Imaging of chorioretinal anastomoses in vascularized retinal pigment epithelium detachments

Review of type 3 macular neovascularization in age-related macular degeneration: no DRAMA (Deep Retinal Age-related Microvascular Anomalies)

Type 3 macular neovascularization (MNV) is a unique form of neovascular age-related macular degeneration (AMD) that presents distinct pathogenetic features, clinical manifestations, and prognostic considerations when compared to types 1 and 2 MNV. Insights gained from clinicopathological correlations, bridging in vivo examination techniques with ex vivo histological analysis, have significantly enhanced our comprehension of this MNV phenotype, shaped current management strategies and influenced future directions for therapeutics. The particularities of type 3 MNV, which may largely stem from its origin from the retinal vasculature, are critically important for predicting the disease course. Our current understanding suggests that type 3 MNV occurs in response to retinal pigment epithelium (RPE) disruption and photoreceptor loss when neovessels originating from the deep capillary plexus are accompanied by activated Müller glia as they infiltrate sub-retinal pigment epithelium basal laminar deposits. Dysregulation of angiogenic and angiostatic factors are thought to play a key role in its pathogenesis. The prognosis for type 3 MNV is likely bilateral involvement and progression towards macular atrophy. It may be imperative for practitioners to distinguish type 3 MNV from other mimicking pathologies such as intraretinal microvascular anomalies, which are also part of the type 3 disease spectrum. For instance, deep retinal age-related microvascular anomalies (DRAMA) may present with similar features on multimodal imaging yet may necessitate distinct management protocols. Distinguishing between these conditions may be vital for implementing tailored treatment regimens and improving patient outcomes in the diverse landscape of AMD phenotypes in the future.

Current Perspectives on Type 3 Macular Neovascularization due to Age-Related Macular Degeneration

BACKGROUND

The aim of this review was to systematically summarize the current knowledge on type 3 macular neovascularization (MNV3) in age-related macular degeneration (AMD).

SUMMARY

Recent histopathologic and multimodal imaging findings led to the consensus definition of the new term "type 3 macular neovascularization" in AMD. MNV3 originates in the deep vascular plexus as a neovascular process without connection with the retinal pigment epithelium in the initial stages. This type has numerous clinical and pathomorphologic features that separate it from the other two types of MNV in AMD. Besides, its frequency appears to be higher than previously thought. In optical coherence tomography (OCT), MNV3 can be classified into stages 1-3. Hyperreflective foci in the outer retina possibly represent a precursor lesion. In addition, MNV3 is characterized by a strong association with reticular pseudodrusen, a high rate of bilaterality, close associations with advanced age and arterial hypertension, decreased choroidal thickness, and decreased choriocapillaris flow signals. Data from latest anti-vascular endothelial growth factor studies in MNV3 suggest that the OCT biomarkers in intraretinal and subretinal fluids should be interpreted differently than in the other types. Additionally, data from MNV3 eyes should be analyzed separately, allowing optimal type-specific treatment strategies in the future.

KEY MESSAGES

This review highlights the need for accurate characterization of neovascular AMD lesions and an MNV type-specific approach, particularly for MNV3.

Towards a better understanding of non-exudative choroidal and macular neovascularization

Non-exudative macular and choroidal neovascularization (MNV and CNV) usually refers to the entity of treatment-naïve type 1 neovascularization in the absence of associated signs of exudation. Histopathological studies, dating back in the early 70s, identified the presence of non-exudative MNV, but the first clinical report of this finding was in the late 90s using indocyanine green angiography in eyes with age-related macular degeneration (AMD). With more advanced retinal imaging, there has been an ever increasing appreciation of non-exudative MNV associated with AMD and CNV with other macular disorders. However, consensus regarding the exact definition and the clinical management of this entity is lacking. Furthermore, there may be variation in the imaging features and clinical course suggesting that a spectrum of disease may exist. Herein, we review the large body of published work that has provided a better understanding of non-exudative MNV and CNV in the last decade. The prevalence, multimodal imaging features, clinical course, and response to treatment are discussed to elucidate further key insights about this entity. Based on these observations, this review also proposes a new theory about the origin and course of different sub-types of non-exudative MNV/CNV which can have different etiologies and pathways according to the clinical context of disease.

Intraretinal Cysts as a Manifestation of Retinal Angiomatous Proliferation in Optical Coherence Tomography Angiography

Background and Objectives: Intraretinal cysts are common pathology observed inspectral domain optical coherence tomography (SDOCT) in patients with neovascular form of age-related macular degeneration (AMD). The aim of the study was to determine if the presence of intraretinal cysts is positively correlated with diagnosis of retinal angiomatous proliferation (RAP) in optical coherence tomography angiography (OCTA). Material and Methods: A total of 21 eyes with intraretinal cysts in SDOCT exam (Group1) and 21 eyes with subretinal fluid(Group 2) were enrolled into the study. In each eye, the presence of intraretinal neovascularization (IRN) and chorioretinal anastomosis (CRA) was evaluated in OCTA by two experienced graders. Results: IRN was observed in 20 eyes (95.2%) from Group 1 and 5 eyes (23.8%) from Group 2. Features of CRA were found in 18 eyes (80.95%) and 16 eyes (76.2%) respectively for Group 1 and 2. Patients with cysts are 50 (95% CI: 5.43−460.52) times more likely to have IRN (p < 0.001). Conclusions: The presence of intraretinal cysts on SDOCT retinal sections in eyes with neovascular AMD corresponds to the presence of IRN on OCTA examination. The results indicate that the absence of a cyst does not exclude the presence of IRN and CRA which can be identified on OCTA.

