FROM DRUSEN TO TYPE 3 MACULAR NEOVASCULARIZATION.

PURPOSE: To investigate the imaging features preceding the occurrence of type 3 (T3) macular neovascularization (MNV) using tracked spectral-domain optical coherence tomography. METHOD: From a cohort of eyes with T3 MNV and ≥ 12 months of previously tracked spectral-domain optical coherence tomography, T3 lesions that developed above soft drusen were selected for optical coherence tomography analysis. Retinal imaging findings at the location where type T3 MNV occurred were analyzed at each follow-up until the onset of T3 MNV. The following optical coherence tomography parameters were assessed: drusen size (height and width), outer nuclear layer/Henle fiber layer thickness at the drusen apex, and the presence of intraretinal hyperreflective foci, retinal pigment epithelium disruption, incomplete retinal pigment epithelium and outer retina atrophy, and complete retinal pigment epithelium and outer retina atrophy. RESULTS: From a cohort of 31 eyes with T3 MNV, T3 lesions developed above soft drusen in 20 eyes (64.5%). Drusen showed progressive growth ( P < 0.001) associated with outer nuclear layer/Henle fiber ( P < 0.001) thinning before T3 MNV. The following optical coherence tomography features were identified preceding the occurrence of T3 MNV, typically at the apex of the drusenoid lesion: disruption of the external limiting membrane/ellipsoid zone and/or the retinal pigment epithelium, hyperreflective foci, and incomplete retinal pigment epithelium and outer retina atrophy/complete retinal pigment epithelium and outer retina atrophy. CONCLUSION: The results demonstrate specific anatomic alterations preceding the occurrence of T3 MNV that most commonly originates above soft drusen. Drusen growth, reduced outer nuclear layer/Henle fiber thickness, and retinal pigment epithelium atrophy at the drusen apex precede the development of T3 MNV. Identifying these optical coherence tomography features should warrant close monitoring for identification of T3 MNV, which can benefit from prompt intravitreal anti-vascular endothelial growth factor therapy.

HISTOLOGY, DIMENSIONS, AND FLUORESCEIN STAINING CHARACTERISTICS OF NODULAR AND CUTICULAR DRUSEN IN AGE-RELATED MACULAR DEGENERATION.

PURPOSE: To enable in vivo analysis of drusen composition and lifecycle, the macular nodular and cuticular drusen were assessed using histology. METHODS: Median and interquartile range of base widths of single (nonconfluent) nodular drusen in three sources were determined histologically: 43 eyes of 43 clinically undocumented donors, in an online resource; one eye with punctate hyperfluorescence in fluorescein angiography; and two eyes of one patient with bilateral "starry sky" cuticular drusen. All tissues were processed for high-resolution epoxy-resin histology and for cuticular drusen, transmission electron microscopy. RESULTS: All drusen localized between the retinal pigment epithelium basal lamina and inner collagenous layer of the Bruch membrane. They were solid, globular, homogeneously stained with toluidine blue, and uncovered by basal laminar deposit and basal mounds. Median base widths were 13.0 µ m (Source 1, N = 128 drusen, interquartile range 7.7, 20.0 µ m), 15.3 µ m (Source 2, N = 87, interquartile range 10.6, 20.5 µ m), and 7.3 µ m (Source 3, N = 78, interquartile range 3.9, 14.1 µ m). CONCLUSION: In three samples, >90% of solitary nodular drusen were <30 µ m, the visibility threshold in color fundus photography; these drusen are hyperfluorescent in fluorescein angiography. Whether these progress to soft drusen, known as high-risk from epidemiology studies and hypofluorescent, may be determinable from multimodal imaging datasets that include fluorescein angiography.

BILATERAL MACULAR CHOROIDAL ABNORMALITIES WITH DRUSENOID DEPOSITS IN PATIENTS WITH UNILATERAL PERIPHERAL EXUDATIVE HEMORRHAGIC CHORIORETINOPATHY.

