-
Biomolecules May 2023Age-related macular degeneration (AMD) causes vision loss in the elderly population. Dry AMD leads to the formation of Drusen, while wet AMD is characterized by cell... (Review)
Review
Age-related macular degeneration (AMD) causes vision loss in the elderly population. Dry AMD leads to the formation of Drusen, while wet AMD is characterized by cell proliferation and choroidal angiogenesis. The retinal pigment epithelium (RPE) plays a key role in AMD pathogenesis. In particular, helioreceptor renewal depends on outer segment phagocytosis of RPE cells, while RPE autophagy can protect cells from oxidative stress damage. However, when the oxidative stress burden is too high and homeostasis is disturbed, the phagocytosis and autophagy functions of RPE become damaged, leading to AMD development and progression. Hence, characterizing the roles of RPE cell phagocytosis and autophagy in the pathogenesis of AMD can inform the development of potential therapeutic targets to prevent irreversible RPE and photoreceptor cell death, thus protecting against AMD.
Topics: Aged; Humans; Phagocytosis; Autophagy; Macular Degeneration; Oxidative Stress; Epithelial Cells; Retinal Pigments
PubMed: 37371481
DOI: 10.3390/biom13060901 -
Investigative Ophthalmology & Visual... Oct 2022To determine if increasing drusen height correlates with predictive optical coherence tomography (OCT) biomarkers of atrophy.
PURPOSE
To determine if increasing drusen height correlates with predictive optical coherence tomography (OCT) biomarkers of atrophy.
METHODS
Retrospective cross-sectional study that enrolled patients with drusen associated with intermediate AMD. Macular drusen were classified as small, intermediate, large, or very large based on OCT quartile measurement of height. Drusen diameter was also tabulated. The presence and localization of the OCT biomarkers of atrophy were assessed: disruption of the external limiting membrane and ellipsoid zone, intraretinal hyper-reflective foci, RPE disruption, choroidal hypertransmission, and presence of hyporeflective cores. Predictive OCT biomarkers of atrophy were correlated with drusen height.
RESULTS
A total of 155 eyes from 104 patients met the inclusion and exclusion criteria. The mean age was 75.7 ± 8.7 years, and patients were predominantly female (74.0%). The mean visual acuity was logMAR 0.2 ± 0.2 (Snellen equivalent 20/32). The average drusen height was 134.6 ± 107.5 µm and the greatest horizontal diameter was 970.7 ± 867.4 µm. Disruption of the external limiting membrane and ellipsoid zone, RPE thickening or thinning, intraretinal hyper-reflective foci, choroidal hypertransmission, and presence of hyporeflective cores (P < 0.05) were more common in eyes with large drusen and very large drusen versus small or intermediate drusen. All biomarkers were positively correlated with drusen height. OCT biomarkers of atrophy were predominantly located at the apex of the drusen.
CONCLUSIONS
Predictive OCT biomarkers of atrophy, specifically signs of RPE breakdown and disruption, occur more commonly in large or very large drusen, especially in drusen with greater height and separation of the RPE from the underlying choroid.
Topics: Humans; Female; Aged; Aged, 80 and over; Male; Tomography, Optical Coherence; Fluorescein Angiography; Retrospective Studies; Macular Degeneration; Retinal Pigment Epithelium; Cross-Sectional Studies; Retinal Drusen; Atrophy; Calcinosis; Biomarkers
PubMed: 36306145
DOI: 10.1167/iovs.63.11.24 -
Cureus Feb 2023Age-related macular degeneration (AMD) is a highly prevalent macular condition that primarily affects the older population. It is the primary cause of blindness amongst... (Review)
Review
Age-related macular degeneration (AMD) is a highly prevalent macular condition that primarily affects the older population. It is the primary cause of blindness amongst the elderly population. It is an inflammatory disease that characteristically shows choroidal neovascularization and geographic atrophy. The exact pathomechanism of developing AMD is not known. However, certain factors such as increased age, smoking, genetic factors and certain environmental factors are usually associated with the development of the disease. AMD also involves oxidative stress-mediated destruction of retinal pigment epithelial cells and, consequently, that of retinal photoreceptors. Alzheimer's disease (AD) is a degenerative disorder involving the nervous system that usually affects people aged 65 and over. Both AMD and AD are age-related, degenerative conditions that have several similarities and share many of the same risk factors such as vascular conditions like arteriosclerosis, high blood pressure and obesity. It is believed that the early emergence of the clinical manifestations of AMD and AD may also be significantly influenced by oxidative stress and genetic polymorphism in complement factor H. A common pathogenic pathway between AD and AMD is quite likely. Amyloid-β is an aberrant protein that accumulates within the brains of Alzheimer's patients and appears as plaques on magnetic resonance imaging (MRI). These plaques are a pathognomonic sign of Alzheimer's disease. Similar to this, amyloid-β deposits are reported to build up beneath the retina of AMD patients, which appear as tiny clusters of protein-lipid substances known as drusen. It has also been found that individuals suffering from AMD exhibit an increased chance of developing AD than those with no AMD.
