PURPOSE: To compare choroidal vascular features of eyes with and without subretinal drusenoid deposits (SDD), using swept-source optical coherence tomography (SS OCT). DESIGN: Multicenter, cross-sectional study. METHODS: We prospectively recruited patients with intermediate age-related macular degeneration (AMD), without other vitreoretinal pathology. All participants underwent complete ophthalmic examination, color fundus photography (used for AMD staging), and spectral-domain OCT (to evaluate the presence of SDD). SS OCT was used to obtain automatic macular choroidal thickness (CT) maps, according to the Early Treatment Diabetic Retinopathy Study (ETDRS) sectors. For data analysis, we considered mean choroidal thickness as the arithmetic mean value of the 9 ETDRS sectors. SS OCT en face images of choroidal vasculature were also captured and converted to binary images. Choroidal vascular density (CVD) was calculated as a percent area occupied by choroidal vessels in a 6-mm-diameter submacular circular. Choroidal vessel volume was calculated by multiplying the average CVD by macular area and CT. Multilevel mixed linear models (to account for the inclusion of 2 eyes of same subject) were performed for analysis. RESULTS: We included 186 eyes (n = 118 subjects), 94 (50.5%) presenting SDD. Multiple regression analysis revealed that, controlling for age, eyes with SDD presented a statistically thinner mean CT (ß = -21.9, P = .006) and CT in all the individual ETDRS fields (ß ≤ -18.79, P ≤ .026). Mean choroidal vessel volume was also significantly reduced in eyes with SDD (ß = -0.003, P = .007). No significant associations were observed with mean CVD. CONCLUSION: In subjects with intermediate AMD, choroidal thickness and vessel volume are reduced in the presence of subretinal drusenoid deposits.
PURPOSE: To differentiate the plasma metabolomic profile of patients with age related macular degeneration (AMD) from that of controls, by Nuclear Magnetic Resonance (NMR) spectroscopy. METHODS: Two cohorts (total of 396 subjects) representative of central Portugal and Boston, USA phenotypes were studied. For each cohort, subjects were grouped according to AMD stage (early, intermediate and late). Multivariate analysis of plasma NMR spectra was performed, followed by signal integration and univariate analysis. RESULTS: Small changes were detected in the levels of some amino acids, organic acids, dimethyl sulfone and specific lipid moieties, thus providing some biochemical information on the disease. The possible confounding effects of gender, smoking history and age were assessed in each cohort and found to be minimal when compared to that of the disease. A similar observation was noted in relation to age-related comorbidities. Furthermore, partially distinct putative AMD metabolite fingerprints were noted for the two cohorts studied, reflecting the importance of nutritional and other lifestyle habits in determining AMD metabolic response and potential biomarker fingerprints. Notably, some of the metabolite changes detected were noted as potentially differentiating controls from patients diagnosed with early AMD. CONCLUSION: For the first time, this study showed metabolite changes in the plasma of patients with AMD as compared to controls, using NMR. Geographical origins were seen to affect AMD patients´ metabolic profile and some metabolites were found to be valuable in potentially differentiating controls from early stage AMD patients. Metabolomics has the potential of identifying biomarkers for AMD, and further work in this area is warranted.
PURPOSE: To assess the relationship between baseline age-related macular degeneration (AMD) and disease stage, as well as optical coherence tomography features seen in AMD, with 3-year changes in dark adaptation (DA). METHODS: Prospective longitudinal study including patients with AMD and a comparison group (n = 42 eyes, 27 patients). At baseline and 3 years, we obtained color fundus photographs, spectral-domain optical coherence tomography, and rod-mediated DA (20 minutes protocol). Multilevel mixed-effect models were used for analyses, with changes in rod intercept time at 3 years as the primary outcome. As some eyes (n = 11) reached the DA testing ceiling value at baseline, we used 3-year changes in area under the DA curve as an additional outcome. RESULTS: Baseline AMD, AMD stage, and hyperreflective foci on optical coherence tomography were associated with larger changes in rod intercept time at 3 years. When change in area under the DA curve was used as an outcome, in addition to these features, the presence of retinal atrophy and drusenoid pigment epithelial detachment had significant associations. New subretinal drusenoid deposits at 3 years were also associated with more pronounced changes in rod intercept time and area under the DA curve. CONCLUSION: Specific optical coherence tomography features are associated with DA impairments over time, which supports that structural changes predict functional loss over 3 years.