PURPOSE: To investigate bilateral macular features on optical coherence tomography in patients with unilateral peripheral exudative hemorrhagic chorioretinopathy (PEHCR). METHODS: In this cross-sectional study, optical coherence tomography features of affected eyes (PEHCR group, n = 30) and unaffected contralateral eyes (contralateral group, n = 30) were investigated. Age-matched and sex-matched patients with polypoidal choroidal vasculopathy (PCV group, n = 51) and healthy controls (normal group, n = 50) were included to compare choroidal thickness, measured at six points apart from the fovea, with the PEHCR group. RESULTS: Subretinal drusenoid deposits were the most common feature in the PEHCR (20%) and contralateral (23%) groups, followed by soft drusen. Although the macular choroid was comparably thin in both the PEHCR and contralateral groups, pachyvessels were also observed. The choroids of the PEHCR group were significantly thinner than those of the normal group at the subfovea and 1-mm temporal to the fovea and considerably thinner than those of the polypoidal choroidal vasculopathy group from 3-mm nasal to 3-mm temporal to the fovea. CONCLUSION: In patients with unilateral PEHCR, bilateral choroidal thinning and drusenoid deposit accumulation were noted in the macula. The pathophysiology of PEHCR may be a rare peripheral complication of age-related macular degeneration with pathologic choroid.

SUBRETINAL DRUSENOID DEPOSITS AND SOFT DRUSEN: Are They Markers for Distinct Retinal Diseases?

PURPOSE: Soft drusen and subretinal drusenoid deposits (SDDs) characterize two pathways to advanced age-related macular degeneration (AMD), with distinct genetic risks, serum risks, and associated systemic diseases. METHODS: One hundred and twenty-six subjects with AMD were classified as SDD (with or without soft drusen) or non-SDD (drusen only) by retinal imaging, with serum risks, genetic testing, and histories of cardiovascular disease (CVD) and stroke. RESULTS: There were 62 subjects with SDD and 64 non-SDD subjects, of whom 51 had CVD or stroke. SDD correlated significantly with lower mean serum high-density lipoprotein (61 ± 18 vs. 69 ± 22 mg/dL, P = 0.038, t-test), CVD and stroke (34 of 51 SDD, P = 0.001, chi square), ARMS2 risk allele (P = 0.019, chi square), but not with CFH risk allele (P = 0.66). Non-SDD (drusen only) correlated/trended with APOE2 (P = 0.032) and CETP (P = 0.072) risk alleles (chi square). Multivariate independent risks for SDD were CVD and stroke (P = 0.008) and ARMS2 homozygous risk (P = 0.038). CONCLUSION: Subjects with subretinal drusenoid deposits and non-SDD subjects have distinct systemic associations and serum and genetic risks. Subretinal drusenoid deposits are associated with CVD and stroke, ARMS2 risk, and lower high-density lipoprotein; non-SDDs are associated with higher high-density lipoprotein, CFH risk, and two lipid risk genes. These and other distinct associations suggest that these lesions are markers for distinct diseases.

A COMMON FINDING IN FOVEAL-SPARING EXTENSIVE MACULAR ATROPHY WITH PSEUDODRUSEN IMPLICATES BASAL LAMINAR DEPOSITS.

PURPOSE: To characterize structural and clinical alterations preceding the diffuse macular atrophy in extensive macular atrophy with pseudodrusen (EMAP) and their evolution toward atrophic changes. METHODS: A retrospective chart review was performed of patients with early-onset reticular pseudodrusen (i.e., pre-EMAP) younger than 55 years and EMAP with foveal sparing. Patients were included if they had complete medical records and multimodal imaging. RESULTS: A total of 12 patients were reviewed, of whom 4 of 12 patients (7 eyes) presented a pre-EMAP stage, characterized by the presence of pseudodrusen-like deposits without atrophic changes, while the remaining 8 of 12 patients (10 eyes) exhibited EMAP with foveal sparing (60.1 ± 6.4 years). Subretinal deposits of various stages tended to fade, leaving subretinal pigment epithelium accumulation of hyperreflective material with a physical separation between the retinal pigment epithelium-basal lamina and the Bruch membrane, along with the persistence of hyperreflective material after retinal pigment epithelium loss. These findings preceded atrophy development in a pre-EMAP stage and the EMAP stage with foveal sparing. CONCLUSION: Our findings presented distinct multimodal imaging features in eyes with reticular pseudodrusen depicting a peculiar phenotype of rapidly progressing atrophy in midlife. The disease spectrum may include other forms of geographic atrophy allied by thickened basal laminar deposits.

