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Uveitis
Published in Mostafa Khalil, Omar Kouli, The Duke Elder Exam of Ophthalmology, 2019
Mostafa Khalil, Omar Kouli, Obaid Kousha
The ciliary body consists of three layers: stroma (connective tissue where the vascular supply is found), muscle (parasympathetic innervation via CNIII) and epithelium. The blood supply to the ciliary body is via the anterior and long posterior ciliary arteries. The ciliary body is divided into two parts: pars plana and pars plicata. Pars plana: Avascular. Lies between the ora serrata and ciliary processes of the pars plicata. Functionless, often used as a site for intravitreal injections or vitreous removal (pars plana vitrectomy).Pars plicata: Highly vascularized. Forms attachments for the lens zonules. Functions include aqueous humour formation, lens accommodation and aqueous drainage via uveoscleral outflow.
Vitreoretinal surgical anatomy
Published in A Peyman MD Gholam, A Meffert MD Stephen, D Conway MD FACS Mandi, Chiasson Trisha, Vitreoretinal Surgical Techniques, 2019
The ciliary body is composed of two parts: the pars plicata and the pars plana (Fig. 1.5a). The pars plicata extends from the iris root posteriorly approximately 2.5 mm and contains 70–80 ciliary processes that secrete aqueous humor. The pars plana portion of the ciliary body is 3 mm in width nasally and 4.5 mm temporally. The posterior portion of the pars plana meets the ora serrata and is overlapped by the vitreous base more temporally than nasally.
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.
Current Concepts of the Uveitis-Glaucoma-Hyphema (UGH) Syndrome
Published in Current Eye Research, 2023
Meera S. Ramakrishnan, Kenneth J. Wald
Clinical examination findings are often underappreciated. Iris transillumination along the length of the haptic is specific for iris to haptic chafing- other types of transillumination are not (Figure 5). Thereafter, the examination requires a widely dilated pupil for evaluation. Assessment of haptic position is often best by viewing the eye tangentially by rotating the slit lamp (Figure 6). Gonioscopy can be helpful in some cases. Clinical determination of haptic position can be difficult and diagnostic imaging of this area of the eye is limited. Anterior segment OCT does not image posterior to the iris, but can be used to screen for IOL-iris contact or IOL tilt prior to proceeding with UBM.24 Ultrasound biomicroscopy (UBM) has limited depth of field (5 mm) and resolution of 50 microns, requires a water-bath immersion with direct contact to the eye, and longer acquisition times, but can be used to evaluate IOL position relative to the posterior iris. In a case series by Piette et al. UBM identified PCIOL haptic contact with the iris pigment epithelium, pars plicata, or angle recess near a filtering bleb ostium, and one case of ACIOL haptic erosion into the ciliary body.25 Intraoperatively, the area can be analyzed with an endoscope, however the use of this technique in vitreoretinal surgery is rare. The author has worked on a prototype retractable intraocular mirror to be used during vitreous surgery for this purpose.
Visualisation of peripheral retinal degenerations and anomalies with ocular imaging
Published in Seminars in Ophthalmology, 2022
Rene Cheung, Angelica Ly, Paula Katalinic, Minas Theodore Coroneo, Andrew Chang, Michael Kalloniatis, Michele C. Madigan, Lisa Nivison-Smith
Dentate processes are normal anterior extensions of retina that project 0.5–2.5 mm from the adjacent retina circumferentially. Large dentate processes project further onto the pars plana of the ciliary body, and giant processes extend to the pars plicata. On UWF pseudocolour imaging, dentate processes appear as thin projections in the peripheral retina, also visible in red-free but less so in green-free UWF images (Figure 2). Histologically, dentate processes may have retinal thinning (particularly towards anterior edge), broad areas of attachment between RPE and retina and cystoid degeneration.31 A small study (48 eyes without visual complaints related to retinal disease) reported large dentate processes in 91% of asymptomatic eyes, and giant processes in 19% of eyes mostly in the supero-nasal quadrant.32
Drug-induced Uveitis in HIV Patients with Ocular Opportunistic Infections
Published in Ocular Immunology and Inflammation, 2020
Ilaria Testi, Aniruddha Agarwal, Rupesh Agrawal, Sarakshi Mahajan, Alessandro Marchese, Elisabetta Miserocchi, Vishali Gupta
The relatively high incidence of hypotony in patients with cidofovir-induced uveitis appears to be correlated to the drug-related damage to ciliary body with a mechanism similar to the one resulting in nephrotoxicity.23–26 A reduction in intraocular pressure (IOP) can be observed irrespective of the development of uveitis. In addition, in HIV-infected patients, the IOP is usually lower than normal.31 Authors have postulated that the mechanism of hypotony is correlated to the failure of aqueous humor production in the ciliary body due to the damage to the non-pigmented epithelium of pars plicata. To support this hypothesis, attenuation of pars plicata and atrophy of ciliary body with loss of ciliary processes have been detected by ultrasound biomicroscopy and a reduction in aqueous flow rate has been demonstrated after 2–4 weeks of intravitreal administration of the drug by fluorophotometry.23 Similarly, Akler et al. found a mean increase in serum creatinine over baseline measurements in patients developing uveitis, suggesting that a decrease in renal excretion of the drug due to its nephrotoxicity, inducing acute tubular necrosis, might be correlated with increased circulating drug levels and thus, toxicity in eyes tissues.25