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Optical coherence tomography (OCT) has become one of the most relevant diagnostic tools for retinal diseases. Besides being a non-invasive technique, one distinguished feature is its unique capability of providing (in vivo) cross-sectional view of the retinal. Specifically, OCT images show the retinal layers. From the clinical point of view, the identification of the retinal layers opens new perspectives to study the correlation between morphological and functional aspects of the retinal tissue. The main contribution of this paper is a new method/algorithm for the automated segmentation of cross-sectional images of the retina of healthy eyes, obtained by means of spectral domain optical coherence tomography (SD-OCT). Specifically, the proposed segmentation algorithm provides the automated detection of different retinal layers. Tests on experimental SD-OCT scans performed by three different instruments/manufacturers have been successfully carried out and compared to a manual segmentation made by an independent ophthalmologist, showing the generality and the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

This study evaluated the effect of color on nonius horopter between color normal and color deficient subjects. Horopter curves were plotted and analyzed for blue (450 nm), green (518 nm), yellow (589 nm) and red (634 nm) wavelengths in four subjects. Color normals and color deficient subjects showed similar horopter plots. One color normal and one color deficient subject perceived red horopter in front of blue and the other two subjects had the opposite effect. Based on these results it was concluded that the changes seen in the horopter for the different wavelengths is purely an optical effect with the primary cause being chromostereopsis due to chromatic aberration. [ABSTRACT FROM AUTHOR]

The purpose of the work was to assess the contrast sensitivity function of individuals wearing gas permeable (GP) multifocal contact lenses, soft bifocal contact lenses, and GP monovision lenses. Twenty-six females and six males between the ages of 42 and 65 participated in this study. The study included subjects wearing monovision (N = 8), the Acuvue Bifocal (Johnson & Johnson) (N = 8), Essential GP Multifocal (Blanchard) lenses (N = 8) and progressive addition spectacle lenses (PAL) (N = 8), with PAL wearers forming the control group. Measurements of binocular contrast sensitivity were obtained using the VISTECH 6500 system. Thresholds for each spatial frequency were fit to the equation CS(k) = ak exp(-bk) [1 + c exp(bk)]-1/2, to describe the human contrast sensitivity function. The area under the contrast sensitivity function (CSF) curve was calculated for all four groups and compared. An index of performance was obtained, which was defined as the ratio of CSF with the contact lens correction to the CSF with spectacles. Of the contact lens wearing groups, GP multifocal contact lens wearers had the highest contrast sensitivity at all the spatial frequencies. Soft bifocal contact lens wearers exhibited higher contrast sensitivity than monovision wearers at all spatial frequencies. Subjects wearing GP multifocals had the largest area under the CSF; followed by those wearing soft bifocals, with monovision wearers having the smallest area. GP multifocals have the best visual function at 0.98, soft bifocals have an index of 0.65 and monovision has an index of 0.59. This study quantifies the visual performance of the three lens systems by measuring the area under the CSF curve. In addition, it provides indices of visual function with the contact lenses that will be helpful for analyses and comparisons in future studies. [ABSTRACT FROM AUTHOR]

The aim of the work was to compare the acceptance and feasibility of high add spectacles over other low vision aids (telescope and magnifiers) in patients in tertiary eye care centres in western India. Materials used included visual acuity charts, pinhole, retinoscope and trial lenses, slit lamp, indirect ophthalmoscope, low vision assessment equipment and high add spectacles and other optical low vision aids. Retrospectively, 128 eyes from patient prescriptions who reported to the OPD, in different ophthalmological and optical set-ups, of western India were studied. The subjects were enrolled irrespective of the cause of low vision. All patients underwent routine examination of vision and anterior segment of the eye in the OPD, followed by applanation tonometry and dilated retinal examination. The patients considered for low vision prescription underwent complete low vision assessment with both spectacles and other optical low vision aids. It was prescribed as per clinical acceptance. The number of accepted as spectacles and other low vision aids (telescopes and magnifiers) were analysed for acceptability and feasibility. The average age of presentation was 44.05 years and ranged from 6 to 84 years. There were 77 males. One prescription for each patient, either for a low vision or a spectacle was accepted. The complaints were mainly regarding distance and near vision. Only 54 (42.19%) subjects had a problem of mobility with the rest comfortable both in a known and unknown atmosphere. Near vision could be improved to N8, N6 in 74.2% with a good reading speed and acceptable field and reading distance. 53.12% subjects had a vision improvement of about Snellen's 6/24 to 6/9 partial though the field was constricted. 25.78% was overall clinical acceptance of the telescopic prescription; only five (15.15%) subjects bought the prescribed telescopes. The overall clinical acceptance for spectacle low vision aids prescription was 74.22% and acceptance level 94.7% (only five rejections). The statistical analysis was done by Chi-square test, standard error of proportion and z test to find the significance of difference in prescription and acceptance and the acceptability of spectacles over other low vision aids. The value for the Chi-square test was, p=<0.001, which showed that the difference between the prescription of both spectacles and other low vision aids and acceptance by patients for the same was of high statistical significance. The test of error of proportion followed by the z test showed a value of p< 0.01. It expressed that there was an absolute preference for high add spectacles over the other low vision aids which was of high statistical significance. The study reveals even though telescopes are absolute vision enhancers they are not readily acceptable to the patients though the vision is good with the low vision aids other than the high add spectacle aids. [ABSTRACT FROM AUTHOR]

Recent progress in several fields has radically changed the expectations of low vision individuals. These changes augment existing prescription eye-care and electronic reading machines to improve recovery of visual function. Companies are reporting incidences of multi-line gains in visual acuity as their products for macular degeneration move through FDA approval stages. Funding for this research is rapidly increasing. The range of suitable lighting products and their sphere of application is expanding, facilitating gains in functional vision under more flexible conditions. There is mounting evidence that the use of electronic readers not only solves reading problems but fosters gains in visual capacity, providing significant improvement in reading stamina and confidence. [ABSTRACT FROM AUTHOR]