Transcriptional and Distributional Profiling of Microglia in Retinal Angiomatous Proliferation

Macular neovascularization type 3, formerly known as retinal angiomatous proliferation (RAP), is a hallmark of age-related macular degeneration and is associated with an accumulation of myeloid cells, such as microglia (MG) and infiltrating blood-derived macrophages (MAC). However, the contribution of MG and MAC to the myeloid cell pool at RAP sites and their exact functions remain unknown. In this study, we combined a microglia-specific reporter mouse line with a mouse model for RAP to identify the contribution of MG and MAC to myeloid cell accumulation at RAP and determined the transcriptional profile of MG using RNA sequencing. We found that MG are the most abundant myeloid cell population around RAP, whereas MAC are rarely, if ever, associated with late stages of RAP. RNA sequencing of RAP-associated MG showed that differentially expressed genes mainly contribute to immune-associated processes, including chemotaxis and migration in early RAP and proliferative capacity in late RAP, which was confirmed by immunohistochemistry. Interestingly, MG upregulated only a few angiomodulatory factors, suggesting a rather low angiogenic potential. In summary, we showed that MG are the dominant myeloid cell population at RAP sites. Moreover, MG significantly altered their transcriptional profile during RAP formation, activating immune-associated processes and exhibiting enhanced proliferation, however, without showing substantial upregulation of angiomodulatory factors.

Clinical Pathological Features and Current Animal Models of Type 3 Macular Neovascularization

Type 3 macular neovascularization (MNV3), or retinal angiomatous proliferation (RAP), is a distinct type of neovascular age-related macular degeneration (AMD), which is a leading cause of vision loss in older persons. During the past decade, systematic investigation into the clinical, multimodal imaging, and histopathological features and therapeutic outcomes has provided important new insight into this disease. These studies favor the retinal origin of MNV3 and suggest the involvement of retinal hypoxia, inflammation, von Hippel–Lindau (VHL)–hypoxia-inducible factor (HIF)–vascular endothelial growth factor (VEGF) pathway, and multiple cell types in the development and progression of MNV3. Several mouse models, including the recently built Rb/p107/Vhl triple knockout mouse model by our group, have induced many of the histological features of MNV3 and provided much insight into the underlying pathological mechanisms. These models have revealed the roles of retinal hypoxia, inflammation, lipid metabolism, VHL/HIF pathway, and retinoblastoma tumor suppressor (Rb)–E2F cell cycle pathway in the development of MNV3. This article will summarize the clinical, multimodal imaging, and pathological features of MNV3 and the diversity of animal models that exist for MNV3, as well as their strengths and limitations.

THE RAP STUDY, REPORT TWO: The Regional Distribution of Macular Neovascularization Type 3, a Novel Insight Into Its Etiology

PURPOSE

To explore the regional distribution of macular neovascularization type 3 (MNV3).

METHODS

Seventy-eight eyes of 78 patients were reviewed. We defined the location of each lesion after applying a modified ETDRS grid and the incidence of simultaneous MNV1 or 2. Also, we investigated the distribution of MNV3 at the outline of the foveal avascular zone and when the diameter of foveal avascular zone was less than 325 µm.

RESULTS

The distribution of MNV3 was 4 lesions (5%) from the center to 500 µm, 72 (92%) from 500 µm to 1500 µm, and 2 (3%) from 1,500 µm to 3000 µm. The distribution in respect of the ETDRS fields was 7 (9%) nasal, 16 (20%) superior, 32 (40%) temporal, and 23 (31%) inferior. No additional MNV1 or 2 were found elsewhere. Most lesions tended to distribute along straight bands radiating from the perifoveal area, mainly in the temporal half (72%). None of the cases had MNV3 at the boundary of the foveal avascular zone. Only five cases had foveal avascular zone diameter of less than 325 µm, the closest lesion was 425 µm away from the center.

CONCLUSION

MNV3 lesions are most likely neither symmetrical nor uniformly distributed. They have a higher affinity to distribute radially in the temporal perifoveal area.

Unaffected fellow eye neovascularization in patients with type 3 neovascularization: Incidence and risk factors

Purpose

To evaluate the incidence and risk factors of neovascularization in unaffected fellow eyes of patients diagnosed with type 3 neovascularization in Korea.

Methods

This retrospective study included 93 unaffected fellow eyes of 93 patients diagnosed with type 3 neovascularization. For initial type 3 neovascularization diagnosis, optical coherence tomography and angiography were conducted. These baseline data were compared between patients with and without neovascularization in their fellow eyes during the follow-up period.

Results

The mean follow-up period was 66.1±31.1 months. Neovascularization developed in 49 (52.8%) fellow eyes after a mean period of 29.5±19.6 months. In the fellow eye neovascularization group, the incidence of soft drusen and reticular pseudodrusen was significantly higher than that in the non-neovascularization group (83.7% vs. 36.5%, p<0.001; 67.3% vs. 40.9%, p = 0.017, respectively), but the choroidal vascularity index (CVI) showed a significantly lower value (60.7±2.0% vs. 61.7±2.5%; p = 0.047). The presence of reticular pseudodrusen was related with the duration from baseline to development of fellow eye neovascularization (p = 0.038).

Conclusion

Neovascularization developed in 52.8% of unaffected fellow eyes. The presence of soft drusen, reticular pseudodrusen, and lower CVI values can be considered risk factors of neovascularization in unaffected fellow eyes of patients with type 3 neovascularization. The lower CVI values suggest that choroidal ischemic change may affect the development of choroidal neovascularization in these patients.

SUB-RETINAL PIGMENT EPITHELIUM MULTILAMINAR HYPERREFLECTIVITY AT THE ONSET OF TYPE 3 MACULAR NEOVASCULARIZATION

PURPOSE

To report the prevalence and treatment outcomes of eyes with sub-retinal pigment epithelium (sub-RPE) multilaminar hyperreflectivity at the onset/clinical detection of Type 3 macular neovascularization (MNV) secondary to exudative age-related macular degeneration.

METHODS

Retrospective analysis of consecutive patients diagnosed with Type 3 MNV secondary to age-related macular degeneration was performed. Eyes presenting with sub-RPE multilaminar hyperreflectivity on structural optical coherence tomography at the onset of Type 3 MNV were included in this study. An age-, sex-, and stage-matched control group was composed of eyes affected by Type 3 MNV without sub-RPE multilaminar hyperreflectivity. Prevalence and treatment outcomes after anti-vascular endothelial growth factor injections at 1-year follow-up were analyzed in both groups.