Drusenoid Pigment Epithelial Detachment: Genetic and Clinical Characteristics.

Few studies report drusenoid pigment epithelial detachment (DPED) in Asians. In this multicenter study, we report the clinical and genetic characteristics of 76 patients with DPED, and, for comparison, 861 patients with exudative age-related macular degeneration (AMD) were included. On the initial presentation, the mean best-corrected visual acuity was 0.087 ± 0.17 (logMAR unit), and mean DPED height and width were 210 ± 132 and 1633 ± 1114 µm, respectively. Fifty-one (67%) patients showed macular neovascularization in the contralateral eye. The risk allele frequency of both ARMS2 A69S and CFH I62V was significantly higher in DPED than in typical AMD and polypoidal choroidal vasculopathy (PCV) (ARMS2 A69S risk allele frequency: DPED 77% vs. typical AMD 66% vs. PCV 57%, CFH I62V risk allele frequency: DPED 87% vs. typical AMD 73% vs. PCV 73%), although the risk allele frequency of both genes was similar between the DPED group and retinal angiomatous proliferation (RAP) group (ARMS2 A69S: p = 0.32, CFH I62V, p = 0.11). The prevalence of reticular pseudodrusen (RPD) was highest in RAP (60%), followed by DPED (22%), typical AMD (20%), and PCV (2%). Although the prevalence of RPD differs between DPED and RAP, these entities share a similar genetic background in terms of ARMS2 and CFH genes.

Choriocapillaris dropout in early age-related macular degeneration.

Loss of choriocapillaris (CC) in advanced age-related macular degeneration (AMD) is well documented but changes in early AMD have not been quantified. Postmortem eyes from donors with clinically documented early AMD were examined in choroidal whole mounts to determine the area, pattern, and severity of CC loss. Choroids from postmortem human eyes without AMD (n = 7; mean age = 86.1) and from eyes with a Grade 2 clinical classification of early AMD (n = 7; mean age = 87) were immunolabeled with Ulex europaeus agglutinin (UEA) lectin-FITC to stain blood vessels. Whole mounts were imaged using confocal microscopy and image analysis was performed to determine the area of vascular changes and density of vasculature (percent vascular area, %VA). All areas evaluated had a complete RPE monolayer upon gross examination. In age-matched control eyes, the CC had broad lumens and a homogenous pattern of freely interconnecting capillaries. The mean %VA ± standard deviation in submacula of control subjects was 78.1 ± 3.25%. In eyes with early AMD, there was a significant decrease in mean %VA to 60.1 ± 10.4% (p < 0.0001). The paramacular %VA was not significantly different in eyes with or without AMD. The area of submacular choroid affected by CC dropout was 0.04 ± 0.09 mm2 in control eyes. In eyes with early AMD, the mean area affected by CC dropout was significantly increased (10.4 ± 6.1 mm2; p < 0.001). In some cases, incipient neovascular buds were observed at the border of regions with CC dropout in early AMD choroids. In conclusion, UEA lectin-labeled choroidal whole mounts from donors with clinically documented early AMD has provided a unique opportunity to examine regional changes in vascular pathology associated with choriocapillaris. The study demonstrated attenuation of submacular CC in early AMD subjects but no vascular pathology was observed outside the submacular region. While the affected area in some eyes was quite extensive histologically, these changes may not be detectable clinically using standard in vivo imaging.

A DOUBLE-MASKED, RANDOMIZED, SHAM-CONTROLLED, SINGLE-CENTER STUDY WITH PHOTOBIOMODULATION FOR THE TREATMENT OF DRY AGE-RELATED MACULAR DEGENERATION.

