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OPTICS

Optics

What is Accommodation? The ability of one eye to change focus for objects viewed at different distance. -for each unit dipper of accommodation exerted, a given amount of convergence also occurs. 33cm 6m
What is Diopter? A unite of measurement of the power of a prism. 1 diopter brings parallel rays of light to focus at a distance of 1 meter.
What is Refractive Error? A condition where parallel rays of light entering the eye do not come to a focus properly on the retina.
What is Emmetropia? Normal refractive error.
what is Hyperopia? Farsightedness (hypermetropia) lights come in focus BEHIND the eye. (globe is smaller then average).
what is Myopia? Nearsightedness lights come in focus IN FRONT of the eye. (globe is usually bigger then average).
what is Astigmatism? Prevents lights from coming into a single focus on the retina because of different degrees of the retraction in various meridians of the eye.
what is Anisometropia? Refractive error of the eye is unequal.
what is Mydriasis? Enlargment (dilation) of the pupils. happens in dark or when using certain pharmacological agents.
what is Miosis? Constriction of the pupil. occurs when accommodating, bright light stimulus, or certain pharmacological agents.
what is Nystagmus? eyes make short, rhythmic movements when they should be static.
what is Ptosis? Drooping or abnormal closure of the eye lids.
what is Abduction? Rotation of the eye outward (toward the temple)
what is Adduction? rotation of the eye inward towards the nose.
what is Bielschowsky heads tilt test? a diagnostic test used to identify the weak muscle in cases where a vertical deviation its present.
what is Bifoveal fixation? a state in which the object of regard is imaged on both foveae at the same time given rise to binocular single vision.
what is Binocular single vision? the ability to use both eyes together to see objects as one.
what is Conjugate movements (versions)? movement of both eyes in the same direction. > > or << or ^^ etc.
what is Convergence? movements of both eyes towards the midline. > <
what is Depression? movement of both eyes downwards.
what is diplopia? Double vision.
what is Disjugate movements (vergences)? movements of the two eyes in opposite directions, as in covariance and divergence. (>)(<) (<) (>)
what is dissociation? disruption of fusion.
what is divergence? Disjunctive movements of bOTH eyes away from the midline. (<) (>)
what is elevation? movement of both eyes upward (^)(^)
what is emmetropia? No refractive error.
what are the 6 extraocular muscles? medical rectus, lateral rectus superior rectus inferior rectus superior oblique inferior oblique
what are the primary and secondary actions for medical and lateral rectus? medical rectus primary: adduction secondary none lateral rectus primary: abduction secondary none
what are the primary and secondary actions for the superior and inferior rectus? superior rectus primary: elevation secondary: intorsion, adduction inferior rectus primary: depression secondar: extorsion, adduction
what are the primary and secondary actions for the superior and inferior obliques? superior oblique primary: intorsion secondary: depression, abduction inferior oblique primary: extorsion secondary: elevation,abduction
what is a fixation point? the object of attention or object of regard.
what is fixing eye? the straight eye, the eye that looks at the object of regard.
what is the fovea and where is it located? The fovea is is the area of the retina that has the capability of most distinct vision. Located in the center of the macula.
what is fusion? the mental ability to blend two similar images (one formed on each retina) and perceive them as one.
what is Heterophora (phoria)? a deviation that is present only when fusion is disrupted, a LATENT deviation.
what is hyperdeviation? it is upward deviation of ONE eye.
what is heterotropia (tropia)> a misalignment of the visual axes as in esoTROPIA or exoTROPIA, a MANIFEST deviation.
what is hyperopia? and what type of lens do we use to correct for it? farsightedness, the rays of light come a focus behind the eye. Corrected with a CONVEX (plus) lens. (_)
what is hypodeviation? downward deviation of ONE eye.
true or false constant (tropic ) intermitten, or latent (phoric)
what type of deviations can there be? eso- exo- hyper- hypo- and they can all be constant, or intermittent, or latent deviation.
whats intorsion? wheel like rotation of the eyes moves towards the midline.
what is extorsion? wheel like rotation of the eyes moves away from the midline.
what is miosis? contraction of the pupil as normally occurs when accommodating or stimuli to bright lights can also be pharmacologically induced.
what is mydriasis? enlargement of the pupil as normally occurs when its dark or when certain pharmacologically are used.
what is myopia and what type of lens do we use to correct for it? Nearsightedness, rays of light come to focus in front of the eye. we correct this by using a CONCAVE (minus) lens. )_(
what is nystagmus? A condition in which the eyes make short, rhythmic movements while they normally should be static
what is occlusion? a method of patching one eye to insure use of the other eye.
what is the name of the right eye? Oculus Dexter (OD)
what is the name of the left eye? Oculus Sinster (OS)
what is the name for both eyes together? Oculi Unitas (OU)
what is Orthophoria? Straight eyes, the normal position of eyes.
what is Paralysis? The complete inability of an extraocular muscle to act.
whats the straight ahead position of the eyes called? Primary position.
what three cranial nerves supply innervation to the extraocular muscles? 3rd cranial nerve : Oculomotoer nerve 4th CN: Trochlear nerve 6th CN : Abducens nerve
where does the 3rd CN Oculomotor enter the eye? What does the 3rd CN Oculomotor nerve do for the eye? It enters the orbit via the superior orbital fissure and innervates muscles that enable most movements of the eye and that raise the eyelid.
What eye muscles does the 3rd CN innervate? inferior rectus, medial rectus, superior rectus, inferior oblique and levator palpebrae.
What does the 4th CN, trochlear nerve, do for the eye and what muscle does it innervate? motor nerve that innervates the superior oblique muscle which operates through the pulley-like trochlea to which allows it to have the intorsion, abduction, and depression movements.
What does the 6th CN do for the eye muscles, and what muscle does it innervate? The abducens nerve is a nerve that controls the movement of the lateral rectus muscle, responsible for outward gaze.
what are paired primary movers called? Yoke muscles, which when paired produce coordinated movements in the 8 cardinal gazes.
what are we testing when we test yoke muscles? Version testing. (elevation depression in both eyes. )
Created by: Hebaalbaiaty