Visual Acuity

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Kinetic visual acuity is correlated with functional visual acuity at higher speeds

Kinetic visual acuity is correlated with functional visual acuity at higher speeds

Objective To measure the kinetic visual acuity (KVA) which is the ability to identify approaching objects and the functional visual acuity (FVA) which is continuous VA during 1 min under binocular and monocular condition (non- dominant eye shielding) for healthy subjects, and related ocular parameters to explore their correlation and implication in aspect of integrated visual function. Methods The mean age of the 28 participants was 38.6±8.9 years (range, 23–57 years; 6 women). A KVA metre (AS- 4F α ) and FVA metre (AS-28) were used to measure KVA and FVA, respectively. Multiple regression analysis was conducted to explore correlations among the measured visual function and related parameters, including age, binocularity, best- corrected visual acuity, refraction and tear break- up time.
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Effects of molting on the visual acuity of the blue crab, Callinectes sapidus

Effects of molting on the visual acuity of the blue crab, Callinectes sapidus

The natural history of the blue crab is well documented, and evidence indicates that mating is limited to the time period surrounding female molting, with courtship behavior involving both chemical and visual cues (Van Engle, 1958; Teytaud, 1971; Gleeson, 1980). Males are described as using a repertoire of visual cues during courtship, including waving the claws, standing tall on the walking legs and rhythmically waving the swim paddles (Teytaud, 1971). The paddling maneuver may also function in directing chemical cues towards potential mates (Kamio et al., 2008). In courting blue crabs, males should be fully capable of receiving chemical and visual cues, whereas in females, reception of visual cues will depend on the molting stage of the female receiver. If a female pairs with a male 3 to 4days prior to molting or well after molting, visual cues may factor into her mate choice. However, because females tend to resist pairing until 1 to 2days before molting (Jivoff and Hines, 1998), when visual acuity is poor, visual cues may not be reliable when choosing a mate and females may instead depend upon chemical cues. The visual constraints of molting may select for multimodal cues in this species. Multimodal communication is fairly common (Hughes, 1996; Hölldobler, 1999), especially in the context of mating (Papke et al., 2006; Uetz and Roberts, 2002), and signals displayed over two modalities may increase the probability of reception (Cardé and Baker, 1984; Conner, 1987). In the blue crab, chemical and visual cues may function redundantly to overcome differences in receiver ability or temporary sensory limitations.
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Meta-analysis of LCPUFA Supplementation of Infant Formula and Visual Acuity

Meta-analysis of LCPUFA Supplementation of Infant Formula and Visual Acuity

contacted for additional information. Whenever we did not receive in- formation, the number of subjects that participated in the following visual acuity assessment was used. If visual acuity was reported for each eye sepa- rately, the average visual acuity of both eyes was calculated and used. Data on additional potentially moderating vari- ables such as number of subjects, start date and duration of LCPUFA supple- mentation, and dose of eicosapentaenoic acid (EPA), DHA, and AA in the supple- mented formula were collected from each trial. Individual study quality was evaluated by using Jadad scale. 38 Using
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Effect of Amblyopia Patch Therapy on Visual Acuity and CSF of Children
 

Effect of Amblyopia Patch Therapy on Visual Acuity and CSF of Children  

7. Zhou, Y., Huang, C., Xu, P., Tao, L., Qiu, Z., et al., Perceptual learning improves contrast sensitivity and visual acuity in adults with anisometropic amblyopia. Vision Res, 2006; 46: 739–750. 8. Heravian, J., Mahjoob, M., Khabbaz-khoob,

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Optokinetic stimuli: motion sickness, visual acuity and eye movements