RESULTS

Nineteen treatment-naïve eyes of 19 patients (8 men/11 women, mean age 83 ± 8 years old) presenting with sub-RPE multilaminar hyperreflectivity before or at the onset/clinical detection of Type 3 MNV were included from a cohort of 162 eyes with treatment-naïve Type 3 MNV. This accounts for an estimated prevalence of 11.7% (5.8-15.2, 95% confidence intervals). No significant differences were disclosed between cases studied and the control group (143 eyes of 143 patients) in age, sex, best-corrected visual acuity at baseline, and number of injections. Best-corrected visual acuity did not improve during the 1-year follow-up in patients showing sub-RPE multilaminar hyperreflectivity (P = 0.45), whereas best-corrected visual acuity significantly increased in the control group (P < 0.001). The presence of sub-RPE multilaminar hyperreflectivity in the context of Type 3 MNV was significantly associated with regressive calcific drusen (P < 0.001) and multiple Type 3 lesions/eye (P < 0.001).

CONCLUSION

The detection of multilaminar hyperreflectivity at the onset/clinical detection of Type 3 MNV suggests that chronic exudation (i.e., the "onion-sign") in the sub-RPE space (i.e., focal sub-RPE neovascularization) may precede the onset/clinical detection of Type 3 MNV. Sub-retinal pigment epithelium multilaminar hyperreflectivity at the onset of Type 3 MNV may be an important predictor of poor visual outcome in these eyes.

SENSITIVITY OF 840-nm SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY IN DETECTING TYPE 1 NEOVASCULARIZATION ACCORDING TO THE HEIGHT OF THE ASSOCIATED PIGMENT EPITHELIAL DETACHMENT

PURPOSE

To evaluate the ability of optical coherence tomography angiography (OCTA) to detect abnormal vascular blood flow in Type 1 neovascularization (NV) with or without significant pigment epithelial detachment (PED).

METHODS

Consecutive age-related macular degeneration patients with either treatment-naive or anti-vascular endothelial growth factor-treated Type 1 NV were divided into 2 groups based on the PED height on structural OCT: greater than 250 μm (Group 1) versus less than 250 μm (Group 2). Two independent senior retina specialists analyzed the OCTA images (Zeiss Angioplex OCT, Carl Zeiss AG, Jena, Germany) using the automatic slabs alone (first reader) versus automatic and manual segmentation slabs (second reader).

RESULTS

In Group 1, 15 men and 42 women, aged from 51 years to 97 years (mean: 87.5), were included. Optical coherence tomography angiography was able to show an abnormal blood flow suggestive of Type 1 NV in 23 (40.3%) of 57 eyes for the first reader and in 32 (56.1%) of 57 eyes for the second reader. In Group 2, 7 men and 30 women, aged from 60 years to 96 years (mean: 80.2), were included. The first and second readers were able to observe an image suggestive of Type 1 NV in 33/37 (89.2%) and 37/37 (100%) of eyes, respectively.

CONCLUSION

The ability of OCTA to detect an abnormal blood flow in Type 1 NV was found to highly depend on the height of the associated PED and the use of manual segmentation slabs. Our results suggest that automatic slabs of OCTA should be interpreted with caution for the diagnosis of vascularized PED. The diagnosis of Type 1 NV using OCTA requires the use of manual segmentation and a multimodal imaging approach, especially when the height of the associated PED is >250 μm.

Indocyanine green angiographic findings in presumed intraocular tuberculosis

PURPOSE

To study features of Indocyanine green angiography (ICGA) in patients with presumed intraocular tuberculosis.

METHODS

Retrospective study of 48 consecutive patients (77 eyes) who underwent ICGA. The following signs were analysed: choroidal perfusion inhomogeneity, early hyperfluorescent stromal vessels, round or oval hypofluorescent dark dots (HDDs), hypofluorescent geographic lesions (HGLs), fuzzy or lost pattern of large stromal choroidal vessels, disc hyperfluorescence and diffuse late choroidal hyperfluorescence.

RESULTS

Among 44 eyes of 29 patients with no clinical evidence of choroidal involvement, only 7 eyes of 6 patients had no ICGA evidence of choroidal involvement. On the other hand, ICGA findings suggesting choroidal involvement were noted in 37 (84.1%) eyes of 23 patients in the form of HDDs in all 37 (100%) eyes, HGLs in 7 (18.9%) eyes, disc hyperfluorescence in 20 (45.5%) eyes, fuzzy stromal vessels in 17 (38.6%) eyes, early hyperfluorescent stromal vessels in 13 (29.5%) eyes, late pinpoint hyperfluorescence in 11 (25%) eyes and late diffuse choroidal hyperfluorescence in 7 (15.9%) eyes. Among 33 eyes of 19 patients with clinically evident choroidal involvement, the following findings were identified; HDDs in 12 (36.4%) eyes, HGLs in 10 (30.3%) eyes, both HDDs and HGLs in 9 (27.3%) eyes, disc hyperfluorescence in 11 (33.3%) eyes, early hyperfluorescent stromal vessels in 7 (21.2%) eyes, fuzzy stromal vessels in 6 (18.2%) eyes and late diffuse choroidal hyperfluorescence was present in 2 (6.1%) eyes.

CONCLUSIONS

ICGA is necessary in identifying and diagnosing subclinical tuberculous choroidal involvement. The most prevalent ICGA finding was persistent HDDs.

Characteristics of Pachychoroid Diseases and Age-Related Macular Degeneration: Multimodal Imaging and Genetic Backgrounds

The emergence of pachychoroid disease is changing the concept of age-related macular degeneration (AMD). The concept of pachychoroid diseases was developed through clinical observation of multimodal images of eyes with AMD and central serous chorioretinopathy; however, recent genetic studies have provided a proof of concept for pachychoroid spectrum disease, which should be differentiated from drusen-driven AMD. The genetic confirmation of pachychoroid concept further provides novel viewpoints to decode previously reported findings, which facilitates an understanding of the true nature of pachychoroid diseases and AMD. The purpose of this review was to elucidate the relationship between pachychoroid diseases and AMD by interpreting previous findings on pachychoroid diseases and AMD from the novel viewpoints of genetic associations. We confirmed that previous genetic studies supported the concept of pachychoroid diseases. From a genetic viewpoint, the presence of thick choroid and the presence of choroidal vascular hyperpermeability were important characteristics of pachychoroid spectrum diseases. Previous studies have also suggested the classification of polypoidal choroidal vasculopathy (PCV) into two subtypes, pachychoroid neovasculopathy and drusen-driven PCV. Genetic viewpoints will be beneficial to rearrange subtypes of drusen-driven AMD and pachychoroid spectrum diseases. Further genetic studies are needed to investigate pachyvessels, pachydrusen and the significance of polypoidal lesions in pachychoroid neovasculopathy and drusen-driven AMD/PCV.

