Search results
Results from the WOW.Com Content Network
A cover test or cover-uncover test is an objective determination of the presence and amount of ocular deviation. It is typically performed by orthoptists, ophthalmologists and optometrists during eye examinations . The two primary types of cover tests are: the unilateral cover test (or the cover-uncover test).
Presbyopia is physiological insufficiency of accommodation associated with the aging of the eye that results in progressively worsening ability to focus clearly on close objects. [4] Also known as age-related farsightedness [5] (or age-related long sight in the UK [6] ), it affects many adults over the age of 40. A common sign of presbyopia is difficulty reading small print which results in ...
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. [1] It is used by ophthalmologists and orthoptists in order to measure the vertical and horizontal deviation and includes both manifest and latent components. [1]
Eye care professionals use prism correction as a component of some eyeglass prescriptions. A lens which includes some amount of prism correction will displace the viewed image horizontally, vertically, or a combination of both directions.
If the patient saw a red line to the right and white light to the left, they are said to have esotropia or esophoria (uncrossed diplopia) in which base out (BO) prisms of increasing strength are used until the lines are superimposed.
Convergence disorder. Specialty. Ophthalmology, optometry. Convergence insufficiency is a sensory and neuromuscular anomaly of the binocular vision system, characterized by a reduced ability of the eyes to turn towards each other, or sustain convergence .
Specialty. Ophthalmology. Esophoria is an eye condition involving inward deviation of the eye, usually due to extra-ocular muscle imbalance. It is a type of heterophoria .
In an ophthalmic lens, both the front and back surfaces have a positive radius, resulting in a positive/convergent front surface and a negative/divergent back surface. The difference in curvature between the front and rear surface leads to the corrective power of the lens.
Refractive error is a problem with focusing light accurately on the retina due to the shape of the eye and/or cornea. [1] The most common types of refractive error are near-sightedness, far-sightedness, astigmatism, and presbyopia. [1]
To transfer dγ into the usual unit of minutes of arc, a multiplicative constant c is inserted whose value is 3437.75 (1 radian in arcminutes ). In the calculation a, dz and z must be in the same units, say, feet, inches, cm or meters.