Choroidal Melanoma: An Overview

Pigmented fundus lesions on fundoscopic examination are not an uncommon finding. Pigmented tumoral lesions can arise from the retinal epithelium or choroidal melanocytes causing a spectrum of disorders, ranging from choroidal naevus and foreign bodies to the rarer choroidal melanoma. As choroidal melanoma is the most common primary malignant intraocular tumour, this educational review aims to provide a structured overview of this topic to students and junior doctors, to help establish an understanding of such a rare but life-threatening condition. This will also provide the reader with an insight on referral guidelines in the United Kingdom, a brief overview of various treatments, and factors that affect patient’s prognosis.

Approaches to antiangiogenic therapy for aneurysmal type 1 neovascularization

Purpose. To study the primary response to anti-VEGF therapy with Aflibercept in patients with aneurysmal type 1 neovascularization (AN type 1). Material and methods. 11 patients with type I AN were examined. All patients underwent a standard ophthalmological examination and additionally underwent: determination of the maximum corrected visual acuity according with ETDRS (Early Treatment Diabetic Retinopathy Study) charts, OCT, OCT-angiography and indocyanine-green angiography to clarify the diagnosis. Results. According to the results of the study, against the background of three loading injections, there is a significant decrease in the height of RPE detachment (p=0.029), an unreliable decrease in the central retinal thickness (p=0.088) due to resorption of sub- and intraretinal fluid, and an increase in BCVA (p=0.285), due to compliance with the regime. At the 12th month of the study, there was an increase in the central thickness of the retina and the height of RPE detachment. The achieved results were not preserved, which can be explained by compliance with loading doses and further non-compliance with the interval between injection. On average, 6.5 IVIs were performed per year. Conclusions. Against the background of anti-VEGF therapy with aflibercept in patients with type I aneurysmal neovascularization, a positive effect of treatment is observed. But it is necessary to carry out regular monitoring and treatment to maintain the achieved results. Key words: polypoidal choroidal vasculopathy, aflibercept, anti-VEGF, retinal epithelium pigment detachment, aneurysmal neovascularization.

Calcium waves facilitate and coordinate the contraction of endfeet actin stress fibers in Drosophila interommatidial cells

Actomyosin contraction shapes the Drosophila eye’s panoramic view. The convex curvature of the retinal epithelium, organized in ∼800 close-packed ommatidia, depends upon a fourfold condensation of the retinal floor mediated by contraction of actin stress fibers in the endfeet of interommatidial cells (IOCs). How these tensile forces are coordinated is not known. Here, we discover a novel phenomenon: Ca2+ waves regularly propagate across the IOC network in pupal and adult eyes. Genetic evidence demonstrates that IOC Ca2+ waves are independent of phototransduction, but require inositol 1,4,5-triphosphate receptor (IP3R), suggesting these waves are mediated by Ca2+ releases from ER stores. Removal of IP3R disrupts stress fibers in IOC endfeet and increases the basal retinal surface by ∼40%, linking IOC waves to facilitating stress fiber contraction and floor morphogenesis. Further, IP3R loss disrupts the organization of a collagen IV network underneath the IOC endfeet, implicating ECM and its interaction with stress fibers in eye morphogenesis. We propose that coordinated Ca2+ spikes in IOC waves promote stress fiber contractions, ensuring an organized application of the planar tensile forces that condense the retinal floor.Summary StatementCa2+ waves have an important role in generating tensile forces to shape the Drosophila eye’s convex curvature. Coordinated Ca2+ spikes facilitate actomyosin contractions at the basal endfeet of interommatidial cells.

Structural and vascular features in cavitary congenital optic disc anomaly associated with metaphyseal acroscyphodysplasia

Purpose: To evaluate the radial peripapillary vascular plexus of a cavitary congenital optic disc anomaly in a young patient with recessive autosomal metaphyseal acroscyphodysplasia using optical coherence tomography angiography (OCTA). Methods: Observational case report. Results: A 17-year-old man, with diagnosis of metaphyseal acroscyphodysplasia was referred to Eye Clinic for fundus examination and multimodal imaging for retinal epithelium hypertrophy in the right eye. Clinical examination showed cup-shaped metaphyses, short stature, hyperthelorism, and telecanthus. An optic disc coloboma was detected in the right eye on fundus examination. Wide field en-face Optical Coherence Tomography (OCT) showed a hyporeflective area corresponding to the right optic disc coloboma. At OCTA examination, the whole papillary region revealed a rarefaction of the vascular network, while the ganglion cell complex’s and retinal fiber layers’ parameters were normal in both eyes. Conclusion: The presence of coloboma disc congenital defect linked to embryological abnormalities during the development process could pave the way for a wider understanding of the pathogenesis of metaphyseal acroscyphodysplasia by increasingly framing it as a systemic disease.

Preliminary Anatomical Assessment of the Eye of the African Giant Rat (Cricetomys gambianus)

Eleven African giant rats were caught, bilaterally enucleated and the globes were routinely processed for light microscopy. Eye weight, vertical and horizontal corneal diameters, as well as vertical, horizontal and axial eye diameters were obtained from each globe. Observed external macroscopic ocular features were typical of mammalian eyes comprising cornea, sclera and attached extraocular muscles. The eye dimensions were however generally smaller than those of humans. The large mean corneal diameter to mean eye diameter ratio of 0.86 as well as the scanty retinal ganglion cells observed are associated with morphological adaptations for nocturnal vision. Pigments observed in the retinal epithelium suggests absence of tapetum lucidum, indicating a sub-optimal nocturnal visual capability. This study has provided scientific documentation of some ocular morphological characteristics of the giant rat and has shown that the eye of this species will be anatomically unsuitable for xenotransplantation in humans.

Dynamic Hh signaling can generate temporal information during tissue patterning

ABSTRACTThe differentiation of tissues and organs requires that cells exchange information in space and time. Spatial information is often conveyed by morphogens, molecules that disperse across receiving cells generating signaling gradients. Cells translate such concentration gradients into space-dependent patterns of gene expression and cellular behavior [1, 2]. But could morphogen gradients also convey developmental time? Here, investigating the developmental role of Hh on a component of the Drosophila visual system, the ocellar retina, we discovered that ocellar cells use the non-linear gradient of Hh as a temporal cue, collectively performing the biological equivalent of a mathematical logarithmic transformation. In this way, a morphogen diffusing from a non-moving source is decoded as a wave of differentiating photoreceptors that travels at constant speed throughout the retinal epithelium.