Intraretinal Fluid Accumulation Research Articles

A hybrid approach using CNN and active contour model for automated segmentation of macular edema

Macula is the part of retina responsible for sharp and clear vision. Macular edema is caused by the accumulation of intraretinal fluid (IRF) in the macula, which is further distinguished by the compromised integrity of the blood-retinal barrier, particularly evident in the retinal vasculature. This results in swelling, that may lead to vision impairment and is the dominant sign of several ocular diseases, including age-related macular degeneration, diabetic retinopathy, etc. Quantitative analysis of the fluid regions in macular edema helps in ascertaining the severity as well as the response to treatment of the diseases. Optical coherence tomography (OCT) is a major tool used by ophthalmologists for visualizing edema. The prevalent practice for diagnosing and treating macular edema involves measuring Central Retinal Thickness (CRT). Segmenting the IRF in OCT images offers the potential for a more accurate and better quantification of macular edema. This paper proposes a novel method combining convolutional neural network (CNN) and active contour model for segmenting the IRF to ascertain the severity of macular edema. The IRF region is initially segmented using an encoder-decoder architecture. Contour evolution is then performed on this segmented image to demarcate the IRF boundaries. The advantage of the method is that it does not require precisely labeled images for training the CNN. A comparison of the experimental results with models employing CNN alone and with other state-of-the art methods demonstrates the superior performance and consistency of the proposed method.

Опыт применения препарата фарицимаб при неоваскулярной форме возрастной макулярной дегенерации

The purpose of the study was to evaluate the effectiveness and safety of a novel antiVEGF agent faricimab in patients with neovascular age-related macular degeneration (nAMD) in real-world clinical practice. Material and methods. It was a retrospective study including 66 patients (68 eyes) with nAMD treated at our center from August to December 2023. The follow-up period ranged from two to four months. Group 1 included 10 treatment-naïve patients (10 eyes) who received monthly loading intravitreal faricimab injections 0.05 mL (6 mg). A total of 32 injections were performed (mean number of injections per eye = 3.2 ± 0.8). Group 2 included 57 patients (58 eyes) who were previously treated with other anti-VEGF agents using treat-and-extend (TAE) approach. They were switched to faricimab, and a total of 136 injections (mean number of injections per eye = 2.3 ± 1.0) were performed. Optical coherence tomography (OCT) was used to assess the central retinal thickness (CRT), the presence of subretinal fluid (SRF) and intraretinal fluid (IRF), the sub-retinal pigment epithelium (RPE) fluid, as well as changes over time in the pigment epithelial detachment (PED) in all patients. Results. In Group 1, the baseline CRT was 320.8 ± 37.0 µm and significantly decreased after the second injection to 232.5 ± 44.1 µm (р = 0.012). IRF, SRF and sub-PED fluid at the baseline were present in 90.0%, 90.0%, and 70.0% of the eyes, respectively. After the second injection, these proportions decreased to 0.0%, 0.0%, and 22.2%, respectively (p < 0.01). After the second faricimab injection, the PED completely resolved in 50 % (n=5) of Group 1 eyes, and the rest of the eyes showed decreased PED. In Group 2, the baseline CRT value was 287.6 ± 79.3 µm and significantly decreased to 241.2 ± 42.3 µm (p < 0.001). At the time of switching, IRF, SRF and sub-PED fluid at the baseline were present in 37.9%, 57.2%, and 13.8%, respectively. However, after switching, there was a decrease only in the IRF accumulation (17.2 %; p = 0.03), while the proportions of eyes with the SRF and the sub-PED fluid did not change significantly and were 43.1 % (р = 0.08) and 10.3 % (p = 0.69), respectively. In most eyes (63.1 %), there were no changes in PED condition over time. Conclusion. Treatment-naïve patients with nAMD receiving loading therapy with faricimab demonstrated significant improvement of all anatomic parameters, while antiVEGF-treated patients tended to demonstrate improvement in some parameters. Further long-term studies are needed to assess the functional outcomes of faricimab treatment, a possibility to extend the inter-injection intervals, and to compare the effectiveness and safety of this drug with other anti-VEGF agents. Keywords: age-related macular degeneration, anti-VEGF therapy, faricimab, optical coherence tomography

RUPTURED RETINAL ARTERIAL MACROANEURYSMS ASSOCIATED WITH HEMORRHAGIC BACILLARY LAYER DETACHMENTS.

