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This video demonstrates what is involved when performing a prism cover test. Purpose. measuring strabismus. 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 ...
In studies that used standardized definitions of convergence insufficiency, investigators have reported a prevalence of 4.2–6% in school and clinic settings. The standard definition of convergence insufficiency is exophoria greater at near than at distance, a receded near point of convergence, and reduced convergence amplitudes at near.
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 alternating cover test. the unilateral cover test (or the cover-uncover test).
Grade 4 anterior chamber angle. open angle between cornea and iris. AC 3/4. Grade 3 anterior chamber angle. AC 2/4. Grade 2 anterior chamber angle. AC 1/4. Grade 1 anterior chamber angle. AC 0/4.
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.
Heterophoria is an eye condition in which the directions that the eyes are pointing at rest position, when not performing binocular fusion, are not the same as each other, or, "not straight". This condition can be esophoria, where the eyes tend to cross inward in the absence of fusion; exophoria, in which they diverge; or hyperphoria, in which ...