Optokinetic stimuli: motion sickness, visual acuity and eye movements

Background: It is commonly assumed that motion sickness caused by moving visual scenes arises from the illusion of self-motion (i.e. vection). Hypotheses: Both studies reported here investigated whether sickness and vection were correlated. The first study compared sickness and vection created by real and virtual visual displays. The second study investigated whether visual fixation, to suppress eye movements, affected motion sickness or vection. Method: In the first experiment, subjects viewed an optokinetic drum and a virtual simulation of the optokinetic drum. The second experiment investigated two conditions on a virtual display: (i) moving black and white stripes and (ii) moving black and white stripes with a stationary cross on which subjects fixated to reduce eye movements. Results: In the first study, ratings of motion sickness were correlated between the conditions (real and the virtual drum), as were ratings of vection. With both conditions, subjects with poor visual acuity experienced greater sickness. There was no correlation between ratings of vection and ratings of sickness in either condition. In the second study, fixation reduced motion sickness but had no affect on vection. Motion sickness was correlated with visual acuity without fixation, but not with fixation. Again, there was no correlation between vection and motion sickness. Conclusions: Vection is not the primary cause of sickness with optokinetic stimuli. Vection appears to be influenced by peripheral vision whereas motion sickness is influenced by central vision. When the eyes are free to track moving stimuli, there is an association between visual acuity and motion sickness. Virtual displays can create vection and may be used to investigate visually-induced motion sickness.
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The effect of transcorneal electrical stimulation in visual acuity: Retinitis pigmentosa

The effect of transcorneal electrical stimulation in visual acuity: Retinitis pigmentosa

Before beginning the patient’s stimulation, slit-lamp examinations and ophthalmoscopy were performed, vis- ual acuity (VA) was tested using Early Treatment Dia- betic Retinopathy Study (ETDRS) eye chart, Humphrey 24-2 BB visual fields (Humphrey Instruments, San Lean- dro, CA, USA) and visionmonitor8k electrophysiological recordings (Metrovision, Pérenchies, France) baseline and every 10 weeks. After those examinations, we chose the eye with the worst visual acuity (lower than 20/20) or worst visual capacity (ETDRS characters read) as the eye under test. To assess the changes induced by TES, those examinations and tests were repeated every five weeks for each patient, in order to monitor the TES effect.
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Visual acuity in ray finned fishes correlates with eye size and habitat

Visual acuity in ray finned fishes correlates with eye size and habitat

Visual acuity (the ability to resolve spatial detail) is highly variable across fishes. However, little is known about the evolutionary pressures underlying this variation. We reviewed published literature to create an acuity database for 159 species of ray-finned fishes (Actinopterygii). Within a subset of those species for which we had phylogenetic information and anatomically measured acuity data (n=81), we examined relationships between acuity and both morphological (eye size and body size) and ecological (light level, water turbidity, habitat spatial complexity and diet) variables. Acuity was significantly correlated with eye size (P<0.001); a weaker correlation with body size occurred via a correlation between eye and body size (P<0.001). Acuity decreased as light level decreased and turbidity increased; however, these decreases resulted from fishes in dark or murky environments having smaller eyes and bodies than those in bright or clear environments. We also found significantly lower acuity in horizon-dominated habitats than in featureless or complex habitats. Higher acuity in featureless habitats is likely due to species having absolutely larger eyes and bodies in that environment, though eye size relative to body size is not significantly different from that in complex environments. Controlling for relative eye size, we found that species in complex environments have even higher acuity than predicted. We found no relationship between visual acuity and diet. Our results show that eye size is a primary factor underlying variation in fish acuity. We additionally show that habitat type is an important ecological factor that correlates with acuity in certain species.
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Visual acuity evaluation in children with hydrocephalus: An electrophysiological study with  sweep visual evoked potential

Visual acuity evaluation in children with hydrocephalus: An electrophysiological study with sweep visual evoked potential

Our results agree with these studies, since it shows a reduction in visual acuity of children who were derived more than 15 days compared with the group of children drifted up to 15 days. Our data related to the findings of Fobe et al., [8] and Heinsenbergen et al. [13] suggest that the time between diagnosis and the derivation need to be as short as possible to reduce losses of cortical functions, since our results suggest that the shorter this period, the better the visual acuity measured. The visual acuity of children who were not derived showed values that were below expectations, suggesting an subclinical impair- ment possibly due to the increased pressure.
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Acute decrease of visual acuity and exophthalmos in a male patient

Acute decrease of visual acuity and exophthalmos in a male patient

The mucocoele was evacuated by functional endo- scopic sinus surgery under systemic antibiotic proph- ylaxis. The post-operative ophthalmologic examina- tion revealed progression of the visual acuity to 5/10 in the left eye and stability in the right eye. R

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Evaluation of contrast visual acuity in patients with retinitis pigmentosa

Evaluation of contrast visual acuity in patients with retinitis pigmentosa

with the “distance” in CAT-CP as “long”. In addition to that, we have adjusted the result statistically by using ANCOVA analysis. Thus, we believe that comparison of the two methods would be feasible. However, in a closed field view, in which the light source could be more directional, enhanced glaring and/or scattering might have a greater influence in patients with retinitis pigmentosa. If glaring really matters, tinted eye glasses may be helpful for patients with retinitis pigmentosa who have decreased photopic contrast visual acuity.