PURPOSE: To characterize the plasma metabolomic profile of patients with age-related macular degeneration (AMD) using mass spectrometry (MS). DESIGN: Cross-sectional observational study. PARTICIPANTS: We prospectively recruited participants with a diagnosis of AMD and a control group (>50 years of age) without any vitreoretinal disease. METHODS: All participants underwent color fundus photography, used for AMD diagnosis and staging, according to the Age-Related Eye Disease Study classification scheme. Fasting blood samples were collected and plasma was analyzed by Metabolon, Inc. (Durham, NC), using ultrahigh-performance liquid chromatography (UPLC) and high-resolution MS. Metabolon's hardware and software were used to identify peaks and control quality. Principal component analysis and multivariate regression were performed to assess differences in the metabolomic profiles of AMD patients versus controls, while controlling for potential confounders. For biological interpretation, pathway enrichment analysis of significant metabolites was performed using MetaboAnalyst. MAIN OUTCOME MEASURES: The primary outcome measures were levels of plasma metabolites in participants with AMD compared with controls and among different AMD severity stages. RESULTS: We included 90 participants with AMD (30 with early AMD, 30 with intermediate AMD, and 30 with late AMD) and 30 controls. Using UPLC and MS, 878 biochemicals were identified. Multivariate logistic regression identified 87 metabolites with levels that differed significantly between AMD patients and controls. Most of these metabolites (82.8%; n = 72), including the most significant metabolites, belonged to the lipid pathways. Analysis of variance revealed that of the 87 metabolites, 48 (55.2%) also were significantly different across the different stages of AMD. A significant enrichment of the glycerophospholipids pathway was identified (P = 4.7 × 10) among these metabolites. CONCLUSIONS: Participants with AMD have altered plasma metabolomic profiles compared with controls. Our data suggest that the most significant metabolites map to the glycerophospholipid pathway. These findings have the potential to improve our understanding of AMD pathogenesis, to support the development of plasma-based metabolomics biomarkers of AMD, and to identify novel targets for treatment of this blinding disease.
Biofluid biomarkers of age-related macular degeneration (AMD) are still lacking, and their identification is challenging. Metabolomics is well-suited to address this need, and urine is a valuable accessible biofluid. This study aimed to characterize the urinary metabolomic signatures of patients with different stages of AMD and a control group (>50 years). It was a prospective, cross-sectional study, where subjects from two cohorts were included: 305 from Coimbra, Portugal (AMD patients n = 252; controls n = 53) and 194 from Boston, United States (AMD patients n = 147; controls n = 47). For all participants, we obtained color fundus photographs (for AMD staging) and fasting urine samples, which were analyzed using H nuclear magnetic resonance (NMR) spectroscopy. Our results revealed that in both cohorts, urinary metabolomic profiles differed mostly between controls and late AMD patients, but important differences were also found between controls and subjects with early AMD. Analysis of the metabolites responsible for these separations revealed that, even though distinct features were observed for each cohort, AMD was in general associated with depletion of excreted citrate and selected amino acids at some stage of the disease, suggesting enhanced energy requirements. In conclusion, NMR metabolomics enabled the identification of urinary signals of AMD and its severity stages, which might represent potential metabolomic biomarkers of the disease.
