Andre Romano

A review of optical coherence tomography angiography (OCTA)

Optical coherence tomography angiography (OCTA) is a new, non-invasive imaging technique that generates volumetric angiography images in a matter of seconds. This is a nascent technology with a potential wide applicability for retinal vascular disease. At present, level 1 evidence of the technology’s clinical applications doesn’t exist. In this paper, we introduce the technology, review the available English language publications regarding OCTA, and compare it with the current angiographic gold standards, fluorescein angiography (FA) and indocyanine green angiography (ICGA). Finally we summarize its potential application to retinal vascular diseases. OCTA is quick and non-invasive, and provides volumetric data with the clinical capability of specifically localizing and delineating pathology along with the ability to show both structural and blood flow information in tandem. Its current limitations include a relatively small field of view, inability to show leakage, and proclivity for image artifact due to patient movement/blinking. Published studies hint at OCTA’s potential efficacy in the evaluation of common ophthalmologic diseases such age related macular degeneration (AMD), diabetic retinopathy, artery and vein occlusions, and glaucoma. OCTA can detect changes in choroidal blood vessel flow and can elucidate the presence of choroidal neovascularization (CNV) in a variety of conditions but especially in AMD. It provides a highly detailed view of the retinal vasculature, which allows for accurate delineation of the foveal avascular zone (FAZ) in diabetic eyes and detection of subtle microvascular abnormalities in diabetic and vascular occlusive eyes. Optic disc perfusion in glaucomatous eyes is notable as well on OCTA. Further studies are needed to more definitively determine OCTA’s utility in the clinical setting and to establish if this technology may offer a non-invasive option of visualizing the retinal vasculature in detail.

Corneal infections after implantation of intracorneal ring segments.

Purpose: To report risk factors, clinical course, and outcome in patients with infectious keratitis following implantation of intracorneal ring segments (ICRS). Methods: The records of 8 patients with culture-proven infectious keratitis after ICRS (Ferrara® or Intacs®) implantation were retrospectively reviewed. Age, gender, corneal findings, ocular abnormalities, the condition that led to ICRS implantation, immediate prior use of a contact lens, elapsed time between implantation and the onset of symptoms, previous medications, and systemic disorders were noted. Results: Culture-positive infectious keratitis developed in 7 eyes of 7 patients (2 men and 5 women) with a mean age of 35 years who underwent Ferrara implantantion for the treatment of keratoconus and in a 29-year-old man who underwent Intacs implantation for correction of low myopia. Contact lens use, diabetes, and trauma were factors possibly associated with the risk of infection in three cases. Microorganisms, identified in all cases, included Staphylococcus aureus, Streptococcus viridans, Streptococcus pneumoniae, Pseudomonas sp, Nocardia sp, Klebsiella sp, and Paecylomices sp. Onset of symptoms of infection varied from less than 1 week to 22 months postoperatively, depending on the infecting organism. Conclusions: Infectious keratitis following ICRS implantation is a sight-threatening complication for which early recognition and rapid institution of appropriate treatment may result in a better visual outcome.

Idiopathic limbal stem cell deficiency.

PURPOSE To describe and to characterize the clinical findings and prognosis of patients with idiopathic limbal stem cell deficiency (LSCD). DESIGN Retrospective case series. PARTICIPANTS/METHODS We reviewed records from seven patients whose LSCD had been diagnosed clinically and confirmed by impression cytology and in whom the cause of LSCD was never identified. A detailed history, clinical records, and results of slit-lamp biomicroscopy, photography, vital staining, and impression cytology were evaluated. RESULTS Six of seven patients (86%) were women, indicating a female predominance. Two patients were from the same family, whereas one other had a positive family history. Severe photophobia was noted in all patients and reduced vision in three patients. The main clinical findings included superficial vascularization, worse in the superior followed by the inferior and nasal cornea. The limbal regions showed a loss of limbal palisades of Vogt, and the adjacent peripheral cornea revealed an irregular and hazy epithelium with positive late fluorescein staining and the presence of conjunctival goblet cells by impression cytology. LSCD was bilateral in all patients but asymmetric in four. During a mean follow-up of 6.1+/- 3.8 years, the visual acuity decreased in both eyes of one patient after cataract extraction and in both eyes of two other patients without surgery. The process of conjunctivalization advanced in four patients (57%) and remained stable in three (43%) without surgical intervention. CONCLUSIONS Idiopathic LSCD is a rare and as yet poorly recognized clinical entity, and the findings reported herein may help explore how progressive loss of limbal stem cells occurs. Correct diagnosis of idiopathic LSCD is important so that the patient will not be subjected to unnecessary surgeries, which may actually severely worsen the clinical course.

