OPTICAL COHERENCE TOMOGRAPHY AND OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY EVALUATION OF COMBINED HAMARTOMA OF THE RETINA AND RETINAL PIGMENT EPITHELIUM

Role of optical coherence tomography angiography in retinal tumors: A narrative review

Intraocular tumors constitute a small subset of cases in ophthalmologic practice. Proper diagnosis of intraocular tumors is crucial because some pose threat to vision and life, while others may indicate underlying systemic disorders. Intraocular tumors comprise benign and malignant lesions affecting the retina, choroid, optic disc, iris, and ciliary body. Retinal tumors can be classified as vascular, neural, glial, and retinal pigment epithelial tumors. Optical coherence tomography angiography (OCTA) is a noninvasive imaging modality employed in diagnosis and management of retinal and choroidal vascular diseases, and has enhanced our knowledge in better understanding of the vascular physiology and pathology. Multiple case reports and small series evaluating the role of OCTA in retinal tumors are published in literature. OCTA helps in better understanding of the vascularity of intraocular tumors. In addition to this, OCTA has its role in clinical practice. It helps in identification of small retinal capillary hemangioblastoma (RCH), assessment of treatment response, and identification of tumor recurrence in RCH. It aids in identification of retinal astrocytic hamartoma missed on clinical examination and differentiating retinal astrocytic hamartoma and presumed solitary circumscribed retinal astrocytic proliferation. It helps in assessment of risk of tumor recurrence in retinoblastoma. It helps in differentiating tumors of retinal pigment epithelium (RPE) origin from pigmented tumors of the choroid. It also helps in detection of choroidal neovascular membrane in combined hamartoma of the retina and RPE.

Advances in multimodal imaging for diagnosis of pigmented ocular fundus lesions

Pigmented ocular fundus lesions can range from benign to malignant. While observation is reasonable for asymptomatic benign lesions, early recognition of tumours that are vision or life threatening is critical for long-term prognosis. With recent advances and increased accessibility of multimodal imaging, it is important that providers understand how to best use these tools to detect tumours that require early referral to subspecialty centres. This review aims to provide an overview of pigmented ocular fundus lesions and their defining characteristics using multimodal imaging. We cover the spectrum of pigmented ocular fundus lesions, including freckle and focal aggregates of normal or near-normal uveal melanocytes, retinal pigment epithelium (RPE) hyperplasia, congenital hypertrophy of the RPE, RPE hamartoma associated with familial adenomatous polyposis, congenital simple hamartoma of the RPE, combined hamartoma of the retina and RPE (congenital hypertrophy of the RPE), choroidal nevus, melanocytosis, melanocytoma, melanoma, adenoma, and RPE adenocarcinoma. We describe key diagnostic features using multimodal imaging modalities of ultra-widefield fundus photography, fundus autofluorescence, optical coherence tomography (OCT), enhanced-depth imaging OCT, ultrasonography, fluorescein angiography, indocyanine green angiography, and OCT angiography (OCTA), with particular attention to diagnostic features that could be missed on fundus examination alone. Finally, we review what is on the horizon, including applications of artificial intelligence. Through skilled application of current and emerging imaging technologies, earlier detection of sight- and life-threatening melanocytic ocular fundus tumours can lead to improved patient prognosis.

OCTA-based research on changes of retinal microcirculation in digestive tract malignancy

PURPOSE

This cross-sectional study measured retinal vessel density (VD) in patients with digestive tract malignancy by optical coherence tomography angiography (OCTA), and compared them with healthy controls to explore the retinal microcirculation changes in patients with digestive tract malignancy.

METHODS

106 eligible participants were divided into three groups: gastric cancer (GC) group (36 individuals), colorectal cancer (CRC) group (34 individuals), and healthy control group (36 individuals). Angio 6 × 6 512 × 512 R4 and ONH Angio 6 × 6 512 × 512 R4 modes were performed to collect retinal vessel density data centered on fovea and papillary, respectively. The retina was automatically segmented into different layers (superficial vascular plexus (SVP), the inner retinal layer, radial peripapillary capillary plexus (RPCP), deep vascular plexus (DVP)) and areas to analyze.