PURPOSE: To examine the relationship between dark adaptation (DA) and optical coherence tomography (OCT)-based macular morphology in age-related macular degeneration (AMD). DESIGN: Prospective, cross-sectional study. PARTICIPANTS: Patients with AMD and a comparison group (>50 years) without any vitreoretinal disease. METHODS: All participants were imaged with spectral-domain OCT and color fundus photographs, and then staged for AMD (Age-related Eye Disease Study system). Both eyes were tested with the AdaptDx (MacuLogix, Middletown, PA) DA extended protocol (20 minutes). A software program was developed to map the DA testing spot (2° circle, 5° superior to the fovea) to the OCT B-scans. Two independent graders evaluated the B-scans within this testing spot, as well as the entire macula, recording the presence of several AMD-associated abnormalities. Multilevel mixed-effects models (accounting for correlated outcomes between 2 eyes) were used for analyses. MAIN OUTCOME MEASURES: The primary outcome was rod-intercept time (RIT), defined in minutes, as a continuous variable. For subjects unable to reach RIT within the 20 minutes of testing, the value of 20 was assigned. RESULTS: We included 137 eyes (n = 77 subjects), 72.3% (n = 99 eyes) with AMD and the remainder belonging to the comparison group. Multivariable analysis revealed that even after adjusting for age and AMD stage, the presence of any abnormalities within the DA testing spot (ß = 4.8, P < 0.001), as well as any abnormalities in the macula (ß = 2.4, P = 0.047), were significantly associated with delayed RITs and therefore impaired DA. In eyes with no structural changes within the DA testing spot (n = 76, 55.5%), the presence of any abnormalities in the remaining macula was still associated with delayed RITs (ß = 2.00, P = 0.046). Presence of subretinal drusenoid deposits and ellipsoid zone disruption were a consistent predictor of RIT, whether located within the DA testing spot (P = 0.001 for both) or anywhere in the macula (P < 0.001 for both). Within the testing spot, the presence of classic drusen or serous pigment epithelium detachment was also significantly associated with impairments in DA (P ≤ 0.018). CONCLUSIONS: Our results suggest a significant association between macular morphology evaluated by OCT and time to dark-adapt. Subretinal drusenoid deposits and ellipsoid zone changes seem to be strongly associated with impaired dark adaptation.
Ocular ischemia is one of the leading causes of blindness. It is related to various ocular diseases and disorders, including age-related macular degeneration, diabetic retinopathy, glaucoma, and corneal injury. Ocular ischemia occurs due to an abnormal supply of oxygen and nutrients to the eye, resulting in ocular metabolic dysfunction. These changes can be linked with pathologic conditions in the eye, such as inflammation, neovascularization, and cell death, ultimately leading to vision loss. The current treatment care for ocular ischemia is limited. Peroxisome proliferator-activated receptor α (PPARα) is a nuclear receptor protein functioning in regulating lipid metabolism, fatty acid oxidation, and glucose homeostasis. Recently, PPARα activation has been suggested as a useful therapeutic target in treating ocular ischemia. However, its applications have not been well summarized. In this review, we cover an overview of the therapeutic roles of PPARα activation in various ocular ischemic conditions with recent experimental evidence and further provide clinical implications of its therapeutic applications. Our review will enable more approaches to comprehensively understand the therapeutic roles of PPARα activation for preventing ocular ischemic diseases.
Topic: To evaluate whether differences exist in systemic complement activation profiles in patients with early to intermediate nonexudative age-related macular degeneration (AMD) or geographic atrophy (GA) compared with control participants without AMD. Clinical Relevance: Complement inhibition has emerged as a therapeutic strategy for GA, although clinical trials to date have yielded mixed results. Despite these efforts, no clear consensus exists regarding what portions of the complement pathway are dysregulated in AMD or when this dysregulation occurs relative to AMD stage. Although past studies have compared systemic complement activation profiles in patients with AMD versus in control participants without AMD, differences in AMD case definition and differing analytical approaches complicate their interpretation. Methods: We performed a systematic review by identifying articles from database inception through October 11, 2020, that reported systemic complement activation profiles in patients with early or intermediate nonexudative AMD or GA versus control participants without AMD by searching PubMed, Google Scholar, and Embase. Risk of bias was assessed using a modified Newcastle-Ottawa score. Results: The 8 reviewed studies included 2131 independent participants. Most studies report significantly higher systemic levels of products associated with complement activation and significantly lower systemic levels of products associated with complement inhibition in patients with early and advanced nonexudative AMD compared with control participants without AMD. Discussion: Evidence suggests that systemic complement overactivation is a feature of early or intermediate and advanced nonexudative AMD. However, given significant heterogeneity, these findings are not conclusive and warrant further investigation.
