Ad
related to: base up and down prism
Search results
Results from the WOW.Com Content Network
The prism base utilised. For example, Base in (BI), Base out (BO), Base up (BU) or Base down (BD). The angle of the deviation with the units in prism dioptres; Which eye is fixating and which eye is deviating; Whether the test was performed with or without an abnormal head posture; Examples of recording
If the line appears below the light, there will be a hyper-deviation in which base down prisms are used to measure and correct the deviation. If the line appears above the light, there will be a hypo-deviation and base up prisms are used measure and correct the deviation.
When measuring horizontal fusion ranges, base in prisms assess fusional divergence while base out prisms assess fusional convergence. The vertical fusional vergence amplitude can also be measured with base up and base down prisms although the horizontal PFR is typically the main focus when testing.
The Four Prism Dioptre Reflex Test (also known as the 4 PRT, or 4 Prism Dioptre Base-out Test) is an objective, non-dissociative test used to prove the alignment of both eyes (i.e. the presence of binocular single vision) by assessing motor fusion.
In optics, a dispersive prism is an optical prism that is used to disperse light, that is, to separate light into its spectral components (the colors of the rainbow). Different wavelengths (colors) of light will be deflected by the prism at different angles. [1]
An optical prism is a transparent optical element with flat, polished surfaces that are designed to refract light. At least one surface must be angled — elements with two parallel surfaces are not prisms. The most familiar type of optical prism is the triangular prism, which has a triangular base and rectangular sides.
The base is the thickest part of the lens and is opposite from the apex. Light will be bent towards the base and the image will be shifted towards the apex. In an eyeglass prescription, the base is typically specified as up, down, in, or out, but left and right are also used sometimes.
In geometry, a prism is a polyhedron comprising an n-sided polygon base, a second base which is a translated copy (rigidly moved without rotation) of the first, and n other faces, necessarily all parallelograms, joining corresponding sides of the two bases.
In order to design such a prism, we let ¯ =, and simultaneously solving equations and gives δ 1 ( λ ¯ ) = − δ 2 ( λ ¯ ) = − Δ ( 1 V 2 − 1 V 1 ) − 1 , {\displaystyle \delta _{1}({\bar {\lambda }})=-\delta _{2}({\bar {\lambda }})=-\Delta {\Big (}{\frac {1}{V_{2}}}-{\frac {1}{V_{1}}}{\Big )}^{-1}\ ,}
An accretionary wedge or accretionary prism forms from sediments accreted onto the non-subducting tectonic plate at a convergent plate boundary. Most of the material in the accretionary wedge consists of marine sediments scraped off from the downgoing slab of oceanic crust , but in some cases the wedge includes the erosional products of ...