What is the Landolt ring chart?
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A visual acuity test chart that uses rings with a gap to determine the direction of the gap, allowing for assessment of visual acuity.
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What is the Landolt ring chart?
A visual acuity test chart that uses rings with a gap to determine the direction of the gap, allowing for assessment of visual acuity.
What does a visual acuity of 20/200 to 20/400 indicate?
A visual acuity of 20/200 to 20/400 indicates severe low vision, which is considered legal blindness by US definition. Individuals at this level can generally orient and move but may have difficulty with traffic signs and reading without high-power magnifiers.
What is myopia?
A refractive error where distant objects appear blurry while close objects can be seen clearly, often referred to as nearsightedness.
What is the significance of a visual acuity of less than CF 4 ft?
A visual acuity of less than CF 4 ft indicates nearly total blindness, where vision is unreliable except under ideal circumstances, and individuals must rely on non-visual devices.
What is the definition of Legal Blindness?
Legal blindness is defined as severe visual impairment in both eyes, which is often used to determine eligibility for disability benefits.
What are pseudoisochromatic color plates?
Pseudoisochromatic color plates are a set of multicolored dot patterns used to evaluate color vision, where patients with normal color vision can easily detect specific numbers and figures embedded in the pattern, while those with impaired color vision may not.
What are some pitfalls to avoid in visual acuity measurement?
Pitfalls include ensuring that all lenses, projectors, and charts are clean, paying attention to distances and calibrations for each type of acuity screen, avoiding glare on the viewing chart or in patients' eyes, and using appropriate tests for the patient's abilities.
What is Near Point of Convergence (NPC)?
The NPC is the point where a single image can no longer be maintained, noted when the image doubles or one eye deviates from the fixation target.
What is the purpose of using habitual correction during visual acuity tests?
Using habitual correction allows the patient to see as clearly as possible during the test, providing a more accurate assessment of their visual acuity.
What is the significance of recording acuity values for each eye separately?
Recording acuity values for each eye separately allows for a detailed assessment of visual function and helps identify any discrepancies in vision between the two eyes.
What is the procedure for Testing Near Visual Acuity?
The procedure involves the patient wearing their habitual corrective lens, holding a near card at a specified distance, occluding one eye at a time, and reading the smallest legible characters, with acuity values recorded for each eye and binocularly.
What is the importance of occluding the eye not being tested?
Occluding the eye not being tested helps to isolate the visual function of the eye being assessed, ensuring accurate measurement of visual acuity.
What is convergence insufficiency?
A condition where the eyes do not work together properly while focusing on a nearby object, affecting binocular visual acuity.
What does the notation '20/40 − 2' indicate in visual acuity testing?
'20/40 − 2' indicates that the patient was able to read the 20/40 line but missed 2 letters on that line.
What is the purpose of retesting acuity with both eyes simultaneously?
Retesting acuity with both eyes simultaneously helps to assess the combined visual function and can provide a more comprehensive understanding of the patient's overall visual acuity.
What are some testing methods for toddlers and preliterate children?
Testing methods for toddlers and preliterate children include picture charts, Lea symbols, the Landolt C or tumbling E test, and the HOTV chart.
What does the abbreviation 'OU' represent in visual acuity testing?
'OU' represents 'both eyes (together)', indicating that the visual acuity measurement is for both eyes simultaneously.
What is Near Point of Accommodation (NPA)?
The NPA is the point (in centimeters or inches) where the patient can no longer bring the image into clear focus.
What is the procedure for testing Near Point of Accommodation (NPA)?
The procedure involves placing a near testing card at 16 inches from the patient, asking them to read a specific line, moving the card closer until the letters blur, and recording that distance.
What is the procedure for testing Near Point of Convergence (NPC)?
The procedure involves holding a target at approximately 16 inches from the patient, moving it closer until the image doubles, and observing eye convergence.
What does it mean to occlude the left eye during visual acuity testing?
To occlude the left eye means to cover it with an occluder to prevent vision, ensuring that only the right eye is tested for visual acuity.
How can tear film abnormalities affect visual acuity?
Tear film abnormalities, such as dry eye syndromes, can decrease visual acuity, but their effects can be minimized by the generous use of artificial tear preparations.
What is latent nystagmus?
Latent nystagmus is a condition that occurs only when one eye is occluded, causing the unoccluded eye to develop nystagmus, resulting in lower measured visual acuity compared to binocular acuity.
What does presbyopia refer to?