Lipid-rich drusen are the sine qua non of age-related macular degeneration (AMD), the leading cause of blindness in older adults in the developed world. Efforts directed at uncovering effective therapeutic strategies have led to the hypothesis that altered lipid metabolism may play a pathogenic role in AMD. This hypothesis is supported by the fact that: (1) drusen, the hallmark histopathologic feature of AMD, are composed of lipids, (2) polymorphisms of genes involved in lipid homeostasis are associated with increased odds of AMD, (3) metabolomics studies show that patients with AMD have alterations in metabolites from lipid pathways, and (4) alterations in serum lipid profiles as a reflection of systemic dyslipidemia are associated with AMD. There is strong evidence that statins, which are well described for treating dyslipidemia and reducing risk associated with cardiovascular disease, may have a role for treating certain cohorts of AMD patients, but this has yet to be conclusively proven. Of interest, the specific changes in serum lipoprotein profiles associated with decreased cardiovascular risk (i.e., high HDL levels) have been shown in some studies to be associated with increased risk of AMD. In this review, we highlight the evidence that supports a role for altered lipid metabolism in AMD and provide our perspective regarding the remaining questions that need to be addressed before lipid-based therapies can emerge for specific cohorts of AMD patients.
PURPOSE: To study the effect of statin exposure on the progression from non-exudative to exudative age-related macular degeneration (AMD). METHODS: Retrospective cohort study of commercially insured patients diagnosed with non-exudative AMD (n = 231,888) from 2007 to 2015. Time-to-event analysis of the association between exposure to lipid-lowering medications and time from non-exudative AMD to exudative AMD diagnosis was conducted. Outcome measures included progression to exudative AMD, indicated by diagnosis codes for exudative AMD or procedural codes for intravitreal injections. RESULTS: In the year before and after first AMD diagnosis, 11,330 patients were continuously prescribed lipid-lowering medications and 31,627 patients did not take any lipid-lowering medication. Of those taking statins, 21 (1.6%) patients were on very-high-dose lipophilic statins, 644 (47.6%) on high-dose lipophilic statins, and 689 (50.9%) on low-dose lipophilic statins. We found no statistically significant relationship between exposure to low (HR 0.89, 95% CI 0.83 to 1.38) or high-dose lipophilic statins (HR 1.12, 95% CI 0.86 to 1.45) and progression to exudative AMD. No patients taking very-high-dose lipophilic statins converted from non-exudative to exudative AMD, though this difference was not statistically significant due to the subgroup size (p = .23, log-rank test). CONCLUSIONS: No statistically significant relationship was found between statin exposure and risk of AMD progression. Interestingly, no patients taking very-high-dose lipophilic statins progressed to exudative AMD, a finding that warrants further exploration.
PURPOSE: Choroidal neovascularization (CNV) is a major cause of visual loss with age-related macular degeneration (AMD). We evaluated whether blockade of phosphatidyl-inositol-3-kinase (PI3K) and the mammalian target of rapamycin (mTOR), by impairing VEGF-A and other growth factor receptors like platelet-derived growth factor (PDGF), would reduce laser-induced CNV in mice. METHODS: Choroidal neovascularization lesions were induced in C57BL/6 mice. Two groups of mice received oral GSK2126458 (3 mg/kg) or vehicle for 14 days following laser, whereas three groups were treated with GSK2126458 (6 μg/eye), aflibercept (2 μL/eye), or vehicle intravitreally on days 0 and 7 after laser. Vascular leakage was measured by fluorescein angiography (FA) on day 14. Choroidal neovascularization membranes were evaluated on choroidal flat mounts following FITC-dextran perfusion, as well as ED1 and isolectin B4 (IB4) immunohistochemistry. RESULTS: Oral and intravitreal (IVT) GSK2126458 reduced leakage and area of CNV lesions. Greater probability of leaking lesions (∼60%; P < 0.05) was observed in both vehicle groups. Fluorescein isothiocyanate-dextran-labeled total CNV burden area (total lesion area/eye) was reduced ∼67% (P < 0.05) and 35% (P = 0.0528) after oral and IVT GSK2126458 administration. GSK2126458 treatment reduced lesion size by ∼80% (P < 0.05) and 50% (P < 0.05) for oral and IVT control groups. Aflibercept did not alter lesion size (∼27% reduction). CONCLUSIONS: Phosphatidyl-inositol-3-kinase/mTOR is involved in laser-induced CNV angiogenic processes. GSK2126458 effectively reduces CNV size and leakage. Choroidal neovascularization size following IVT GSK2126458 was smaller than after oral administration. Therefore, inhibition of PI3K/mTOR pathways may be more effective due to blockade of action of multiple growth factors.