RESULTS

At the optic nerve head (ONH) region, the VD of the inner retinal layer increased in both GC and CRC groups in all quadrants and areas. In the papillary area, VD in the inner retinal layer, SVP, and RPCP increased in the GC and CRC groups. In the parapapillary area, VD in the inner retinal layer increased in the GC and the CRC groups. Significant increase in the global VD were found in the GC group of the RPCP and SVP. Regarding the macular region, no statistical differences were observed in each layer.

CONCLUSIONS

The study suggested that retinal vessel density changed in patients with digestive tract malignancy, especially in the inner retinal layer of the ONH region, revealing the potential relevance of the relation between gastrointestinal cancer and retinal microcirculation.

Quantitative Assessment of Retinal and Choroidal Microvasculature in Asymptomatic Patients with Carotid Artery Stenosis

SIGNIFICANCE

Carotid disease contributes to 15 to 20% of all ischemic strokes, one of the leading causes of permanent disabilities and mortality globally. With its growing prevalence and the inflicted disability rates, screening for anomalies that precede the onset of its serious complications is of crucial global significance.

PURPOSE

This study aimed to assess the relationship between retinal and choroidal perfusion changes with the degree of stenosis using quantitative swept-source optical coherence tomography angiography in patients with internal carotid artery stenosis.

METHODS

A retrospective cohort study was conducted in 72 eyes with carotid stenosis. According to the degree of stenosis, the participants were divided into a healthy group (group 1: 34 eyes), a mild-moderate stenosis group (group 2: 22 eyes), and a severe stenosis group (group 3: 16 eyes). Swept-source optical coherence tomography angiography was performed to scan macular fovea. Capillary density values in the different retinal and choroidal layers were the major measurements for our study.

RESULTS

Mean vessel density in the midchoroid layer was significantly higher in groups 2 and 3 compared with group 1. Deep choroid disclosed significantly superior vascular density values in group 3 compared with groups 2 and 1. Superficial and deep capillary plexus showed decreased vascular density values when comparing group 3 with groups 1 and 2, although they were not significant.

CONCLUSIONS

Our report provides the first evidence that choroidal microvascular changes were correlated with severity of carotid artery stenosis. Optical coherence tomography angiography can sensitively detect subtle, early changes in the ocular blood in carotid disease representing a useful, noninvasive, and objective approach to the retinal microvasculature.

Description and surgical management of epiretinal membrane due to combined hamartoma of the retina and retinal pigment epithelium

Purpose

To outline the characteristics of Combined Hamartoma of the Retina and Retinal Pigmentation Epithelium (CHRRPE) and provide a comprehensive overview of surgical management of epiretinal membrane (ERM) caused by CHRRPE.

Main text

CHRRPE is a rare ocular tumor. It clinically mimics other diseases such as retinoblastoma and choroidal melanoma. The present study reviewed the multimodal imaging of CHRRPE, highlighted the multimodal imaging modalities which are useful for revealing the unique features of CHRRPE and hence allowing physicians to confirm the diagnosis.Although most of CHRRPEs are benign harmatoma, progressive visual loss may occur because of the traction of the tumor and other complications. It is treated through surgical removal of the ERM caused by CHRRPE to free retina from the traction. Currently, there is no consensus on the surgical management of CHRRPE. Therefore, the current review was designed to explore the surgical management of ERM caused by CHRRPE and hence provide updated data on this subject.

Conclusions

Multimodal imaging technologies, especially optical coherence tomography (OCT), significantly contributes to the diagnosis of CHRRPE and visual prognosis. Surgical management of CHRRPE through removal of ERM is beneficial in patients with worsening VA which is secondary to ERM which is associated with CHRRPE. However, the strategy is limited to patients with long-standing poor vision. However, earlier surgical therapy and subsequent postoperative amblyopia therapy can be explored for children of amblyogenic age.

Optical Coherence Tomography Angiography in Pediatric Retinal Disorders

Purpose:

The rapid and noninvasive nature of optical coherence tomography angiography (OCTA) makes it a potentially valuable tool for imaging the retina in children. With the optimization of tabletop systems and the development of experimental handheld OCTA devices, there is expanded potential for OCTA in the clinic and the operating room. This article reviews the utility of OCTA in some of the most common pediatric retinal disorders.

Methods:

A thorough computerized PubMed search was performed to review relevant published journal articles to contextualize and identify the role of OCTA in common retinal disorders with vascular involvement affecting children. Pertinent results and findings from original investigations and case reports were summarized.