Presbyopia refers to the condition where the near point of accommodation recedes with age, making it difficult to focus on close objects.
What is the normal range for NPC?
The normal range for the near point of convergence (NPC) is between 6 cm and 10 cm, regardless of a person's age.
What is Visual Impairment?
Visual impairment refers to a condition where a person cannot achieve normal vision (20/20) even with optical correction such as eyeglasses or contact lenses.
What is the criterion for Severe Visual Impairment?
Severe visual impairment is characterized by corrected distance visual acuity being less than 20/160, including ranges from 20/200 to 20/400.
What is the crowding phenomenon in amblyopia?
The crowding phenomenon refers to the tendency of amblyopic patients to identify smaller optotypes more easily when viewed singly rather than in a line with figures on both sides.
What is glare in the context of visual function?
Glare occurs when light from a single bright source scatters across the visual field, reducing the quality of the visual image and potentially causing distorted vision.
What is the 15-hue test?
The 15-hue test, also known as the Farnsworth-Munsell D-15 test, consists of 15 pastel-colored chips that patients must arrange in a related color sequence, which is obvious to those with normal color vision but challenging for patients with color deficits.
What is the significance of a pinhole improving visual acuity by 2 lines or more?
If the pinhole improves the patient's acuity by 2 lines or more, it suggests that the patient likely has a refractive error, as the pinhole allows for better light entry without the need for refraction by the cornea or lens.
What factors can affect a patient's preferred reading distance during Near Acuity Testing?
A patient's preferred reading distance can vary based on the types of near activities they engage in and whether they use near spectacles.
What is the role of special lenses in astigmatism?
Corneal or lenticular astigmatism might necessitate the use of special spectacle or contact lenses to correct the visual impairment.
What does Snellen acuity measure?
Snellen acuity measures the resolving ability of the eye using targets that subtend a visual angle of 5 minutes of arc.
What is the significance of Visual Acuity in determining disability?
Visual acuity is an important factor used by examiners to estimate a patient's potential disability and to determine appropriate reading aids and distances.
What is the Pinhole Acuity Test?
The Pinhole Acuity Test is a method used to assess visual acuity by having the patient read a testing chart through a pinhole occluder, which allows only central rays of light to enter, helping to determine if reduced visual acuity is due to a refractive error.
Why is it important to use different charts or optotype sequences during visual acuity testing?
Using different charts or optotype sequences is important because patients may memorize the sequence of images they have seen multiple times, which can affect the accuracy of the test results.
What does the Snellen acuity expression represent?
The Snellen acuity expression represents the distance at which a patient can read a specific line of optotypes, with the numerator indicating the distance from the chart and the denominator indicating the size of the optotype read correctly.
How is visual acuity recorded when a patient misses letters?
Visual acuity is recorded with a superscript notation indicating the number of letters missed, for example, 20/40 − 2 if two letters are missed on the 20/40 line.
What does CF stand for in visual acuity testing?
CF stands for 'counting fingers,' which is used to record the longest distance at which a patient can accurately count fingers displayed by the examiner.
What does NLP mean in visual acuity testing?
NLP stands for 'no light perception,' indicating that the patient cannot perceive any light.
What does the abbreviation 'cc' stand for in visual acuity testing?
'cc' stands for 'with correction', indicating that corrective lenses were worn during the visual acuity test.
What is the purpose of measurement notation in visual acuity testing?
Measurement notation provides a standardized way to express visual acuity measurements, facilitating communication and documentation.
What is Pinhole Visual Acuity?
A method of testing visual acuity where the patient looks through a pinhole occluder to determine the sharpest image they can see on a distance chart.
What is presbyopia?
A condition associated with aging that results in a gradual loss of the eye's ability to focus on nearby objects.
What is accommodative insufficiency?
A condition where the eye has difficulty focusing on near objects due to inadequate accommodation.
What type of visual aids are suggested for profound visual impairment (20/500 to 20/1000)?
For profound visual impairment (20/500 to 20/1000), limited spot reading with visual aids is possible, and high-power magnifiers are typically required.
What is the significance of horizontal OKN by 3 months of age?
Horizontal OKN should be present by 3 months of age, indicating normal visual development and the ability to track moving objects.
What is the purpose of low-vision testing?
Low-vision testing aims to assess the visual capabilities of patients who cannot read the largest line on a standard visual acuity chart, often by using shorter distances or alternative methods to measure acuity.
What constitutes Profound Visual Impairment?
