Imaging of iris vasculature: current limitations and future perspective.

Fluorescein and indocyanine green angiography have been the traditional ways to image the vasculature of the iris in the last few decades. Because of the invasive nature of these procedures, they are performed in rare situations, and thus, our understanding about iris vasculature is very limited. Optical coherence tomography angiography (OCTA) is a noninvasive imaging method that enables the detailed visualization of the retinal and choroidal vascular networks. More recently, it has been also used for the examination of the iris vasculature in healthy and disease eyes. However, there is a lack of uniformity in the image acquisition protocols and interpretations in both healthy and pathological conditions. Artifacts of iris OCTA include shadowing, motion, segmentations errors, mirror effects. OCTA devices have an eye-tracking system designed for the posterior segment and the applications of these systems on the anterior segment can determine motion lines, vessel duplication, and vessel discontinuity. OCTA of the iris should always be performed under ambient room lighting to create miosis and reduce iris vasculature changes during the examination. In the near future, eye-tracking systems specifically designed for the iris vessels could permit the follow-up function, and the development of new OCTA metrics could reveal interesting applications of this new imaging technique.

A Panel of Broad-Spectrum Antivirals in Topical Ophthalmic Medications from the Drug Repurposing Approach during and after the Coronavirus Disease 2019 Era.

The coronavirus disease 2019 (COVID-19) represents a global concern of public health caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Its clinical manifestations are characterized by a heterogeneous group of symptoms and pictures (ranging from asymptomatic to lethal courses). The prevalence of conjunctivitis in patients with COVID-19 is at present controversial. Although it has been reported that only 0.9% developed signs of conjunctivitis, other report indicates that up to 31.6% of hospitalized patients had conjunctivitis. Considering the widespread use of topical ophthalmic medications (e.g., eye drops) by the general population, for various reasons (e.g., artificial tears, anti-glaucoma medications, topical antibiotics, etc.), the existence of their side effects as antiviral action should be investigated in-depth because it could possibly explain the aforementioned controversial data and represent a potential antiviral treatment for SARS-CoV-2 replication/diffusion on the ocular surface. Here, we discuss and elucidate the antiviral side effect of many eye drops and ophthalmic ointments commonly used for others purposes, thus showing that these secondary effects (not to be confused with the 'adverse effects') might be of primary importance in a number of viral infections (e.g., those for which there is no validated treatment protocol), according to a drug repurposing approach. Some active ingredients or excipients described here have activity against other types of viruses, thus suggesting potential broad-spectrum applications.

Fourier-Domain OCT Imaging of the Ocular Surface and Tear Film Dynamics: A Review of the State of the Art and an Integrative Model of the Tear Behavior During the Inter-Blink Period and Visual Fixation.

In the last few decades, the ocular surface and the tear film have been noninvasively investigated in vivo, in a three-dimensional, high resolution, and real-time mode, by optical coherence tomography (OCT). Recently, OCT technology has made great strides in improving the acquisition speed and image resolution, thus increasing its impact in daily clinical practice and in the research setting. All these results have been achieved because of a transition from traditional time-domain (TD) to Fourier-domain (FD) technology. FD-OCT devices include a spectrometer in the receiver that analyzes the spectrum of reflected light on the retina or ocular surface and transforms it into information about the depth of the structures according to the Fourier principle. In this review, we summarize and provide the state-of-the-art in FD-OCT imaging of the ocular surface system, addressing specific aspects such as tear film dynamics and epithelial changes under physiologic and pathologic conditions. A theory on the dynamic nature of the tear film has been developed to explain the variations within the individual compartments. Moreover, an integrative model of tear film behavior during the inter-blink period and visual fixation is proposed.

Efficacy and Safety of Combined Vitrectomy with Intravitreal Dexamethasone Implant for Advanced Stage Epiretinal Membrane.