Although drusen have long been acknowledged as a primary hallmark of dry age-related macular degeneration (AMD) their role in the disease remains unclear. We hypothesize that drusen accumulation increases the barrier to metabolite transport ultimately resulting in photoreceptor cell death. To investigate this hypothesis, a computational model was developed to evaluate steady-state oxygen distribution in the retina. Optical coherence tomography images from fifteen AMD patients and six control subjects were segmented and translated into 3D in silico representations of retinal morphology. A finite element model was then used to determine the steady-state oxygen distribution throughout the retina for both generic and patient-specific retinal morphology. Oxygen levels were compared to the change in retinal thickness at a later time point to observe possible correlations. The generic finite element model of oxygen concentration in the retina agreed closely with both experimental measurements from literature and clinical observations, including the minimal pathological drusen size identified by AREDS (64 μm). Modeling oxygen distribution in the outer retina of AMD patients showed a substantially stronger correlation between hypoxia and future retinal thinning (Pearson correlation coefficient, r = 0.2162) than between drusen height and retinal thinning (r = 0.0303) indicating the potential value of this physiology-based approach. This study presents proof-of-concept for the potential utility of finite element modeling in evaluating retinal health and also suggests a potential link between transport and AMD pathogenesis. This strategy may prove useful as a prognostic tool for predicting the clinical risk of AMD progression.
Genome-wide association studies (GWAS) have identified genetic variants associated with age-related macular degeneration (AMD), one of the leading causes of blindness in the elderly. However, it has been challenging to identify the cell types associated with AMD given the genetic complexity of the disease. Here we perform massively parallel single-cell RNA sequencing (scRNA-seq) of human retinas using two independent platforms, and report the first single-cell transcriptomic atlas of the human retina. Using a multi-resolution network-based analysis, we identify all major retinal cell types, and their corresponding gene expression signatures. Heterogeneity is observed within macroglia, suggesting that human retinal glia are more diverse than previously thought. Finally, GWAS-based enrichment analysis identifies glia, vascular cells, and cone photoreceptors to be associated with the risk of AMD. These data provide a detailed analysis of the human retina, and show how scRNA-seq can provide insight into cell types involved in complex, inflammatory genetic diseases.
PURPOSE: To review the roles of analytic and innovative thought in advancing knowledge, using past examples in ophthalmology, and to explore potential strategies to improve our understanding of age-related macular degeneration (AMD) and develop new therapies. DESIGN: Presented as the 2018 Charles L. Schepens, MD, Lecture at the American Academy of Ophthalmology Retina Subspecialty Day, Chicago, Illinois, on October 26, 2018. PARTICIPANTS: None. METHODS: Review of published literature and sources on creativity and innovation. MAIN OUTCOME MEASURES: Recommendations for future AMD research. RESULTS: Innovative solutions to problems often seem intuitively obvious in hindsight. Yet, some problems seem impossible to solve. In the 1990s, AMD was a significant unmet need, with only destructive therapies for neovascular disease. This changed with the development of 2 therapies: (1) verteporfin photodynamic therapy (PDT) and (2) anti-vascular endothelial growth factor (VEGF) therapies, which are now administered to millions of people annually around the world. Now, we are frustrated by the lack of therapies for early and intermediate AMD and geographic atrophy. Photodynamic therapy and anti-VEGF drug development occurred through a combination of analytic thought and creative disruption through innovation. To get past our current impasse in understanding and treating AMD, we need to harness both analysis and innovation. We have many important building blocks in place-information on genetics, clinical findings, imaging, and histology-and have identified key pathways and potential therapeutic targets. Perhaps we need additional investigation, analysis, and integration to improve our understanding through work on structure/function and genotype/phenotype correlations and development of imaging and systemic biomarkers. We likely also need an innovative disruption. This innovation might be the concept that there are subtypes of early and intermediate AMD characterized by specific clinical phenotypes, genotype, functional characteristics, and biomarkers that are dependent on particular pathways and treatable with a specific agent. We need to encourage innovation in each of us within our research and clinical community. CONCLUSIONS: Although we have accumulated extensive knowledge about AMD, we are currently at an impasse in the development of new treatments. We need to continue the analytic process, but at the same time encourage innovative disruption to develop successful AMD therapies.
