IN THIS ISSUE:
• Spectacle Lens Corrections Increase Peripheral Hyperopic Refractive Error
Some have suggested, based on animal studies, that peripheral hyperopic defocus may drive myopia progression. In that context, our authors note that spectacle lenses that correct myopia in children can increase hyperopic defocus in the peripheral retina. The amount of hyperopic defocus increases with eccentricity. (p. 4)
• Lysozyme and Lens Care Solutions Alter Action of Tear Lipids
Tear lipids facilitate aqueous layer spread on the cornea after a blink. Our authors note that human tear lipids form multilayers rather than monolayers. In reconstituted thick multilayer tear lipid films, they demonstrated that lysozyme and surfactant-containing multipurpose lens care solutions alter the dynamics of the lipids. (p. 10)
• Peripheral Fields Fine Tune the Gait for Mobility Safety
Our authors suggest that exteroceptive (static) cues are provided by the central visual field to plan gait adaptations required to safely negotiate an obstacle, whereas exproprioceptive (dynamic) information is provided by the peripheral visual field to “fine tune” the adaptive gait. (p. 21)
• Is All Well Using Optotypes to Assess Contrast Sensitivity?
Our authors say “not really,” because there is a dependence on the optotype style. For example, there are small differences with Landolt C and tumbling E targets. A possible solution is offered whereby the optotypes contain only specific spatial frequencies. (p. 28)
• Quality of Life for Intellectually Disabled Children with Vision Impairment
Severe visual impairments have a negative impact on children's quality of life, but this has not been studied in intellectually disabled children who have a high prevalence of severe visual impairment. Our authors found it necessary to modify existing instruments to study the quality of life in these children. (p. 37)
• Does Convergence Change Eye Shape?
The authors find that the mechanical influence of convergence on eye length is limited or nonexistent. However, small but statistically significant changes in corneal topography were found following the convergence. They feel that this has implications for refractive error development. (p. 45)
• Levodopa Inhibits the Development of Form-Deprivation Myopia
In animal studies, visual deprivation leads to a myopic refractive error and, also, reduces the retinal concentration of dopamine. In guinea pigs, levodopa (used to treat human Parkinson's disease) partly inhibits myopia development. This raises questions about its possible application to humans for this purpose. (p. 53)
• Astigmatism Induced by Lateral Rectus Recession?
Our authors found that larger recessions induced greater astigmatism 1 week after surgery, but after that time, the amount and type of astigmatism was not different between the large and moderate recession groups. (p. 61)
• A Lensmeter that Determines Both Lens and Prism Power with Refractive Index?
A new method of measuring lens and prism refractive index, involving immersion in solution, is offered to provide clinicians this information. Our author believes that this might be incorporated into new lensmeter designs. (p. 66)
• Back and Front Vertex Power in a Simpler Form
The traditional approach to defining back and front vertex power is not easy to understand or teach, especially with astigmatism. New definitions are offered that are intended to make the concepts clearer. (p. 70)