Bacillary layer detachments (BALAD) are a recently recognized form of retinal detachment involving a splitting of photoreceptors at the inner segment myoid zone, with separation of the external limiting membrane and ellipsoid zone on optical coherence tomography (OCT). A growing number of disease processes are recognized to cause BALAD, and here we present three of the first cases of hemorrhagic retinal artery macroaneurysms that resulted in BALAD. A retrospective review of three patients who presented for acute, painless, monocular vision loss was performed. Multimodal imaging including fundus photography and OCT are included in this analysis. Three elderly female patients, all with a history of hypertension, presented with ruptured macroaneurysms involving the macula. All three patients had evidence of BALAD on OCT. Various management strategies were used. Hemorrhagic retinal arterial macroaneurysms can be associated with BALAD, observed best on OCT. This is most likely secondary to the rapid accumulation of intraretinal fluid during the hemorrhage, which leads to an avulsion at the inner segment myoid zone-a site of inherent structural weakness in the photoreceptors. Visual recovery may be improved in instances of hemorrhagic macroaneurysms associated with BALAD, similar to other disease entities where BALAD occurs, although further research is needed.

Intraocular Pressure Lowering Associated With Worsening Optic Pit-Like Retinoschisis.

In this article, we present a case of optic pit-like macular retinoschisis in the absence of advanced glaucomatous cupping. Intraocular pressure (IOP)-lowering therapy, which was started due to an early concern for glaucoma, caused a worsening of the retinoschisis, which subsequently resolved on discontinuation of the IOP-lowering therapy. Lower IOP likely triggered intraretinal fluid accumulation by facilitating a translaminar gradient from the subarachnoid to intraretinal space. [Ophthalmic Surg Lasers Imaging Retina 2024;55:100-102.].

Investigating the associations of macular edema in retinitis pigmentosa

Macular edema (ME), the accumulation of intraretinal fluid in the macula, is a common sight affecting sequelae of retinitis pigmentosa (RP). However, it is unclear why some patients develop ME, and others do not. This study aims to identify associations between clinical-genetic factors in RP with ME. Patients with clinically confirmed RP cases were identified from the inherited retinal disease database at a large tertiary referral academic center. Demographic and genetic testing findings were noted. Additionally, optical coherence tomography volume scans were graded using a validated grading system. One hundred and six patients (73.1%) were found to have ME in at least one eye (OD = 88, mean = 37.9%, OS = 98, mean = 31.7%). Structurally, the presence of epiretinal membrane (ERM) (p < 0.007) and vitreo-macular traction (VMT) (p < 0.003) were significantly associated with ME. Additionally, X-linked (p < 0.032) and autosomal dominant inheritance (p < 0.039) demonstrated a significant association with ME, with RP1 (p < 0.045) and EYS (p < 0.017) pathogenic variants also significantly associated with ME. This study, in a large cohort of RP patients, confirms previous retinal structural associations for ME in RP and identifies potential new genetic associations.

Loss-balanced parallel decoding network for retinal fluid segmentation in OCT

As a leading cause of blindness worldwide, macular edema (ME) is mainly determined by sub-retinal fluid (SRF), intraretinal fluid (IRF), and pigment epithelial detachment (PED) accumulation, and therefore, the characterization of SRF, IRF, and PED, which is also known as ME segmentation, has become a crucial issue in ophthalmology. Due to the subjective and time-consuming nature of ME segmentation in retinal optical coherence tomography (OCT) images, automatic computer-aided systems are highly desired in clinical practice. This paper proposes a novel loss-balanced parallel decoding network, namely PadNet, for ME segmentation. Specifically, PadNet mainly consists of an encoder and three parallel decoder modules, which serve as segmentation, contour, and diffusion branches, and they are employed to extract the ME’s characteristics, the contour area features, and to expand the ME area from the center to edge, respectively. A new loss-balanced joint-loss function with three components corresponding to each of the three parallel decoding branches is also devised for training. Experiments are conducted with three public datasets to verify the effectiveness of PadNet, and the performances of PadNet are compared with those of five state-of-the-art methods. Results show that PadNet improves ME segmentation accuracy by 8.1%, 11.1%, 0.6%, 1.4% and 8.3%, as compared with UNet, sASPP, MsTGANet, YNet, RetiFluidNet, respectively, which convincingly demonstrates that the proposed PadNet is robust and effective in ME segmentation in different cases.

