Background: The World Health Organization estimates that there are 517 million people in the world who are visually impaired due to uncorrected presbyopia. Equal sphere ready-made bifocal and single vision reading spectacles are an inexpensive alternative to custom made spectacles. Methods: A visual satisfaction questionnaire was administered before patients were examined at an outreach clinic and again after ready-made bifocals or reading spectacles were dispensed. The results of both sets of questions along with presenting acuities, corrected acuities, refractive data, and willingness to pay were analyzed. Results: There was an unmet need of 38% (of the 338 subjects that needed glasses only 208 had them). There was no gender bias; the unmet need was higher in the rural areas (47% rural, 36% urban). Those who could not read were 3.4 times less likely to have the glasses they needed than the literate. Unmet need decreased with every level of education. Those without any schooling showed 77% prevalence of unmet need and those with university education had an unmet need rate of 32%. Ready-made spectacles were dispensed to 89.5% of those examined. The ready-made bifocals were very well accepted, with the percentage of subjects giving the highest satisfaction rating improving from a presenting value of 11% to 89.4% with the bifocals at distance and from 6.6% to 89.4% at near. Distance visual acuity of 20/40 or better improved from the presenting value of 60% to 84.5% and near vision of 20/40 or better improved from the presenting value of 44% to 97%. With ready-made single vision readers, functionally good near vision (20/40 or better) improved from a presenting value of 38% to 97%. The highest ranking for near satisfaction improved from 6.3% to 86.6%. The subjects indicted that they would be willing to pay US$18.39 to replace the bifocals and US$16.67 to replace the readers. Conclusion: There is a high unmet need for vision correction in the population over age 35 in Nicaragua. Dissatisfaction with distance and near vision is very high. Although custom made glasses are ideal, ready-made bifocals and ready-made single vision readers are an acceptable and affordable alternative.

Background. The United States military relies on visual acuity standards to assess enlistment induction and military occupational specialty eligibility. In addition, the military recently instituted the Vision Readiness and Classification System to monitor Soldiers' combat vision readiness. The primary aim of this study was to investigate the relationship between visual acuity and marksmanship performance using a single blind randomized trial with the Engagement Skills Trainer 2000. Methods. Marksmanship performance was evaluated in 28 subjects under simulated day and night conditions with habitual spectacle prescription and contact lenses that created visual blur. Results. The relationship between visual acuity and marksmanship performance was found to have a statistically significant correlation of -0.735 with a 95% confidence interval from -0.790 to -0.669. Subsequently, 54 percent of the variance in marksmanship performance was accounted for by visual acuity. In addition, a panel poison regression model using an independent correlation structure revealed significant differences (p< .001) as visual acuity decreased from 20/25 to 20/50. Conclusions. Marksmanship performance decreases as visual acuity decreases. This relationship supports the use of a visual acuity requirement in the assessment of military readiness.

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The purpose of this study was to observe the joint reposition error and tactile acuity of patients with chronic mild to moderate neck pain and compare those values to healthy controls to further investigate the effect of neck pain on neck function and the need for sensorimotor training in patients with chronic neck pain. In spite of some inconsistencies in the literature and methodology, both the two-point discrimination test and the joint reposition error test can give clinicians valuable, inexpensive and quick objective data that can be used in the diagnostic portion of an examination as well as in designing and assessing change during a rehabilitation program. This study found a significant increase in neck joint reposition error (JRE) in flexion in participants suffering from neck pain when compared to healthy controls. JRE averaged 2.75° ± 1.52° in flexion healthy controls and 4.53° ± 1.74° in flexion in participants with chronic neck pain. Additionally, the dermatome found to be most affected by neck pain was C5. Further research is needed to examine both the effect of proprioceptive training on neck pain and the effectiveness of the two-point discrimination threshold test and the joint reposition error test as diagnostic tools and indicators of progress in the treatment of chronic neck pain.

The purpose of this study was to determine the effect of a program of rhythmic training upon the ability to perform music at sight. In addition to examining the overall sight-reading improvement, rhythm reading improvement was also investigated. The program of rhythmic training utilized the Temporal Acuity Products (TAP) system as the rhythm training aid. From these findings it was concluded that the program of rhythmic training did not affect the ability to perform music at sight. A transfer of rhythm reading to sight-reading did no take place. Results of the retention test indicated an improvement in the experimental group's scores over an extended period of time. This improvement revealed that when subjects were tested after two months, the program of rhythmic training did have an effect on sight-reading ability. It was also concluded that there might be a hierarchy of skills in which rhythmic training is only one aspect. Furthermore, there could be a combination of skills which must improve simultaneously in order to effect overall sight-reading ability.

<p>Motion blur is a form of image quality degradation, showing as content in the image smearing and not looking sharp. It is usually seen in photography due to relative motion between the camera and the scene (either camera moves or objects in the scene move). It is also seen in human vision systems, primarily on digital displays.</p> <p><br></p> <p>It is often desired to remove motion blurriness from images. Numerous works have been put into reducing motion blur <em>after</em> the image has been formed, e.g., for camera-captured ones. Unlike post-processing methods, we take the approach to prevent/minimize motion blur for both human and camera observation by pre-processing the source image. The pre-processed images are supposed to look sharp upon blurring. Note that, only pre-processing methods can deal with human-observed blurriness since the imagery can't be modified after it is formed on the retina.</p> <p><br></p> <p>Pre-processing methods face more fundamental challenges than post-processing ones. A problem inherent to such methods is the appearance of ringing artifacts which are intensity oscillations reducing the quality of the observed image. We found that these ringing artifacts have a fundamental cause rooted in the blur kernel. The blur kernel usually have very low amplitudes in some frequencies, significantly attenuating the signal intensity in these frequencies when it convolves an image. Pre-processing methods can usually reconstruct the targeted image to the observer but inevitably lose energy in those frequencies, appearing as artifacts. To address the artifact issue, we present a few approaches: (a) aligning the image content and the kernel in the frequency domain, and (b) redistributing their intensity variations elsewhere in the image. We demonstrate the effectiveness of our method in a working prototype, in simulation, and with a user study.</p>

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