Search results
Results from the WOW.Com Content Network
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.
Properties. A triangular prism has 6 vertices, 9 edges, and 5 faces. Every prism has 2 congruent faces known as its bases, and the bases of a triangular prism are triangles. The triangle has 3 vertices, each of which pairs with another triangle's vertex, making up another 3 edges.
The prism fusion range (PFR) or fusional vergence amplitude is a clinical eye test performed by orthoptists, optometrists, and ophthalmologists to assess motor fusion, specifically the extent to which a patient can maintain binocular single vision in the presence of increasing vergence demands.
The prism cover test (PCT) is an objective measurement and the gold standard in measuring strabismus, i.e. ocular misalignment, or a deviation of the eye. It is used by ophthalmologists and orthoptists in order to measure the vertical and horizontal deviation and includes both manifest and latent components. [1]
D nd (or D nv), [2n,2 +], (2*n) has vertical mirror planes between the horizontal rotation axes, not through them. As a result, the vertical axis is a 2 n -fold rotoreflection axis. D nh is the symmetry group for a regular n -sided prism and also for a regular n-sided bipyramid .
A prescription of −1.00 +0.25 × 180 describes a lens that has a horizontal power of −1.00 D and a vertical power of −0.75 D. Only ophthalmologists write prescriptions in + cylinder. An optometrist would write a prescription in - (minus) cylinder.
A Fresnel lens ( / ˈfreɪnɛl, - nəl / FRAY-nel, -nəl; / ˈfrɛnɛl, - əl / FREN-el, -əl; or / freɪˈnɛl / fray-NEL [1]) is a type of composite compact lens which reduces the amount of material required compared to a conventional lens by dividing the lens into a set of concentric annular sections.
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.
Congenital fourth nerve palsy is a condition present at birth characterized by a vertical misalignment of the eyes due to a weakness or paralysis of the superior oblique muscle. Other names for fourth nerve palsy include superior oblique palsy and trochlear nerve palsy.
Diopside is a monoclinic pyroxene mineral with composition MgCaSi. 2O. 6. It forms complete solid solution series with hedenbergite ( FeCaSi. 2O. 6) and augite, and partial solid solutions with orthopyroxene and pigeonite. It forms variably colored, but typically dull green crystals in the monoclinic prismatic class.