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Other Biomedical Imaging Techniques
Published in Kayvan Najarian, Robert Splinter, Biomedical Signal and Image Processing, 2016
Kayvan Najarian, Robert Splinter
Retinal imaging also has several medical and diagnostics applications. The clinical diagnostic value of retinal recognition is evident in the identification of retinal arterial and venous blockage, epiretinal membrane formation, diagnosis of macular degeneration, occurrence of macular edema, macular hole formation, retinal tearing, retinal detachment (often experienced in diabetic patients), and degeneration of the photoreceptor rods in the retina (which is often a hereditary disease). Several of the pathological conditions best identified by retinal scans will eventually result in blindness if not caught in time.
Medical Applications of Fiber-Optic Sensors
Published in Krzysztof Iniewski, Ginu Rajan, Krzysztof Iniewski, Optical Fiber Sensors, 2017
In the case of retinal microsurgery, accurate and precise tool tip control is crucial. Nowadays, microforceps are used to peel epiretinal membrane (a micron scale layer of scar tissue formed on the retinal surface causing distorted and/or blurred vision) without damaging its neurons. For a better control and precision, built-in fiberscope and a force-sensing FBG to provide force feedback have been reported.139, 140
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.
Intraoperative OCT microscopy in 3D
Published in Expert Review of Medical Devices, 2021
Adam Wylęgała, Adam Sendecki, Edward Wylęgała
We want to bring our ophthalmology colleagues’ attention to a new microscope that we have found to be very useful in ocular surgery. During microsurgery, the view of tissue is limited to the surface of the first non-translucent layer. However, intraoperative Optical Coherence Tomography (iOCT) can help visualize all structures within the penetration limit with histological accuracy. Such a system can display the OCT scans intraoperatively on a head-up display directly in the eyepieces of a microscope [1]. The primary benefit is the immediate feedback that the surgeon receives with regards to tissue anatomies such as graft detachment, epiretinal membrane peel, or macular edema. However, viewing OCT in an eyepiece together with a live image may be considered a distraction for some surgeons [2]. More recently, a new concept of an operating microscope was developed with a three dimensional (3-D) heads-up display. In this method, the surgeon watches the procedure on a large TV screen while wearing lightweight polarizing glasses. The main benefit is a more ergonomic position of the head and neck. Furthermore, such systems can, in theory, provide a broader field of view and brighter image [3].
A perspective of contemporary cataract surgery: the most common surgical procedure in the world
Published in Journal of the Royal Society of New Zealand, 2020
Charles N. J. McGhee, Jie Zhang, Dipika V. Patel
A study by Nicholas et al. (2006) demonstrated that routine cataract surgery causes an increase in macular thickness, particularly one day postoperatively. Interestingly, this increased macular thickness had still not begun to normalise 6-weeks post-operatively. However, correlations between macular thickness and visual acuity were variable (Nicholas et al. 2006). Interestingly, in prospective cataract studies in NZ, the incidence of cystoid macular oedema one month post-operatively has remained consistent over time, affecting in 3.8% of eyes in the year 2000 (Riley et al. 2002) and 3.7% of eyes in 2017 (Han, Patel, Wallace, et al. 2019). Cystoid macular oedema therefore continues to be a significant cause of compromised postoperative vision despite surgical advances. A recent review highlighted the risk factors for cystoid macular oedema, which include intraoperative complications such as posterior capsule rupture and preoperative factors including diabetes mellitus, uveitis, retinal vein occlusion, and epiretinal membrane (Han, Patel, Squirrell, et al. 2019). Interestingly, large systematic reviews appear to come to contradictory conclusions when considering the benefit of both treatment and prophylaxis of cystoid macular oedema (Han, Patel, Squirrell, et al. 2019). Recently, a randomised controlled multicentre clinical trial; the PREvention of Macular EDema after cataract surgery (PREMED) study reported the lowest incidence of clinically significant macular oedema was observed in the combination (steroid-NSAID) treatment group (1.5%), compared to bromfenac (3.6%), or dexamethasone alone (5.1%) (Wielders, Schouten, Winkens, van den Biggelaar, Veldhuizen, Findl, et al. 2018). Diabetic patients who received subconjunctival triamcinolone injection exhibited lower macular thickness and macular volume at 6 and 12 weeks post-operatively and none developed macular oedema (Wielders, Schouten, Winkens, van den Biggelaar, Veldhuizen, Murta, et al. 2018).