PURPOSE: To present the current understanding of age-related macular degeneration (AMD) pathogenesis, based on clinical evidence, epidemiologic data, histopathologic examination, and genetic data; to provide an update on current and emerging therapies; and to propose an integrated model of the pathogenesis of AMD. DESIGN: Review of published clinical and experimental studies. METHODS: Analysis and synthesis of clinical and experimental data. RESULTS: We are closer to a complete understanding of the pathogenesis of AMD, having progressed from clinical observations to epidemiologic observations and clinical pathologic correlation. More recently, modern genetic and genomic studies have facilitated the exploration of molecular pathways. It seems that AMD is a complex disease that results from the interaction of genetic susceptibility with aging and environmental factors. Disease progression also seems to be driven by a combination of genetic and environmental factors. CONCLUSIONS: Therapies based on pathophysiologic features have changed the paradigm for treating neovascular AMD. With improved understanding of the underlying genetic susceptibility, we can identify targets to halt early disease and to prevent progression and vision loss.
PURPOSE: To correlate a genetic risk score based on age-related macular degeneration (AMD) susceptibility genes with the risk of AMD in the second eye. METHODS: This is a retrospective, open cohort study consisting of 891 unilateral AMD patients, who were followed for at least 12 months and recruited from three institutes. DNAs were genotyped using Illumina OmniExpress, HumanOmni2.5-8, and/or HumanExome. Survival analyses and Cox proportional hazard models were used to examine the association between 11 AMD susceptibility genes and the duration until second-eye involvement in 499 samples from Kyoto University, which were replicated in two other cohorts. Genetic risk score (GRS) was also evaluated. RESULTS: The ARMS2 rs10490924 recessive model (hazard ratio [HR]meta = 2.04; Pmeta = 3.4 × 10-3) and CFH rs800292 additive model (HRmeta = 1.77; Pmeta = 0.013) revealed significant associations with second-eye involvement. The dominant model of TNFRSF10A rs13278062, VEGFA rs943080, and CFI rs4698775 showed consistent effects across three datasets (I2 = 0%; HRmeta = 1.46, 1.30, 1.51, respectively). The GRS using these five single nucleotide polymorphisms (SNPs) was also significantly associated (HRmeta [per score] = 2.42; P = 2.2 × 10-5; I2 = 0%). After 10 years from the first visit, the patients within the top 10% by GRS showed a 51% hazard rate, in contrast to 2.3% among patients within the lowest 10% by GRS. CONCLUSIONS: We demonstrated that the GRS using ARMS2, CFH, TNFRSF10A, VEGFA, and CFI was significantly associated with second-eye involvement. Genetic risk has high predictive ability for second-eye involvement of AMD.
We observed that the third leading cause of blindness in the world, age-related macular degeneration (AMD), occurs at a very low documented frequency in a population-based cohort from Timor-Leste. Thus, we determined a complete catalog of the ancestry of the Timorese by analysis of whole exome chip data and haplogroup analysis of SNP genotypes determined by sequencing the Hypervariable I and II regions of the mitochondrial genome and 17 genotyped YSTR markers obtained from 535 individuals. We genotyped 20 previously reported AMD-associated SNPs in the Timorese to examine their allele frequencies compared to and between previously documented AMD cohorts of varying ethnicities. For those without AMD (average age > 55 years), genotype and allele frequencies were similar for most SNPs with a few exceptions. The major risk allele of HTRA1 rs11200638 (10q26) was at a significantly higher frequency in the Timorese, as well as 3 of the 5 protective CFH (1q32) SNPs (rs800292, rs2284664, and rs12066959). Additionally, the most commonly associated AMD-risk SNP, CFH rs1061170 (Y402H), was also seen at a much lower frequency in the Korean and Timorese populations than in the assessed Caucasian populations (C ~7 vs. ~40%, respectively). The difference in allele frequencies between the Timorese population and the other genotyped populations, along with the haplogroup analysis, also highlight the genetic diversity of the Timorese. Specifically, the most common ancestry groupings were Oceanic (Melanesian and Papuan) and Eastern Asian (specifically Han Chinese). The low prevalence of AMD in the Timorese population (2 of 535 randomly selected participants) may be due to the enrichment of protective alleles in this population at the 1q32 locus.