OCT-A characterisation of recurrent type 3 macular neovascularisation

Purpose

To investigate optical coherence tomography angiography (OCT-A) findings in recurrent type 3 macular neovascularisation (MNV).

Methods

In this retrospective cohort study, consecutive patients with type 3 MNV secondary to age-related macular degeneration underwent OCT-A at three different time points: baseline, after anti-vascular endothelial growth factor treatment with complete resolution of the exudative signs (ie, non-exudative stage) and at the recurrence of exudation (ie, recurrence stage). Demographics and clinical findings were analysed, including OCT-A features of type 3 MNV recurrence.

Results

Twelve eyes (12 patients, mean age 78±7 years) were included. Using OCT-A, at baseline all type 3 MNVs showed the presence of detectable flow downgrowing from the deep vascular complex (DVC) to the retinal pigment epithelium (RPE)/sub-RPE space. 6/12 eyes (50%) showed anomalous flow under the RPE, while the other 6 eyes showed flow reaching the RPE without anomalous flow in the sub-RPE space. At the non-exudative stage (after treatment), BCVA and CMT significantly improved (p=0.004 and p=0.036), and flow inside the retinal lesions reduced; interestingly the connection to the RPE/sub-RPE space regressed. At the time of recurrence, all type 3 MNVs showed the presence of intra/sub-retinal exudation with restoration of the flow deepening from the DVC to the RPE/sub-RPE space.

Conclusions

Detectable flow deepening from the DVC to the RPE/sub-RPE space using OCT-A is mandatory to have a new exudation secondary to recurrent type 3 MNV. Early detection of type 3 MNV recurrence by OCT-A characterisation may prompt retreatment and potentially prevent progression to late stages of the disease.

Optical coherence tomography angiography in myopic choroidal neovascularization after intravitreal ranibizumab

PURPOSE:

To describe the optical coherence tomography angiography characteristics of myopic patients with choroidal neovascularization secondary to pathologic myopia during ranibizumab therapy.

METHODS:

Nineteen patients were enrolled in this prospective study (13 females, 6 males, mean age 55.25 ± 9.63 years) for a total of 20 eyes examined (14 right eyes, 6 left eyes). Images were analyzed independently by two examiners.

RESULTS:

Mean follow-up was 5.75 ± 1.88 months, with a mean intravitreal injections of 1.90 ± 0.44. Mean best-corrected visual acuity at baseline was 0.39 ± 0.18 logMAR versus 0.26 ± 0.16 logMAR 6 months after treatment. The neovascular area (Z = -2.091, p = 0.037) was significantly reduced after treatment, whereas vessel density was not (Z = -1.848, p = 0.065). Moreover, the best-corrected visual acuity was increased (Z = -3.055, p = 0.002). Neovascular area was significantly correlated with best-corrected visual acuity, at both baseline and follow-up (p < 0.05).

CONCLUSION:

Our data suggest that optical coherence tomography angiography is a reproducible non-invasive examination with which to monitor changes in the neovascular area in patients with pathologic myopia treated with ranibizumab.

The Nature and Frequency of Neovascular Age-Related Macular Degeneration

PURPOSE

This study was designed to evaluate the frequency and nature of neovascularization in age-related macular degeneration (ARMD) utilizing the combination of digital imaging techniques, fluorescein angiography (FA), indocyanine green (ICG) angiography, and optical coherence tomography (OCT).

METHODS

A complete clinical examination was performed on 100 eyes of 93 consecutive newly diagnosed patients with neovascular ARMD. Digital fluorescein angiography, ICG angiography, and OCT were also used in evaluating those patients. Comparison of the imaging techniques to determine their value in studying the nature of the lesions.

RESULTS

On the basis of existing fluorescein standards, 15 eyes were diagnosed with classic choroidal neovascularization (CNV), 15 with minimally classic CNV, and 70 with occult CNV. ICG angiography was superior for detecting the active vascular component in polypoidal CNV (16 eyes) and retinal angiomatous proliferation (14 eyes). OCT was more sensitive than FA for determining the presence of cystoid macular edema evident in the vast majority of eyes with retinal angiomatous proliferation (RAP).

CONCLUSIONS

These results suggest that FA, ICG angiography, and OCT, when used in combination, will assist clinicians in best determining the precise nature of the neovascular process in ARMD.

Combined Surgical Ablation and Intravitreal Triamcinolone Acetonide for Retinal Angiomatous Proliferation

Purpose

Neovascular age-related macular degeneration (ARMD) with retinal angiomatous proliferation (RAP) has a poor natural history and the efficacy of any treatment has not yet been established. The authors describe a combined surgical treatment.

Methods

A 76-year-old woman presented with a best-corrected visual acuity (BCVA) of 20/600 in the right eye and macula with stage 3 RAP as identified by fluorescein angiography (FA), indocyanine green angiography (ICGA), and optical coherence tomography (OCT). After a standard three-port pars plana core vitrectomy (PPV), endodiathermy of the arteriolar and venous feeder vessels of each lesion was performed, intraretinal RAP feeder vessels were cut with manual vertical intraocular scissors, and 0.1 mL of triamcinolone acetonide (TAAC) was injected intravitreally At 1 and 4 weeks and at the sixth month, the patient underwent a complete eye examination, FA, ICGA, and OCT to assess outcomes and complications.

Results

Six months later, BCVA was stable at 20/300, intraocular pressure was 15 mmHg, anterior segment and vitreous cavity were clear without evidence of TAAC granules, and retina was attached. FA and ICGA showed a complete occlusion of the RAP and absence of leakage or ischemia and OCT demonstrated decreased macular thickness with resolution of both intraretinal edema and pigment epithelium detachment, and the restoration of the normal macular profile. At the end of follow-up, the authors did not observe any ocular or systemic complication.

