Visual Fields
What method of perimetry is the most widely used and is essentially a screening test?
CVF: Confrontation visual field test
Mydriatic drops act on what musculature to dilate the pupil?
iris dilator muscle
what is astigmatism?
a refractive error cause by the non spherical (cylinder) surface of the corneas or lens, or both
The difference between the two meridians is the amount of corneal _________
Astigmatism
The Condition in which eyes shift involuntarily in a rhythmic beating motion is called _________.
Nystagmus
Where in the VF is the physiologic blind spot located?
15 degrees temporal to fixation.
Timolol is used in GLC management by decreasing what?
The formation of aqueous humor.
Two prims placed apex to apex form the basis of what type of lens?
concave (minus)
What amount of corneal astigmatism does the following demonstrate? 44:00 @ 18/ 46.50 @ 108
2.5 Diopters
What is the diff between a tropia & a phoria?
Tropia= is a misalignment that continually manifests
Phoria= is a misalignment found only when covering one eye.
When should the perimetrist add the complete cylindrical power to the lens holder as opposed to the spherical equivalent?
If cylinder is greater than 1 diopter.
Why are cycloplegic drop essential in the fraction of children's eyes?
They paralyze the ciliary muscle so that the eye is no longer able to accommodate.
what do convex lenses do to light rays
converge them
The distance between the two points at the edge of the reflected mire of the surface being measured is referred to as the _____ ______.
Chord Length
What is Stereopsis?
Visual blending of 2 similar (not identical) images, one falling on each retina, into one, with visual perception of solidity and depth.
What is the most common type of visual field defect indicated in a hysterical patient?
Tubular or spiral
Subconjunctival injections are used primarily to treat what condition?
Intraocular infections and inflammation.
What is the refractive index of crown glass?
1.523
What type of corneal astigmatism does the following demonstrate? 45.00 @ 180/ 46.50 @ 90?
With the rule
How does maddox rod dissociate the eyes and prevent fusion?
It changes the size, shape, and color of a point of light to a line (a streak) of light so that fusion is impossible.
Which defect is a complete nerve fiber bundle defect emanating from blind spot, arching over or under the macula and ending on the nasal horizontal line?
Bjerrum's scotoma or arcuate scotoma
What is the ocular stain used to identify defects on the conjunctiva?
Lissamine Green Stain
yaz. freebieeee
True or False: with traditional methods of patient fixation, the readings will always be the apex of the cornea.
False. There are a number of corneal condition s that apex of the cornea will not measure. ALTERNATIVE METHODS OF FIXATION WILL NE BESSARY TO FIND THE CORNEAL APEX.
Name the primary and secondary actions of the superior oblique muscle.
Primary action: Intorsion (rotation downward and inward toward the nose)
Secondary action: Depression & abduction