Photopigment Bleaching Phenomenon on Fluorescein Angiography in a Patient with Impending Central Retinal Vein Occlusion

Purpose: To present the second case of photopigment bleaching phenomenon in fluorescein angiography (FA) and the first case of this phenomenon due to impending central retinal vein occlusion (CRVO). Case Report: A 32-year-old healthy female noticed blurred vision in her right eye one day before presentation. Despite the 20/20 visual acuity at presentation, mild increased retinal vascular tortuosity and unilateral photopigment bleaching phenomenon in FA was observed in the right eye. Three weeks later, she developed a complete CRVO with visual acuity reduction to 20/40 that responded well to the intravitreal injection of aflibercept. Conclusion: Impending CRVO can cause unilateral photopigment bleaching phenomenon in FA that may be due to retinal ischemia

Oguchi Disease Associated with Keratoconus

This is a Photo Essay and does not have an abstract. Please download the PDF or view the article in HTML

SARS-CoV-2 susceptibility and COVID-19 disease severity are associated with genetic variants affecting gene expression in a variety of tissues

Variability in SARS-CoV-2 susceptibility and COVID-19 disease severity between individuals is partly due to genetic factors. Here, we identify 4 genomic loci with suggestive associations for SARS-CoV-2 susceptibility and 19 for COVID-19 disease severity. Four of these 23 loci likely have an ethnicity-specific component. Genome-wide association study (GWAS) signals in 11 loci colocalize with expression quantitative trait loci (eQTLs) associated with the expression of 20 genes in 62 tissues/cell types (range: 1:43 tissues/gene), including lung, brain, heart, muscle, and skin as well as the digestive system and immune system. We perform genetic fine mapping to compute 99% credible SNP sets, which identify 10 GWAS loci that have eight or fewer SNPs in the credible set, including three loci with one single likely causal SNP. Our study suggests that the diverse symptoms and disease severity of COVID-19 observed between individuals is associated with variants across the genome, affecting gene expression levels in a wide variety of tissue types

A first update on mapping the human genetic architecture of COVID-19

peer reviewe

The properties of hot extruded binary magnesium calcium alloy for use as a biodegradable material within bone

The development of the suitable strategies to enhance the normally poor corrosion resistance and mechanical properties of magnesium alloys is an important issue that must be solved in order that magneiusm-based materials have wider biomedical applications. The work described in the thesis consists of two processing part: 1) Mg-xCa alloy preparation; in which five different mixture of commercially pure Mg (99.999% ) and granules of Mg-40%Ca were die-cast and 2) extruding one of the as-cast Mg-xCa alloy from the casting process with optimum properties resulted from tests accomplished, at ram speeds of 26, 52 and 65rpm and temperatures 250°c, 350°c and 450°c. Optical microscopy observations of as-cast products and compositional analysis accomplished by EDS and X-RD showed that Mg-xCa (x= 0.7%, 1%, 1.9%, 2.8% and 3.6%) were composed of two phases, a(Mg) as the grain matrix and Mg2Ca on the grain boundaries. The hardness test results also showed that the Vickers hardness rates will increase by increasing the Ca content in the Mg-Ca alloys which was mainly due to the grain refinement and increment of Mg2Ca volume hindering the dislocations movements; According to the corrosion potential values, in-vitro corrosion rate and pH values, it was found out that binary Mg-Ca alloys with greater Ca contents corrodes faster than alloys containing less Ca; thus, increases the pH of the SBF solution and hydrogen evoluted from cathodic reaction more than others, that is predominantly due to grain refinement and increased Mg2Ca by adding more Ca. Finally by comparing the results acquired from tests and findings of Li et al. (2008) the Mg-1%Ca was selected as the the best compromise between mechanical properties, degradation behavior and biocompatibility of the implant. Since the higher ram speeds in extrusion develop finer grain structure (Y. Uematsu et al. 2006) it was expected that the corrosion rate decreased by grain refinement, but based on the results of electrochemical and immersion test conducted on as-extruded Mg-1%Ca products, the corrosion rate is lowest for the temperatures around 350 ºc and ram speeds of approximately 50 rpm. The hardness rates of the samples were enhanced at higher ram speeds and lower processing temperatures which is mainly because of grain refinement and possible phase precipitations

Paradoxical head tilt in unilateral traumatic superior oblique palsy

Purpose: We report a patient with abnormal head posture following ocular blunt trauma. Methods: This is report of a case that despite findings compatible with diagnosis of left superior oblique (SO) palsy, the patient acquired an ipsilateral (left) head tilt. The interesting observation in our patient was reduction of left hypertropia and consequent less diplopia with ipsilateral head tilt. Results: After blunt trauma, our patient adopted paradoxical left head tilt and consequently less diplopia despite acquired left SO palsy. Left inferior oblique myectomy resulted in significant improvement of patient's strabismus and abnormal head position. Conclusion: Traumatic SO palsy may present with paradoxical head tilt. Keywords: SO palsy, Head tilt, Traumatic strabismu

Consequences of inadvertent intravitreal Mitomycin C injection

Abstract Background Mitomycin C (MMC) as an alkylating agent is miscellaneous an antineoplastic, antibiotic and ophthalmic agent. Here we aim to report a case of inadvertent intravitreal MMC injection instead of Avastin in case of diabetic macular edema. Case presentation A 53 years old woman was planned to receive intravitreal Avastin injection, but accidentally, 0.05 ml of MMC 0.2% was injected. Best corrected visual acuity (BCVA) was 20/160 before injection. After 2 days, patient was referred to a tertiary referral eye center. BCVA was hand motion at presentation. Intraocular pressure was 4 mmHg. In slit lamp exams, conjunctival injection, corneal edema, Descemet fold, anterior chamber and anterior vitreous cells were presented. Pars plana vitrectomy with peripheral vitreous shaving and silicone oil tamponade was performed. Electroretinography showed undetectable responses. Ultrasound biomicroscopy showed ciliary body shortening and detachment. Optical coherent tomography showed diffuse retinal edema the day after surgery, subretinal fluid pockets in 2 weeks, and atrophy with undetectable and intertwined layers 2 months later. Gradually, like the retina, iris became atrophic and pigments were dispersed diffusely over the lens and endothelium. Conclusion MMC is showed to be severely toxic to intraocular tissues. In our case, iris and ciliary body became atrophic. Ciliary body detachment induced hypotony. Moreover, MMC induces retinal necrosis and atrophy. Visual outcome is profoundly poor