Conclusions

Surgical approach to RAP stage 3 with intravitreal injection of 4 mg of TAAC was safe and anatomically effective.

Optical Coherence Tomography (OCT) in Retinal Angiomatous Proliferation (RAP)

Purpose

To verify the utility of optical coherence tomography (OCT) for diagnosing retinal angiomatous proliferations (RAP) in patients with exudative age-related macular degeneration (AMD).

Methods

Multiple cross-sections were taken with OCT from 41 eyes of 39 consecutive patients with AMD and RAP. The presence and the location of the angiomatous complexes had already been documented by fluorescein angiography (FA) and high-speed confocal indocyanine green videoangiography (ICGA).

Results

RAP was detectable by OCT scans in all 41 eyes, appearing as a focal hyper-reflecting area in the neuroretinal layers; it was frequently located close to the inner surface of the retinal pigment epithelium (29 eyes [70.7%]). All eyes had either no or only a low-reflecting OCT signal surrounding the RAP, caused by serous intraretinal edema. Only 13 eyes (31.7%), however, had large serous retinal detachment (SRD). OCT detected pigment epithelium detachment in 31 eyes (75.6%), but none had underlying choroidal neovascularization.

Conclusions

OCT findings confirm the intraretinal localization of the RAP which are always associated with impressive exudative phenomena. OCT is therefore a useful diagnostic tool, adding information to FA and high-speed ICGA.

Incidence and risk factors of massive subretinal hemorrhage in retinal angiomatous proliferation

Objective

To evaluate the incidence and associated risk factors of massive subretinal hemorrhage (SRH) in patients with retinal angiomatous proliferation (RAP).

Methods

A total of 187 eyes of 135 treatment-naıve patients diagnosed with RAP were evaluated retrospectively. Clinical records including the time between the initial visit, last anti-vascular endothelial growth factor (VEGF) treatment, last stable examination, and the date of massive SRH were reviewed. Imaging findings including indocyanine green angiography (ICGA) and optical coherence tomography (OCT) were analyzed.

Results

Massive SRH developed in 18 eyes (9.6%) a median of 20 months after the initial presentation. Kaplan-Meier survival analysis revealed that the incidence (2.8, 5.8, 13.1, and 21.0% after 1,2,5 and 10 years, respectively) continuously increased. Among 14 eyes with discernable vascular anastomosis on baseline ICGA, 13 (92.8%) showed retinal arteriole involvement. On spectral-domain OCT imaging of the last visit prior to the massive SRH, a layered lamellar tissue complex was noted under the retinal pigment epithelium in 9 of 13 eyes, which was significantly associated with massive SRH[hazard ratio(HR),5.883;P = .010]. The average time between the last stable examination/last injection and the massive SRH was 2 and 5 months, respectively. The patients were treated with anti-VEGF, gas and recombinant tissue plasminogen activator injection; however, all except one eye had visual acuity worse than 20/1000 at the final visit.

Conclusions

Massive SRH can occur in RAP in the course of anti-VEGF treatment, resulting in severe vision loss. A proactive dosing regimen may be more appropriate for these RAP eyes.

A Novel Nanoparticle Mediated Selective Inner Retinal Photocoagulation for Diseases of the Inner Retina

A novel nanoparticle mediated methodology for laser photocoagulation of the inner retina to achieve tissue selective treatment is presented.

METHODS

Transport of 527, 577, and 810 nm laser, heat deposition, and eventual thermal damage in vitreous, retina, RPE, choroid, and sclera were modeled using Bouguer-Beer-Lambert law of absorption and solved numerically using the finite volume method. Nanoparticles were designed using Mie theory of scattering. Performance of the new photocoagulation strategy using gold nanospheres and gold-silica nanoshells was compared with that of conventional methods without nanoparticles. For experimental validation, vitreous cavity of ex vivo porcine eyes was infused with gold nanospheres. After ~6 h of nanoparticle diffusion, the porcine retina was irradiated with a green laser and imaged simultaneously using a spectral domain optical coherence tomography (Spectralis SD-OCT, Heidelberg Engineering).

RESULTS

Our computational model predicted a significant spatial shift in the peak temperature from RPE to the inner retinal region when infused with nanoparticles. Arrhenius thermal damage in the mid-retinal location was achieved in ~14 ms for 527 nm laser thereby reducing the irradiation duration by ~30 ms compared with the treatment without nanoparticles. In ex vivo porcine eyes infused with gold nanospheres, SD-OCT retinal images revealed a lower thermal damage and expansion at RPE due to laser photocoagulation.

CONCLUSION

Nanoparticle infused laser photocoagulation strategy provided a selective inner retinal thermal damage with significant decrease in laser power and laser exposure time.

SIGNIFICANCE

The proposed treatment strategy shows possibilities for an efficient and highly selective inner retinal laser treatment.

Clinicopathologic Correlation of Anti-Vascular Endothelial Growth Factor-Treated Type 3 Neovascularization in Age-Related Macular Degeneration

PURPOSE

To correlate histologic results with previously recorded multimodal imaging results from a patient with type 3 neovascularization secondary to age-related macular degeneration (AMD).

DESIGN

Case study, clinical imaging, laboratory imaging, and eye-tracked clinicopathologic correlation.

PARTICIPANT

An 86-year-old white woman with type 3 neovascularization secondary to AMD treated with 6 intravitreal injections of bevacizumab.

METHODS

Multimodal retinal imaging at each clinic visit was correlated with ex vivo and high-resolution histologic images of the preserved donor eye. Clinical imaging included serial near-infrared reflectance and eye-tracked spectral-domain OCT. Eye tracking, applied to the donor eye, enabled identification of histologic features corresponding to clinical OCT signatures.

MAIN OUTCOME MEASURES

Histologic correlates for clinical OCT signatures were sought, including reflectivity of the vascular complex, intraretinal hyperreflective foci and intraretinal cellularity, analysis of the topography of pathologic features, and evaluation of the sub-retinal pigment epithelium (RPE) plus basal lamina (BL) space.

