Optometry and vision science : official publication of the American Academy of Optometry
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Randomized Controlled Trial
Synergeyes versus soft toric lenses: vision-related quality of life.
The purpose of this study is to contrast the clinical and vision-related quality of life outcomes between Synergeyes, a hybrid contact lens, and Bausch & Lomb Soflens 66 Toric contact lenses in a cross-over design. Also, to determine subject preference of one mode of lens wear over the other. ⋯ Bausch & Lomb Soflens 66 Toric lenses were more comfortable and were perceived to produce less symptoms of dryness, itchiness, and lens awareness than Synergeyes lenses. Synergeyes lenses gave better visual acuity than the soft toric lenses.
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Controlled Clinical Trial
Refractive error and visual acuity changes in orthokeratology patients.
To evaluate the refractive error and visual acuity (VA) at various contrast levels in the two eyes of overnight orthokeratology (ortho-k) subjects, and to compare their postortho-k VA with the best corrected VA of spectacle-wearing control subjects matched for age, gender, and initial refractive error. ⋯ Postortho-k visual outcomes were compromised primarily due to the presence of residual refractive error. Although the uncorrected postortho-k VA was comparable to the best corrected VA of the spectacle wearers at high-contrast levels, it was worse at low-contrast levels and caused a significant between-eye difference at all contrast levels. Therefore, we suggested that monocular VA at high- and low-contrast levels should be evaluated for ortho-k patients.
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Controlled Clinical Trial
Gas permeable (GP) versus non-GP lens wearers: accuracy of orthokeratology in myopia reduction.
The primary objective of this study is to determine whether there are significant differences in visual and refractive outcomes between gas permeable (GP) and non-GP wearers following a 1-month period of overnight orthokeratology (OK). ⋯ Although the non-GP group has higher post-OK visual acuity and spherical equivalent statistically, the GP group has attained an average unaided acuity of >20/20 and residual myopia <0.5 D. Clinically, this shows that OK can be a promising technique in GP wearers.
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Infection and inflammation during contact lens wear is often associated with microbial contamination of lenses. Several different types of microbes that colonize lenses can lead to infection and inflammation, but the most common cause of infection (microbial keratitis; MK) remains the Gram-negative bacterium Pseudomonas aeruginosa. P. aeruginosa has a battery of cell-associated and extracellular virulence factors it can use to initiate and maintain infection. ⋯ These cytokines or chemokines recruit white blood cells, predominantly polymorphonuclear leukocytes, to the infection in order that they can phagocytose and kill the P. aeruginosa. However, continued recruitment and presence of these polymorphonuclear neutrophils and other white blood cells in the corneal tissue leads to destruction of corneal cells and tissue components. This can ultimately lead to scarring and vision loss.
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Comparative Study
Visual performance of subjects wearing presbyopic contact lenses.
The purpose of this study is to assess the visual performance of subjects wearing gas-permeable (GP) multifocal contact lenses, soft bifocal contact lenses, GP monovision lenses and spectacles. ⋯ Subjects wearing GP multifocals, soft bifocals, monovision, and PAL spectacles have good binocular contrast sensitivity, satisfactory binocular low and high contrast acuity, and increased sensitivity to glare. Presbyopic subjects requiring the use of contact lenses under dim light levels could benefit from GP multifocal lenses. Contrast and glare sensitivity evaluations provide significant information regarding the visual performance of the presbyopic contact lenses and should be included in regular presbyopic contact lens fitting.