Cleavage of corneal basement membrane components by ethanol exposure in laser-assisted subepithelial keratectomy.

Purpose: To determine the anatomic cleavage plane after exposure to 20% ethanol for approximately 20 to 25 seconds to create an epithelial flap in laser‐assisted subepithelial keratectomy (LASEK). Setting: Ocular Surface Research & Education Foundation, Miami, Florida, and Hermann Eye Center Refractive Surgery Center, Houston, Texas, USA. Methods: Immunofluorescence staining using monoclonal antibodies against laminin 5, collagen VII, and integrins &bgr;1 and &bgr;4 was performed to determine the anatomic location of the cleavage plane in an epithelial flap created by 20‐second exposure to 20% ethanol in cadaver eyes and in epithelial flaps obtained from LASEK patients. Results: Immunofluorescence staining to laminin 5 and integrin &bgr;4 was patchy in the lifted flap and the remaining corneal basement membrane. Immunostaining to collagen VII, the main component of anchoring fibrils, remained exclusively in the corneal bed. Immunostaining to integrin &bgr;1, present in the pericellular location of all epithelial cell layers, remained exclusively in the epithelial flap. This finding was consistent in cadaver corneas and LASEK epithelial flaps. Conclusion: The cleavage plane of the ethanol‐induced corneal epithelial flap is located between the lamina lucida and the lamina densa of the basement membrane, where integrin &bgr;4 interacts with laminin 5 to form hemidesmosomes.

Clinical OCT angiography atlas

PART I: TECHNOLOGY AND INTERPRETATION Section 1: Methods and Techniques of OCT Angiography Examination * Principles of Optical Coherence Tomography Angiography * Interpretation of Optical Coherence Tomography Angiography * Optical Coherence Tomography Angiography: Terminology * Techniques for Using OCT Angiography for Clinical Examination * Clinical Applications of OCT SSADA Angiography in Everyday Clinical Practice Section 2: OCT Angiography Examination of Structure and Histology * Retinal Normal Vascularization PART II: OCT ANGIOGRAPHY STUDY OF DISEASES AND DISORDERS Section 3: Anterior Segment OCT Angiography Examination * Corneal and Anterior Segment OCT Angiography Section 4: Retina OCT Angiography Examination: Age-related Macular Degenerations * OCT Angiography Examination of Choroidal Neovascular Membrane in Exudative Age-Related Macular Degeneration * OCT Angiography Examination of Choroidal Neovascular Membrane in Other Disorders * OCT Angiography Follow-up of Choroidal Neovascularization After Treatment * Non-Neovascular Age-related Macular Degeneration Section 5: Retina OCT Angiography Examination: Other Macular Diseases * OCT Angiography Findings in Central Serous Chorioretinopathy * OCT Angiography Examination of Type 2 Idiopathic Macular Telangiectasia * OCT Angiography of Vascular Occlusions * Diabetic Retinopathy * OCT Angiography in Diabetic Retinopathy * OCT Angiography Examination of Foveal Avascular Zone Section 6: Myopia and Pathologic Myopia * OCT Angiography Examination in High Myopia Section 7: Choroid * OCT Angiography Examination of Choroidal Nevi and Melanomas Section 8: Glaucoma and Optic Nerve * OCT Angiography Examination in Glaucoma PART III: FUTURE DEVELOPMENTS IN OCT ANGIOGRAPHY Section 9: Future Developments in OCT Angiography Examination * Ultrahigh Speed Swept Source Technology for OCT Angiography Index

Clinical treatment of corneal infection due to Fonsecaea pedrosoi: case report

UNLABELLED To report an unusual case of fungus keratitis due to Fonsecaea pedrosoi that developed after corneal trauma. CASE REPORT A 18-year-old male presented with a corneal ulcer in the right eye, 28 days after a trauma with glass fragments. Corneal scrapings were collected for smears and culture. Dematiaceous hyphae were seen on wet mounts of the scrapings and dark pigmented colonies grew repetitively on the culture media; all colonies were identical, and were subsequently identified as Fonsecaea pedrosoi. Treatment was initiated with topical natamycin at one hour intervals, 200 mg oral ketoconazole per day and later changed to a combination of 200 mg ketoconazole and amphotericin B. In humid tropical regions Fonsecaea pedrosoi is one of the primary causes of human chronic cutaneous mycosis, chromoblastomycosis. Combination of systemic and topical antifungal medications may provide the best option for cure in corneal chromoblastomycosis.