Place of intravitreal dexamethasone implant in the treatment armamentarium of diabetic macular edema.

Diabetic macular edema (DME) is a very important and well-known cause of visual loss in diabetics. Blood–retina barrier disruption and consequent intraretinal fluid accumulation may lead to retinal thickening at the posterior pole namely DME. Even though it is not clearly understood, current evidence suggests that chronic low-grade inflammation characterized with various cytokines has a major role in the occurrence of DME. Clinical trials are continuously shaping our treatment approaches for the eyes with DME. Today, vascular endothelial growth factor (VEGF) inhibitor and steroid administrations are the main alternatives in DME treatment. Dexamethasone (DEX) implant (Ozurdex®; Allergan, Inc., Irvine, CA, United States) was approved by the United States Food & Drug Administration in 2014 for DME treatment. The implant is made up of a biodegradable solid copolymer that is broken down by releasing its active ingredient into the vitreous cavity over time. Biphasic release feature of this sustained-release drug delivery system ensures its efficacy for up to 6 mo with an acceptable and manageable safety profile. DEX implant provides a favorable anatomical and functional outcome in DME as shown in several randomized-controlled studies but has a relatively higher ocular side-effect profile such as increased risk of cataract formation and raised intraocular pressure when compared to the gold standard anti-VEGF agents. Thus, DEX implant becomes the second-line treatment option demonstrating inadequate clinical response to anti-VEGF therapy. However, it can be preferred as the first-line treatment in vitrectomized and pseudophakic eyes. Even in some selected conditions DEX implant is favored over anti-VEGF agents where the use of VEGF-inhibitors is either inappropriate or contraindicated such as the patients with a recent history of a major cardiovascular or cerebrovascular event, pregnancy and noncompliant to frequent visits. This mini-review briefly overviews the efficacy, safety profile and complications of DEX implant and summarizes the outcome of DEX implant administration in major clinical studies on DME treatment.

Multimodal imaging of bilateral immunogammopathy maculopathy associated to Waldenström's macroglobulinemia.

Our aim is to report a case with bilateral Waldenström's macroglobulinemia (WM) associated maculopathy, assessed with multimodal imaging including swept source optical coherence tomography (SS-OCT) and OCT-Angiography (OCT-A). Observational case report. A 61-year-old diabetic woman with history of treated WM currently in remission, presented with progressive bilateral visual loss. Best-corrected visual acuity was 20/100 in the right eye (RE) and 20/200 in the left eye (LE). Fundus examination showed bilateral microaneurysms and retinal punctuate hemorrhages and a large macular serous detachment in the LE. There was no retinal ischemia on FA nor macular dye leakage. SS-OCT showed a significant schisis-like intraretinal fluid accumulation in the RE and a large prominent macular detachment with significant subretinal fluid accumulation in the LE. Retinal and choriocapillaris vascular densities were normal on OCT-A. Our case illustrated characteristic multimodal imaging findings in WM associated maculopathy such as schisis-like intraretinal fluid accumulation and angiographically silent serous macular detachment. OCT-A could non-invasively analyze macular vascular densities layer-by-layer, without noticing any vascular anomaly.