Results:

The ability to quickly collect both qualitative and quantitative information about retinal microvasculature, in both the clinic and operating room settings, with OCTA, has led to the uncovering of microvascular features and morphologic changes in many pediatric retinal disorders such as Coats Disease, familial exudative vitreoretinopathy, incontinentia pigmenti, sickle cell retinopathy, Stargardt Disease, X-linked juvenile retinoschisis, retinopathy of prematurity, diabetic retinopathy in type 1 diabetes, pediatric retinal tumors, and choroidal neovascularization.

Conclusions:

OCTA is a relevant tool to aid early detection, guide intervention, monitor treatment response, and understand pathogenesis in a number of pediatric retinal disorders.

Macular Changes Observed on Optical Coherence Tomography Angiography in Patients Infected With Human Immunodeficiency Virus Without Infectious Retinopathy

Purpose

As the human immunodeficiency virus (HIV) pandemic is far from over, whether there are subclinical macular changes in HIV-positive patients is something that should not be overlooked. We aimed to apply optical coherence tomography angiography (OCTA) to assess the macular structure and microvasculature changes in patients with HIV without infectious retinopathy.

Methods

HIV-positive and -negative participants were included and classified into three groups: HIV-negative, HIV-positive, and HIV-positive with microvasculopathy. OCTA parameters regarding macular structure and microvasculature were analyzed.

Results

Compared with the HIV-negative group, the superficial retinal vessel density (VD) in the parafovea sectors and the whole Early Treatment of Diabetic Retinopathy Study (ETDRS) grid and the choroidal vascularity index (CVI) in the whole ETDRS grid were significantly decreased in the HIV-positive and HIV-positive with microvasculopathy groups (p < 0.05). No differences were found in OCTA parameters between the HIV-positive and HIV-positive with microvasculopathy groups. Retinal, retinal nerve fiber layer-ganglion cell layer-inner plexiform layer (RNFL-GCL-IPL), RNFL, GCL-IPL, and INL thickness showed a negative association with the duration of HIV diagnosis or antiretroviral therapy (ART) (all p < 0.05). All OCTA microvasculature parameters showed no association with HIV-related clinical variables (all p > 0.05).

Conclusions

Subclinical macular changes existed in HIV-infected patients without clinical infectious retinopathy. Substructures from inner retinal layers might be associated with HIV infection or ART duration.

Total flow intensity, active flow intensity and volume related flow intensity as new quantitative metrics in optical coherence tomography angiography

Optical coherence tomography (OCT) angiography (OCTA) is a non-invasive tool for the in-vivo study of the intraretinal vascular network. It is based on the analysis of motion particles within the retina to reconstruct the paths followed by the erythrocytes, i.e. retinal capillaries. To date, qualitative and quantitative information are based on the morphological features disclosed by retinal capillaries. In the present study, we proposed new quantitative functional metrics, named Total Flow Intensity (TFI), Active Flow Intensity (AFI), and Volume-related Flow Intensity (VFI), based on the processing of the blood flow signal detected by OCTA. We studied these metrics in a cohort of healthy subjects, and we assessed their clinical utility by including a cohort of age-matched patients affected by Stargardt disease. Moreover, we compared TFI, AFI, and VFI to the widely used vessel density (VD) parameter. TFI, AFI, and VFI were able to describe in detail the different properties of the retinal vascular compartment. In particular, TFI was intended as the overall amount of volumetric retinal blood flow. AFI represented a selective measure of voxels disclosing blood flow signal. VFI was developed to put in relationship the volumetric blood flow information with the not vascularized retinal volume. In conclusion, TFI, AFI, and VFI were proposed as feasible functional OCTA biomarkers based on the analysis of retinal blood flow signal.

FINGERPRINT SIGN OF THE HENLE FIBER LAYER

PURPOSE

To describe the appearance of concentric, fingerprint-like waves within the Henle fiber layer (HFL) using en face optical coherence tomography in patients with tractional pathologies of the retina.

METHODS

Retrospective analysis of six eyes of six patients imaged by optical coherence tomography with volumetric slabs positioned at the level of the HFL.

RESULTS

Optical coherence tomography data from six patients with tractional vitreoretinal pathology were reviewed. Concentric, fingerprint-like microwaves were visualized through en face optical coherence tomography in all six study eyes at the level of the HFL. This finding resembled the finding of HFL waves previously noted histopathologically from force exerted on this layer.

