAION. Self reported information regarding past and current use of Viagra and/or Cialis was obtained via a telephone questionnaire from interviewers who were not blind to case status. RESULTS: Overall, males with NAION were no more likely to report a history of Viagra or Cialis use compared to similarly aged controls (odd ratio (OR) 1.75, 95% confidence interval (CI) 0.48 to 6.30 and OR 1.82, 95% CI 0.21 to 15.39). However, for those with a history of myocardial infarction, a statistically significant association was observed (OR 10.7, 95% CI 1.3 to 95.8). A similar association was observed for those with a history of hypertension though it lacked statistical significance (OR 6.9, 95% CI 0.8 to 63.6). CONCLUSIONS: For men with a history of myocardial infarction or hypertension the use of Viagra or Cialis may increase the risk of NAION. Physicians prescribing these medications to patients with these conditions should warn them about the potential risk of NAION.

The relation between C reactive protein and age related macular degeneration in the Cardiovascular Health Study.

AIM: To test the hypothesis that individuals with age related macular degeneration (AMD) have increased C reactive protein (CRP) levels. METHODS: A cross sectional study design using data from the Cardiovascular Health Study (CHS), a longitudinal study that enrolled older adults from four communities in the United States from 1989 to 1990, was employed to investigate the existence of an association between AMD and CRP levels in this population. Fundus photographs from 1997 and 1998 were used to identify individuals with (n=390) and without AMD (n=2365). The association between AMD and CRP levels (measured at baseline) was compared, adjusting for the potentially confounding effect of demographic, lifestyle, and health related characteristics. RESULTS: Among the 2755 CHS participants with gradable fundus photographs, 390 were identified as having AMD. Overall, median CRP levels among those with AMD (1.76 mg/l) were similar to those without AMD (1.77 mg/l). CRP levels were categorised into quartiles and compared between those with and without AMD. Relative to those in the lowest quartile (0.07-0.93 mg/l), the odds ratios (OR) in the higher quartiles, adjusted for demographic, lifestyle, and health related characteristics were increased but not statistically significant (0.94-1.77 mg/l: OR=1.14, 95% CI 0.82 to 1.60; 1.78-3.04 mg/l: OR=1.24, 95% CI 0.88 to 1.75; >3.04 mg/l: OR=1.24, 95% CI 0.87 to 1.78). CONCLUSIONS: In the CHS, there is no evidence that CRP levels are associated with AMD. These data do not support the theory alleging non-specific systemic inflammation in the aetiology and natural history of this disease.

The association between statin use and age related maculopathy.

AIMS: To evaluate the association between age related maculopathy (ARM) and statin use. METHODS: A nested case-control study among patients at the Veterans Affairs Medical Center in Birmingham, Alabama, with newly diagnosed ARM (cases) between 1997 to 2001 were selected and age matched to non-ARM controls. RESULTS: 550 incident cases of ARM were identified and matched to 5500 controls. Overall, cases were 70% (OR 0.30, 95% CI 0.21 to 0.45) less likely to have received and filled a statin prescription relative to the controls. This association was present among both current and past (OR 0.34, 95% CI 0.21 to 0.53 and OR 0.26, 95% CI 0.14 to 0.47, respectively) statin users. When considering use of statin and/or non-statin lipid lowering medications, a significant risk reduction was observed for statin only users (OR 0.30, 95% CI 0.20 to 0.45) and combined statin and non-statin users (OR 0.20, 95% CI 0.06 to 0.64); there was no significant association for non-statin only users (OR 0.47, 95% CI 0.20 to 1.13). CONCLUSIONS: The results of this study suggest that subjects with ARM were significantly less likely to have filled a statin prescription. Future clinical research initiatives should include a clinical trial to provide direct evidence of the effectiveness of statins in lowering the incidence and progression of ARM.

Delays in rod-mediated dark adaptation in early age-related maculopathy.