PURPOSE: The LIGHTSITE I study investigated the efficacy and safety of photobiomodulation (PBM) treatment in subjects with dry age-related macular degeneration. METHODS: Thirty subjects (46 eyes) were treated with the Valeda Light Delivery System, wherein subjects underwent two series of treatments (3× per week for 3-4 weeks) over 1 year. Outcome measures included best-corrected visual acuity, contrast sensitivity, microperimetry, central drusen volume and drusen thickness, and quality of life assessments. RESULTS: Photobiomodulation-treated subjects showed a best-corrected visual acuity mean letter score gain of 4 letters immediately after each treatment series at Month 1 (M1) and Month 7 (M7). Approximately 50% of PBM-treated subjects showed improvement of ≥5 letters versus 13.6% in sham-treated subjects at M1. High responding subjects (≥5-letter improvement) in the PBM-treated group showed a gain of 8 letters after initial treatment (P < 0.01) and exhibited earlier stages of age-related macular degeneration disease. Statistically significant improvements in contrast sensitivity, central drusen volume, central drusen thickness, and quality of life were observed (P < 0.05). No device-related adverse events were reported. CONCLUSION: Photobiomodulation treatment statistically improved clinical and anatomical outcomes with more robust benefits observed in subjects with earlier stages of dry age-related macular degeneration. Repeated PBM treatments are necessary to maintain benefits. These pilot findings support previous reports and suggest the utility of PBM as a safe and effective therapy in subjects with dry age-related macular degeneration.

Drusen in patient-derived hiPSC-RPE models of macular dystrophies.

Age-related macular degeneration (AMD) and related macular dystrophies (MDs) are a major cause of vision loss. However, the mechanisms underlying their progression remain ill-defined. This is partly due to the lack of disease models recapitulating the human pathology. Furthermore, in vivo studies have yielded limited understanding of the role of specific cell types in the eye vs. systemic influences (e.g., serum) on the disease pathology. Here, we use human induced pluripotent stem cell-retinal pigment epithelium (hiPSC-RPE) derived from patients with three dominant MDs, Sorsby's fundus dystrophy (SFD), Doyne honeycomb retinal dystrophy/malattia Leventinese (DHRD), and autosomal dominant radial drusen (ADRD), and demonstrate that dysfunction of RPE cells alone is sufficient for the initiation of sub-RPE lipoproteinaceous deposit (drusen) formation and extracellular matrix (ECM) alteration in these diseases. Consistent with clinical studies, sub-RPE basal deposits were present beneath both control (unaffected) and patient hiPSC-RPE cells. Importantly basal deposits in patient hiPSC-RPE cultures were more abundant and displayed a lipid- and protein-rich "drusen-like" composition. Furthermore, increased accumulation of COL4 was observed in ECM isolated from control vs. patient hiPSC-RPE cultures. Interestingly, RPE-specific up-regulation in the expression of several complement genes was also seen in patient hiPSC-RPE cultures of all three MDs (SFD, DHRD, and ADRD). Finally, although serum exposure was not necessary for drusen formation, COL4 accumulation in ECM, and complement pathway gene alteration, it impacted the composition of drusen-like deposits in patient hiPSC-RPE cultures. Together, the drusen model(s) of MDs described here provide fundamental insights into the unique biology of maculopathies affecting the RPE-ECM interface.

Novel Programmed Cell Death as Therapeutic Targets in Age-Related Macular Degeneration?

Age-related macular degeneration (AMD) is a leading cause of severe visual loss among the elderly. AMD patients are tormented by progressive central blurring/loss of vision and have limited therapeutic options to date. Drusen accumulation causing retinal pigment epithelial (RPE) cell damage is the hallmark of AMD pathogenesis, in which oxidative stress and inflammation are the well-known molecular mechanisms. However, the underlying mechanisms of how RPE responds when exposed to drusen are still poorly understood. Programmed cell death (PCD) plays an important role in cellular responses to stress and the regulation of homeostasis and diseases. Apart from the classical apoptosis, recent studies also discovered novel PCD pathways such as pyroptosis, necroptosis, and ferroptosis, which may contribute to RPE cell death in AMD. This evidence may yield new treatment targets for AMD. In this review, we summarized and analyzed recent advances on the association between novel PCD and AMD, proposing PCD's role as a therapeutic new target for future AMD treatment.

Comparison of histologic findings in age-related macular degeneration with RPE flatmount images.