Diagnostic and therapeutic approaches to optic disc pit maculopathy in children

Background: Optic disc pit (ODP) is a rare congenital defect of the optic disc that can lead to maculopathy and gradual visual impairment. This review summarizes our current knowledge on the diagnostic and therapeutic approaches to ODP maculopathy (ODP-M) in children.&#x0D; Methods: A thorough literature search was performed using the PubMed/MEDLINE database from 1960 to 2020. An additional search was conducted using Google Scholar for completeness.&#x0D; Results: ODP-M is characterized by the accumulation of subretinal and/or intraretinal fluid. The exact pathogenetic mechanisms are not fully understood, and the origin of the fluid remains unknown. Although ODP-M is more likely to occur during the third or fourth decade of life, cases of children with serous retinal detachment have been recorded. Early diagnosis of ODP-M and prompt, appropriate management are crucial, particularly in patients of amblyogenic age. In adults, ODP-M may resolve spontaneously, but most cases require surgical intervention to prevent permanent loss of vision. However, the fact that ODP-M may spontaneously resolve in children cannot be ignored. Various surgical methods have been described, including pars plana vitrectomy (PPV) combined with various techniques, including laser photocoagulation, intravitreal gas injection, and macular buckling. &#x0D; Conclusions: PPV remains the mainstay surgical approach for ODP-M. However, ODP-M may differ between children and adults. Children constitute a unique population of patients that require a different and probably more tailor-made approach. Detailed clinical examination, combined with a thorough analysis of retinal imaging, may improve our understanding of the background and pathophysiology of the disease and eventually provide us with new insights into the management of ODP-M in the pediatric population.&#x0D; &#x0D; How to cite this article: Kalogeropoulos D, Asproudis I, Ch’ng SW, Mitra A, Sharma A, Katsikatsos K, Asproudis C, Kalogeropoulos C. Diagnostic and therapeutic approaches to optic disc pit maculopathy in children. Med Hypothesis Discov Innov Optom.2021 Spring; 2(1): 24-35. DOI: https://doi.org/10.51329/mehdioptometry122&#x0D;

Unilateral acute macular edema with serous macular detachment after bilateral phacoemulsification

Two cases of unilateral macular edema with serous macular detachment occurring 1 day after uneventful bilateral phacoemulsification procedures are reported. Both patients underwent sequential bilateral phacoemulsification for refractive lens exchange. On postoperative day 1, corrected distance visual acuity (CDVA) was recorded between 6/24 and 6/48 in the affected eyes of cases 1 and 2, respectively. In both cases, optical coherence tomography showed serous macular detachment with significant intraretinal fluid accumulation. Central foveal thickness (CFT) was recorded as 583 μm in case 1 and 822 μm in case 2. In case 1, the fluid was completely resorbed by postoperative day 3 with no additional treatment. Final CDVA and CFT in case 1 were 6/6 and 292 μm, respectively. Resolution of edema was more prolonged in case 2 and occurred by postoperative day 8, after the addition of nepafenac 0.1% on day 2. Final CDVA and CFT in case 2 were 6/6 and 299 μm, respectively.

Torpedo maculopathy: A case series - insights into basic pathology.

Torpedo maculopathy is a benign retinal disorder whose pathophysiological origins are currently poorly understood. A number of theories have been postulated, with stable developmental anomalies of the retinal pigment epithelium taking the forefront. Four clinical cases are outlined of patients with macular torpedo lesions, with differing clinical presentation. In all four cases, this reveals very thin retinal pigment epithelium and outer retina associated with the lesion. In a single case, the oldest patient of the group, there is the additional finding of subretinal and intraretinal fluid accumulation. The contrast between this case and the other cases suggests that while initially this benign pathology might start with structurally normal retina with no fluid accumulation, dysgenetic changes in the retinal pigment epithelium might lead to secondary accumulation of fluid over time. Whether indeed this disorder might be progressive in nature, or whether in fact it is a static, non-progressive developmental abnormality as formerly thought, requires further elucidation.

Iris aneurysm in feline hypertensive oculopathy.

To describe and document the prevalence and cause of iris aneurysm in feline hypertensive oculopathy. Privately owned cats with systemic hypertension presented for sudden visual deficits and/or hyphema. A retrospective search of medical records of cats with systemic hypertension was performed in a specialized eye practice from October 2001 to August 2016. Inclusion criteria used for further evaluation were (1) systolic blood pressure exceeding 170mmHg measured by Doppler ultrasound, (2) typical fundus changes consistent with systemic hypertension (retinal folds, retinal edema, intraretinal bullous fluid accumulation, retinal detachment-partial or total, intra-/preretinal bleeding) in at least one eye, and (3) at least one follow-up visit with documented response to therapy with amlodipine. Cats with bilateral hyphema were excluded. A total of 206 cats fulfilled the inclusion criteria. Twenty-eight cats (14%) showed an aneurysm of the iridal vessels, 21 75% with some amount of hyphema. In total, hyphema was present in 62 cats (30%). Pearson correlation of fundus changes, hyphema, and aneurysm was performed. A high correlation between fundus changes without posterior segment hemorrhage and hyphema was found. The histopathology of one eye showed iridial vascular changes compatible with an aneurysm. In 75 cats, additional blood analysis was performed. Presumed chronic kidney disease (80%) was the most common cause of systemic hypertension with eye disease, followed by hyperthyroidism (20%). Vascular changes of the iris compatible with aneurysms were seen in 14% of cats with systemic hypertension and may result in vascular rupture and acute hyphema.

