Age-related Maculopathy Group Research Articles

COMPARISON OF CHOROIDAL THICKNESS AMONG PATIENTS WITH HEALTHY EYES, EARLY AGE-RELATED MACULOPATHY, NEOVASCULAR AGE-RELATED MACULAR DEGENERATION, CENTRAL SEROUS CHORIORETINOPATHY, AND POLYPOIDAL CHOROIDAL VASCULOPATHY

To compare choroidal thicknesses among eyes with early age-related maculopathy (ARM), neovascular age-related macular degeneration, polypoidal choroidal vasculopathy, and central serous chorioretinopathy. Patients with age-related maculopathy (37 eyes), neovascular age-related macular degeneration (24 eyes), polypoidal choroidal vasculopathy (12 eyes), and central serous chorioretinopathy (31 eyes) underwent spectral-domain optical coherence tomography evaluations using a choroid scanning protocol. A horizontal linear section comprising 50 averaged scans was obtained of each macula. The choroidal thickness was measured from the outer border of the retinal pigment epithelium to the inner scleral border. Twenty-nine subjects with healthy eyes served as a control group. Analysis of covariance tests were performed to evaluate the effects of various diagnoses on choroidal thickness after removal of variance (covariates = gender, age, and refractive error). Among the different covariates, age was associated with choroidal thickness (fovea: F = 12.067, P = 0.001). After controlling for age differences, the choroid was thicker in polypoidal choroidal vasculopathy (319.92 ± 68.66 μm) and central serous chorioretinopathy (367.81 ± 105.56 μm) patients than in controls (241.97 ± 66.37 μm) and age-related maculopathy patients (186.62 ± 64.02 μm). However, there were no significant differences in mean choroidal thickness between neovascular age-related macular degeneration (226.46 ± 102.87 μm) and any of the other diagnoses. The choroid was thicker in eyes with polypoidal choroidal vasculopathy or central serous chorioretinopathy than in control or age-related maculopathy groups.

Topography of Cone Dark Adaptation Deficits in Age-Related Maculopathy

Despite widespread agreement that dark adaptation is abnormal in age-related maculopathy (ARM), the optimal retinal location for detection of this deficit is unclear. We quantified the diagnostic potential of cone dark adaptation as a function of retinal eccentricity and compared this with the diagnostic potential of the time to the rod-cone-break (RCB). Cone dark adaptation was monitored after an 80% cone photopigment bleach in 10 subjects with ARM and 10 age-matched controls, using four achromatic annuli (0.5, 2, 7, and 12° radius) centered on the fovea. Threshold recovery data were modeled and the time constant of cone recovery (τ), final cone threshold, and time to RCB were determined. Diagnostic potential was evaluated by constructing receiver operating characteristic curves for these parameters. Cone τ was significantly longer for the ARM group at 2, 7, and 12°. The greatest difference between groups was observed at 12° from fixation. At this location, the mean τ was 3.49 (±2.02) min and 0.64 (±0.38) min for ARM and control subjects, respectively (p = 0.002), and time to RCB was 17.68 (±5.37) min and 9.05 (±2.11) min for ARM and control subjects, respectively (p = 0.001). Correspondingly, receiver operating characteristic curves showed that the diagnostic potential of dark adaptometry is greatest for stimuli presented 12° from fixation; for cone τ, the area under the curve = 0.99 ± 0.02 and for time to RCB, area under the curve = 0.96 ± 0.04. This study has shown cone-mediated dark adaptation to be significantly impaired in ARM. Our results provide compelling evidence in support of the diagnostic potential of cone dark adaptation and the use of annular stimuli at 12°. The observation that cone τ is highly diagnostic at this eccentricity is significant clinically because this parameter may be quantified within a few minutes.

Do lutein, zeaxanthin and macular pigment optical density differ with age or age-related maculopathy?