Purpose: To visualize and analyze ex vivo flatmounted human RPE morphology from patients with age-related macular degeneration (AMD), and to compare the morphology with histologic findings. To establish whether the sub-RPE structures identified en face in RPE flatmount preparations are drusen with histopathological registration in serial sections. To detect characteristic patterns found en face in RPE with the same structures in histological cross sections from eyes from cadavers of patients with AMD. Methods: Twenty-eight postmortem eyes from 14 patients (16 eyes with AMD and 12 age-matched control eyes) were oriented and microdissected yielding a RPE-choroid preparation. The tissues were flatmounted, stained with Alexa Fluor 635 Phalloidin (AF635-phalloidin) for f-actin and propidium iodide for DNA, and imaged using confocal microscopy. Portions of tissue from macular regions were processed for electron microscopic examination. After confocal imaging, the samples were remounted for histologic processing, embedded in paraffin, and serially sectioned perpendicular to the plane of the RPE-choroid sheet. Scaled two-dimensional (2D) maps of drusen locations found with the histological cross sections were constructed and correlated with the en face confocal microscopic images. Results: Twenty-eight postmortem eyes with a mean time of death to tissue preservation of 23.7 h (range 8.0­51 h) from 14 donors (seven women and seven men) with an average age of 78 years (range 60­93 years) were evaluated. Eight donors had AMD, and six served as controls. Scattered small, hard drusen were present in the periphery of the eyes with AMD and the healthy eyes. The macular region of the eyes with AMD contained small (<63 µm), medium (63.0­124 µm), and large ( ≥ 125 µm) drusen. The RPE was arranged in rosette-like structures overlying small drusen, attenuated overlying medium-sized drusen, and consisted of large multinucleated cells overlying large drusen. The RPE in the area of geographic atrophy was attenuated and depigmented. Conclusions: Confocal images of flatmounts from eyes with AMD showed RPE patterns overlying various types of drusen and geographic atrophy that correlated with histologic characteristics. We propose RPE repair mechanisms that may result in the patterns that we observed.

FOCAL DISRUPTIONS IN ELLIPSOID ZONE AND INTERDIGITATION ZONE ON SPECTRAL-DOMAIN OPTICAL COHERENCE TOMOGRAPHY IN PACHYCHOROID PIGMENT EPITHELIOPATHY.

PURPOSE: To describe a distinctive focal disruption of the ellipsoid zone (EZ)/interdigitation zone (IZ) determined by spectral-domain optical coherence tomography in eyes with pachychoroid pigment epitheliopathy. METHODS: Twenty patients with focal EZ/IZ disruptions associated with pachychoroid without history or findings indicative of subretinal fluid were evaluated. Detailed clinical/imaging characteristics and their longitudinal changes were evaluated. RESULTS: A total of 27 lesions from 21 eyes were included. The mean subfoveal choroidal thickness was 450 µm. In six of seven eyes with previous imaging data to compare, characteristic drusenoid lesions associated with thick choroid preceded focal EZ/IZ disruptions at the corresponding sites. Dilated outer choroidal vessels were noted beneath the focal EZ/IZ disruption in 24 lesions (88.9%), with attenuation of choriocapillaris in 18 lesions (66.7%). The external limiting membrane was intact in all lesions. All except three eyes did not show morphologic changes, and mean visual acuity was maintained (Snellen equivalent, 20/25) during a mean follow-up period of 20 months. CONCLUSION: Focal disruptions of the EZ/IZ band can develop in pachychoroid eyes in the absence of subretinal fluid, with a stable clinical course, and possibly as a result of regression of drusenoid lesions. This may represent an atrophic form of pachychoroid manifestation.

PREVALENCE AND CLINICAL CHARACTERISTICS OF PACHYDRUSEN IN POLYPOIDAL CHOROIDAL VASCULOPATHY: Multimodal Image Study.

