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Common Vitreoretinal Procedures
Published in Pradeep Venkatesh, Handbook of Vitreoretinal Surgery, 2023
MTM has only recently become well characterized, so authors have used their own means of classifying the condition. As there is yet no consensus classification, study design, management approaches, and outcome measures would be variable. Classifications are evidently dependent on OCT characteristics and have three essential components: changes on the surface of the retina [vitreomacular attachment, VMT, epimacular membrane (EMM)], intraretinal changes [inner retinal layers, outer retinal layers, involving all layers], and status of the foveal contour [unchanged, lamellar hole, full thickness hole and macular detachment]. Other associated findings include those of dome-shaped macula, posterior staphyloma, and macular atrophy or scar [secondary to neovascular membrane]. The area of schisis too could be focal [involving fovea, perifovea, or peripapillary region] or diffuse [involving a larger area of the macula]. These possibly represent stages in the evolution of MTM. While the detection of MTM is straightforward, the treatment is very challenging as there are no international guidelines on how frequently these patients must be followed, at what visual acuity or symptoms surgical intervention must be considered, what the most appropriate intervention is, and how long could observation be considered without jeopardizing final outcome. In addition, information on the risk-to-benefit ratio of early versus delayed intervention, based on multicentric trials, is lacking. Options available for managing patients with MTM include observation, small-gauge vitreoretinal surgery, and macular buckle. Patients with MTM detected incidentally and with good visual acuity could be observed closely in the initial period, and then the follow-up interval could be gradually increased. Patients should also be encouraged to check the gross visual acuity [near and distance with spectacles] in each eye at 4-week intervals and to report immediately on noting an appreciable difference. The role of monitoring with an Amsler grid is not known. Risk factors for early progression include higher axial length, presence of posterior staphyloma, status of fellow eye, female gender, and persisting papillovitreal traction. The effect of cataract surgery on MTM remains unexplored.
Secondary infection with rhino-orbital cerebral mucormycosis associated with COVID-19
Published in Orbit, 2022
Liane O. Dallalzadeh, Daniel J. Ozzello, Catherine Y. Liu, Don O. Kikkawa, Bobby S. Korn
Ophthalmic exam revealed intraocular pressure of 55 OS, left relative afferent pupillary defect, proptosis, periorbital edema and conjunctival chemosis. On dilated fundoscopic exam, he was found to have optic disc pallor with diffuse vessel attenuation and retinal whitening including the perifovea concerning for ophthalmic artery occlusion. He underwent urgent lateral canthotomy and cantholysis for orbital compartment syndrome. MRI with contrast was concerning for fungal invasion throughout the left sinonasal cavity and orbit with flow void through the left ophthalmic artery and superior ophthalmic vein and scattered intracranial infarcts (Figure 1). Chest X-Ray was also notable for bilateral perihilar and basal opacities concerning for COVID-19 pneumonitis. Given extensive disease, poor prognosis, and rapid decline, endoscopic sinus debridement was deferred by the head and neck service. The patient was started on intravenous amphotericin, isovuconazole, and micafungin for suspected mucormycosis. He was treated with remdesivir without intravenous corticosteroids for COVID-19 pneumonitis given concern for concurrent fungal infection. Without improvement, he was transitioned to comfort care by family on day 4 at our institution before expiring.
An Overview of Preferred Retinal Locus and Its Application in Biofeedback Training for Low-Vision Rehabilitation
Published in Seminars in Ophthalmology, 2022
Shengnan Li, Xuan Deng, Jinglin Zhang
Additionally, Schumacher etal.1811 used fMRI to measure brain activity in the calcarine sulcus while visually stimulating peripheral retinal regions in patients with macular disease. Their results showed that visual stimulation (a fixation cross) of PRL in the retina increased brain activity in the cortex, normally representing central vision relative to the visual stimulation of the perifovea and relative to stimulation in the periphery of age-matched control participants. In brief, the activation of the “fovea” cortex by peripheral stimuli was observed. These data directly combined cortical reorganization with behavioral adaptations adopted by macular damaged patients. fMRI, also used in Baker’s study,15 showed a similar significant activation of peripheral stimuli relative to the fixation baseline at the occipital pole of all participants with complete loss of foveal visual input. All the above-mentioned evidence clearly indicates that cortical plasticity in the visual system remains in patients suffered CVL in life and that the functionalization of PRL is based on visual cortical reorganization which lies on complete foveal visual input loss.
Low-Intensity Laser Light Projection for Improved Reading Abilities in Low-Vision Patients
Published in Current Eye Research, 2021
Adiel Barak, Roy Schwartz, Gilad Rabina, Adi Kremer, Anat Loewenstein, Shulamit Schwartz
The most affected area in age-related macular degeneration is the central macular region while the peripheral retina usually remains intact. The macular region refers to the central 5.50 mm diameter of the posterior pole of the retina and includes the foveola, fovea, parafovea, and perifovea. The diameters of the outer boundaries of these zones are 0.35 mm, 1.50 mm, 2.50 mm, and 5.50 mm, respectively.6 Visual acuity is better at the center of the macula because of the higher photoreceptors concentration in this area and decreases eccentrically. The mean logMAR corrected distance visual acuity in the healthy population declines to 0.3 at 0.25° (degree) from the foveola, 0.48 logMAR at 0.60°, 0.60 logMAR at 2.50°, 0.70 logMAR at 4.20° and 1 logMAR outside 9.20°.6 Thus, the outlying areas of the macula and peripheral retina have a visual potential of no better than 1 logMAR. The density of the central scotoma determines the degree of difficulty in performing routine tasks, causing patients to develop a preferred retinal locus to compensate for the diseased macula. Although the aim of anti-vascular endothelial growth factor agents is to dry the macula, the macula undergoes remodeling during the reparative process, and the morphologic features of the anti-vascular endothelial growth factor-treated macula may vary from subtle retinal pigment epithelial changes to submacular fibrosis. Visual rehabilitation depends on the fixation.7–9