PubMed: 36938233
DOI: 10.7759/cureus.34920 -
Ophthalmic Research 2022Age-related macular degeneration (AMD) is a complex, multifactorial, progressive retinal disease that affects millions of people worldwide and has become the leading... (Review)
Review
Age-related macular degeneration (AMD) is a complex, multifactorial, progressive retinal disease that affects millions of people worldwide and has become the leading cause of visual impairment in developed countries. The disease etiopathogenesis is not understood fully, although many triggers and processes that lead to dysfunction and degeneration of the retinal pigment epithelium (RPE) have already been identified. Thus, the lack of cellular control of oxidative stress, altered proteostasis, dysfunction of lipid homeostasis, and mitochondrial dysfunction form an internal feedback loop that causes the RPE to fail and allows accumulation of abnormal misfolded proteins and abnormal lipids that will form drusen. An inadequate antioxidant response, deficits in autophagy mechanisms, and dysregulation of the extracellular matrix (ECM) help to increase the deposition of abnormal drusen material over time. The drusen then act as inflammatory centers that trigger chronic inflammation of the subretinal space in which microglia and recruited macrophages are also involved, and where the complement system is a key component. Choriocapillaris degeneration and nutritional influences are also classic elements recognized in the AMD pathophysiology. The genetic component of the disease is embodied in the recognition of the described risk or protective polymorphisms of some complement and ECM related genes (mainly CFH and ARMS2/HTRA1). Thus, carriers of the risk haplotype at ARMS2/HTRA1 have a higher risk of developing late AMD at a younger age. Finally, gut microbiota and epigenetics may play a role in modulating the progression to advanced AMD with the presence of local inflammatory conditions. Because of multiple implicated processes, different complex combinations of treatments will probably be the best option to obtain the best visual results; they in turn will differ depending on the type and spectrum of disease affecting individual patients or the disease stage in each patient at a specific moment. This will undoubtedly lead to personalized medicine for control and hopefully find a future cure. This necessitates the continued unraveling of all the processes involved in the pathogenesis of AMD that must be understood to devise the combinations of treatments for different concurrent or subsequent problems.
Topics: Humans; Macular Degeneration; High-Temperature Requirement A Serine Peptidase 1
PubMed: 35613547
DOI: 10.1159/000524942 -
Ophthalmic Research 2021Geographic atrophy (GA) secondary to age-related macular degeneration accounts for close to one-quarter of cases of legal blindness in the USA and the UK. Despite this... (Review)
Review
Geographic atrophy (GA) secondary to age-related macular degeneration accounts for close to one-quarter of cases of legal blindness in the USA and the UK. Despite this notable disease burden, the pathophysiology of GA is complex and not fully understood, and there is currently no approved treatment to prevent or slow its progression. GA is heterogeneous in its appearance and extent, and underlying associated traits such as drusen and complement factor polymorphisms vary between patients and by ethnicity, posing a challenge for treatment development. The root cause of vision loss in GA is photoreceptor death; therefore, protecting photoreceptors from damage and delaying their degeneration are key to successful GA treatment. There are multiple neuroprotective pathways that may contribute to protecting photoreceptors from damage, and compounds that target these pathways include antioxidants, neurotrophic factors, and catalases. However, the efficacy of previously trialled neuroprotective therapies in GA, such as brimonidine, tandospirone, and NT-501, has been inconsistent; this may be due to their target of action, method of delivery, and/or suboptimal duration of action. Neurotrophic factors, or molecules involved in neuroprotective signalling cascades, may be ideal agents for further investigation for the treatment of GA. Future neuroprotective strategies in GA must focus on the development of agents with a long duration of action that can combat the progression of chronic damage in GA to provide clinically meaningful benefits for patients.