PURPOSE: To investigate the prevalence of a newly defined drusen type, pachydrusen, soft drusen, and subretinal drusenoid deposits in eyes with polypoidal choroidal vasculopathy and fellow eyes and the relationship between each drusen type and the choroidal thickness, vascular morphology, and hyperpermeability. METHODS: The 169 eyes of 90 patients with polypoidal choroidal vasculopathy were retrospectively reviewed. The prevalence of each drusen type was evaluated using color fundus photography and optical coherence tomography. The choroidal thickness and presence of pachyvessels on optical coherence tomography and choroidal vascular hyperpermeability on indocyanine green angiography were compared among the drusen groups. RESULTS: Pachydrusen, soft drusen, and subretinal drusenoid deposits were found in 49.3%, 12.3%, and 6.9% in polypoidal choroidal vasculopathy eyes. The mean subfoveal choroidal thickness of the pachydrusen, soft drusen, and subretinal drusenoid deposit groups was 403.1, 184.4, and 176.4 µm. The pachydrusen group showed significantly thicker choroid than the others. The choroidal hyperpermeability was noticed at 41.7%, 0%, and 0% and the pachyvessel was observed at 80.6%, 44.4%, and 40% in pachydrusen, soft drusen, and subretinal drusenoid deposit groups, respectively. CONCLUSION: In patients with polypoidal choroidal vasculopathy, pachydrusen was prevalent and associated with thicker choroid. Polypoidal choroidal vasculopathy with pachydrusen was highly associated with choroidal vascular hyperpremeability and pachyvessel morphology than other types of drusen.

CLINICOPATHOLOGIC CORRELATION OF GEOGRAPHIC ATROPHY SECONDARY TO AGE-RELATED MACULAR DEGENERATION.

PURPOSE: In an eye with geographic atrophy (GA) secondary to age-related macular degeneration, we correlated ex vivo histologic features with findings recorded in vivo using optical coherence tomography (OCT), near-infrared reflectance imaging, and fundus autofluorescence. METHODS: In the left eye of an 86-year-old white woman, in vivo near-infrared reflectance and eye-tracked OCT B-scans at each of 6 clinic visits and a baseline fundus autofluorescence image were correlated with high-resolution histologic images of the preserved donor eye. RESULTS: Clinical imaging showed a small parafoveal multilobular area of GA, subfoveal soft drusen, refractile drusen, hyperreflective lines near the Bruch membrane, subretinal drusenoid deposit (reticular pseudodrusen), and absence of hyperautofluorescent foci at the GA margin. By histology, soft drusen end-stages included avascular fibrosis with highly reflective cholesterol crystals. These accounted for hyperreflective lines near the Bruch membrane in OCT and plaques in near-infrared reflectance imaging. Subretinal drusenoid deposit was thick, continuous, extracellular, extensive outside the fovea, and associated with distinctive retinal pigment epithelium dysmorphia and photoreceptor degeneration. A hyporeflective wedge corresponded to ordered Henle fibers without cellular infiltration. The external limiting membrane descent, which delimits GA, was best visualized in high-quality OCT B-scans. Retinal pigment epithelium and photoreceptor changes at the external limiting membrane descent were consistent with our recent histologic survey of donor eyes. CONCLUSION: This case informs on the extent, topography, and lifecycle of extracellular deposits. High-quality OCT scans are required to reveal all tissue features relevant to age-related macular degeneration progression to GA, especially the external limiting membrane descent. Histologically validated signatures of structural OCT B-scans can serve as references for other imaging modalities.

Choroidal morphology under pachydrusen.

IMPORTANCE: To reveal choroidal morphological profiles under pachydrusen. BACKGROUND: Drusen in pachychoroid disorders show certain differences from conventional drusen and are recently named as "pachydrusen." This study analysed the specific choroidal morphology under pachydrusen. DESIGN: This study is a cross-sectional case series. PARTICIPANTS: Enrolled were 136 eyes with pachydrusen from 134 patients. METHODS: The presence of pachydrusen in fundus area covered by a 12 × 9 mm2 optical coherence tomography (OCT) image was accessed in eyes with pachychoroid-related diseases or their fellow eyes using colour fundus photography and swept source OCT. Choroidal morphology under the pachydrusen was analysed using OCT B-scans and en face images. MAIN OUTCOME MEASURES: Choroidal thicknesses and topographical correlation between pachydrusen and pachyvessels. RESULTS: A total of 225 pachydrusen in 136 eyes were analysed. The mean number of pachydrusen was 1.65 ± 1.07 per eye. Most pachydrusen were located para- or perifoveally (37 subfoveal, 86 parafoveal and 102 perifoveal). The proportion of Haller's layer to total choroidal thickness was higher at the area of the pachydrusen compared to the subfovea (0.881 ± 0.081 vs 0.765 ± 0.111, P < 0.001). In multimodal image analysis, 90.1% of pachydrusen identified using fundus photography and OCT B-scan were located at the area of a dilated Haller vessel (pachyvessel) seen on en face images. CONCLUSIONS AND RELEVANCE: Choroidal morphology under the pachydrusen showed increased Haller's layer thickness with an attenuated choriocapillaris layer, which is the hallmark of pachychoroid definition. Topographically, their locations correlated with the underlying pachyvessel.

