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Common Vitreoretinal Procedures
Published in Pradeep Venkatesh, Handbook of Vitreoretinal Surgery, 2023
Standard ILM peeling has a high rate of efficacy in patients with hole sizes of about 400 microns. As the hole size increases, standard peeling has a lower chance of anatomical success, and so one could adopt one of a dozen approaches that have now been described, mostly in small case series. These approaches include inverted flap, multilayered flap, autologous serum, transplantation of autologous ILM, autologous full-thickness retinal tissue, amniotic membrane, and lens capsule. While these approaches may achieve mechanical anatomical closure, claims of significant recovery of visual function and functional integration of the transplant with the recipient’s retinal layers defies the long-established observations on the limitations of photoreceptor recovery. Any improvement in visual recovery can only be explained by some narrowing of the visual angle. Contraction of the transplanted tissue [like any scar tissue] could draw in the margins of the large macular hole closer, resulting in narrowing of the visual angle [hill of vision]. Commonly reported complications after macular hole surgery include cataract, raised IOP, peripheral break formation, retinal detachment, RPE alterations [Figure 10.15], endophthalmitis, cystoid macular edema, and late reopening of the macular hole. Rarely, iatrogenic hole could also occur within the area of ILM peeling [Figure 10.16].
Suprachoroidal–transretinal stimulation: a new approach for retinal prostheses
Published in A Peyman MD Gholam, A Meffert MD Stephen, D Conway MD FACS Mandi, Chiasson Trisha, Vitreoretinal Surgical Techniques, 2019
Kanda Hiroyuki, Sawai Hajime, Fukuda Yutaka, Morimoto Takeshi, Nakauchi Kazuaki, Fujikado Takashi, Tano Yasuo
With minimum stimulus intensity, the area where the EPs were recorded was limited to around a few hundred square micrometers, which is roughly 2% of the whole surface area of the superior colliculus, or 6.4 mm. With this ratio, the area of the stimulated retina can be calculated as 1.1 mm2, assuming that the total retinal surface area is 57 mm2 in rats,16 and without taking the retinocollicular magnification factor into consideration. Even such a rough estimation allows us to expect that a single STS to the human eye could activate about 1 mm2 of the retina. Thus, the method of retinal stimulation used in this study can excite a very small area of the superior colliculus, indicating that the retina is focally stimulated. A distance of 1 mm on the human retina corresponds to a visual angle of approximately 3.4°.17
Eyesight standards for beach lifeguards
Published in Mike Tipton, Adam Wooler, The Science of Beach Lifeguarding, 2018
The most commonly used, rapid, simple and economical test of visual acuity is the optotype or chart test. One such test is the Snellen chart (rows of letters of decreasing font size [3]); other opto-type alternatives include the Landolt C, Sloan, BSI (British Standard Institution) and E charts. The standard definition of visual acuity is the ability of the eye to resolve a spatial pattern separated by a visual angle of one minute of arc. With the Snellen chart, normal visual acuity is recorded as 20/20 (feet) or 6/6 (metres) using a diffusely illuminated chart without glare. This means that at 6 m the test subject should be able to see the same as a ‘normal’ person with good eyesight. A score of 6/12 means that a test subject can see the same at 6 m as a ‘normal’ person with good eyesight can see at 12 m. The maximum acuity of the human eye without visual aids is generally thought to be about 6/4. The Snellen fraction may also be expressed as a decimal, where 6/6 =1; 6/12 = 0.5.
The Efficacy of Golimumab Against Non-Infectious Uveitis: A PRISMA-Compliant Systematic Review and Meta-Analysis
Published in Ocular Immunology and Inflammation, 2023
Katsuya Okada, Yi Zhou, Noriyasu Hashida, Tatsuya Takagi, Yu-Shi Tian
The primary outcome of efficacy was the number of remission in patients and eye inflammation during the follow-up of the GOL treatment. Remission was identified as complete control of interocular inflammation or inactive uveitis based on the standardization of uveitis nomenclature. The secondary outcomes included the rates of uveitis relapses/attacks per 100 person-years at baseline versus the end of GOL treatment, the number of improved patients during the GOL treatment, and changes in best-corrected visual acuity (BCVA) measurements, central macular thickness (CMT), and systemic CS-sparing between baseline and the end of GOL treatment. Valid BCVA values were derived from the standard Snellen chart and could be transformed to log of the minimum angle of resolution (LogMAR). Visual acuity improvements and deterioration were defined as a change in doubling the visual angle in at least one eye (i.e., three lines on the decimal scale). CMT was measured using optical coherence tomography regardless of the presence of edema. CS-sparing effects were reported or could be transformed to the mean daily dose (mg) of prednisone.
A novel combined visual scanning and verbal cuing intervention improves facial affect recognition after chronic severe traumatic brain injury: A single case design
Published in Neuropsychological Rehabilitation, 2021
Suzane Vassallo, Jacinta Douglas
A subset of 72 coloured photographs were selected from the Radboud Faces Database (RaFD) (Langner et al., 2010) with permission granted to the first author for their use. This subset included male and female, adult and child Dutch Caucasian faces that portrayed one of the following six universal expressions (Ekman & Friesen, 1971): happy, sad, angry, disgusted, surprised, anxious. Twelve photographs of each expression were selected on the basis that each had a high inter-rater reliability (≥75%) (Langner et al., 2010) and were taken in frontal gaze. Two separate sets of facial stimuli (36 stimuli in each set) were created for the study and, respectively, they included 6 of each facial expression. One stimulus set was used for baseline and the second set was used for the intervention condition. Both at the first baseline visit and at the single final follow up visit, all 72 stimuli were presented in random order. Each stimulus set was matched for gender, adult, child, emotion, emotional valence and average inter-rater reliability (which was 94%). Each face stimulus was resized to a 1024 × 883 pixel jpeg file to enable its display on the eye tracker monitor. The visual angle subtended by the face stimulus was 13.8° × 12.3° (width x height, W × H) at the eye tracker's optimal viewing distance of 60 cm.
Structuralist Mental Representation of Dual-action Demands: Mechanisms of Improved Dual-task Performance after Practice in Older Adults
Published in Experimental Aging Research, 2021
Stimuli were presented on a 17-inch color monitor that was connected to a Pentium 1 PC. Experiments were carried out using ERTS software (Experimental Runtime System; Beringer, 2000). Participants performed a visual-manual and an auditory-vocal task (see Figure 1). In the visual-manual task, a circle appeared in one of two possible locations on the screen (left or right). Participants responded manually, indicating the location of the circle with the (spatially) corresponding index or ring finger of the right hand. The circles were white and were horizontally arranged on a black background. Each circle subtended approximately 2.5 cm, which corresponds to a 2.38 ° visual angle, from a viewing distance of 60 cm. Three horizontal white lines served as placeholders at the possible left and right stimulus locations plus a middle location to indicate the central location of the screen. All circles subtended approximately 8.99 °. Responses were recorded with a response board connected to the computer.