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Baseline visual acuity strongly predicts visual acuity gain in patients with diabetic macular edema following anti-vascular endothelial growth factor treatment across trials

Baseline visual acuity strongly predicts visual acuity gain in patients with diabetic macular edema following anti-vascular endothelial growth factor treatment across trials

bevacizumab, and aflibercept. These clinical trials have shown wide variations in efficacy in terms of visual acuity (VA) gains in patients with DME, not only among trials with different anti-VEGF agents or regimens but also between trials with similar agent and regimen. For instance, in the RESTORE trial in DME, ranibizumab 0.5 mg administered according to a pro re nata (PRN) regimen (plus laser) resulted in 12-month gain of only 6.4 letters, 4 in contrast to a gain of nine letters with

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The effects of macular ischemia on visual acuity in diabetic retinopathy

The effects of macular ischemia on visual acuity in diabetic retinopathy

a large sample size, in an area with a relative paucity of data. We used FA grading software, equipped with standard planimetric tools, which allowed quantification of novel morphological parameters, and combined these measurements with detailed statistical analysis. As anticipated, data regarding VA and areas of ischemia were negatively skewed, with 39.7% of patients in our cohort not having any evidence of DMI. As a result, the application of linear regression would have a substantial leverage on the slope of mean regression lines. Our application of quantile regression is more robust to outliers and allowed for an increased depth of analysis in the examination of an inferential target, such as VA, in a given proportion of the population. For example, patients with small or large FAZ areas may respond differently to ischemia with corresponding changes to visual acuity. Multivariable quantile regression analysis also accounted for concurrent DME, a confounder of the relationship between DMI and VA, often overlooked in other studies.
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A comparison of mesopic visual acuity and objective visual quality following cataract surgery with hydrophobic acrylic intraocular lenses

A comparison of mesopic visual acuity and objective visual quality following cataract surgery with hydrophobic acrylic intraocular lenses

Patient records were reviewed for candidates who would meet the inclusion criteria and these patients were invited to visit the clinic for participation in the study. Patients seen in clinic who met the inclusion criteria were also invited to participate in the study. The study was explained to the patients and written informed consent to participate was obtained. The monocular CDVA of the patients was tested using Snellen visual acuity charts at 6 m under mesopic room illumination and OSI was measured by an optical quality analysis system using double-pass wavefront method (Acu- Target HD; Visiometrics SL, Terrassa, Spain).
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Improvement of visual acuity in diabetic and nondiabetic patients after Nd:YAG laser capsulotomy

Improvement of visual acuity in diabetic and nondiabetic patients after Nd:YAG laser capsulotomy

unpredictable, and inadequate stability of the eye or relative contraindications such as glass IOL, known or suspected cystoid macular edema, active intraocular inflammation and high risk for retinal detachment. Prior to capsulotomy, the patient’s visual function was recorded with their pupil in a normal physiological state in terms of best-corrected visual acuity (BCVA) using a Snellen VA chart kept at 6 m (20 ft) from the patient’s eyes.

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Influence of degraded visual acuity from light scattering goggles on obstacle gait

Influence of degraded visual acuity from light scattering goggles on obstacle gait

Experiments were performed with a within-subject design. Each subject walked on a 6 m path with three obstacles set at intervals of 150 cm with or without de- grading visual input conditions by simulation. For the condition of degraded visual input, subjects put on light- scattering goggles covered by packed plastic, and their visual acuity and contrast sensitivity decreased uniformly to 0.01 and B-1 (Vistech). Previous studies examining the gait on the obstacle course selected the obstacles with various heights (2 to 20 cm) [8]. We used three ob- stacle heights mimicking daily living environment as follows: that of the slight buckle of carpets or mats (5 cm), that of a common bump in the house (10 cm), and that of stairs (20 cm) (width: 10 cm).
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Correlation between Fluorescein Angiographic Findings and Visual Acuity in Behçet Retinal Vasculitis