Effect of light and diurnal variation on macular thickness in X-linked retinoschisis: a case series.

Diurnal variations in foveal thickness have been reported in several ocular pathologies including X-linked retinoschisis (XLRS), but its underlying mechanism is poorly understood. Rods are active under scotopic conditions with high metabolic demand, and its decrease may have positive effect on metabolic activity and macular thickness. The purpose of this study is to evaluate whether exposure to light and diurnal variation influence macular thickness in XLRS patients. Five patients with clinical suspicion of XLRS underwent RS1 gene sequencing and optical coherence tomography measurements at three consecutive times: morning following sleep in a dark room, morning following sleep in an illuminated room, and late afternoon following sleep in an illuminated room. Central macular thickness (CMT) was compared between measurements, and molecular analysis was performed. Five RS1 mutations were identified: p.Gly140Arg, p.Arg141Cys, p.Gly109Glu, p.Pro193Leu, and p.Arg200His in patients 1-5, respectively. Two patients (4-5) had atrophied macula and were excluded from macular thickness variation analysis. A significant decrease in CMT between morning and afternoon measurements was observed in all patients (1-3: mean: 455.0 ± 32μm to 342.17 ± 39μm, 25%). Morning measurements following sleep in an illuminated room show a CMT reduction in all eyes of all patients with a mean reduction of 113μm (mean: 547.17 ± 105μm to 455.0 ± 32μm, 17%). Among XLRS patients, CMT decreased at the afternoon compared to the morning of the same day and may be reduced following sleep in an illuminated room. These results help shed light on the pathophysiologic process underlying intraretinal fluid accumulation involved with the disease.

Optical coherence tomogrpaphy in differential diagnosis of retinal arteriolar macroaneurysms

Aim. To study the prevalence and topographical distribution of retinal exudation in eyes with retinal arteriolar macroaneurysms (RAM) and in those with macular branch retinal vein occlusions (mBRVO).&#x0D; Methods. The prevalence of optical coherence tomography (OCT) signs (different types of retinal hemorrhages and accumulation of fluid as well as hard and soft exudates) was evaluated in 28 eyes with RAM (22 males, 6 females, mean age 66.0 9.9 years) versus 17 eyes with mBRVO (9 males, 7 females, mean age 56.9 10.5 years). Topographical distribution of retinal exudation on OCT retinal maps was evaluated in 7 RAM eyes (6 males, 1 female, mean age 66.0 11.7 years) and 8 mBRVO eyes (5 males, 3 females, mean age 60.1 19.2 years). The measures were 1) position of the point of the maximum retinal thickness in relation to the macular center and RAM, 2) difference between maximum retinal thickness in the macular center and that at the site of RAM localization (surrogate control point in mBRVO eyes).&#x0D; Results. Soft exudates and intraretinal fluid accumulation were mostly associated with mBRVO (p = 0.007 and p 0.001, respectively), while hard exudates were found almost exclusively in RAM eyes (p 0.001). Central retinal thickness in RAM eyes was lower than that of mBRVO eyes, 453.1 148.6 m and 797.5 179.6 m, respectively (p = 0.001). The point of maximum retinal thickness was found at the site of RAM localization in 8 out of 9 RAM cases (88.9%), and within the central subfield in 8 out of 8 mBRVO cases (100%). The difference between maximum retinal thickness in the macular center and at the site of RAM localization (surrogate control point in mBRVO eyes) was 77.9 174.1 m and 148.3 100.4 m for RAM and mBRVO eyes, respectively (p 0.001).&#x0D; Conclusions. Evaluation of exudative signs and their topographic distribution based on OCT data may be used for differential diagnosis and laser treatment planning in RAM.