OBJECTIVE: To determine whether there are disturbances in the rod-mediated kinetics of dark adaptation in early age-related maculopathy (ARM). DESIGN: Comparative, observational case series. PARTICIPANTS: Twenty older adults with early ARM as defined by one or more large (> 63 microm) drusen, focal hyperpigmentation, or both, but no choroidal neovascularization or geographic atrophy, and 16 adults in the same age range with none of these fundus features. All participants had 20/25 visual acuity or better in the tested eye. METHODS: Dark adaptation functions were measured using a modified Humphrey Field Analyzer (Zeiss Humphrey Systems, Dublin, CA) to assess the rate of rod-mediated sensitivity recovery at 12 degrees on the vertical meridian in the inferior visual field after exposure to the equivalent of a 98% bleach. Baseline (prebleach) scotopic sensitivity, visual acuity, contrast sensitivity, and photopic sensitivity were also measured. MAIN OUTCOME MEASURES: Rod-cone break; second and third components of rod-mediated dark adaptation; time to baseline sensitivity; and baseline (prebleach) scotopic sensitivity. RESULTS: Although their visual acuity was at least 20/25, patients with early ARM on average exhibited deficits in almost all rod-mediated parameters of dark adaptation as compared with age-similar healthy participants. For example, the rod-cone break was delayed approximately 10 minutes in early ARM patients as compared with healthy participants. Age-related maculopathy patients were more likely to fall outside the normal reference range for variables representing dark adaptation kinetics than for steady-state visual functions such as scotopic sensitivity. For example, 85% of ARM patients fell outside the normal reference range in at least one dark adaptation kinetic parameter, whereas only 25% of ARM patients fell outside the normal reference range for steady-state scotopic sensitivity. CONCLUSIONS: Rod-mediated kinetic parameters of dark adaptation, which reflect the sensitivity recovery of the visual cycle, are disrupted early in ARM pathogenesis.

Timed instrumental activities of daily living tasks: relationship to visual function in older adults.

PURPOSE: To identify instrumental activities of daily living (IADL) tasks whose completion time is related to visual function in older adults. METHODS: Visual function (acuity, contrast sensitivity, and useful field of view) and the time to complete 17 visual tasks of everyday life were measured in a sample of 342 older adults (mean age 71 years, range 56 to 86) recruited from eye clinics. The timed IADL (TIADL) tasks included a variety of visual activities such as reading ingredients on cans of food and instructions on medicine bottles, finding a phone number in a directory, locating items on a crowded shelf and in a drawer, and using a screwdriver. RESULTS: Multiple regression analysis indicated that poorer scores for acuity, contrast sensitivity, and useful field of view were independently associated with longer times to complete visual TIADL tasks, even after adjusting for age, educational level, depression, and general health. Cognitive status also had a significant, independent association with timed task performance. CONCLUSIONS: Older adults' timed performance in everyday tasks is related to various aspects of visual function independent of the influences of other functional and health problems and advanced age. This suggests that TIADL tasks may eventually be useful as performance outcomes in intervention evaluations targeted at reversing vision impairment or minimizing its impact. To understand the relationship between vision impairment and TIADL task performance in older adults, cognitive impairment needs to be taken into account because it has a relatively strong and independent relationship with visual TIADL task performance.

Visual risk factors for crash involvement in older drivers with cataract.