RESULTS

Clinical imaging showed a deep neovascular lesion in close relationship with a mixed serous and drusenoid pigment epithelium detachment (PED), characteristic of type 3 neovascularization. Antiangiogenic therapy achieved a complete resolution of exudation. The PED progressively flattened with each treatment, leaving a persistent triangular hyperreflectivity in the outer retina. This persistent deep lesion histologically correlated with a vascular complex implanted into sub-RPE basal laminar deposit. No connection between the choriocapillaris and the sub-RPE plus BL space was observed. Both RPE-derived and lipid-filled cells were correlated with clinical intraretinal hyperreflective foci. The sub-RPE plus BL space contained macrophages, lymphocytes, Müller cell processes, and subducted RPE.

CONCLUSIONS

Clinicopathologic correlation of type 3 neovascularization showed vascular elements of retinal origin accompanied by collagenous material and Müller cell processes implanting into thick sub-RPE basal laminar deposit, which may simulate the appearance of chorioretinal anastomosis. Surrounding RPE-derived and lipid-filled cells thought to be microglia correlated with clinical intraretinal hyperreflective foci.

TYPE 3 NEOVASCULARIZATION IMAGED WITH CROSS-SECTIONAL AND EN FACE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY

PURPOSE

To study the cross-sectional and en face optical coherence tomography angiography (OCTA) findings in Type 3 neovascularization (NV).

METHODS

Optical coherence tomography angiography imaging of 27 eyes of 23 patients with Type 3 NV was analyzed with 9 eyes having consecutive follow-up OCTA studies.

RESULTS

Type 3 NV appeared as a linear high-flow structure on cross-sectional OCTA corresponding to a high-flow tuft of vessels seen on en face OCTA. Cross-sectional OCTA seemed to enable the distinction between vascular and nonvascular intraretinal hyperreflective foci. Two patterns of flow were observed; Pattern 1 (11%): a flow signal confined to the neurosensory retina and Pattern 2 (74%): a flow signal extending through the retinal pigment epithelium. No definitive retinal-choroidal anastomosis was observed; however, projection artifacts confounded the interpretation of deeper structures. An increase in the intensity of the high-flow tuft was seen during the progression or recurrence of Type 3 NV. Intravitreal anti-vascular endothelial growth factor therapy caused a reduction in the intensity of the high-flow tuft which was not sustained.

CONCLUSION

Compared with conventional imaging, OCTA may improve detection and delineation of vascular changes occurring in Type 3 NV. Cross-sectional and en face OCTA may prove useful in studying the pathogenesis and guiding the management of these lesions.

Vascular Density in Retina and Choriocapillaris as Measured by Optical Coherence Tomography Angiography

PURPOSE

To measure the density of the superficial retinal small vessel network (SRSVN), superficial retinal capillary network (SRCN), deep retinal capillary network (DRCN), and choriocapillaris and the size of the foveal avascular zone (FAZ) in the superficial retinal layer in normal eyes.

DESIGN

Prospective observational cross-sectional study.

METHODS

In healthy Chinese volunteers, the retinal and choroidal vasculature was visualized by split-spectrum amplitude decorrelation angiography-associated optical coherence tomography (RTVueXR Avanti device; Optovue Inc, Fremont, California, USA).

RESULTS

Among 105 healthy participants (age: 35.9 ± 13.8 years) mean FAZ measured 0.35 ± 0.12 mm(2), and mean density of SRSVN, SRCN, DRCN, and choriocapillaris was 8.54% ± 0.92%, 31.8% ± 2.6%, 45.8% ± 3.3%, 44.4% ± 3.3%, and 44.5% ± 2.7%, respectively. In multivariate analysis, higher SRSVN density was associated with younger age (P = .001; standardized regression coefficient β: -0.28), male sex (P = .008; β: -0.23), lower SRCN density (P < .001; β: -0.40), and larger mean choriocapillaris vessel diameter (P = .001; β: 0.30). Higher SRCN density was correlated with male sex (P = .007; β: -0.19), lower SRSVN density (P < .001; β: -0.44), and higher density of the radial peripapillary capillary density (P = .004; β: 0.20). Higher DRCN density was correlated with younger age (P < .001; β: -0.31), female sex (P = .002; β: 0.22), higher SRCN density (P < .001; β: 0.38), and higher choriocapillaris density (P < .001; β: 0.39). Higher choriocapillaris network density in the central region was associated with higher DRCN density (P < .001; β: 0.43) and lower radial peripapillary capillary density (P = .005; β: -0.26). All retinal vascular parameters were not significantly correlated with axial length or subfoveal choroidal thickness.

CONCLUSIONS

The density of the macular vascular networks decreases with older age and is independent of axial length and subfoveal choroidal thickness in healthy individuals.

Resistance to anti-VEGF therapy in neovascular age-related macular degeneration: a comprehensive review

As a progressive chronic disease, age-related macular degeneration (AMD) is the leading cause of irreversible vision impairment worldwide. Experimental and clinical evidence has demonstrated that vascular endothelial growth factor (VEGF) plays a vital role in the formation of choroidal neovascularization. Intravitreal injections of anti-VEGF agents have been recommended as a first-line treatment for neovascular AMD. However, persistent fluid or recurrent exudation still occurs despite standardized anti-VEGF therapy. Patients suffering from refractory or recurrent neovascular AMD may develop mechanisms of resistance to anti-VEGF therapy, which results in a diminished therapeutic effect. Until now, there has been no consensus on the definitions of refractory neovascular AMD and recurrent neovascular AMD. This article aims at clarifying these concepts to evaluate the efficacy of switching drugs, which contributes to making clinical decision more scientifically. Furthermore, insight into the causes of resistance to anti-VEGF therapy would be helpful for developing possible therapeutic approaches, such as combination therapy and multi-target treatment that can overcome this resistance.

Outcomes in Eyes with Retinal Angiomatous Proliferation in the Comparison of Age-Related Macular Degeneration Treatments Trials (CATT)

PURPOSE

To compare baseline characteristics, visual acuity (VA), and morphologic outcomes between eyes with retinal angiomatous proliferation (RAP) and all other eyes among patients with neovascular age-related macular degeneration (NVAMD) treated with anti-vascular endothelial growth factor (VEGF) drugs.

