By definition an ophthalmic prism is wedge-shaped lens of glass or plastic that is thicker at one edge (the base) than at its opposite edge (the apex). Prisms usually are prescribed to correct faulty eye-muscle imbalances in which both eyes do not act as a team. In these cases, the refractive doctor prescribes the proper
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Tints, Filters and Sunglasses
Tinted lenses are worn for the sake of appearance, comfort (discomfort glare), vision (disability glare) and protection against UV exposure. Sunglasses typically reduce transmission to 15%-25% and can be even darker for very bright conditions such as snow. At least 8% transmission is required to drive a car safely. Wearing
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The Issue of Adaptation
“These aren’t working for me.” This isn’t what we want to hear from our patients. Before you fit progressives, please consider the following variables and realize that adaptation issues are a challenge that every Optician faces.
If working with a multifocal patient, is this their
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SLAB-OFF EXPLAINED
On occasion we have patients who come in with a prescription showing a significant power difference between the right and left eyes. Sometimes this variance is rather significant, around four diopters, or less significant, at around two diopters. This condition is called anisometropia, and is often congenital but can also be caused
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All about anti–reflective coatings
Anti-reflection coatings are made from extremely thin layers of different dielectric materials that are applied in a high vacuum onto both surfaces of the lens. The quality of the AR depends upon the number of layers applied to the lens. The early coatings had only a single layer of magnesium fluoride
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Another interesting test
Joseph, you are Balanced-brained, which means that you rely equally on both the left and right hemispheres of your brain.
You have a balanced brain — able to draw on the strengths of both the right and left hemispheres depending on context. Typically, people with balanced right and left hemispheres are very comfortable with
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