Correlation between Fluorescein Angiographic Findings and Visual Acuity in Behçet Retinal Vasculitis

The demographic and clinical data gathered were age at the time of diagnosis, gender, laterality, HLA-B51 status, duration of follow up, best corrected Snellen visual acuity (BCVA) at initial presentation, at 2 years within +/- six months and at the last follow up. For BCVA at 2 years, the visit closest to the 2 year time point within a 3 months window was count- ed as the visit to be used. All patients were examined by the same uveitis specialist (SCL). Ophthalmic examinations in- cluded a slit lamp examination, a dilated fundus examina- tion, and measurement of the intraocular pressure. Further, the Standardization of Uveitis Nomenclature (SUN) Group grading scheme was used for the assessment of the degree of inflammation in the anterior chamber and the vitreous. 13
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The Retinal Layers in the Preservation of Visual Acuity in the Early Stages of Idiopathic Intracranial Hypertension

The Retinal Layers in the Preservation of Visual Acuity in the Early Stages of Idiopathic Intracranial Hypertension

In IIH patients, visual damage is insidiously advancing and the central visual acuity is preserved until late stages. In some previous studies, the overall thinning of the macula in resolving papilledema was reported [21,22]. Brian E. et al reported significant thinning of the GCL and inner plexiform layer in patients with papilledema compared to controls, and suggested that thinner nuclear layers in the macula might be a reliable method to quantify subclinical atrophy in eyes with resolving papilledema [23]. Thus, performing OCT in patients with IIH is gradually becoming more important to measure and follow-up subclinical atrophy.
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The effects of lubricant eye drops on visual function as measured by the Inter-blink interval Visual Acuity Decay test

The effects of lubricant eye drops on visual function as measured by the Inter-blink interval Visual Acuity Decay test

Methods: This controlled, randomized, double-masked crossover study compared the effects of a polyethylene glycol/propylene glycol-based (PEG/PG) tear and a carboxymethylcellulose sodium (CMC)/glycerin tear on the visual acuity decay between blinks of dry eye patients. At visit 1 (Day 0), baseline IVAD measurements were recorded prior to instillation of a single drop of randomized study medication. IVAD testing was repeated at 15-, 45-, and 90-minutes post-instillation. Reading rate and functional blink rate were also evaluated. At the second visit (Day 7 ± 3), study procedures were repeated using crossover treatment.
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AN OBSERVATIONAL STUDY ON GRATING VISUAL ACUITY ASSESSMENT OF CHILDREN WITH DEVELOPMENTAL DELAY

AN OBSERVATIONAL STUDY ON GRATING VISUAL ACUITY ASSESSMENT OF CHILDREN WITH DEVELOPMENTAL DELAY

LEA grating acuity test was administered in a study to evaluate the relationship between the head posture and visual acuity of children with nystagmus. The tests were applied under two occasions i.e. with and without proper head posture. The study concludes that visual responses are affected with the pursuit of traditional postural alignment (da Costa, Lopes, Nakanami ,2014). A large cohort was conducted for children with cerebral visual impairment on contributing factors to Visually Evoked Potential (VEP), Grating Acuity Deficit (GAD) and inter- ocular acuity difference. The results indicated variable severity of VEP, GAD was found with CVI, more than half of the children with severe deficits. Children older to them and those are under anti-seizure therapy showed high risk for larger deficits (Cavascan, Salamao, Sacai, Pereira, Rocha, Berezovsky, 2014).
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DETERMINATION OF VISUAL ACUITY AND VISUAL AXIS OF BROWNMARBLED GROUPER, Epinephelus fuscoguttatus TO DEVELOP A DEMAND FEEDING SYSTEM

DETERMINATION OF VISUAL ACUITY AND VISUAL AXIS OF BROWNMARBLED GROUPER, Epinephelus fuscoguttatus TO DEVELOP A DEMAND FEEDING SYSTEM

17. Matthiessen L. (1880). Untersuchungen uber den Aplanatismus die Periscopie der Krystalllinsen in den Augen der Fische. Pflugers Arch. Gesamte Physiol. Menschen Tiere. 21: 287 - 307. As cited in: Neave D. A. (1984). The development of visual acuity in larval plaice (Pleuronectes platessa L.) and turbot (Scophthalmus maximus L.). Journal of Experimental Marine Biology and Ecology 78: 167 - 175.

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