Type 1 diabetes mellitus (type 1 DM) is one of the most prevalent endocrinological diseases among children and young adults, with a growing incidence rate reaching up to 2.9 new cases per year per 100,000 persons below 15 years of age. We report a rare case of a 20-year-old female patient with type 1 DM, hemoglobin D (HbD) heterozygote variant and high myopia of -10.00 spheric diopters, and describe the retinal microvascular alterations visible on OCT angiography (angio-OCT). The patient also presented with a severe stature deficit (less than three standard deviations) and delayed puberty, which could not be explained only by suboptimal glycemic control and indicated possible hypopituitarism. HbA1c level evaluated with the high-performance liquid chromatography (HPLC) method was 6.5%, a falsely low value due to HbD hemoglobinopathy. On ophthalmic evaluation, the angio-OCT scan showed the following retinal microvascular alterations in the right eye (RE): the FAZ (Foveal Avascular Zone) area was 0.39 mm2, the FAZ perimeter was 2.88 mm, and the circularity index was 0.58. The following alterations were shown in the left eye (LE): the FAZ area was 0.34 mm2, the FAZ perimeter was 3.21 mm, and the circularity index was 0.41. Clinicians should consider high-performance retinal screening methods such as angio-OCT evaluation for young type 1 DM patients, especially for those with associated pathologies like high myopia and hemoglobinopathies. Moreover, multiple evaluation methods of HbA1c values are mandatory as hemoglobinopathies can interfere with the accuracy of HbA1c assay methods.

BACKGROUND: Retinal arterial occlusive events in young patients are rare. However, because of physiological multifactorial adaptations during pregnancy, retinal vascular occlusive disease may occur spontaneously. In addition, a patent foramen ovale is a risk factor for an ischemic thromboembolic event. Since fluorescein angiography, a central tool in the evaluation of these occlusions, should be avoided during pregnancy, optical coherence tomography angiography, a novel technique, offers a good opportunity for visualizing vascular perfusion of retinal tissue.
METHODS: Here we present a case series of three patients (Caucasian, nonsmoker) who visited our clinic owing to acute visual impairment and central scotoma. Using regular optical coherence tomography and optical coherence tomography angiography, retinal vascular occlusions were detected, thus initiating the evaluation of systemic risk factors. We report two patients (30 and 32 years old) who developed cilioretinal artery occlusion but whose etiology differed: one was of thromboembolic origin associated with patent foramen ovale, while the other was caused by hemodynamic blockade secondary to central retinal vein occlusion. In both cases, optical coherence tomography angiography revealed reperfusion of the cilioretinal artery occlusion. However, transient ischemia led to retinal atrophy after a few weeks. In the third patient (32 years old), 8 weeks after onset of scotoma, optical coherence tomography angiography revealed atrophy of the middle layers and impaired perfusion in the deep capillary plexus, and thus a paracentral acute middle maculopathy was diagnosed. All patients regained normal visual acuity and had otherwise uncomplicated pregnancies, and laboratory blood tests did not reveal any defects or alterations.
CONCLUSIONS: As shown here, optical coherence tomography angiography enables risk-free imaging of retinal vessel perfusion during pregnancy. Together with regular optical coherence tomography, it allows one to predict functional outcome according to the existing retinal occlusion-related atrophy.

BACKGROUND: To review the existing literature about the optical coherence tomography angiography (OCTA) findings regarding peripapillary and macular vessel density (VD) in patients with pseudoexfoliative glaucoma (PXG).
METHODS: A comprehensive search of the PubMed database was conducted to include articles up to November 1, 2021, using an appropriate search algorithm. The retrieved articles were assessed for eligibility and filtered manually to exclude duplicates, while articles and book chapters cited in the reference lists of the eligible articles obtained by this method were reviewed so as not to miss any relevant studies.
RESULTS: There is consistency among the studies published so far that a significant decrease in peripapillary VD exists in eyes with PXG compared to controls, and macular VD has also been reported to be significantly lower in PXG eyes than controls. However, the existing literature remains controversial regarding OCTA findings in eyes with PXG compared to those with primary open-angle glaucoma (POAG). Several studies have found that peripapillary VD and macular VD were significantly lower in PXG than POAG, while other studies reported no significant difference.
CONCLUSIONS: Eyes with PXG were found to present decreased peripapillary and macular VD compared to control eyes, suggesting that a vascular component, including optic nerve hypoperfusion, may be implicated in the pathogenesis of PXG.

There are various hypotheses for the anatomic origin of a choroidal macrovessel. We assess whether a choroidal macrovessel is a dilated posterior ciliary artery. A systematic review of published literature on choroidal macrovessels was performed with two additional cases from our institution. We compared the visible entry and vascular course of the macrovessel in the published literature. We performed a comparative analysis using indocyanine green angiography, swept source optical computed tomography, and 3D reconstruction of two choroidal macrovessels using 3D Slicer (Harvard, Boston, USA, https://www.slicer.org/). From the 14 studies found, 18 cases met inclusion criteria. The reported literature and our two cases showed a radiating course along a sectoral distribution pattern of either short or long posterior ciliary arteries. Our review of literature and 3D reconstruction analysis support the hypothesis that choroidal macrovessels are dilated posterior ciliary arteries.