Profound visual impairment is defined as corrected distance visual acuity being less than 20/400, which includes ranges from 20/500 to 20/1000.
What is the smallest angle discernible for normal human vision?
One minute is the smallest angle discernible for normal human vision.
What is Amblyopia?
Amblyopia is a visual disorder characterized by a difference in optically correctable acuity of more than 2 lines between both eyes, resulting from abnormal visual input in early childhood. It is commonly referred to as 'lazy eye.'
What are the reading aids recommended for a visual acuity of 20/80 to 20/160?
For a visual acuity of 20/80 to 20/160, strong reading glasses or vision magnifiers are recommended, as they usually provide adequate reading ability, although this level is typically insufficient for a driving license.
What is the significance of the letter L in visual acuity testing?
The letter L is the easiest letter to recognize during visual acuity testing and can be mistaken for few letters other than the letter I, making misinterpretation of other letters, like B, less significant.
Why should the term 'blindness' be avoided when counseling patients with severe visual impairment?
The term 'blindness' should be avoided because most patients with severe visual impairment have some useful vision, and many demonstrate significant resourcefulness.
What are some common abbreviations used in visual acuity testing records?
Common abbreviations include C, S, M (central, steady, maintained fixation) and F & F (fixes and follows), which are used for preverbal or nonverbal children.
What neurologic factors can influence visual acuity testing?
Neurologic factors such as visual field defects, optic nerve lesions, pupillary abnormalities, and impairment by drugs can all influence visual acuity testing.
What visual acuity is typically required for an unrestricted driver's license?
Most states require visual acuity to be correctable to 20/40 or better in at least one eye for an unrestricted driver's license.
What is the recommended approach for testing acuity in patients with low vision?
For patients unable to resolve the largest optotype, they should be positioned 10 feet from a well-illuminated test chart, with the eye not being tested occluded, and the testing distance halved until they can identify half the optotypes on a line.
What is the effect of dirty lenses on visual acuity?
Dirty lenses of any kind, whether trial lenses, phoropter lenses, eyeglass lenses, or contact lenses, will decrease acuity, resulting in falsely low measurements.
What is the effect of patient fatigue on acuity measurements?
Patient fatigue or boredom can affect acuity measurements, making it difficult to assess their true visual acuity.
What are the implications of motility defects on visual acuity measurement?
Motility defects such as nystagmus or other movement disorders can interfere with the ability to align the fovea on the object of regard, leading to lower acuity measurements.
What is the near point of convergence (NPC)?
The near point of convergence (NPC) is the nearest point to which both eyes can converge and still maintain a single image.
What is the significance of light perception (LP) in visual acuity testing?
LP indicates that the patient can perceive light, and it can be further specified as 'LP with projection' or 'LP without projection' based on the patient's ability to identify the direction of the light.
What should be used to attract an infant's attention during visual testing?
A small toy or other sight-stimulating object that does not produce sound, held about 1–2 feet from the infant's face.
What is the purpose of using an occluder during a visual acuity test?
An occluder is used to cover the eye that is not being tested, ensuring that only one eye is evaluated at a time for accurate measurement.
What does 'NPA' stand for in visual acuity notations?
'NPA' stands for 'Near Point of Accommodation', which refers to the closest point at which the eye can focus on an object.
What is unilateral amblyopia?
Unilateral amblyopia is a condition where one eye has reduced vision due to causes such as anisometropia, strabismus, or unilateral media opacities like congenital cataracts.
What does contrast sensitivity measure?
Contrast sensitivity measures the ability to discern relative darkness and brightness, as well as the ability to see details, edges, and borders of images.
What are common causes of color vision differences between two eyes?
Color vision differences between two eyes may indicate optic nerve or retinal disease, with common abnormalities including X-linked congenital red-green deficiencies.
What are the characteristics of the HOTV optotypes used in visual acuity testing?
The HOTV optotypes are symmetric, useful for matching, and particularly effective for nonverbal or illiterate patients, making them suitable for testing young children.
What is Optokinetic Nystagmus (OKN)?
Optokinetic Nystagmus (OKN) is a reflexive eye movement that can be elicited by moving a regularly striped object in front of a viewer, indicating the ability to discriminate detail.
What is the role of the pinhole test in visual acuity assessment?
The pinhole test is used to recheck visual acuity when it is worse than 20/20, helping to determine if the reduced acuity is due to refractive error or other factors.
What does HM indicate in visual acuity testing?