DESIGN

Prospective cohort study within the Comparison of Age-Related Macular Degeneration Treatments Trials (CATT).

PARTICIPANTS

Patients with NVAMD.

METHODS

Reading center staff evaluated digital color fundus photographs, fluorescein angiography (FA) images, and optical coherence tomography (OCT) scans of eyes with NVAMD treated with either ranibizumab or bevacizumab over a 2-year period. Retinal angiomatous proliferation was identified by the intense intra-retinal leakage of fluorescein in combination with other associated features.

MAIN OUTCOME MEASURES

Visual acuity; fluorescein leakage; scar; geographic atrophy (GA) on FA; retinal thickness, fluid, and subretinal hyperreflective material (SHRM) on OCT; and the number of intravitreal anti-VEGF injections at 1 and 2 years.

RESULTS

Retinal angiomatous proliferation was present in 126 of 1183 (10.7%) study eyes at baseline. Mean VA improvement from baseline was greater (10.6 vs. 6.9 letters; P = 0.01) at 1 year, but similar at 2 years (7.8 vs. 6.2 letters; P = 0.34). At 1 year, eyes with RAP were more likely to have no fluid (46% vs. 26%; P < 0.001) on OCT, no leakage on FA (61% vs. 50%; P = 0.03), and greater reduction in foveal thickness (-240 μm vs. -161 μm; P < 0.001). They were more likely to demonstrate GA (24% vs. 15%; P = 0.01) and less likely to have scarring (17% vs. 36%; P < 0.001) or SHRM (36% vs. 48%; P = 0.01). These results were similar at 2 years. The mean change in lesion size at 1 year differed (-0.27 DA vs. 0.27 DA; P = 0.02), but was similar at 2 years (0.49 DA vs. 0.79 DA; P = 0.26). Among eyes treated PRN, eyes with RAP received a lower mean number of injections in year 1 (6.1 vs. 7.4; P = 0.003) and year 2 (5.4 vs. 6.6; P = 0.025).

CONCLUSIONS

At both 1 and 2 years after initiation of anti-VEGF treatment in CATT, eyes with RAP were less likely to have fluid, FA leakage, scar, and SHRM and more likely to have GA than eyes without RAP. Mean improvement in VA was similar at 2 years.

Long-Term Management of RAP Lesions in Clinical Practice: Treatment Efficacy and Predictors of Functional Improvement

PURPOSE

To evaluate the long-term efficacy of ranibizumab in the treatment of retinal angiomatous proliferation (RAP) and to identify predictors of functional outcome.

METHODS

Retrospective case series comprised 79 eyes of 68 consecutive patients with RAP followed up ≥36 months. Primary end-points were best-corrected visual acuity (BCVA) and central macular thickness (CMT) variation at 36 months and at the last visit.

RESULTS

Mean follow-up time was 59.8 ± 16.0 months. All eyes were treated with pro re nata ranibizumab, with (n = 33) or without (n = 46) photodynamic therapy (PDT). Stabilization or improvement in BCVA was observed in 50.6% of the patients at 36 months, and in 40.5% at the end of the follow-up, where 20.3% preserved reading vision. A significant decrease in CMT was observed at 36 months (p < 0.001), but not at the end of the follow-up. Geographic atrophy (GA) was present in 59.5% of the eyes at the final visit. Baseline subretinal fluid was associated with better visual outcomes (p = 0.001). Results of combination treatment with intravitreal ranibizumab and PDT did not significantly differ from ranibizumab monotherapy.

CONCLUSION

Modest functional outcomes can be expected from the long-term treatment of RAP lesions in clinical practice, most likely due to the advent of GA. Baseline subretinal fluid positively correlated with final BCVA.

En face OCT angiography demonstrates flow in early type 3 neovascularization (retinal angiomatous proliferation)

INTRODUCTION

The characteristics of type 3 neovascularization (NV), also known as retinal angiomatous proliferation, have been well described clinically, as well as with fluorescein angiography (FA), indocyanine green angiography, and optical coherence tomography (OCT). OCT angiography (OCT-A) is a novel and non-invasive technique for imaging retinal microvasculature by detecting changes, with respect to time, in reflectivity related to blood flow.

METHOD

In this case series, we describe two patients who presented with type 3 NV and underwent clinical examination and multimodal imaging, including OCT-A.

RESULTS

In the first patient, OCT-A demonstrated flow within two separate lesions in the same eye, one of which was only weakly detected by FA. In the second patient, sequential OCT-A demonstrated a reduction in intralesional flow following intravitreal therapy.

CONCLUSIONS

OCT-A may have a role in the early diagnosis of type 3 NV and in assessing the response to treatment. Further studies are needed to determine sensitivity and specificity.

Characteristic findings of optical coherence tomography in retinal angiomatous proliferation

Purpose

To identify the unique pathologic findings of retinal angiomatous proliferation (RAP) in optical coherence tomography (OCT).

Methods

Retrospectively, 29 eyes of 25 patients with age-related macular degeneration and complicated RAP were analyzed. All 29 eyes had choroidal neovascularization (CNV) in the area of pigment epithelial detachment (PED) or adjacent to it, which was visible with fluorescein angiography or indocyanine green angiography. Cross-sectional images were obtained by OCT scanning through the CNV lesions.

Results

Six distinctive findings of OCT included drusen (100%), inner retinal cyst (80%), outer retinal cyst (68%), fibrovascular PED (84%), serous retinal detachment (40%), and PED (68%).

Conclusions

Through analysis of OCT findings, we revealed six different types of lesions distinctive of RAP which may provide helpful diagnostic information for subsequent treatment and predicting the prognosis of RAP.

Reproducibility of fluorescein and indocyanine green angiographic assessment for RAP diagnosis: a multicenter study

PURPOSE

To explore the interobserver agreement in the diagnosis of retinal angiomatous proliferation (RAP) using fluorescein (FA) and indocyanine green angiographies (ICGA) and to detect which morphologic features of the neovascular lesion are associated with RAP diagnosis.

METHODS

In this cross-sectional study, consecutive patients with newly diagnosed neovascular age-related macular degeneration (AMD) evaluated in 8 retina centers were considered. The FA and ICGA were obtained in all centers according to a standard protocol, both performed either as a static or as a dynamic examination. All images were graded by 2 observers from different institutions.