This review presents a systematic analysis of the literature regarding the pachychoroid disease spectrum nomenclature, diagnosis criteria and therapeutic options. Pachychoroid related diseases are a new concept, introduced into the ophthalmological nomenclature in 2013 and evolving both as concept and as classification since then. The six disorders included in this phenotype have some common characteristics (thick choroid, pachyvessels, attenuation of the choriocapillaris), but also show individual features. The classification of the pachychoroid spectrum was revised many times, with the recent addition of the focal choroidal excavation (FCE) and peripapillary pachychoroid syndrome (PPS). As the terminology is developing, so is the number of case reports and case series from the initial report in 2013 to 57 reports in 2019. This review takes into account both the current literature and the clinical experience of the authors, emphasizing the understanding of the pathogenesis and aiming to update the therapeutic options available.

For over four decades, efforts have been underway for the evaluation of sickle cell retinopathy (SCR) in an attempt to identify peripheral high-risk vascular abnormalities based on Goldberg\'s classification (gold-standard) (1971). The macula is an area in the center of the retina that is responsible for high-resolution central vision and is also affected in SCR. With the development of new technologies for retinal imaging, the macula became a main focus of interest in the study of sickle cell disease (SCD). Optical coherence tomography angiography is a modern non-invasive method that allows qualitative and quantitative analysis of the retinal vascular network in the macular region. We identified 86 studies on SCD and optical coherence tomography angiography. Of those, 12 met the inclusion criteria for this systematic review. The prevalence of sickle cell maculopathy was 45.6% in the SCD population and it increased with age. We present the main vascular findings and discuss visual impairment and pathophysiology, genotypes, and peripheral high-risk vascular abnormalities. The role of the hematologist, general practitioner, and pediatrician in treatment is also reviewed.

Susac syndrome is a rare condition presumed to be immune-mediated occlusion of small arterial vasculature principally of the brain, inner ear, and retina. Clinically, the syndrome manifests as a pathognomonic triad of encephalopathy, hearing loss, and branch retinal artery occlusion. Early recognition and diagnosis is important as delayed treatment may be profound and result in deafness, blindness, dementia, and other neurological deficits. The plethora of imaging technology, including magnetic resonance imaging, retinal fluorescein angiography, optical coherence tomography, and optical coherence tomography angiography, allows deeper and more discrete anatomical-physiological correlation of underlying pathology, early diagnosis, and imaging biomarkers for early detection of relapse during follow-up. We highlight the current clinical classification of Susac syndrome, available investigations, treatment, and care pathways.

OBJECTIVE: Diabetic retinopathy (DR) is one of the leading causes of blindness worldwide. Accurate investigative tools are essential for the early diagnosis and monitoring of the disease. Optical coherence tomography angiography (OCTA) is a recently developed technology that enables visualisation of the retinal microvasculature.
METHODS: A systematic review of the literature was performed to examine the diagnostic use of OCTA in DR to date. Medline, EMBASE, and Cochrane databases were searched to find relevant studies. Sixty-one original studies were selected for the review.
CONCLUSIONS: OCTA has demonstrated the ability to identify microvascular features of DR such as microaneurysms, neovascularisation, and capillary non-perfusion. Furthermore, OCTA is enabling quantitative evaluation of the microvasculature of diabetic eyes. It has demonstrated the ability to detect early microvascular changes, in eyes with or without clinically evident DR. It has also been shown to detect progressive changes in the foveal avascular zone, and vascular perfusion density, with worsening severity of disease. It provides three-dimensional visualisation of the individual retinal vascular networks and is thereby enhancing our understanding of the role of the deeper vasculature in the pathogenesis of diabetic retinopathy and maculopathy.
CONCLUSIONS: However, limitations exist with current OCTA technology, in respect to the small field of view, image quality, projection artefact, and inaccuracies in analysis of the deeper vascular layers. While questions remain regarding its practical applicability in its present form, with continuing development and improvement of the technology, the diagnostic value of OCTA in diabetic retinopathy is likely to become evident.

We report a case of idiopathic paracentral acute middle maculopathy with typical optical imaging and clinical features. A 26-year-old Chinese policeman presented with a 20-day history of paracentral scotoma in the left eye after early wake-up and long-time working in front of computer the day before. He experienced sudden-onset strong flash in his left eye. Paracentral scotoma appeared in his left eye after 6hours of rest. The general history was negative. His best corrected visual acuity was 20/20 OU. Anterior segment, dilated fundus examination, papillary evaluation and intraocular pressure were normal. Fuorescein angiography and blue light fundus autofluorescence showed no significant abnormality. In multicolor photography, the lesion was visible on the monochromic infrared/blue reflectance images and not clear in green reflectance. The 10 degree visual field examination revealed superior paracentral relative scotoma. Multifocal electroretinogram revealed reduced response in central area in the left eye. Spectral-domain optical coherence tomography showed that hyperreflective plaque was present at the IPL/INL/OPL level with hyperreflective point at the GCL. The plaque became thinner 3 months later and diminished 6 months later with obviously atrophied INL. In the 3 months follow-up, transverse scan revealed that there was a well-demarcated hypo-refractive lesion in IPL and hyper-refractive lesion in INL. OCTA revealed the deceased flow signal intensity of focal deep capillaries. En face OCT imaging of the left eye revealed a relative well-defined, hypo-refractive lesion and non-flow area localized at the level of the deep capillary plexus.

Over the last decade, there has been an expansion of imaging modalities available to clinicians to diagnose and monitor the treatment and progression of diabetic retinopathy. Recently, advances in image technologies related to OCT and OCT angiography have enabled improved visualization and understanding of this disease. In this review, we will describe the use of imaging techniques such as colour fundus photography, fundus autofluorescence, fluorescein angiography, infrared reflectance imaging, OCT, OCT-Angiography and techniques in adaptive optics and hyperspectral imaging in the diagnosis and management of diabetic retinopathy.