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Gene Therapy for Retina and Eye Diseases
Published in Yashwant V. Pathak, Gene Delivery Systems, 2022
Despite the success, researchers are still conservative towards the usage of viral vectors. Viral vectors like AAV require subretinal administration, and thus bring up an important issue of surgical considerations. Subretinal administration requires trained surgeons to perform pars plana vitrectomy, sometimes under subretinal optical coherence tomography (OCT) (10). Subretinal injection complications include macular holes, unresolved retinal detachment, choroidal effusion, hypotonia, and retinal tears (11–14). Formation of a subretinal bleb limits the benefit to that anatomical area and does not transduce the entire retina (10).
Parenteral Drug Administration: Routes of Administration and Devices
Published in Sandeep Nema, John D. Ludwig, Parenteral Medications, 2019
Himanshu Bhattacharjee, Vivian Loveless, Laura A. Thoma
Entry into the vitreous humor is accomplished by injection through the pars plana (junction of retina and ciliary body) with a 25-gauge stainless steel needle. The vitreous appears to be an inert fluid which is not replaced once removed. During injection, great care must be taken not to detach the retina. Again, a volume of fluid equal to that to be injected must be removed before instillation. Generally, not more than 0.1 mL may be injected due to rise in intraocular pressure. Injection of steroids into this chamber can be dangerous, resulting in destruction of the retina (retinal necrosis).
Undesirable and Unpleasant Adverse Side Effects of the Whole Body Vibration Exercises
Published in Redha Taiar, Christiano Bittencourt Machado, Xavier Chiementin, Mario Bernardo-Filho, Whole Body Vibrations, 2019
D. da Cunha de Sá-Caputo, Christiano Bittencourt Machado, Redha Taiar, Mario Bernardo-Filho
Vela et al. (2010) presented cases of intraocular lens (IOL) dislocation that appeared shortly after the individuals exercised on an oscillating/vibratory platform. Spontaneous late dislocation of an IOL in the capsular bag has been described as a serious complication of cataract surgery. Vela et al. (2010) have reported clinical cases of IOL dislocation that appeared immediately after the exposition to whole-body vibration. A 71-year-old woman who presented with lens subluxation in the right eye and complete posterior IOL dislocation in the left eye after exercising on an oscillating/vibratory platform for ten minutes. The corrected distance visual acuity (CDVA) was 20/32 in the right eye and counting fingers (CF) in the left eye. A 62-year-old woman who presented with unilateral IOL dislocation within the capsular bag in the right eye one day after using an oscillating/vibratory platform. The CDVA was CF in the right eye and 20/20 in the left eye. It is necessary to consider that the patients had no history of ocular or systemic disorders. Timing from IOL implantation to dislocation was approximately six and four years, respectively. Pars plana vitrectomy with removal of the dislocated IOL was performed in both subjects. It is marked that the movement produced in whole-body vibration would be sufficient to induce an in-the-bag dislocation. However, in predisposed eyes presenting weakness or damage of the zonular fibers, vibration may facilitate IOL dislocation. Considering the adverse side effects, it is signalized that subjects with predisposition to IOL dislocation may be at increased risk when using vibration devices. In addition, it is suggested that cataract surgeons should be aware of this potential complication with IOL dislocation related to the exposition to whole body mechanical vibration.
Anterior Segment Optical Coherence Tomography in Pediatric Ocular Pathology: Imaging Study of 115 eyes
Published in Expert Review of Medical Devices, 2023
AS-OCT has been invaluable in studying corneal and conjunctival diseases. Increased corneal reflectivity was observed in 34 (29.6%) eyes with varying pathologies ranging from corneal tears (Figure 1h), corneal scars (Figure 1a and b) at varying depths [8 (7%)], corneal opacification in 5.2%, calcium deposition in band keratopathy [2 (1.7%)] (Figure 1d) and Peter’s anomaly [1(0.9%)]. Corneal thickness was increased in 28 (24.3%) eyes, mostly with corneal edema, manifesting also with bullae [5(4.3%)] (Figure 1e). Corneal stromal thinning was observed in 31 (27%) eyes with mostly scars and keratoconus (Figure 1b). A conjunctival flap was seen in one case of ocular mucous membrane pemphigoid (OMMP) which was treated surgically with a Gunderson flap for a previous perforation (Figure 1a). Subconjunctival silicon oil was observed in one eye with secondary glaucoma after a previous pars plana vitrectomy and silicon oil tamponade.
Numerical simulation of mechanical properties of epiretinal membrane peeling
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2023
Shaofeng Han, Xiaohan Yang, Yang Yang, Yu Zheng, Wu Liu, Dongmei Du
An epiretinal membrane (ERM) is a proliferation at the vitreoretinal junction, which is mostly idiopathic and related to an abnormality of the vitreoretinal interface accompanied by a posterior vitreous detachment (Hui et al. 1988; Mitchell et al. 1997). ERM contraction may exert tangential traction on the macular retina causing significant loss of visual acuity, and surgical removal is the common treatment of ERM. The standard procedure in the field of vitreoretinal surgery is the use of pars plana vitrectomy (PPV) combined with membrane peeling (Charles 2003; Chang et al. 2013; Sharma et al. 2014). However, there are rarely published guidelines for the direction of optimal stretching of the membrane edge and the mechanical behavior of the ERM, which mainly depend on the experience of the surgeon (Kumagai et al. 2004; Chang 2012; Roizenblatt et al. 2019). Hence, it is necessary to analyze the dynamics involved in the removal of ERMs.
Recent developments in imaging and surgical vision technologies currently available for improving vitreoretinal surgery: a narrative review
Published in Expert Review of Medical Devices, 2023
Elham Sadeghi, Sashwanthi Mohan, Danilo Iannetta, Jay Chhablani
Additionally, many surgeons use the endo-illumination probe for chopping the dropped nucleus fragment [132–134]. This device can be used in all vitrectomy standard settings currently available, from 23 G to 27 G, including endolaser, Pars plana vitrectomy, membrane peeling, scleral buckling, and phacoemulsification with poor red reflex. The Chandelier can also be combined with Ngenuity 3D visualization systems [135–138].