Imaging in ocular toxoplasmosis.

Ocular toxoplasmosis (OT) is the most important and frequent cause of retinitis and posterior uveitis, and can causes blindness secondary to direct involvement of the macula or optic disc, or secondary to vitreoretinal complications. The frequency of OT varies in different regions, being common in most of the western countries. OT represents 50% to 85% of all posterior uveitis cases in Brazil and 25% in the United States. Toxoplasmosis is transmitted usually by the ingestion of undercooked lamb, pork, and chicken, as well as food and water contaminated by the feces of infected cats. OT is a disease caused by a congenital or postnatally acquired infection and it is impossible to clinically differentiate them in most cases, because at the time ocular lesions occur, serology shows only IgG antibodies against the toxoplasma. Fetal toxoplasmosis tends to occur only when the woman acquires the first infection during or months before the pregnancy. Children are usually born with subclinical infections and OT develops up to decades later. OT in immunocompetent patients is characterized by an acute inflammatory granulomatous necrotizing inflammation of the retina and choroid. It can be widespread in the eye and involve the vitreous, ciliary body, iris, anterior chamber, cornea, and trabecular meshwork. Acute and new lesions are usually intensely white with overlying vitreous inflammatory haze and will occasionally develop retinal vasculitis with

Bilateral macular hemorrhage as a complication of drug-induced anemia: a case report.

IntroductionBilateral macular hemorrhage is a rare ocular finding and to the best of our knowledge, this is the first report of such hemorrhages as a presentation of drug-induced anemia.Case presentationWe describe the case of a 14-year-old Caucasian boy who presented with a toxoplasmic retinochoroiditis and was treated with sulfadiazine and pyrimethamine. Three months later, he presented with a bilateral macular hemorrhage as a complication of a toxic induced anemia.ConclusionOur patient presented with toxic anemia secondary to the treatment of a very common disease, ocular toxoplasmosis. Prophylactic use of folinic acid could prevent such complications but in many cases, it is not prescribed owing to its cost or is mistakenly substituted with folic acid, which does not present as a valid substitute.

Optical Coherence Tomography Angiography of Chorioretinal Diseases.

Fluorescein angiography (FA) and indocyanine green angiography (ICGA) have been the gold standard for the evaluation of retinal and choroidal vasculature in the last three decades and have revolutionized the diagnosis of retinal and choroidal vascular diseases. The advantage of these imaging modalities lies in their ability to document retinal and choroidal vasculature through the dynamic assessment of contrast transit over time in the intravascular and extravascular spaces. However, disadvantages include the absence of depth resolution, blurring of details by contrast leakage, and the inability to selectively evaluate different levels of the retinal and choroidal microvasculature. In addition, these angiographic methods require intravenous dye, which may cause adverse reactions such as nausea, vomiting, and rarely, anaphylaxis. Optical coherence tomography angiography (OCTA) is a noninvasive imaging technique that, in contrast to dye-based angiography, is faster and depth-resolved, allowing in some cases for more precise evaluation of the vascular plexuses of the retina and choroid. The method has been demonstrated in the assessment of various vascular diseases such as venous occlusions, diabetic retinopathy, macular neovascularization, and others. Limitations of this imaging modality include a small registered field of view and the inability to visualize leakage and dye transit over time. It is also subject to a variety of artifacts, including those generated by blinking and eye movement during image acquisition. However, more than an alternative for FA and ICGA, OCTA is bringing new insights to our understanding of retinal and choroidal vascular structure and is changing fundamental paradigms in the clinical management of pathologic conditions. [Ophthalmic Surg Lasers Imaging Retina. 2016;47:848-861.].

Diagnostic Techniques: Optical Coherence Tomography

Optical coherence tomography (OCT) is a powerful imaging technique that provides cross-sectional imaging of the internal microstructures of biological tissues. Among several implementations of OCT, spectral-domain OCT (SD-OCT) provides high-resolution, high-sensitivity, and high-speed imaging. Such implementations enable visualization of the microstructures of the human eye by noninvasive and noncontact measurement. High sensitivity of OCT detection enables imaging of structures with very low optical scattering, such as the retina. The high axial and lateral resolution enables the precise morphological investigation of various pathological conditions. Recently, hardware and software upgrades have improved the ability to better evaluate intraocular tumors.