Retinal vascular analysis in a fully automated method for the segmentation of DRT edemas using OCT images

Optical Coherence Tomography (OCT) is a well-established medical imaging technique that allows a complete analysis and evaluation of the main retinal structures and their histopathology properties. Diabetic Macular Edema (DME) implies the accumulation of intraretinal fluid within the macular region. Diffuse Retinal Thickening (DRT) edemas are considered a relevant case of DME disease, where the pathological regions are characterized by a “sponge-like” appearance and a reduced intraretinal reflectivity, being visible in OCT images. Additionally, the presence of other structures may alter the OCT image characteristics, confusing the pathological identification process. This is the case of the retinal vessels over all the eye fundus, whose presence produce shadow projections over the retinal layers that may hide the “sponge-like” appearance of the DRT edemas.Thus, in this paper, we present a proposal for the automatic extraction of DRT edemas, also using as reference the information provided by the automatic identifications of the retinal vessels in the OCT images. To do that, firstly, the system delimits three retinal regions of interest. These retinal regions facilitate the posterior identification of the vessel structures and the segmentation of the DRT regions. For the identification of the vessels structures, the method combined the localization of the upper bright vascular profiles with the presence of their corresponding lower dark vascular shadows. Finally, a learning strategy is implemented for the segmentation of the DRT edemas. Satisfactory results were obtained, reaching values of 0.8346 and 0.9051 of Jaccard index and Dice coefficient, respectively, for the extraction of the existing DRT edemas.

Alternative treatment methods in eyes with pseudophakic cystoid macular edema

Cystoid macular edema is a common cause for unexplained painless vision loss after cataract surgery. Even the pathogenesis of pseudophakic cystoid macular edema (PCME) still remains undefined, it can most frequently occur in eyes with high vasoactive profile and risk of inflammation. Increased inflammation, ultimately leading to the breakdown of the blood-retinal barrier and cystic accumulation of extracellular intraretinal fluid. The natural history of PCME is spontaneous resolution without any treatment in most of patient, but it may take weeks or months, in addition permanent visual morbidity may occured in some cases. Therefore there is lack of consensus regarding treatment approach for this common ocular condition. In this review treatment alternatives of PCME and its relation with underlying patho-physiologic mechanism are evaluated.

Automatic macular edema identification and characterization using OCT images

Background and objectiveThe detection and characterization of the intraretinal fluid accumulation constitutes a crucial ophthalmological issue as it provides useful information for the identification and diagnosis of the different types of Macular Edema (ME). These types are clinically defined, according to the clinical guidelines, as: Serous Retinal Detachment (SRD), Diffuse Retinal Thickening (DRT) and Cystoid Macular Edema (CME). Their accurate identification and characterization facilitate the diagnostic process, determining the disease severity and, therefore, allowing the clinicians to achieve more precise analysis and suitable treatments. MethodsThis paper proposes a new fully automatic system for the identification and characterization of the three types of ME using Optical Coherence Tomography (OCT) images. In the case of SRD and CME edemas, multilevel image thresholding approaches were designed and combined with the application of ad-hoc clinical restrictions. The case of DRT edemas, given their complexity and fuzzy regional appearance, was approached by a learning strategy that exploits intensity, texture and clinical-based information to identify their presence. ResultsThe system provided satisfactory results with F-Measures of 87.54% and 91.99% for the DRT and CME detections, respectively. In the case of SRD edemas, the system correctly detected all the cases that were included in the designed dataset. ConclusionsThe proposed methodology offered an accurate performance for the individual identification and characterization of the three different types of ME in OCT images. In fact, the method is capable to handle the ME analysis even in cases of significant severity with the simultaneous existence of the three ME types that appear merged inside the retinal layers.

In Vivo Multimodal Imaging and Analysis of Mouse Laser-Induced Choroidal Neovascularization Model.

Laser-induced choroidal neovascularization (CNV) is a well-established model to mimic the wet form of age-related macular degeneration (AMD). In this protocol, we aim to guide the reader not simply through the technical considerations of generating laser-induced lesions to trigger neovascular processes, but rather focus on the powerful information that can be obtained from multimodal longitudinal in vivo imaging throughout the follow-up period. The laser-induced mouse CNV model was generated by a diode laser administration. Multimodal in vivo imaging techniques were used to monitor CNV induction, progression and regression. First, spectral domain optical coherence tomography (SD-OCT) was performed immediately after the lasering to verify a break of Bruch's membrane. Subsequent in vivo imaging using fluorescein angiography (FA) confirmed successful damage of Bruch's membrane from serial images acquired at the choroidal level. Longitudinal follow-up of CNV proliferation and regression on days 5, 10, and 14 after the lasering was performed using both SD-OCT and FA. Simple and reliable grading of leaky CNV leasions from FA images ispresented. Automated segmentation for measurement of total retinal thickness, combined with manual caliber application for measurement of retinal thickness at CNV sites, allow unbiased evaluation of the presence of edema. Finally, histological verification of CNV is performed using isolectin GS-IB4 staining on choroidal flatmounts. The staining is thresholded, and the isolectin-positive area is calculated with ImageJ. This protocol is especially useful in therapeutics studies requiring high-throughput-like screening of CNV pathology as it allows fast, multimodal, and reliable classification of CNV pathology and retinal edema. In addition, high resolution SD-OCT enables the recording of other pathological hallmarks, such as the accumulation of subretinal or intraretinal fluid. However, this method does not provide a possibility to automate CNV volume analysis from SD-OCT images, which has to be performed manually.