Background and aims Current age-related macular disease (ARMD) treatment includes antioxidant supplementation. Lutein (L) and zeaxanthin (Z) are antioxidants that make up macularpigment within the retina and may reduce the risk of developing ARMD. Ageing and smoking are leading risk factors for developing ARMD. We investigated differences in dietary, supplemental and retinal L and Z, and smoking habits in healthy younger eyes (HY), healthy older eyes (HO) and eyes with an early form of ARMD called age-related maculopathy (ARM). Methods HO, HY and ARM groups were assessed for dietary intakes of L and Z using food diaries. Smoking habits and self-administered quantities of L and Z were obtained via questionnaire. Retinal L and Z levels (macularpigmentopticaldensity, or MPOD) were determined using heterochromatic flicker photometry. Results No significant difference was demonstrated for dietary L and Z intake (?2 = 4.983, p = 0.083) or for MPOD between groups (F = 0.40, p = 0.67). There was a significant difference between the HY (mean ± sd: 1.20 ± 2.99), HO (4.51 ± 7.05) ARM groups (9.15 ± 12.28) for pack years smoked (?2 = 11.61, p = 0.03). Conclusions Our results do not support the theory that ARM develops as a result of L and Z deficiency. Higher pack years smoked may be a factor in disease development. Dietary and supplementary L and Z levels must be obtained when assessing MPOD between groups or over time.

Relationship between macular pigment and mesopic visual function in early age‐related maculopathy

Abstract Purpose Psychophysical studies have demonstrated that several parameters of visual function deteriorate in the early stages of age‐related maculopathy (ARM). This study was performed to analyze whether the variability in high (HC) and low (LC) ‐contrast visual acuity (VA) and contrast sensitivity (CS) at mesopic light level is attributable to differences in macular pigment optical density (MPOD) in early ARM patients. Methods Measurements were obtained from 40 eyes of adults (65 ± 7 years) with early ARM and 34 age‐matched healthy control eyes (67 ± 6 years). MPOD was estimated at the fovea using the Metropsis Test (Cambridge Research System). Visual acuity (VA) was measured with the best spectacle correction using high‐contrast (96%) and low‐contrast (10%) logMAR letter charts under mesopic luminance conditions (0.1 to 0.2 cd/m2). Mesopic contrast sensitivity (CS) was determined using the Pelli‐Robson chart. Results Foveal MPOD was 0.25 ± 0.14 in eyes without ARM and 0.29 ± 0.22 in eyes with early ARM. Mean mesopic high and low contrast logMAR VA and log CS were significantly worse in the ARM group than in the control group. There was no significant relationship between high HC‐VA and MPOD, LC‐VA and MPOD and between log CS and MPOD in both early ARM and control group. Conclusion No differences in MP optical density were found between eyes with and without early ARM. Mesopic visual function was unrelated to foveal macular pigment optical density in early age‐related maculopathy.

Mesopic visual function as a prognostic indicator of early age‐related maculopathy

Abstract Purpose Rod photoreceptors, which mediate night vision, are vulnerable early in age‐related maculopathy (ARM) pathogenesis. This study was performed to analyze mesopic visual function of early ARM subjects. Methods The samples were 40 early ARM eyes of adults (65 ± 7 years), and 34 age‐matched healthy control eyes (67 ± 6 years). The selected criteria in both samples were: Best‐corrected VA of at least 0.9 decimal. Under photopic (80 cd/m2) and mesopic (0.1 to 0.2 cd/m2) luminance conditions and with the best‐optical correction, the logMAR VA was measured using high‐contrast (HC‐96%) and low‐contrast (LC‐10%) logMAR Bailey‐Lovie letter charts, and the mesopic contrast sensitivity (CS) was assessed with Pelli‐Robson Test Results Photopic high and low‐contrast VA showed no statistically differences between the two groups. Under mesopic conditions, the HC logMAR VA was 0.54 ± 0.13 in ARM group and 0.46 ± 0.10 in Control group. The ARM LC logMAR VA was 0.72 ± 0.11 and the Control LC logMAR VA was 0.99 ± 0.13. Differences in mesopic high and low contrast logMAR VA between the Control and ARM group were statistically significant; the Control group showing best logMAR VA at high and low contrast (p< 0.00). The mesopic ARM logCS was 0.99 ± 0.21 and the mesopic Control logCS was 1.19 ± 0.14. In ARM group, the mean mesopic log CS was 0.2 ± 0.08 log units lower (p< 0.00) than in the Control group. Conclusion The results indicated that assessment of the mesopic high and low contrast logMAR VA and log CS might potentially predict the mesopic visual function and the first night‐vision problems of the early ARM disease process