Exposure to excessive blue LED light damages retinal pigment epithelium and photoreceptors of pigmented mice.

To determine the characteristics of the damages of the retinal pigment epithelium (RPE) and photoreceptors of pigmented mice induced by exposure to blue light emitting diode (LED) light, and to determine the mechanisms causing the damages. Exposure to blue LED light for 3 days induced retinal damage, and the characteristics of the damage differed from that induced by white fluorescent light exposure. Ophthalmoscopy showed that blue LED exposure for 3 days induced white spots on the retina, and histological examinations showed materials accumulated at the IS/OS junction of the photoreceptors. The accumulated materials were stained by ionized calcium binding adapter molecule-1 (Iba-1), a marker for macrophages. The debris was also positive for periodic acid-Schiff (PAS). An enlarging the area of RPE was detected just after the blue LED exposure especially around the optic nerve, and this led to a secondary degeneration of the photoreceptors. Exposure of pigmented mice to 3 consecutive days of blue LED light will cause RPE and photoreceptor damage. The damage led to an accumulation of macrophages and drusen-like materials around the outer segments of the photoreceptors. This blue light exposed model may be useful for investigating the pathogenesis of non-exudative age-related macular degeneration.

DISEASE EXPRESSION IN NONEXUDATIVE AGE-RELATED MACULAR DEGENERATION VARIES WITH CHOROIDAL THICKNESS.

PURPOSE: To investigate the relationship between subfoveal choroidal thickness and disease manifestation in a series of eyes with nonexudative age-related macular degeneration (AMD). METHODS: Retrospective study of eyes with nonexudative AMD. The extracellular deposits present, drusen and subretinal drusenoid deposits (SDD, pseudodrusen) along with a newly recognized form of drusen, pachydrusen, were graded and compared with choroidal thickness as determined by optical coherence tomography. Demographic and imaging information was evaluated with descriptive statistics and generalized estimating equations. RESULTS: There were 94 eyes of 71 patients, who had a mean age of 78.1 years. Soft drusen alone were found in 45 eyes (47.9%) and subretinal drusenoid deposit with or without drusen in 38 (40.4%). Pachydrusen, which were typically larger than 125 µm, often had an irregular outer contour, showed a scattered distribution over the posterior pole and occurred in isolation or in groups of only a few drusen were found in 11 (11.7%). The mean subfoveal choroidal thickness in the soft drusen group was 227.9 µm, in the subretinal drusenoid deposit group 167.3 µm, and in the pachydrusen group 419 µm. The differences between the groups were highly significant. CONCLUSION: Extracellular deposits, subretinal drusenoid deposits and drusen, which are on either side of the retinal pigment epithelium, respectively, are common in nonexudative AMD. A new form of drusen presentation could be differentiated from typical soft drusen and was associated with thicker choroids. Disease manifestation in nonexudative AMD seems to be associated with choroidal thickness. Each of these has potential to lead to specific forms of late AMD.

IMPROVING THE AGE-RELATED MACULAR DEGENERATION CONSTRUCT: A New Classification System.

