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Choroidoretinitis
Published in K. Gupta, P. Carmichael, A. Zumla, 100 Short Cases for the MRCP, 2020
K. Gupta, P. Carmichael, A. Zumla
The choroid is the vascular layer of the eye extending from the optic nerve posteriorly to the ciliary body anteriorly. Together with the iris and ciliary body the choroid constitutes the middle layer of the eye. The retina overlies the choroid. Inflammation of the choroid inevitably affects the retina and thus the term choroidoretinitis.
Treatment of Retinitis Induced by Cytomegalovirus Using Intravitreal Fomivirsen (ISIS 2922)
Published in Eric Wickstrom, Clinical Trials of Genetic Therapy with Antisense DNA and DNA Vectors, 2020
Toxicological studies in mice of one-month, repeat-dose intravenous fomivirsen at 0.2-50 μg/kg every other day produced a toxicological profile similar to those of other phosphorothioate oligonucleotides. Next it was appropriate to evaluate its potential toxicological effects after intravitreal administration. The effects of single-intravitreal doses ranging from 16.5 to 330 μg/eye yielding theoretical vitreal concentrations as high as 40 mM were evaluated in the pigmented rabbit. The drug induced a dose dependent inflammatory response in the eye. At lower doses and earlier time points, the ciliary body was the primary structure affected. At doses that resulted in theoretical concentrations of 20 and 40 μΜ, other ocular structures were affected. In animals treated with 40 μΜ drug, retinal degeneration was observed, probably secondary to inflammation (Fomivirsen Investigator's Brochure, 1996).
Cholinergic Agonists
Published in Sahab Uddin, Rashid Mamunur, Advances in Neuropharmacology, 2020
Rupali Patil, Aman Upaganlawar
The constrictor pupillae muscle runs circumferentially in the iris, whereas ciliary muscle adjusts the curvature of the lens. They both receive parasympathetic supply to the eye. Activation of mAChRs causes contraction of ciliary muscle pulling the ciliary body forward and inward. Tension on the suspensory ligament of the lens gets relaxed; lens bulges more and reduces its focal length, necessary for the eye to accommodate for near vision. The constrictor pupillae adjusts the pupil in response to changes in light intensity and also regulates the intraocular pressure (IOP). Normal IOP (10–15 mmHg above atmospheric) helps to keep the eye slightly distended. Aqueous humor gets secreted slowly and continuously by the cells of the epithelium covering the ciliary body. Aqueous humor is drained into the canal of Schlemm running around the eye close to the outer margin of the iris. One of the commonest preventable cause of blindness associated with glaucoma is abnormally raised IOP. In acute glaucoma, IOP increases due to obstruction to drainage of aqueous humor after dilation of the pupil. Folding of the iris tissue impedes the drainage angle. Muscarinic agonists activate constrictor pupillae muscle and lower the IOP. Normal individual show little effect. Increased tension in the ciliary muscle produced by these drugs helps in improving drainage by realigning the connective tissue trabeculae through which the canal of Schlemm passes (Rang et al., 2011).
Design and Methodology of a Multi-Centre Clinical Trial of Low Dose Laser Cycloplasty for the Treatment of Malignant Glaucoma in China
Published in Ophthalmic Epidemiology, 2022
Haishuang Lin, Jibing Wang, Sujie Fan, Zuohong Wu, Xiaoping Xu, Qinhua Cai, Lijun Zhao, Sumian Cheng, Shaodan Zhang, Yuanbo Liang
LCP was performed under retrobulbar anesthesia or sub-Tenon anesthesia (1:1 mixture of Lidocaine and Bupivacaine) using a transscleral diode 810 nm laser and the contact G-probe. Standard settings are 2000 ms duration and 1100–2000 mW power. The ciliary body was identified by transillumination. The junction between ciliary body band and scleral process (the boundary between translucency and opacity) was 2.0 ± 0.05 mm posterior to the limbus over the conjunctival surface. The G-probe was seated at the anterior aspect of the ciliary body. The treatment consisted of ≤15 applications over 4 to 6 o’clock or 6 to 8 o’clock (60 degrees total) of the ciliary body. Power was modified until an effective bursting sound was obtained and lowered if pigment dispersion or air bubbles was observed in anterior chamber.
Presumed Intraocular Tuberculosis Manifesting as Unilateral Iris Granuloma
Published in Ocular Immunology and Inflammation, 2020
Somasheila I. Murthy, Varsha M. Rathi, Mudit Tyagi, Dilip Kumar Mishra, Rajeev R. Pappuru
The ophthalmic presentations of tuberculosis can be caused by both direct infection or by immune-mediated delayed hypersensitivity reactions.1 The infection may remain confined to eye alone as extra-pulmonary tuberculosis or it can be a part of other organ-system involvement such as pulmonary or miliary tuberculosis. Extra-ocular involvement includes granulomas of the orbit, lid, lacrimal, conjunctiva or sclera and intraocular disease manifesting as anterior or posterior granulomatous inflammation has been frequently reported. Clinical presentation ranges from large keratic precipitates and broad-based synechia to ciliary body involvement. The commonest manifestations of posterior segment involvement such as serpiginous-like choroiditis, vitritis, choroidal tubercles, retinal vasculitis, and optic neuritis are well known.2 The highly vascular uveal tissue allows for hematogenous spread of the bacilli from remote locations and can progress to tubercular granulomatous lesions even in the absence of systemic disease.3 Anterior segment disease alone is less frequent. We report two cases of unilateral iris granulomata in two young patients that responded completely to anti-tubercular therapy.
Static and dynamic pupil characteristics in pseudoexfoliation syndrome and glaucoma
Published in Clinical and Experimental Optometry, 2020
Kemal Tekin, Hasan Kiziltoprak, Mehmet Ali Sekeroglu, Esat Yetkin, Serdar Bayraktar, Pelin Yilmazbas
Pseudoexfoliation syndrome (PES) is a complex and age‐related systemic disorder characterised by the progressive accumulation of abnormal extracellular pseudoexfoliative material in ocular tissues.2015 This accumulation could be detected in almost all the structures of the anterior ocular segment including ciliary body, iris, iridocorneal angle, lens capsule, zonules and cornea.2015 Detecting PES is important since it might be associated with a broad spectrum of ocular manifestations including increased intraocular pressure, cataract formation, zonular instability and phacodonesis, blood‐aqueous barrier dysfunction and inflammation, keratopathy and also markedly increased intra‐operative and post‐operative complications such as insufficient mydriasis, posterior capsule rupture, intraocular lens subluxation, and posterior synechiae.2015 Furthermore, PES is considered to be the most common identifiable reason of open‐angle glaucoma.1994 Pseudoexfoliation glaucoma (PEG) is a common cause of blindness worldwide and tends to be more progressive and serious compared to primary open‐angle glaucoma.1994