Measuring Rod and Cone Dynamics in Age-Related Maculopathy

A cathode-ray-tube (CRT) monitor-based technique was used to isolate clinically significant components of dark adaptation. The utility of the technique in identifying adaptation abnormalities in eyes with age-related maculopathy (ARM) is described. A CRT dark adaptometer was developed to assess cone and rod recovery after photopigment bleach. The following measures were obtained: cone recovery rate (R(c); in decades per minute) and absolute threshold (Tf(c); log candelas per square meter), rod recovery rate (R(r); decades per minute), and rod-cone transition (rod-cone break [RCB], in minutes). These components were isolated by appropriately selecting stimulus size, stimulus location, pigment bleach, and test duration and by coupling the CRT with judiciously selected neutral-density (ND) filters. The protocol was developed by using 5 young observers and was tested on 27 subjects with ARM in the study eye and 22 age-matched control subjects. The parameters necessary for effective isolation of cone and early phase rod dark adaptation were a 2.6 ND filter (for a standard CRT monitor, 0.08-80 cd . m(-2) luminance output); a 4 degrees foveated, 200-ms, achromatic spot; approximately 30% pigment bleaching; and a 30-minute test duration. These settings returned obvious rod and cone recovery curves in control and ARM eyes that were compatible with conventional test methods and identified 93% of participants with ARM as having delayed dynamics in at least one of the parameters. Cone recovery dynamics were significantly slower in the ARM group when compared with age-matched control subjects (R(c), 0.99 +/- 0.35 vs. 2.63 +/- 0.61 decades . min(-1), P < 0.0001). Three of the 27 eyes with ARM did not achieve RCB during the allowed duration (30 minutes). The remaining eyes with ARM (n = 24) exhibited a significant delay in rod recovery (R(r)(,) ARM, 0.16 +/- 0.03 vs. controls, 0.22 +/- 0.02 decades . min(-1), P < 0.0001) and the average time to RCB (+/-SD) in the ARM group was significantly longer than in the control subjects (19.12 +/- 5.17 minutes vs. 10.40 +/- 2.49 minutes, P < 0.0001). The CRT dark-adaptation technique described in this article is an effective test for identifying abnormalities in cone and rod recovery. Slowed cone and rod recovery and a delayed RCB were evident in the eyes with ARM. The test method is potentially useful for clinical intervention trials in which ARM progression is monitored.

Evaluating Retinal Function in Age-Related Maculopathy with the ERG Photostress Test

To evaluate the diagnostic potential of the electroretinogram (ERG) photostress test and the focal cone ERG in age-related maculopathy (ARM). The cohort comprised 31 patients with ARM and 27 age-matched control subjects. The ERG photostress test was used to monitor cone adaptation after intense light adaptation. Focal 41- and 5-Hz cone ERGs were recorded monocularly (central 20 degrees) to assess steady state retinal function. Univariate analysis identified electrophysiological parameters that differed between groups, and receiver operating characteristic (ROC) curves were constructed to assess their diagnostic potential. Logistic regression analysis determined the diagnostic potential of a model incorporating several independent predictors of ARM. The rate of recovery of the ERG photostress test was reduced (recovery was slower) in subjects with ARM. The parameter exhibited good diagnostic potential (P = 0.002, area under ROC curve = 0.74). The implicit times of the 5-Hz (a-wave, P = 0.002; b-wave, P < 0.001) and the 41-Hz (P < 0.001) focal cone ERGs were increased, and the 41-Hz focal cone ERG amplitude (P = 0.003) and focal to full-field amplitude ratio (P = 0.001) were reduced in the ARM group. Logistic regression analysis identified three independent predictors of ARM, including the rate of recovery of the ERG photostress test. Early ARM has a marked effect on the kinetics of cone adaptation. The clinical application of the ERG photostress test increases the sensitivity and specificity of a model for the diagnosis of ARM. Improved assessment of the functional integrity of the central retina will facilitate early diagnosis and evaluation of therapeutic interventions.

Plasma levels of matrix metalloproteinase-2 and -9 (MMP-2 and MMP-9) in age-related macular degeneration

Several studies indicate that age-related macular degeneration (AMD) and atherosclerosis may share common pathogenetic pathways. The aim of this study was to determine the role of systemic matrix metalloproteinases (MMPs) in AMD, given that MMPs are implicated in the pathogenesis of atherosclerosis. This study determined the plasma matrix metalloproteinases (MMP-2 and MMP-9) levels in three groups of subjects: group 1 included subjects with age-related maculopathy (ARM), group 2 included subjects with choroidal neovascularization (CNV) owing to AMD and group 3 consisted of age-matched controls. The mean plasma levels of MMP-2 were not significantly different in the three groups. In contrast, the mean plasma MMP-9 levels were significantly higher in ARM and CNV groups compared to that of the control group. However, there was no significant difference in MMP-9 levels between ARM and CNV groups. This is the first study that reveals a link between raised plasma MMP-9 levels with AMD. Further studies are required to identify the factors that contribute to this association.