Previous models of disease in age-related macular degeneration (AMD) were incomplete in that they did not encompass subretinal drusenoid deposits (pseudodrusen), subtypes of neovascularization, and polypoidal choroidal vasculopathy. In addition, Type 3 neovascularization starts in the retina and may not necessarily involve the choroid. As such, the term choroidal neovascularization is not appropriate for these eyes. The new aspects in the AMD construct are to include specific lipoprotein extracellular accumulations, namely drusen and subretinal drusenoid deposits, as early AMD. The deposition of specific types of deposit seems to be highly correlated with choroidal thickness and topographical location in the macula. Late AMD includes macular neovascularization or atrophy. The particular type of extracellular deposit is predictive of the future course of the patient. For example, eyes with subretinal drusenoid deposits have a propensity to develop outer retinal atrophy, complete outer retinal and retinal pigment epithelial atrophy, or Type 3 neovascularization as specific forms of late AMD. Given Type 3 neovascularization may never involve the choroid, the term macular neovascularization is suggested for the entire spectrum of neovascular disease in AMD. In contrast to older classification systems, the proposed system encompasses the relevant presentations of disease and more precisely predicts the future course of the patient. In doing so, the concept was developed that there may be genetic risk alleles, which are not necessarily the same alleles that influence disease expression.

Retinal Thickness Changes throughout the Natural History of Drusen in Age-related Macular Degeneration.

SIGNIFICANCE: Drusen are associated with retinal thinning in age-related macular degeneration (AMD). These changes, however, have mostly been examined at single time points, ignoring the evolution of drusen from emergence to regression. Understanding the full breadth of retinal changes associated with drusen will improve understanding of disease pathogenesis. PURPOSE: The purpose of this study was to assess how the natural history of drusen affects retinal thickness, focusing on the photoreceptor and retinal pigment epithelium (RPE) layers. METHODS: Spectral domain optical coherence tomography of subjects with intermediate AMD (n = 50) who attended the Centre for Eye Health, Sydney, Australia, for two separate visits (476 ± 16 days between visits) was extracted. Scans were automatically segmented with manufacturer software then assessed for drusen that had emerged, grown, or regressed between visits. For each identified lesion, the thickness of each retinal layer at the drusen peak and at adjacent drusen-free areas (150 µm nasal and temporal to the druse) was compared between visits. RESULTS: Before drusen emergence, the RPE was significantly thicker at the drusen site (14.2 ± 2.6%) compared with neighboring drusen-free areas. There was a 71% sensitivity of RPE thickening predicting drusen emergence. Once drusen emerged, significant thinning of all outer retinal layers was observed, consistent with previous studies. Drusen growth was significantly correlated with thinning of the outer retina (r = -0.38, P < .001). Drusen regression resulted in outer retinal layers returning to thicknesses not significantly different from baseline. CONCLUSIONS: The natural history of drusen is associated with RPE thickening before drusen emergence, thinning of the outer nuclear layer as well as photoreceptor and RPE layers proportional to drusen growth, and return to baseline thickness after drusen regression. These findings have useful clinical applications, providing a potential marker for predicting drusen emergence for AMD prognostic and intervention studies and highlighting that areas of normal retinal thickness in AMD may be former sites of regressed drusen.

Outer Retina and Choroidal Thickness in Intermediate Age-Related Macular Degeneration: Reticular Pseudodrusen Findings.

PURPOSE: To evaluate outer retina and choroidal thickness in subjects with intermediate age-related macular degeneration (iAMD) and to describe associations with the presence of reticular pseudodrusen (RPD). METHODS: This was a retrospective, cross-sectional analysis of 157 consecutive eyes (specifically: 62 eyes classified as having RPD and 95 eyes with drusen ≥125 µm). Only cases with digital color fundus photographs, red-free, and infrared, obtained and graded according to the Age-Related Eye Disease Study to define iAMD, were used for this study. Outer retina and choroidal thickness were manually segmented and quantified at 12 locations in the horizontal meridian. RESULTS: RPD appeared to be associated with thinning of the outer layers even after adjustment for gender and age. The presence of RPD in iAMD decreased with increase of choroidal thickness (total odds ratio [OR] 0.991, 95% confidence interval [CI] 0.985-0.996; nasal OR 0.992, 95% CI 0.986-0.997), with increased thickness of the myoid zone of the photoreceptors (total OR 0.812, 95% CI 0.688-0.958; nasal OR 0.863, 95% CI 0.755-0.987) and with increased thickness of the outer segment of the photoreceptors (total OR 0.850, 95% CI 0.731-0.989; nasal OR 0.857, 95% CI 0.736-0.989). CONCLUSIONS: The greatest differences between eyes with and without RPD are found at the level of the choroidal thickness and at the level of the photoreceptors.