Topics: Atrophy; Geographic Atrophy; Humans; Macular Degeneration; Nerve Growth Factors; Neuroprotective Agents; Retina
PubMed: 34153966
DOI: 10.1159/000517794 -
Acta Ophthalmologica Dec 2022To study age- and sex-adjusted heritability of small hard drusen and early age-related macular degeneration (AMD) in a population-based twin cohort.
PURPOSE
To study age- and sex-adjusted heritability of small hard drusen and early age-related macular degeneration (AMD) in a population-based twin cohort.
METHODS
This was a single-centre, cross-sectional, classical twin study with ophthalmic examination including refraction, biometry, best-corrected visual acuity assessment, colour and autofluorescence fundus photography, and fundus optical coherence tomography. Grading and categorization of drusen was by diameter and location.
RESULTS
The study enrolled 176 same-sex pairs of twins of mean (SD) age 58.6 (9.9) years. The prevalence of the four phenotypes ≥20 small hard macular drusen (largest diameter < 63 μm), ≥20 small hard extramacular drusen, intermediate drusen (63-125 μm) anywhere, and large drusen (>125 μm) anywhere was 12.4%, 36.4%, 5.8%, and 8.4%, respectively, and the respective heritabilities, adjusted for age and sex, were 78.2% [73.5-82.9], 69.1% [62.3-75.9], 30.1% [4.1-56.1], and 65.6% [26.4-100]. Age trajectory analysis supported a gradual transition to larger numbers of small hard drusen with increasing age. The heritability of ≥20 small hard drusen was markedly lower than the 99% found in the 40% overlapping twin cohort that was seen 20 years earlier.
CONCLUSION
Numerous (≥20) small hard drusen and larger drusen that fit the definition of dry AMD were highly heritable. Small hard drusen counts increased with age. Decreasing heritability with increasing age suggests that the impact of behavioural and environmental factors on the development of small hard drusen increases with age.
Topics: Humans; Retinal Drusen; Cross-Sectional Studies; Macular Degeneration; Geographic Atrophy; Twins, Monozygotic; Tomography, Optical Coherence
PubMed: 35322936
DOI: 10.1111/aos.15136 -
Cureus Jul 2023Background Age-related macular degeneration (AMD), diabetic retinopathy (DR), drusen, choroidal neovascularization (CNV), and diabetic macular edema (DME) are...
Background Age-related macular degeneration (AMD), diabetic retinopathy (DR), drusen, choroidal neovascularization (CNV), and diabetic macular edema (DME) are significant causes of visual impairment globally. Optical coherence tomography (OCT) imaging has emerged as a valuable diagnostic tool for these ocular conditions. However, subjective interpretation and inter-observer variability highlight the need for standardized diagnostic approaches. Methods This study aimed to develop a robust deep learning model using artificial intelligence (AI) techniques for the automated detection of drusen, CNV, and DME in OCT images. A diverse dataset of 1,528 OCT images from Kaggle.com was used for model training. The performance metrics, including precision, recall, sensitivity, specificity, F1 score, and overall accuracy, were assessed to evaluate the model's effectiveness. Results The developed model achieved high precision (0.99), recall (0.962), sensitivity (0.985), specificity (0.987), F1 score (0.971), and overall accuracy (0.987) in classifying diseased and healthy OCT images. These results demonstrate the efficacy and efficiency of the model in distinguishing between retinal pathologies. Conclusion The study concludes that the developed deep learning model using AI techniques is highly effective in the automated detection of drusen, CNV, and DME in OCT images. Further validation studies and research efforts are necessary to evaluate the generalizability and integration of the model into clinical practice. Collaboration between clinicians, policymakers, and researchers is essential for advancing diagnostic tools and management strategies for AMD and DR. Integrating this technology into clinical workflows can positively impact patient care, particularly in settings with limited access to ophthalmologists. Future research should focus on collecting independent datasets, addressing potential biases, and assessing real-world effectiveness. Overall, the use of machine learning algorithms in conjunction with OCT imaging holds great potential for improving the detection and management of drusen, CNV, and DME, leading to enhanced patient outcomes and vision preservation.