Plasma levels of matrix metalloproteinase-2 and -9 (MMP-2 and MMP-9) in age-related macular degeneration

Several studies indicate that age-related macular degeneration (AMD) and atherosclerosis may share common pathogenetic pathways. The aim of this study was to determine the role of systemic matrix metalloproteinases (MMPs) in AMD, given that MMPs are implicated in the pathogenesis of atherosclerosis. This study determined the plasma matrix metalloproteinases (MMP-2 and MMP-9) levels in three groups of subjects: group 1 included subjects with age-related maculopathy (ARM), group 2 included subjects with choroidal neovascularization (CNV) owing to AMD and group 3 consisted of age-matched controls. The mean plasma levels of MMP-2 were not significantly different in the three groups. In contrast, the mean plasma MMP-9 levels were significantly higher in ARM and CNV groups compared to that of the control group. However, there was no significant difference in MMP-9 levels between ARM and CNV groups. This is the first study that reveals a link between raised plasma MMP-9 levels with AMD. Further studies are required to identify the factors that contribute to this association.

The Rod-Mediated Multifocal Electroretinogram in Aging and in Early Age-Related Maculopathy

Purpose: To measure function with the rod-mediated multifocal electroretinogram (mfERG) in younger and older subjects with normal vision and with early age-related maculopathy (ARM). Methods: Thirty subjects were studied: 10 healthy subjects with a mean age of 31 years (young group), 10 healthy subjects with a mean age of 71 years (old group), and 10 early ARM subjects with a mean age of 71 years (early ARM group). The influence of cataract was approximated by retesting five subjects of the young group through an 0.3 neutral density filter (ND filter group). We analyzed first-order N1P1-amplitude and P1-implicit time (P1-IT) mfERG responses and correlated them with funduscopic changes as defined by the Age-Related Eye Disease Study (AREDS) group. Results: Averaged concentric ring P1-ITs were significantly delayed in the old (p = 0.02) and early ARM (p < 0.001) compared with the young group and in the early ARM group compared with the old and ND group (p ≤ 0.01). There were no significant differences in N1P1-amplitudes between groups, but there was a significant location effect for all groups with highest mean amplitudes for the most peripheral ring of hexagons (p < 0.01). Significantly delayed overall P1-ITs (p < 0.05) were correlated with progressive funduscopic changes. Conclusions: Aging and early ARM affects the rod-mediated mfERG, and there is good correlation with funduscopic changes. Although a lens effect cannot be excluded, a neuronal transmission alteration at the postreceptoral level is suggested.

Adaptation Responses in Early Age-Related Maculopathy

To investigate the global-flash multifocal electroretinogram (mfERG) in early age-related maculopathy (ARM). Thirty-two eyes from 20 healthy control subjects and 12 age-matched subjects with early ARM were investigated with the conventional and the global-flash mfERG. Early ARM subjects were graded according to an international grading system. The conventional mfERG consisted of 103 hexagons flickering according to a pseudorandom m-sequence. The global-flash mfERG paradigm used four frames starting with the conventional m-sequence stimulation, followed by a dark frame, a global flash, and another dark frame. The responses include a direct response (DR) and a later induced component (IC). The first-order kernel peak-to-trough response densities of the conventional mfERG (N1P1), the global-flash DR and IC, and the implicit times of the conventional P1, global-flash DR, and IC peak were analyzed after averaging the results into five groups according to five field locations: a central area and four quadrants. There was a significant reduction of the global-flash mfERG DR response density (P < or = 0.05) in the early ARM group compared with the control group. Neither the IC response density nor DR and IC implicit times were significantly impaired. However, the superior retina showed longer implicit times than did the inferior retina for the DR in the early ARM group. There was no significant correlation between funduscopic features and the central averaged responses of the global-flash mfERG (for the DR response density: r = -0.19, P = 0.3, or for the DR implicit time: r = -0.18, P = 0.3). None of the conventional mfERG parameters was significantly different between the two groups. The global-flash mfERG detects deficits in early ARM before the conventional mfERG. Retinal ischemia may play a role in producing function impairment in ARM.

