Optometric Terms Flashcards
“A pattern”
a horizontal deviation may be different in upgaze versus downgaze
an “A pattern” deviation shows more eso in upgaze
abduction
movement of the eyes away from the nose
accommodation
the act of focusing the eyes to provide an image clear enough for interpretation
the stimulus to accommodation may come from blur on the retina, or perceived awareness of the proximity of a target
when looking at near objects, accommodation is said to be
“stimulated”
when looking at far objects, accommodation is said to be
“relaxed”
Accommodation is part of the what system?
“idenitifcation system” it tells us the “what is it?” of what we are looking at
accommodative amplitude
the range of distance or lens power over which the patient can stimulate focus to maintain clarity
accommodative insufficiency
a patient who shows a reduced accommodative amplitude
accommodative flexibility
ease with which accommodation can be changed from one distance to another
accommodative infacility
a patient who has reduced accommodative flexibility
accommodative spasm
difficulty releasing (relaxing) accommodation
acquired brain injury (ABI)
- refers to damage to the brain acquired after birth
- It usually affects cognitive, physical, emotional, social or independent functioning
- It can result from TBI (i.e. accidents, falls, assaults, etc.) and nontraumatic brain injury (i.e. cerebral palsy, stroke, brain tumors, infection, poisoning, hypoxia, ischemia, or substance abuse)
visual acuity (VA)
- clearness or sharpness of sight
- the ability to resolve or discriminate contours and to tell when there is a separation of the contour from its background
In the US, visual acuity is usually represented as
A fraction which identifies the size of the smallest letters resolved at the testing distance used
numerator: testing distance used (typically 20’)
denominator: size of the letter read
adduction
movement of the eyes toward the nose
afterimage
a visual sensation that persists after the original light stimulation has ceased
alternating
switching from one eye to the other (in relation to strabismus, it means that either eye may fixate while the other eye deviates)
amblyopia
visual condition in which there is a low or reduced central visual acuity that cannot be “corrected” by traditional refractive means (eg. glasses or contact lenses)
and which is not attributable to disease, injury, or pathology
Amblyopia is said to exist when
there is a set level of acuity, typically 20/40 or worse
or when a difference of 2 or more Snellen acuity lines between the eyes is present
Behaviorally, amblypoia is looked upon as
a dysfunction that hinders a patient’s ability to gather, process, analyze, and respond to visual information in a meaningul way
functional ambloypia
(amblyopia ex anopsia) usually one or more of the following conditions is present before the age of 6:
- significant anisometropia
- constant unilateral esotropia or exotropia
- significant isometropia
- significant unilateral or bilateral astigmatism
- image degradation
Binocular competition in an amblyopic patient causes
adaptations to be made via neural suppression, leading to reduced VA and dysfunctions in the amblyopic eye in such skills as:
- ocular motility
- fixation
- accommodation
- spatial sense
- speed of perception
Vision therapy has a high rate of success for patients with functional amblyopia by improving:
visual acuity and developing abilities in the visual functional areas that are commonly affected by this condition
- ocular motility
- fixation
- accommodation
- spatial sense
- speed of perception
anaglyph
used to provide a stereoscopic 3D effect, when viewed with special anaglyph glasses (each lens a different color, usually red and green or red and blue)
Images are made up of 2 color layers, superimposed, but offset with respect to each other to produce a depth effect. The picture contains two differently filtered colored images, one for each eye. When viewed through anaglyph glasses they produce a unified stereoscopic image
Analytical examination
a comprehensive optometric exam that probes the functioning of the visual system under varying conditions.
The findings from this eval help the dr. understand how vision might be helping or interfering in the patient’s performance, comfort, etc
Angle Kappa
the angle between the pupillary axis and the visual axis
it is termed “positive” when the pupillary axis is nasal to the visual axis and “negative” when the pupillary axis is temporal to the visual axis
what is a normal angle kappa
a positive angle kappa (displacement toward the nose) of up to 5 degrees is normal
aniseikonia
a condition in which the image of an object seen by one eye is different in size and shape from the image seen by the other eye
anisometropia
the condition in which unequal refractive states exist between the eyes
anomalous correspondence (AC)
in strabismus, the condition in which an area other than the fovea of the strabismic eye is “matched” with, or “corresponds” to the fovea of the other eye as far as determining location and direction. This provides the patient with some degree of “depth perception,” and avoids double vision and visual confusion
anterior chamber
the space between the iris and the cornea
antimetropia
the condition where one eye measures hyperopia, and the other eye, myopia
aphasia
loss of the ability to produce and/or comprehend language, due to injury to brain areas specialized for these functions
(Broca’s area, which governs language production
Wernicke’s area, which governs the interpretation of language)
Broca’s area
which governs language production
Wernicke’s area
which governs the interpretation of language
aphasia is not a result of
deficits in sensory, intellectual, or psychiatric functioning, nor due to muscle weakness or a cognitive disorder
apraxia
neurological disorder characterized by loss of the ability to execute or carry out learned purposeful movements, despite having the desire and the physical ability to perform the movements.
it is a disorder of motor planning which may be acquired or developmental
aqueous humor
what is it, what produces it, what does it do
the thin, watery fluid that fills the space between the cornea and the iris (anterior chamber)
It is continually produced by the ciliary body, the part of the eye that lies just behind the iris.
This fluid nourishes the cornea and the lens and gives the front of the eye its form and shape
asthenopia
a constellation of symptoms relating to visual discomfort, usually at near, such as blurry vision, watery eyes, itchy eyes, etc
astigmatism
the refractive condition in which the light rays from an object are not brought to a single point focus at the back of the eye
astigmatism is compensated for by the use of
lenses with cylinder
ataxia
a neurological sign and symptom consisting of gross lack of coordination of muscle movements
a non-specific clinical manifestation implying dysfunction of parts of the nervous system that coordinate movement, such as the cerebellum, the vestibular system, the thalamus, and parietal lobe
autonomic nervous system (ANS)
the part of the peripheral nervous system that acts as a control system, maintaining homeostasis in the body
how can the ANS be divided
by subsystems into the parasympathetic (homeostasis/ rest and digest) nervous system and sympathetic (fight or flight) nervous system
it can also be divided functionally, into its sensory and motor systems
Name 8 activities the ANS affects that are generally performed without conscious control
heart rate, digestion, respiration rate, salivation, perspiration, diameter of the pupils, micturition (urination), and sexual arousal
bagolini lenses
a pair of finely straited lenses that can be used in diagnosing the status of correspondence
bifocal
a lens which contains two different powers for focusing at different distance
typically, the bottom part of the lens is for looking at near distances (13-16”) and the top is for further away
binocular
also, referred to as “fusion”
the simultaneous perception of info from the right eye and the left, organized into a single percept
where does binocularity occur
the brain, not at the retina
4 advantages of binocular vision are
single vision, stereopsis, enlargement of the field of vision, and compensation for the physiological blind spot