PubMed: 37565126
DOI: 10.7759/cureus.41615 -
Translational Vision Science &... Sep 2023The purpose of this study was to determine the impact of prophylactic ranibizumab (PR) injections given every 3 months in eyes with intermediate nonexudative... (Randomized Controlled Trial)
Randomized Controlled Trial
PURPOSE
The purpose of this study was to determine the impact of prophylactic ranibizumab (PR) injections given every 3 months in eyes with intermediate nonexudative age-related macular degeneration (AMD) on drusen volume, macular layer thicknesses, and progression of geographic atrophy (GA) area over 24 months in the PREVENT trial.
METHODS
This post hoc analysis of the prospective PREVENT trial compared eyes with intermediate AMD randomized to PR versus sham injections to determine rates of conversion to neovascular AMD over 24 months. Drusen area and volume, macular thickness and volume, and retinal layer thicknesses were measured on spectral-domain optical coherence tomography images and analyzed. Masked grading of GA area and subretinal drusenoid deposits (SDDs) using fundus autofluorescence images was performed.
RESULTS
There were no statistical differences in drusen area and volumes between groups, and similar reductions in central subfield thickness, mean cube thickness, cube volume, and retinal sublayer thickness from baseline to 24 months (P = 0.018 to < 0.001), with no statistical differences between groups in any of these anatomic parameters. These findings were not impacted by the presence or absence of SDD. Among the 9 eyes with GA in this study, mean GA growth rate from baseline to 24 months was 1.34 +/- 0.79 mm2/year after PR and 1.95 +/- 1.73 mm2/year in sham-treated eyes (P = 0.49), and similarly showed no statistical difference with square root transformation (P = 0.61).
CONCLUSIONS
Prophylactic ranibizumab given every 3 months did not appear to affect drusen volume, macular thinning, or GA progression in eyes with intermediate AMD.
TRANSLATIONAL RELEVANCE
This work investigates the impact of PR on progressive retinal degeneration in a clinical trial.
Topics: Humans; Child, Preschool; Ranibizumab; Angiogenesis Inhibitors; Prospective Studies; Vascular Endothelial Growth Factor A; Visual Acuity; Wet Macular Degeneration; Retina; Geographic Atrophy
PubMed: 37656449
DOI: 10.1167/tvst.12.9.1 -
Ophthalmology. Retina Jul 2023To characterize geographic atrophy (GA) and evaluate differences between Asians and non-Asians.
OBJECTIVE
To characterize geographic atrophy (GA) and evaluate differences between Asians and non-Asians.
DESIGN
Multicenter, retrospective case series.
PARTICIPANTS
Subjects aged ≥ 50 years with GA secondary to age-related macular degeneration in the absence of neovascularization in the study eye and follow-up of ≥ 2 years.
METHODS
The GA lesion characterized at baseline and last follow-up based on multimodal imaging (fundus autofluorescence [FAF], near infrared [NIR], and spectral domain-OCT). Patients were grouped as either Asian or non-Asian.
MAIN OUTCOME MEASURES
Comparison of (1) phenotypes of GA lesions (size, foveal involvement, number of foci, drusen background, and choroid background) and (2) growth rates of GA.
RESULTS
A total of 144 patients (169 eyes) with distribution of 50.9% Asians and 49.1% non-Asians. The age and sex were similar between Asians and non-Asians (Asians: mean age, 77.2 ± 10.1 years, 47.9% female; non-Asians: mean age, 79.7 ± 8.4 years, 58.7% female). Asians exhibited thicker choroids (167 ± 74 versus [vs.] 134 ± 56 μm; P < 0.01) and lower prevalence of drusen (40.7% vs. 66.3%; P < 0.01). At baseline, the GA area was smaller in Asians vs. non-Asians (NIR, 3.7 ± 4.6 vs. 6.3 ± 6.8 mm; P = 0.01: FAF, 2.4 ± 3.4 vs. 8.4 ± 9.6 mm; P < 0.01). Asians had fewer GA foci (1.7 ± 1.3 vs. 2.7 ± 2.2; P < 0.01) compared to non-Asians. The proportion with diffused or banded FAF junctional zone pattern was similar between Asians and non-Asians (44.2% vs. 60.2%; P = 0.20). Asians had a slower GA lesion growth rate than non-Asians (NIR, 0.7 vs. 1.9 mm/year; P < 0.01: FAF, 0.3 vs. 2.0 mm/year; P < 0.01: NIR, 0.2 vs. 0.4 mm/year; P < 0.01 square root transformed: FAF, 0.1 vs. 0.3 mm/year; P < 0.01 square root transformed). The factors associated with GA lesion growth rate are (from the highest effect size) ethnicity, junctional zone FAF pattern, baseline GA area, and number of GA foci. Higher GA lesion growth rate was observed in both Asian and non-Asian subgroups, with drusen or lesion size and FAF patterns meeting inclusion criteria of recent therapeutic trials, but growth rate remained significantly slower in Asians. Eyes with baseline lesion ≥ 5 mm showed the highest growth rate, and the difference between ethnicities was no longer significant (2.6 vs. 3.3 mm/year; P = 0.14).