The macular mapping test: a reliability study

BackgroundAge-related macular degeneration (ARMD) is the leading cause of visual disability in people over 60 years of age in the developed world. The success of treatment deteriorates with increased latency of diagnosis. The purpose of this study was to determine the reliability of the macular mapping test (MMT), and to investigate its potential as a screening tool.MethodsThe study population comprised of 31 healthy eyes of 31 participants. To assess reliability, four macular mapping test (MMT) measurements were taken in two sessions separated by one hour by two practitioners, with reversal of order in the second session. MMT readings were also taken from 17 age-related maculopathy (ARM), and 12 AMD affected eyes.ResultsFor the normal cohort, average MMT scores ranged from 85.5 to 100.0 MMT points. Scores ranged from 79.0 to 99.0 for the ARM group and from 9.0 to 92.0 for the AMD group. MMT scores were reliable to within ± 7.0 points. The difference between AMD affected eyes and controls (z = 3.761, p = < 0.001) was significant. The difference between ARM affected eyes and controls was not significant (z = -0.216, p = 0.829).ConclusionThe reliability data shows that a change of 14 points or more is required to indicate a clinically significant change. This value is required for use of the MMT as an outcome measure in clinical trials. Although there was no difference between MMT scores from ARM affected eyes and controls, the MMT has the advantage over the Amsler grid in that it uses a letter target, has a peripheral fixation aid, and it provides a numerical score. This score could be beneficial in office and home monitoring of AMD progression, as well as an outcome measure in clinical research.

Visuelle Funktion und Lebensqualität bei Patienten mit altersabhängiger Makulopathie: Ergebnisse der Münsteraner Altern- und Retina-Studie (MARS)

The aim of this study was to examine the association between increasing severity of age-related maculopathy (ARM) stages, visual function and quality of life. Using the 25-item version of the National Eye Institute Visual Function Questionnaire (NEI VFQ) in the Münster age and retina study (MARS), 974 patients (normal fundus: n = 208; early ARM: n = 466; late ARM: n = 300) with bilateral gradable fundus photographs were asked about their visual function and quality of life. The NEI VFQ scales with regard to general health, general vision, near vision, distance vision and peripheral vision were assessed. According to the ARM stages, age- and gender-adjusted mean scores were calculated and tested for statistically significant differences. The perception of general health, general vision, near vision, distance vision and peripheral vision was getting worse with increasing severity of ARM stages. Comparing the maculopathy groups, significant differences in age- and gender-adjusted mean scores were found between patients with late ARM and healthy subjects and patients with late and early ARM. Furthermore, we observed for the dimension general vision a significant difference of the mean score between early ARM and healthy control group [mean score; early ARM: 68.7 (0.7) vs. control group: 72.2 (1.1); p = 0.005]. The results of the NEI VFQ reflect the clinical expectation of an inverse relation between increasing severity of ARM stages and visual function and quality of life.

Drusen classification in bilateral drusen and fellow eye of exudative age-related macular degeneration

To assess the value of the modified international classification system in screening high-risk patients with bilateral age-related maculopathy (ARM) from those with lower risk characteristics. In total, 164 digital images of 106 patients with either bilateral ARM (group A) or the fellow eyes of unilateral exudative age-related macular degeneration (AMD) (Group B) were included. Patients with no signs of ARM in both eyes or those with bilateral late AMD were excluded. The images were randomised and then graded by two masked ophthalmologists based on the modified International Classification of ARM. The interobserver consistency between the two graders was high with a Kappa value of 0.82 (SE 0.34, P<0.0001). There were no significant differences in the distribution of the stages of ARM between the two subgroups. Stage 3 was the most common stage in each group for both graders followed by stage 2a in the bilateral drusen group. Stages 1a, 2a and 2b were equally the next common stage in the fellow eye of chordial neovascularisation group. A screening system based on clinical characteristics would be of value in risk prediction in a clinical setting. Type of Drusen alone, as identified by the modified International grading system, may not be reliably predictive in screening for patients who are at high risk of developing choroidal neovascularisation.

Monitoring retinal function in early age-related maculopathy: visual performance after 1 year.