Automatic Segmentation of Diffuse Retinal Thickening Edemas Using Optical Coherence Tomography Images

Diabetic retinopathy is one of the leading causes of vision impairment that is commonly associated to the Macular Edema (ME) disease. The Diffuse Retinal Thickening (DRT) is a ME type derived from the local intraretinal fluid accumulation in the lower retinal layers, producing significant morphological alterations in the eye fundus. The presence and properties of these intraretinal fluids are used by the ophthalmologists as significant indicators of the clinical stage of the ME disease. Given that, the precise identification and segmentation of the DRT edema type allow the early diagnosis of the ME disease which, therefore, permits a better adjustment of the treatments, reducing their costs as well as improving the life quality of the patients.This paper proposes a novel methodology for the automatic identification and segmentation of the DRT edemas using Optical Coherence Tomography (OCT) images as source of information. Firstly, the method identifies four of the principal retinal layers that are used as reference to delimit the outer retina, region where the DRT edemas are typically originated. Inside this region, a large and heterogeneous set of features was defined to recognize the characteristic “sponge-like” patterns of the DRT edema, using intensity, texture and clinically-defined features. For this analysis, four representative classifiers were employed with the best subsets of previously selected features. This methodology was tested using 70 OCT images from where 560 samples were extracted with the presence and absence of DRT edemas. The best results were achieved by the 7-kNN classifier, reaching in the detection stage an accuracy of 0.9366, whereas in the segmentation stage obtained values of 0.6625 and 0.7899 for the Jaccard and Dice coefficients, respectively.

DIAGNOSIS OF TYPE 3 NEOVASCULARIZATION BASED ON OPTICAL COHERENCE TOMOGRAPHY IMAGES.

To evaluate the concordance of an optical coherence tomography (OCT)-based diagnosis of Type 3 neovascularization and an indocyanine green angiography (ICGA)-based diagnosis in neovascular age-related macular degeneration (AMD). This observational case series includes 263 eyes from 263 patients who were diagnosed with treatment-naive neovascular AMD. Patients exhibiting at least three of the following OCT features were diagnosed with Type 3 neovascularization: subfoveal choroidal thickness <200 μm, presence of intraretinal fluid accumulation, absence of subretinal fluid, gently-sloping dome-shaped retinal pigment epithelial detachment or trapezoid-shaped retinal pigment epithelial detachment without an obvious peak, and intraretinal mass lesion. The incidence of cases exhibiting three or more OCT features was compared among different subtypes of neovascular AMD. Additionally, the concordance of OCT-based diagnosis and ICGA-based diagnosis was evaluated. Three or more OCT features were noted in 8 of 82 (9.8%) eyes with typical neovascular AMD, 4 of 147 (2.7%) eyes with polypoidal choroidal vasculopathy, and 30 of 34 (88.2%) eyes with Type 3 neovascularization, respectively. The incidence was significantly greater in Type 3 neovascularization than in the other subtypes of neovascular AMD (P < 0.001). Of patients diagnosed with Type 3 neovascularization using ICGA-based methods, 88.2% were also diagnosed with Type 3 neovascularization using OCT-based methods. Only 5.2% of patients diagnosed with other subtypes of neovascular AMD using ICGA-based methods were diagnosed with Type 3 neovascularization using OCT-based methods. Optical coherence tomography-based diagnosis of Type 3 neovascularization showed relatively high concordance compared with ICGA-based diagnosis. This method may be useful in clinical practice.