CONCLUSIONS
There are differences in GA lesion phenotype, associated features, and growth rate between Asians and non-Asian subjects.
FINANCIAL DISCLOSURE(S)
Proprietary or commercial disclosure may be found after the references.
Topics: Humans; Female; Male; Geographic Atrophy; Ethnicity; Retrospective Studies; Fluorescein Angiography; Disease Progression; Phenotype
PubMed: 36586466
DOI: 10.1016/j.oret.2022.12.013 -
Ophthalmology. Retina May 2023To report the prevalence and topographic distribution of structural characteristics in study participants with age-related macular degeneration (AMD) and controls in the...
PURPOSE
To report the prevalence and topographic distribution of structural characteristics in study participants with age-related macular degeneration (AMD) and controls in the cross-sectional study part of the MACUSTAR study (ClinicalTrials.gov Identifier: NCT03349801).
DESIGN
European, multicenter cohort study.
SUBJECTS
Overall, 301 eyes of 301 subjects with early (n = 34), intermediate (n = 168), and late AMD (n = 43), as well as eyes without any AMD features (n = 56).
METHODS
In study eyes with intermediate AMD (iAMD), the presence of structural AMD biomarkers, including pigmentary abnormalities (PAs), pigment epithelium detachment (PED), refractile deposits, reticular pseudodrusen (RPD), hyperreflective foci (HRF), incomplete/complete retinal pigment epithelium (RPE), and outer retinal atrophy (i/cRORA), and quiescent choroidal neovascularization (qCNV) was systematically determined in the prospectively acquired multimodal retinal imaging cross-sectional data set of MACUSTAR. Retinal layer thicknesses and the RPE drusen complex (RPEDC) volume were determined for the total study cohort in spectral-domain (SD) OCT imaging using a deep-learning-based algorithm.
MAIN OUTCOME MEASURES
Prevalence and topographic distribution of structural iAMD features.
RESULTS
A total of 301 study eyes of 301 subjects with a mean (± standard deviation) age of 71.2 ± 7.20 years (63.1% women) were included. Besides large drusen, the most prevalent structural feature in iAMD study eyes were PA (57.1%), followed by HRF (51.8%) and RPD (22.0%). Pigment epithelium detachment lesions were observed in 4.8%, vitelliform lesions in 4.2%, refractile deposits in 3.0%, and qCNV in 2.4%. Direct precursor lesions for manifest retinal atrophy were detected in 10.7% (iRORA) and 4.2% (cRORA) in iAMD eyes. Overall, the highest RPEDC volume with a median of 98.92 × 10 mm³ was found in iAMD study eyes. Spatial analysis demonstrated a predominant distribution of RPD in the superior and temporal subfields at a foveal eccentricity of 1.5 to 2 mm, whereas HRF and large drusen had a distinct topographic distribution involving the foveal center.
CONCLUSIONS
Detailed knowledge of the prevalence and distribution of structural iAMD biomarkers is vital to identify reliable outcome measure for disease progression. Longitudinal analyses are needed to evaluate their prognostic value for conversion to advanced disease stages.
FINANCIAL DISCLOSURE(S)
Proprietary or commercial disclosure may be found after the references.
Topics: Humans; Female; Middle Aged; Aged; Male; Cross-Sectional Studies; Cohort Studies; Tomography, Optical Coherence; Macular Degeneration; Retinal Drusen; Choroidal Neovascularization; Retinal Detachment; Atrophy
PubMed: 36563964
DOI: 10.1016/j.oret.2022.12.007