To monitor visual performance in early age-related maculopathy (ARM). We measured monocular visual function-high-contrast visual acuity (HC-VA), central visual fields (mean sensitivity, MS), colour vision (desaturated Panel D-15), Pelli-Robson (P-R), and cone- and rod-mediated multifocal electroretinograms (mfERG) in 13 ARM subjects and 13 age-matched control subjects with normal fundi at baseline and after 1 year. All had visual acuity of 6/12 or better. The mfERG data were compared to templates derived from the control group at baseline. We analysed the mfERG results by averaging the central and peripheral fields and the superior and inferior fields (CP and SI methods) and by calculating the local responses. The mean rod-mediated responses were significantly delayed in the ARM group for the CP (P=0.04) and the SI methods (P=0.03) at baseline compared to the control group. This did not change significantly after 1 year, whereas the mean cone-mediated responses were within the normal range at both times. Although the local analysis revealed lower amplitudes for the cone- and rod-mediated responses at baseline this was not found after 1 year and only the local rod-mediated latencies were delayed at both times (P<0.01). HC-VA, desaturated Panel D-15 and P-R were significantly worse in the ARM group (P< or =0.01) at baseline but did not show further significant deterioration. Progressive fundus changes were found in only two subjects (18%). Although there was significant impairment of retinal function in early ARM at baseline no further deterioration was evident after 1 year.

Cone-mediated multifocal electroretinogram in early age-related maculopathy and its relationships with subjective macular function tests

Purpose. To investigate the multifocal electroretinogram (mfERG) and subjective function in early age-related maculopathy (ARM). Methods. Seventeen subjects with early ARM with visual acuity (VA) of 6/12 or better and 20 age-matched control subjects were examined. We assessed mfERGs, high and low contrast distance VA, near VA, low luminance VA, contrast sensitivity, saturated and desaturated Panel D-15 and visual fields (mean sensitivity). The mfERG responses were analysed by comparing central-overall (method 1) and superior-inferior (method 2) ratios. Results. The mfERG did not discriminate between the groups whereas colour vision (tritan deficiency), contrast sensitivity, and high contrast and low contrast VA showed significantly reduced responses for the early ARM group compared with the control group (p ≤⃒ 0.01). The mfERG first-order kernel responses correlated significantly with the desaturated D-15 in both methods (r = −0.5, p ≤⃒ 0.05). Fundus grading was not correlated with the mfERG measures. Conclusions. Although the mfERG correlated significantly with the desaturated D-15 in early ARM, suggesting it operates at a sensitive level, it failed to discriminate between the control and ARM groups. In our sample, the subjective function measures were more sensitive than the mfERG measures.

Retrobulbar circulation in patients with age-related maculopathy.

To investigate retrobulbar circulation in stages of age-related maculopathy (ARM) and in normal fellow eyes of patients with unilateral exudative ARM. Color Doppler Imaging was used to measure circulatory parameters (peak-systolic velocity--PSV, end-diastolic velocity--EDV, pulsatility index--PI and resistivity index--RI) in the central retinal, posterior ciliary and ophthalmic arteries of 44 patients with age-related maculopathy (ARM) and 32 control subjects. Patients with ARM consisted of 11 with early ARM and 33 with late ARM. Twenty-one patients from the exudative ARM group were also included in a study of unilateral exudative ARM circulation. In the study of patients with ARM divided into stages, the PI and RI in the posterior ciliary artery of patients with late ARM were significantly higher than that of the control group (P = 0.0064; P = 0.0124). In the early ARM group, circulatory parameters did not differ significantly from those of the control group. In the study of unilateral exudative ARM, the affected eye showed significantly higher RI, as compared to the control group (P = 0.0157), and the fellow eye had significantly decreased EDV as compared to the control group (P = 0.0164). There was no significant difference in circulatory parameters between the affected and normal fellow eyes of patients with unilateral exudative ARM. PI and RI in patients with late ARM and EDV in fellow eyes of patients with unilateral exudative ARM showed significant changes in the posterior ciliary artery compared to normal controls. Altered circulation in the posterior ciliary artery may be involved in the pathogenesis of ARM.