BACKGROUND: The Impact of Cataracts on Mobility project has previously demonstrated that older drivers with cataract have an elevated risk of motor vehicle collision. OBJECTIVE: To examine what types of visual impairment serve as a basis of the increased crash risk of older drivers with cataract. METHODS AND DESIGN: A cross-sectional analysis was performed on 274 older drivers with cataract and 103 older drivers free of cataract recruited through 12 eye care clinics for the purposes of the Impact of Cataracts on Mobility project, a prospective study on driving mobility in older adults with cataract. Tests measured visual acuity, contrast sensitivity, and disability glare for each eye separately using habitual distance correction. The dependent variable was involvement in at least 1 state-recorded, at-fault vehicle crash during the 5 years prior to study enrollment. RESULTS: Logistic regression evaluated associations (odds ratios [ORs]) between visual function and crash involvement. Better and worse eye models defined on the basis of visual acuity were developed. Associations between each type of visual function and crash involvement were adjusted for age, sex, driving exposure, cognitive status, and other types of visual function. For both the better and worse eye models, contrast sensitivity was independently associated with crash involvement, whereas visual acuity and disability glare were not. Drivers with a history of crash involvement were 8 times more likely to have a serious contrast sensitivity deficit in the worse eye (defined as a Pelli-Robson score of 1.25 or less) than those who were crash-free (OR = 7.86; 95% confidence interval [CI], 1.55-39.79); this association was weaker for the better eye but still statistically significant (OR = 3.78; 95% CI, 1.15-12.48). Crash-involved drivers were 6 times more likely to have severe contrast sensitivity impairment in both eyes (OR = 5.78; 95% CI, 1.87-17.86) than crash-free drivers. A severe contrast sensitivity deficit in only 1 eye was still significantly associated with crash involvement (OR = 2.70; 95% CI, 1.16-6.51). CONCLUSION: Severe contrast sensitivity impairment due to cataract elevates at-fault crash risk among older drivers, even when present in only 1 eye.

Aging and feature search: the effect of search area.

The preattentive system involves the rapid parallel processing of visual information in the visual scene so that attention can be directed to meaningful objects and locations in the environment. This study used the feature search methodology to examine whether there are aging-related deficits in parallel-processing capabilities when older adults are required to visually search a large area of the visual field. Like young subjects, older subjects displayed flat, near-zero slopes for the Reaction Time x Set Size function when searching over a broad area (30 degrees radius) of the visual field, implying parallel processing of the visual display. These same older subjects exhibited impairment in another task, also dependent on parallel processing, performed over the same broad field area; this task, called the useful field of view test, has more complex task demands. Results imply that aging-related breakdowns of parallel processing over a large visual field area are not likely to emerge when required responses are simple, there is only one task to perform, and there is no limitation on visual inspection time.

Aging and spatial localization during feature search.

BACKGROUND: Previous studies indicate that older adults, like young adults, can efficiently search for a briefly presented visual target defined by a single salient feature presented amidst background distractors. However, little is known about older adults' ability to identify the spatial location of targets during this aspect of preattentive processing. OBJECTIVE: This study examined the extent to which older adults exhibit localization problems during feature search for a target with high conspicuity. Their performance was compared to that of younger adults. METHODS: Twenty older adults (mean age 70 years, 8 men and 12 women) and 20 younger adults (mean age 25 years, 6 men and 14 women) with good central and peripheral vision were tested. Subjects were asked to indicate via a computerized touch-screen the location of a briefly presented (80 ms) target presented amidst distracting stimuli (set size 8, 16, or 32). Targets were presented at either 10 degrees, 20 degrees, or 30 degrees eccentricity. The dependent measures were percent correct localization and, for trials in which there were errors, the spatial magnitude of the error. RESULT: Compared to young adults, older adults committed more localization errors during feature search, a problem which was accentuated with increasing target eccentricity. In addition, older adults' mislocalizations deviated from the correct location by greater distances. CONCLUSIONS: Older adults have spatial localization problems in preattentive processing during feature search, which could be detrimental to the guidance and deployment of visual attention.

Visual risk factors for driving difficulty among older drivers.

This study sought to evaluate associations between visual function and self-reported difficulty with driving tasks. Drivers (N = 384) between the ages of 55 and 85 were selected from ophthalmology practices and optometry clinics; three out of four of the sample had cataracts and the remaining were cataract-free. Information on driving exposure and difficulty was obtained via self-report. Visual functional status of all participants was measured with respect to acuity, contrast sensitivity, disability glare and useful field of view. Cognitive impairment was evaluated using the Mattis Organic Mental Syndrome Screening Examination. The results show a pattern of difficulty in high-risk driving situations among those with decreased visual acuity and contrast sensitivity, even after adjustments for age, gender, weekly mileage, and cognitive impairment.

Scotopic sensitivity during adulthood.