CONCLUSION

In retinal pathologies in which specific physical forces act on the retina, volumetric optical coherence tomography may permit visualization of en face concentric, fingerprint-like hyperreflective rings within the HFL. This "fingerprint sign" may represent a biomechanical consequence of traction on the retina and allow clinical decision making based on improved recognition of the existence of such traction.

Congenital focal abnormalities of the retina and retinal pigment epithelium

This paper reviews the published literature on a group of developmental disorders of the retina and retinal pigment epithelium which result in focal abnormalities in one or both eyes. They are often asymptomatic, found on routine examination and are generally non-progressive. Some are associated with other systemic abnormalities.

Optical coherence tomography angiography (OCTA) applications in ocular oncology

Optical coherence tomography angiography (OCTA) is a revolutionary method in the visualization of the vascular system in different retinal and choroidal layers. During the last 4 years since the commercial availability of different OCTA devices, attempts have been made to utilize this technology in various aspects of ocular oncology from the differentiation of benign and malignant lesions to assisting in evaluation of post-treatment complications, such as radiation retinopathy. However, current OCTA technology is restricted by various artefacts and inherent limitations, some of which are more pronounced in the presence of elevated tumoural lesions. Imminent advancements in OCTA systems and image acquisition processes promise a great potential for application of OCTA in ocular oncology.

Age-dependent Changes in the Macular Choriocapillaris of Normal Eyes Imaged With Swept-Source Optical Coherence Tomography Angiography

PURPOSE

Swept-source optical coherence tomography angiography (SS-OCTA) was used to measure the age-dependent changes in macular choriocapillaris (CC) flow deficits (FDs) in normal eyes.

DESIGN

A prospective, cross-sectional study.

METHODS

Subjects with normal eyes ranging in age from their 20s to their 80s were imaged using a 100-kHz SS-OCTA instrument (PLEX Elite 9000, Carl Zeiss Meditec, Dublin, California, USA). Both 3 × 3-mm and 6 × 6-mm scans were used to image the macular CC. Visualization of the CC and quantification of FDs were performed using a previously validated algorithm. The percentage of FDs (FD%) in the central 1-mm circle (C₁), 1.5-mm rim (R_1.5), and 2.5-mm circle (C_2.5) from the 3 × 3-mm and 6 × 6-mm scans and FD% in the 2.5-mm rim (R_2.5) and 5-mm circle (C₅) from the 6 × 6-mm scans were measured and correlated with age and axial length.

RESULTS

A total of 164 subjects were enrolled, with at least 10 subjects from each decade of life. No meaningful correlations were found between FD% and axial length (|r| < 0.30). FD% in all fields increased with increasing age (all r > 0.50; all P < .001); however, the greatest increases were found in the central macula C₁ regions and the smallest increases in the peripheral macula R_2.5 regions.

CONCLUSIONS

In normal aging, the FD% increased with age across the central 5 mm of the macula, but the greatest increase was found in the central 1-mm region of the macula.

Multimodal imaging evaluation of combined hamartoma of the retina and retinal pigment epithelium

PURPOSE

Combined hamartoma of the retina and retinal pigment epithelium is a rare benign tumor characterized by a variable combination of glial, vascular, and pigmented components. The purpose of our study was to analyze the features of combined hamartoma of the retina and retinal pigment epithelium on optical coherence tomography angiography.

METHODS

Small case series of two cases of combined hamartoma of the retina and retinal pigment epithelium with macular and optic nerve involvement, evaluated with multimodal imaging including optical coherence tomography, fluorescein angiography, and optical coherence tomography angiography.

RESULTS

On optical coherence tomography, combined hamartoma of the retina and retinal pigment epithelium is characterized by disruption of the inner neurosensory retina and a variable degree of involvement of the external retina. Optical coherence tomography angiography showed diffuse alterations of the retinal vessels of the superficial and deeper layers, extended to the peripapillary area. Vessel abnormalities included increased tortuosity and caliber of vessels, vascular traction, and vessel stretching within the lesion.

CONCLUSION

Optical coherence tomography angiography allows in-depth multilayer analysis of tumor vascular network, highlighting the fine abnormalities of retinal vasculature characteristic of combined hamartoma of the retina and retinal pigment epithelium.