BACKGROUND: To prevent irreversible vision loss in age-related macular degeneration (AMD), it is critical to detect retinal dysfunction before permanent structural loss occurs. In the current study we evaluated a series of visual function tests to identify potential endpoints to detect visual dysfunction in non-advanced AMD. METHODS: A series of visual function tests were performed on 23 non-advanced AMD subjects (AREDS grade 1-4 on simplified scale) and 34 age-matched normals (AREDS grade 0). Tests included some commonly used endpoints such as ETDRS visual acuity (VA), low luminance (LL) 2.0ND ETDRS VA, MNREAD as well as newly developed tests such as the Ora-VCF™ test, Ora-tablet reading test, color sensitivity etc. Differences between the two groups were compared for each test. Test-retest repeatability and reproducibility was assessed on a subset of subjects and percent agreement was calculated. RESULTS: There was no difference in standard ETDRS VA between non-advanced AMD (0.06 ± 0.02 logMAR) and normal groups (0.04 ± 0.02 logMAR) (p = 0.57). LL 2.0 ETDRS VA and MNREAD showed no difference between the groups (p > 0.05). Ora-VCF™ test was significantly worse in the non-advanced AMD group compared to normals (0.67 ± 0.07 in AMD; 0.45 ± 0.04 in normals, p = 0.005). Non-advanced AMD subjects also had significantly worse reading performance using the Ora-tablet with LL 2.0ND (114.55 ± 11.22 wpm in AMD; 145.17 ± 9.55 wpm in normals p = 0.049). No significant difference between the groups was noted using other tests. Repeatability was 82% for Ora-VCF™ test and 92% for Ora-tablet LL 2.0ND reading. Reproducibility was 89% for both Ora-VCF™ test and Ora-tablet LL 2.0ND reading. CONCLUSION: While there was no significant difference between non-advanced AMD and normal groups using some current common endpoints such as ETDRS VA, LL 2.0 ETDRS VA or MNREAD, Ora-VCF™ test and Ora-tablet LL 2.0ND reading tests were able to identify significant visual dysfunction in non-advanced AMD subjects. These tests show promise as endpoints for AMD studies.
Purpose: Early detection and treatment of age-related macular degeneration require a clear understanding of the early progress of the disease. The purpose of this study was to investigate whether minimal macular ophthalmoscopic changes corresponded to changes in visual function. Methods: Color macular photos from a group of older subjects who were classified as grade 0 on AREDS simplified grading were further evaluated by a retinal specialist using 5x magnification for possible minimal macular anomalies. Group 0-A ( = 15) were defined as subjects with no visible macular anomalies while Group 0-B ( = 19) comprised subjects for whom minimal macular mottling, pigment changes or very small drusen (< 63 µm) were observed in the study eye. All subjects had best VA of 20/25 or better and had no evidence of other retinal diseases in the study eye. All subjects underwent a series of visual function tests such as standard ETDRS VA, low luminance ETDRS VA, Pelli-Robson contrast sensitivity, variable contrast flicker (VCF) sensitivity, and reading speed (words per minute, wpm) using both MNRead and low luminance reading on a tablet. Results: There was no significant difference between the mean age between the two groups (74.8 ± 5.2 years for 0-A vs 74.5 ± 4.4 for 0-B, = 0.82). None of the visual function tests identified any significant difference between the two groups. Mean ETDRS VA was 0.0 ± 0.11 for 0-A subjects and 0.08 ± 0.12 for 0-B ( = 0.063). Mean Pelli-Robson log contrast sensitivity was 1.75 ± 0.29 for 0-A and 1.78 ± 0.17 for the 0-B group ( = 0.73). VCF threshold was 0.47 ± 0.25 for 0-A and 0.43 ± 0.22 for 0-B ( = 0.64). Reading speed using MNRead was 214 ± 47.4 wpm for 0-A and 210 ± 64.7 for 0-B ( = 0.85). Low luminance tablet reading speed was 137 ± 71.8 wpm for 0-A and 151 ± 39.4 (0-B) ( = 0.49). Conclusion: A panel of psychophysical tests did not demonstrate significant differences between subjects with and without minimal macular changes.