Older adults typically exhibit about a half log unit loss in scotopic sensitivity that cannot be attributed to optical factors and retinal disease suggesting a neural origin. Little is understood about the developmental course of this neural deficit as to whether it first appears in late life or gradually emerges during the course of adulthood. To address this developmental issue, scotopic sensitivity was measured in 94 adults ranging in age from the 20s to the 80s. Thresholds were measured at 27 test loci within a 18 degrees radius field. Analogous measurements were made for photopic sensitivity. Fundus photography and a grading scale were used to characterize macular health in subjects over age 49 in order to control for macular disease. Scotopic sensitivity decreased at a rate of 0.08 log units per decade; this decline was better fit by a single line model, not a bilinear model, implying that the impairment does not suddenly emerge in late life but gradually appears over the course of adulthood. Photopic sensitivity also decreased in a linear fashion at a rate of 0.04 log units per decade. Under these test conditions, the rate of scotopic sensitivity decline during adulthood was about double the rate of photopic sensitivity decline.

Exploratory study of incident vehicle crashes among older drivers.

BACKGROUND: As the number of older adult drivers increases, distinguishing safe from unsafe older adult drivers will become an increasing public health concern. We report on the medical and functional factors associated with vehicle crashes in a cohort of Alabama drivers, 55 years old and older. METHODS: This prospective study involved 174 older adults, on whom demographic, medical, functional, and physical performance data were collected in 1991. Subjects were then followed through 1996 for incident vehicle crashes. RESULTS: Sixty-one subjects experienced between one and four police-reported vehicle crashes during the study period. Following adjustment for age, race, days driven per week, and gender, Cox proportional-hazards models showed the following variables to be associated with crash involvement: reported difficulty with yardwork or light housework (relative risk [RR] = 2.1; 95% confidence interval [CI] 1.1, 4.0; p = .02), or opening ajar (RR = 3. 1; 95% CI 1.4, 6.7; p = .004); at least one crash before 1991 (RR = 2.1; 95% CI 1.2, 3.7; p = .008); using hypnotic medication (RR = 2.9; 95% CI 1.3, 6.6; p = .01); self-reported stroke or transient ischemic attack (RR = 2.7; 95% CI 1.1, 6.6; p = .03); scoring within the depressed range on the Geriatric Depression Scale (RR = 2.5; 95% CI 1.1, 6.0; p = .03), and failing the useful field-of-view test (RR = 1.9; 95% CI 1.0, 3.5; p = .05). CONCLUSIONS: Variables related to function, medication use, affect, neurological disease, and visuocognitive skills were associated with vehicle crash involvement in this cohort. Our findings suggest that multifactorial assessments are warranted to identify at-risk older drivers.

Psychophysical evidence for rod vulnerability in age-related macular degeneration.

PURPOSE: To determine whether there is rod system dysfunction in the central retina of patients with age-related macular degeneration (AMD). METHODS: Dark-adapted sensitivity (500-nm stimulus) and light-adapted sensitivity (600 nm) were measured psychophysically at 52 loci in the central 38 degrees (diameter) of retina in 80 patients with AMD, and results were compared with those from older adult normal controls. All dark-adapted data were corrected for preretinal absorption. RESULTS: Mean field dark-adapted sensitivity was significantly lower in AMD patients as a group than in normal subjects. Within the AMD group were subsets of patients with normal mean dark- and light-adapted sensitivities; reduced dark-adapted sensitivities without detectable light-adapted losses; both types of losses; and, least commonly, only light-adapted losses. Regional retinal analyses of the dark-adapted deficit indicated the greatest severity was 2 degrees to 4 degrees or approximately 1 mm from the fovea, and the deficit decreased with increasing eccentricity. CONCLUSIONS: These psychophysical results are consistent with histopathologic findings of a selective vulnerability for parafoveal rod photoreceptors in AMD. The different patterns of rod and cone system losses among patients at similar clinical stages reinforces the notion that AMD is a group of disorders with underlying heterogeneity of mechanism of visual loss. Dark-adapted macula-wide testing may be a useful complement to the more traditional outcome measures of fundus pathology and foveal cone-based psychophysics in future AMD trials.