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Comparative Anatomy and Physiology of the Mammalian Eye
Published in David W. Hobson, Dermal and Ocular Toxicology, 2020
The choroid is the third component of the uvea and, in combination with the iris and ciliary body, comprises the vascular tunic. It extends from the edge of the optic nerve to the pars plana. The choroid is loosely attached to sclera and this zone of transition is termed the suprachoroidal space, a site of uveoscleral outflow. Within this space are found the long posterior ciliary arteries and their corresponding long ciliary nerves which supply the choroid and travel forward to the ciliary body and iris.33
Suprachoroidal hemorrhage
Published in A Peyman MD Gholam, A Meffert MD Stephen, D Conway MD FACS Mandi, Chiasson Trisha, Vitreoretinal Surgical Techniques, 2019
Uday R Desai, Alexander Rubowitz
Pars plana vitrectomy is generally indicated in eyes with associated retinal detachment. Drainage of suprachoroidal blood is begun, with concomitant vitreous replacement with infusion fluid. Initial drainage will allow some space to develop in the anterior portion of the eye. Vitreous attachments in the anterior segment can be relieved with the vit-rector in the limbus or in the pars plana. After relief of anterior traction, additional suprachoroidal hemorrhage is drained. A pars plana infusion cannula is placed after adequate hemorrhage has been cleared. During the process of draining any mobile suprachoroidal hemorrhage, the retina should be evaluated repeatedly to ensure that no additional vitreous traction remains. If traction is seen, additional vitrectomy is completed. Any preretinal and subretinal membranes are removed after vitreous traction has been relieved. The retina should remain mobile, although in many cases completely detached. Retinal breaks are marked with diathermy. A posterior drainage retinotomy is made, and a fluid–air exchange allows flattening of the retina. Laser photocoagulation is applied, surrounding all retinal breaks as well as treating the pre-equatorial retina 360°. An encircling buckle is placed, which can vary from 4 to 7 mm in diameter, depending on the extent of the retinal breaks. Perfluoropropane gas (12–18%) is flushed through the eye by injecting it through a 30-gauge needle attached to a 60-ml syringe. For eyes with extensive breaks, silicone oil may be injected.
Describe the structure and function of the ciliary body
Published in Nathaniel Knox Cartwright, Petros Carvounis, Short Answer Questions for the MRCOphth Part 1, 2018
Nathaniel Knox Cartwright, Petros Carvounis
The ciliary body is triangular in cross-section with its small base facing the anterior chamber. The anterior portion is ridged and called the pars plicata; the posterior portion is flat and known as the pars plana. The pars plicata gives rise to the ciliary processes to which the zonules of the lens attach and it surrounds the periphery of the iris. The pars plana has a scalloped posterior border that fits into the scalloped edge of the retina at the ora serrata.
Nationwide Trends in Vitreoretinal Procedures within Australia
Published in Ophthalmic Epidemiology, 2023
Carmelo Macri, Gurfarmaan Singh, Dinesh Selva, Christopher X Wong, Michelle T Sun, Weng Chan
Procedure type is classified according to the second edition of the International Statistical Classification of Diseases and Related Health Problems, 10th Revision, Australian Modification (ICD-10-AM) and the 3rd to 10th editions of Australian Classification of Health Interventions (ACHI). The procedure codes collected for retinal detachment repair included ‘42773-00 – Repair of detachment by diathermy’, ‘42809-01 – Repair of detachment by photocoagulation’ and ‘42776-00 – Repair of detachment with scleral buckle’. The procedure codes collected for pars plana vitrectomy for indications other than retinal detachment repair included ‘42722-01 – Pars plana vitrectomy with division of vitreal bands’, ‘42725-00 – Pars plana vitrectomy with division of vitreal bands and removal of preretinal membrane’. Intravitreal injections were extracted using ‘42740-03 – Injection of therapeutic substance into the posterior chamber’. There are no separate codes for the type of therapeutic substance injected therefore this code may encompasses agents such as anti-VEGF, dexamethasone or antibiotics.
Treatment of Nanophthalmos Cataracts: Surgery and Complications
Published in Seminars in Ophthalmology, 2022
Mei-Ying He, Jing-Ru Feng, Lu Zhang
In patients with an extremely short axis, cataract surgery is usually tricky because of the crowding of the anterior segment. In addition to using a hypertonic agent to concentrate the vitreous before the operation, combined vitrectomy is also an effective method to increase ACD. Cayatopa et al.45 in patients with ACD <2 mm, limited vitrectomy was performed through the flat part without a perfusion cannula, and a small amount of vitreous fluid was drained to effectively deepen the anterior chamber, increase the operation space, reduce corneal endothelial injury caused by a shallow anterior chamber, and the effect of reducing intraocular pressure after the operation was significant. However, the association between pars plana vitrectomy and posterior capsule rupture is significant.1 In cases where the refractive interstitium is extremely cloudy, and the vitreous cannot be visualized, the probe head should be directed downward to avoid damaging the posterior capsule. Endoscopy-assisted pars plana vitrectomy and lensectomy enables visualization of the operation and overcomes the problems due to poor corneal status and difficulty in dilating the pupil with a small pupil, but the method has weaker stereoscopic vision and a longer learning curve.46
The first gene therapy for RPE65 biallelic dystrophy with voretigene neparvovec-rzyl in Brazil
Published in Ophthalmic Genetics, 2022
Juliana M. Ferraz Sallum, Juliana Godoy, Andrea Kondo, Jose Mauro Kutner, Huber Vasconcelos, Andre Maia
A uncomplicated pars plana vitrectomy was performed. The NGENUITY® 3D Visualization System (Alcon, Geneva, Switzerland) was used for a 23-gauge vitrectomy (Constellation Vision System, Alcon). Sclerotomies were performed 3.5 mm from the limbus. Following a standard core vitrectomy, a posterior vitreous detachment was induced with preservative-free triamcinolone acetonide. A complete vitrectomy was performed. One subretinal injection of 1.5 × 1011 vector genomes VN was administered internal to the upper vascular arcades using a PolyTip Cannula 25 g/38 g (MedOne Surgical, Sarasota, FL, USA) coupled to the Constellation automated injection system. Each dose delivered a total volume of 0.3 mL (300 μL). During the first surgery, a pre-bleb was used and during the second surgery the bleb was raised with the medication.