RESULTS

A total of 201 eyes with neovascular AMD of 155 consecutive patients (mean age 76±8 years) were considered. Overall RAP prevalence was 30% using FA and 26% using ICGA. Patients studied with dynamic angiography were twice as likely to be diagnosed with RAP as those using static angiography. Interobserver agreement for the overall detection of RAP was high using FA (kappa: 0.868; 95% confidence interval [CI]: 0.793-0.944) and very high using ICGA (kappa: 0.905; 95% CI 0.836-0.974). The agreement between the 2 observers tended to be higher for the truncated vessel than for the anastomosis in FA as well as in ICGA, but no comparison yielded statistical significance (p=0.258 and p=0.584, respectively).

CONCLUSIONS

The interobserver agreement for RAP detection was very good both using FA and ICGA, but the overall detection of RAP was higher for dynamic strategy compared with static one.

Retinal angiomatous proliferation in age–related macular degeneration. 2001

BACKGROUND

It is known that choroidal neovascularization (CNV) in age-related macular degeneration (ARMD) may erode through the retinal pigment epithelium, infiltrate the neurosensory retina, and communicate with the retinal circulation in what has been referred to as a retinal–choroidal anastomosis (RCA). This is extremely common in the end stage of disciform disease. In recent years, the reverse also seems to be possible, as angiomatous proliferation originates from the retina and extends posteriorly into the subretinal space, eventually communicating in some cases with choroidal new vessels. This form of neovascular ARMD, termed retinal angiomatous proliferation (RAP) in this article, can be confused with CNV.

PURPOSE

The purpose of this article is 1) to review the clinical and angiographic characteristics of a series of patients with RAP and 2) to propose a theoretical sequence of events that accounts for the neovascularized process.

METHODS

In this retrospective clinical and angiographic analysis, 143 eyes with RAP (108 patients) were reviewed and classified based on their vasogenic nature and course. Clinical biomicroscopic examination, fluorescein angiography, and indocyanine green angiography were used to evaluate patients.

RESULTS

The results of this series suggest that angiomatous proliferation within the retina is the first manifestation of the vasogenic process in this form of neovascular ARMD. Dilated retinal vessels and pre-, intra-, and subretinal hemorrhages and exudate evolve, surrounding the angiomatous proliferation as the process extends into the deep retina and subretinal space. One or more dilated compensatory retinal vessels perfuse and drain the neovascularization, sometimes forming a retinal–retinal anastomosis. Fluorescein angiography in these patients usually revealed indistinct staining simulating occult CNV. Indocyanine green angiography was useful to make an accurate diagnosis in most cases. It revealed a focal area of intense hyperfluorescence corresponding to the neovascularization ("hot spot") and other characteristic findings. Based on understanding of the nature and progression of the neovascularized process, patients with RAP were classified into three vasogenic stages. Stage I involved proliferation of intraretinal capillaries originating from the deep retinal complex (intraretinal neovascularization [IRN]). Stage II was determined by growth of the retinal vessels into the subretinal space (subretinal neovascularization [SRN]). Stage III occurred when CNV could clearly be determined clinically or angiographically. A vascularized pigment epithelial detachment and RCA were inconsistent features of this stage.

CONCLUSIONS

Retinal angiomatous proliferation appears to be a distinct subgroup of neovascular ARMD. It may present in one of three vasogenic stages: IRN, SRN, or CNV. Whereas ICG angiography is helpful in diagnosing RAP and in documenting the stage of the neovascularized process, it is frequently difficult to determine the precise nature and location of the new vessel formation. It is important for clinicians to recognize the vasogenic potential and the associated manifestations of this peculiar form of neovascular ARMD so that a proper diagnosis can be made, and when possible, an appropriate management administered.

Enhanced depth imaging optical coherence tomography

Imaging the choroid with conventional commercial spectral-domain optical coherence tomography (SD-OCT) has been difficult, mainly because of difficulty in signal transmission beyond the retinal pigment epithelium. A recent modification to the standard technique, termed enhanced depth imaging optical coherence tomography (EDI-OCT), was able to image the choroid with reasonable clarity using commercial SD-OCTs. The aim of this article was to review the technique, principle, recent findings, and possible future developments regarding EDI-OCT. A MEDLINE search on all published articles on EDI-OCT was performed up to December 2010. The principle behind EDI-OCT was discussed. Modification to the conventional technique in image acquisition was described and illustrated with figures. EDI-OCT findings in various retinal and choroidal diseases were discussed. Advantages and disadvantages were also discussed. EDI-OCT has proved to be a promising novel technique in imaging the choroid.

Geographic atrophy in retinal angiomatous proliferation

PURPOSE

To describe the occurrence of geographic atrophy in patients with retinal angiomatous proliferation (RAP).

METHODS

Demographics, visual acuity, color fundus photographs, fluorescein and indocyanine green angiograms, and fundus autofluorescence and near-infrared autofluorescence images were reviewed in 53 patients (66 eyes) with RAP.

RESULTS

Of 53 treatment-naive eyes, 19 (36%) had atrophy at baseline. Of 66 eyes, 57 (86%) developed de novo atrophy or enlargement of preexisting areas of atrophy during the follow-up (median, 17 months; range, 3-53 months) after treatment. Areas of atrophy were observed at the site of the RAP (58 of 66 eyes, 88%) of a previously existing pigment epithelial detachment (18 of 44 eyes; 41%) and elsewhere (43 of 66 eyes, 65%). At presentation, RAP was found to be frequently associated with increased autofluorescence at the fovea because of cystoid macular edema (36 of 53 eyes, 68%) and reduced autofluorescence because of hard exudation (38 of 53 eyes, 72%) and intraretinal hemorrhages (32 of 53 eyes, 60%). Background reticular (39%) and homogeneous (36%) autofluorescence were most commonly observed.

CONCLUSION

Geographic atrophy occurs frequently in patients with RAP after treatment. This information, if confirmed in other cohorts, would be valuable for the counseling of patients with this disease and for the understanding of the pathogenesis of this condition and its progression after treatment.