Implantation of a sustained-release ganciclovir implant
A Peyman MD Gholam, A Meffert MD Stephen, D Conway MD FACS Mandi, Chiasson Trisha in Vitreoretinal Surgical Techniques, 2019
The Foscarnet–Ganciclovir Cytomegalovirus Retinitis Trial reported the 6-month cumulative risks of retinal detachment in patients receiving intravenous ganciclovir and foscarnet as 28% and 27%, respectively.4 The incidence of retinal detachment in eyes receiving ganciclovir implants has been reported as ranging from 11% to 23%.18,24 Although eyes with ganciclovir implants appear to have a lower incidence of retinal detachment, the NEI trial did note a nonstatistically significant trend toward earlier occur-rence of detachments in implant eyes compared with those receiving intravenous therapy. The investigators noticed a correlation between postoperative vitreous detachment and the subsequent development of a retinal detachment. They postulated that surgical manipulation of the vitreous might lead to premature posterior vitreous separation that, in turn, can induce retinal tears at the borders of quiescent retinitis.18 Repair of retinal detachments in patients with CMV retinitis is usually accomplished with vitrectomy and silicone oil tamponade (see Chapter 55).
Flashing Lights and Floaters
Amy-lee Shirodkar, Gwyn Samuel Williams, Bushra Thajudeen in Practical Emergency Ophthalmology Handbook, 2019
A vitreous detachment occurs when the ageing vitreous body, which is 4 mL in volume and occupies almost the entirety of the posterior segment, collapses forward and pulls its posterior aspect free from the retina. This can either be a smooth collapse with no retinal tears or haemorrhages, or the blood vessels and retina can be damaged in the separation, resulting in pigment and blood released into the vitreous cavity, and even parts of the retina itself in the form of an operculated tear. Blood and inflammatory debris from diabetes, infection or inflammation of the posterior segment may also cause floaters (see Chapter 14). Diabetic retinopathy is a common cause of posterior segment haemorrhage.
An Asian woman with blurred vision
Tim French, Terry Wardle in The Problem-Based Learning Workbook, 2022
Points to consider in a history of visual loss include: pre-existing refractive error: diabetic patients can have wild refractive changes due to abnormal blood glucose levelsone or both eyes: both eyes implies systemic pathology, whereas one eye is more suggestive of ocular pathologygradual loss of vision versus acute loss: gradual loss implies chronic pathologies such as cataract or retinopathy; acute visual loss is always an emergency, and is usually traumatic or vascular in originpainful versus painless eye: e.g. painful acute glaucomanature of the visual loss: central loss suggests macular pathology; however this may be more readily revealed on examinationred eye: allergic or infective conjunctivitis, acute glaucoma or iritishaloes: glaucomaflashes and floaters: vitreous detachment. Vitreous detachment does not normally affect visual acuity unless a floater is in front of the maculatrauma.
Idiopathic Vitritis after Boston Type 1 Keratoprosthesis Implantation: Incidence, Risk Factors and Outcomes in a Multicentric Cohort
Published in Ocular Immunology and Inflammation, 2022
Clemence Bonnet, Ismael Chehaibou, Reza Ghaffari, Nicholas J. Jackson, Cristina Bostan, Jean-Pierre Hubschman, Mona Harissi-Dagher, Anthony J. Aldave
Retinal detachments were more frequent after keratoprosthesis implantation following vitritis than after procedures without vitritis, partially explaining the higher percentage of eyes that lost 20/200 CDVA and experienced KPro retention failure following the development of vitritis.23 The presence of vitreous inflammation may play a role in the occurrence of retinal detachment by enhancing posterior vitreous detachment and morphological changes of the vitreous base, thereby increasing the risk of retinal breaks.24 Given that retinal detachments are more difficult to diagnose and repair following KPro implantation, and are associated with a poor prognosis, some authors have advocated performing a total pars plana vitrectomy at the time of aphakic KPro implantation, although they have not demonstrated a decrease in the incidence of vitritis or retinal detachment when compared to partial pars plana vitrectomy or anterior vitrectomy at the time of KPro implantation.25,26
Macro- and Microscale Properties of the Vitreous Humor to Inform Substitute Design and Intravitreal Biotransport
Published in Current Eye Research, 2021
Nguyen K. Tram, Courtney J. Maxwell, Katelyn E. Swindle-Reilly
The degradation of the vitreous humor causes complications that could benefit from further investigations. The heterogenization of vitreous humor can disrupt the internal structure of the vitreous humor and unbalance the stress distribution in the eye. As the vitreous phase-separates, the retina experiences increased traction at locations with strong adhesion to the vitreous humor. Interestingly, the adhesion between the vitreous and the retina has been shown to decrease with age.185 This reduction in vitreoretinal adhesion coincides with the timeline of vitreous liquefaction and has been hypothesized to facilitate posterior vitreous detachment, which might protect the retina from tearing or detaching. Induction of posterior vitreous detachment was recently reported, with particular focuses on both vitreous liquefaction and dehiscence of vitreoretinal adhesion.186 A mechanical model of posterior vitreous detachment and generation of vitreoretinal tractions has also been published.187 These are all interesting biomechanical problems that should be further investigated in future studies.
Voretigene neparvovec-rzyl for treatment of RPE65-mediated inherited retinal diseases: a model for ocular gene therapy development
Published in Expert Opinion on Biological Therapy, 2020
Thomas A. Ciulla, Rehan M. Hussain, Audina M. Berrocal, Aaron Nagiel
Although subretinal administration of gene therapy via PPV represents the most common technique, it is still an evolving procedure with novel facilitating technology including digital visualization systems, smaller subretinal cannulas, precision infusion pumps, and intra-operative optical coherence tomography (OCT) to precisely monitor proper bleb formation. Two of the authors have had extensive experience in the procedure, and the steps of the surgery performed by one of the authors (AMB) are described herein. This approach differs from the protocol used in the clinical development of VN due to the evolving advancements of vitreoretinal surgery noted above; a surgical video can be accessed at this reference [53]. A 25-gauge PPV is completed with the NGENUITY® ‘Heads-Up’ 3-D Visualization System (Alcon, Fort Worth, Texas, USA). As the majority of the patients are young, a preexisting posterior vitreous detachment is unlikely. After the hyaloid is lifted and a core vitrectomy performed, dilute triescence is injected to ensure that the entire hyaloid is removed. The periphery is shaved with the assistance of scleral depression and examined for retinal breaks.
Related Knowledge Centers
- Ora Serrata
- Photopsia
- Retina
- Retinal Detachment
- Vitreous Body
- Vitreous Membrane
- Vitreous Base
- Floater
- Temple
- Lattice Degeneration