PURPOSE: To evaluate the efficacy and safety of combined 25-gauge (G) pars plana vitrectomy (PPV) with intravitreal dexamethasone implant (DXI) for the treatment of advanced stage epiretinal membrane (ERM). METHODS: Forty consecutive pseudophakic eyes with idiopathic stage 3-4 ERM and intraretinal cysts were randomly assigned to two treatment groups. Twenty eyes underwent combined 25-G PPV, ERM peeling and slow-release DXI (DEX group), whereas 20 eyes underwent standard 25-G PPV with ERM peeling only (control group). Differences in postoperative best-corrected visual acuity (BCVA), intraocular pressure (IOP), central macular thickness (CMT) were evaluated. RESULTS: In all patients, BCVA significantly increased at 1, 3 and 6 months after surgery compared to baseline (all p < 0.05), but at 3 and 6 months, the visual gain was higher in the DEX group (respectively, p = 0.036, p = 0.006). CMT was significantly lower in DEX group compared to control group at 3 and 6 months after surgery (respectively, p = 0.042, p = 0.003). There was no statistically significant difference in IOP change over the course of the follow-up between groups (p > 0.05). CONCLUSION: Combined 25-G PPV with DXI is associated with better anatomical and functional outcomes in patients with advanced stage ERM.

A study of refractory cases of persistent epithelial defects associated with dry eye syndrome and recurrent corneal erosions successfully treated with cyclosporine A 0.05% eye drops.

Background: Effective and tolerable therapeutic strategies for patients with refractory persistent epithelial defects (PEDs) are limited and generally provide poor outcomes. This retrospective case review describes four refractory cases of PEDs associated with recurrent corneal erosions (RCEs) and dry eye disease (DED), which were successfully treated with cyclosporine eye drops. Methods: Patients were treated with cyclosporine A 0.05% eye drops twice a day for at least 12 months. At enrolling time, each patient was asked to suspend topical steroids or other eye drops used for ocular surface abnormalities with the exception of lubricants and eye washing. A complete evaluation of ocular surface symptoms was performed including the McMonnies Dry Eye Questionnaire, Ocular Surface Disease Index, slit-lamp biomicroscopy, fluorescein break-up time, the fluorescein staining of the cornea and conjunctiva (according to the Oxford grading system), the Schirmer I test, and the meibomian secretion after digital pressure application on the lids. This set of exams was carried out at baseline and repeated at all follow-up assessments. Results: All participants that did not benefit from previous therapies, including corticosteroids tapering schedule, showed an important improvement in the clinical picture after two months with topical cyclosporine medication. Moreover, after 12 months of continuous therapy, all patients showed a clinical improvement in DED signs and symptoms, related to the absence of new RCE episodes. The treatment was well tolerated, and no adverse effects were reported. Conclusion: Although a small number of cases were available of our analysis, the treatment with cyclosporine eye drops represents a promising approach in the management of refractory PEDs with associated ocular comorbidities, since it may reduce the RCE episodes and improve the tear film stability, in absence of systemic or local side effects.

Corneal endothelium features in Fuchs' Endothelial Corneal Dystrophy: A preliminary 3D anterior segment optical coherence tomography study.

PURPOSE: To evaluate the feasibility of 3D anterior segment optical coherence tomography (AS-OCT) for the detection of corneal endothelial features in patients with Fuchs' Endothelial Corneal Dystrophy (FECD). METHODS: Twenty patients with clinical diagnosis of FECD (group A), and 20 control subjects (group B) were enrolled. In all patients a complete ophthalmological examination was performed, including best corrected visual acuity (BCVA), slit lamp examination for subjective grading of FECD and corneal endothelial specular microscopy. A 512x128 AS-OCT cube centered on the corneal apex was performed, and then the inner surface of the cornea was visualized and analyzed individually. RESULTS: Overall, the study participants were adults (mean age was 57.35 ± 8.45 years [mean ± SD] 80% female) with a BCVA ranged from 1.3 to 0 LogMAR. The OCT analysis disclosed three different patterns of the corneal endothelium (1, 2, 3) according to the signal distribution and the level of reflectivity: a homogenous, hypo-reflective surface (pattern 1); the presence of hyper-reflective orange-yellowish points (pattern 2); and a mottled appearance with a variable number of hyper-reflective areas (pattern 3). The distributions of these morphological models in the two populations were as follows: patterns 1, 2 and 3 were observed respectively in 0%, 80%, and 20% of patients in group A, and in 80%, 20% and 0% of subjects in group B. Correlation analysis unveiled a positive relationship between OCT corneal endothelium reflectivity and the clinical severity score (assessed with biomicroscopy), as well as an inverse relationship between the OCT pattern and the integrity of corneal endothelium. CONCLUSION: 3D AS-OCT is a useful tool in investigation of endothelial features and therefore may represent a valuable support in the setting of FECD diagnosis and staging.