Early age-related maculopathy and self-reported visual difficulty in daily life

Purpose To determine whether early age-related maculopathy (ARM) is associated with visual difficulty in daily activities beyond the difficulty that would be expected based on normal retinal aging; to determine whether scotopic sensitivity and visual acuity are associated with visual difficulties in these older adults. Study design Comparative, cross-sectional questionnaire study. Subjects Ninety-two older adults with early ARM in at least one eye as defined by one or more large (>63 μm) drusen and/or focal hyperpigmentation but no choroidal neovascularization or geographic atrophy, acuity of 20/60 or better, and a reference group of 55 older adults in the same age range without these fundus features and acuity of 20/35 or better in each eye. Method Tests of visual acuity and scotopic sensitivity and a general health questionnaire were carried out. The Activities of Daily Vision Scale (ADVS) was administered to assess self-reported visual difficulties in everyday tasks and expressed on a scale of 0 (extreme difficulty) to 100 (no difficulty). Fundus photographs were taken and graded to characterize the presence and severity of ARM to determine eligibility. Results For purposes of analysis, the early ARM group was divided into those whose fellow eye (FE) was 20/60 or better and those whose FE was worse than 20/60. ADVS subscale scores were substantially lower in the early ARM group with FE worse than 20/60 (medians, 58–83) compared with the normal retinal health group (medians, 97–100). Even for those with early ARM with FE 20/60 or better, four of five subscale scores were lower (medians, 81–97), albeit slightly in some cases, than those of the reference group. For both ARM subgroups, the night driving subscale had the lowest scores of all subscales. Persons with early ARM with FE 20/60 or better were more likely to report difficulty on the night driving (odds ratio [OR], 4.3; 95% confidence interval [CI], 1.6–11.4), near vision (OR, 5.0; 95% CI, 1.9–12.9), and glare disability (OR, 2.7; 95% CI, 1.1–6.3) subscales compared with those in normal retinal health, adjusting for age, gender, medical comorbidities, and lens density. For early ARM patients with FE worse than 20/60, there was widespread reporting of difficulty on all subscales (ORs ranging from 4.7–52.9). Poor scotopic sensitivity was highly associated with difficulty on the night driving subscale (OR, 6.6; 95% CI, 1.2–35.5) but not with any other subscale. Acuity worse than 20/25 in both eyes was significantly associated with difficulty on all ADVS subscales; when this acuity impairment was present in one eye only, associations were still significantly present on some subscales, although they were weaker. Conclusions Persons in the early phases of ARM, even when their fellow eye has relatively good acuity, are more likely to experience difficulty in night driving, near vision tasks, and glare disability compared with those in good retinal health. Scotopic dysfunction, a functional marker of early ARM, is linked to reported night driving problems. Even when acuity impairment occurs in one eye only, patients report difficulties with day driving and near and far vision tasks.

The Waterloo Vision and Mobility Study: postural control strategies in subjects with ARM

Binocular vision function and standing balance control was assessed in 16 subjects with age-related maculopathy (ARM) (mean age 73.9 +/- 7.4 years) and 19 controls (mean age 69.1 +/- 5.5 years). Balance control was assessed using the center of pressure signal from force plate data. It was quantified using the root mean square (RMS) error of the amplitude, sampled over a 1 min period. This was evaluated during normal standing, and while the input from the kinesthetic and/or visual systems were disrupted. The two subject groups showed significantly different RMS values across conditions (P < 0.005). The differences in RMS between ARM and control groups were only significant when the input to the kinesthetic sensory system was disrupted. Our results suggest that in the normal standing condition, the kinesthetic and vestibular systems compensated for the lack of useful information from the visual system in ARM subjects. When kinesthetic system input was disrupted, balance control of the ARM group was significantly poorer than the control. There was a weak correlation between postural control and contrast sensitivity. Various strategies for preventing falls in elderly patients with low vision are suggested.

Waterloo Vision and Mobility Study: gait adaptations to altered surfaces in individuals with age-related maculopathy.

Walking is an extremely complex task that can become seriously challenged if one of the sensory systems which provides input to the motor system is compromised. The present study evaluated gait adaptations to altered surface characteristics and high and low ambient light conditions by subjects with age-related maculopathy (ARM). Twenty subjects with ARM and 20 control subjects walked along a 6 m path, along which they met 1 of 3 altered surfaces (compliant, uneven, or shiny). Kinematic data and ground reaction forces information were analyzed to discern gait adaptation strategies used by the ARM group. Ten trials on each surface were collected under both high and low ambient light levels. The ARM subjects were found to be generally more cautious when walking on the altered surfaces. For example, they walked more slowly, with a longer swing time. However, gait adaptations in the ARM group were not merely scaled versions of normal gait but were adjustments to adapt to environmental changes. Gait was modified to avoid tripping over a surface edge, to prevent slipping at heel contact, and to balance during stance. These adaptations enabled subjects to maintain safe mobility when walking in a challenging environment.