HM stands for 'hand motion,' which is recorded when a patient can detect the examiner's hand movement at a specified distance.
What is visual acuity?
Visual acuity refers to an angular measurement that relates testing distance to the minimal object size resolvable at that distance.
What defines Moderate Visual Impairment?
Moderate visual impairment is defined as corrected distance visual acuity (best-corrected VA) being less than 20/60, which includes ranges from 20/70 to 20/160.
What does a 20/20 visual acuity indicate?
A 20/20 visual acuity is considered normal visual acuity, meaning the individual can see at 20 feet what should normally be seen at that distance.
What does the abbreviation PH signify in visual acuity testing?
PH signifies the acuity obtained using the pinhole test, indicating that the measurement was taken while the patient was looking through a pinhole occluder.
What is the Testing Distance Visual Acuity protocol?
The Testing Distance Visual Acuity protocol involves asking the patient to stand or sit at a designated distance (ideally 20 feet) from a well-illuminated wall chart, occluding one eye, and having the patient identify letters or objects on successively smaller optotypes until a certain threshold is reached.
How do lighting conditions affect acuity tests?
Lighting conditions must remain equivalent for acuity tests to be comparable, as variations can influence visibility and accuracy of measurements.
How should one interact with patients who have low vision or are blind?
When interacting with patients who have low vision or are blind, it is important to alert them to your movements beforehand, offer an arm for guidance without grabbing, and use a demeanor and testing approach appropriate for their age.
What is the near point of accommodation (NPA)?
The near point of accommodation (NPA) is the nearest point at which the eye can focus to form a clear image on the retina.
What is the crowding phenomenon in visual acuity testing?
The crowding phenomenon refers to the effect where the presence of nearby letters or objects makes it more difficult for a patient to identify a target, enhancing sensitivity for detecting amblyopia.
What is logMAR notation?
A visual acuity notation that expresses visual acuity as the logarithm of the minimum angle of resolution, with acuity of 20/20 having a logMAR value of 0.
What is the purpose of the Prince or RAF rule in vision testing?
The Prince or RAF rule is used to convert measurements of the near point of accommodation (NPA) expressed in meters into diopters.
What is the purpose of the Pinhole Acuity Test?
The Pinhole Acuity Test is used to determine if a patient's vision can improve with pinhole occlusion, helping to differentiate between refractive errors and other vision issues.
What should be done before conducting a visual acuity examination?
Before conducting a visual acuity examination, it is important to determine if the patient is familiar with the optotypes being used and to choose the appropriate chart based on the patient's comfort with letters or numbers.
What is assessed during the Near Acuity Test?
The Near Acuity Test assesses a patient's ability to see clearly at a normal reading distance, taking into account their preferred reading distance and any near spectacles they may use.
What does decimal notation represent in visual acuity?
A conversion of the Snellen fraction to a decimal format, where Snellen 20/20 equals decimal 1.0, Snellen 20/30 equals decimal 0.7, and Snellen 20/40 equals decimal 0.5.
What is Jaeger notation?
Jaeger notation, also referred to as number acuity, is a system used to indicate near visual acuity on test cards.
What is fixation preference testing?
Fixation preference testing is a method used to detect amblyopia in preverbal children by observing which eye the child prefers to use when both eyes are tested separately.
What impact does chart cleanliness have on visual acuity testing?
If a chart is not kept clean, smaller letters become more difficult to identify, potentially leading to falsely low acuity measurements.
What is a Rosenbaum pocket vision screener?
A Rosenbaum pocket vision screener is a tool used to test near visual acuity, often utilized in clinical settings.
What is the Distance Acuity Test?
The Distance Acuity Test is a vision test performed to measure a patient's ability to see at a distance, typically conducted with and without corrective lenses.
What is the Jaeger (J) notation used for?
A method to express near visual acuity by assigning arbitrary numbers to Snellen equivalent figures.
What does the abbreviation 'sc' indicate in visual acuity testing?
'sc' indicates 'without correction', meaning the visual acuity test was performed without the use of corrective lenses.
What are optotypes in visual acuity testing?
Optotypes are targets used in visual acuity testing that subtend a visual angle on the retina, typically consisting of letters or symbols.
What is Snellen acuity designation?
A method of recording visual acuity by indicating the distance at which a patient can read a specific line on an eye chart, expressed as a fraction (e.g., 5/80).
What is the Snellen notation?
A visual acuity notation that quantifies visual discrimination of fine detail, represented as a fraction where the numerator indicates the distance at which the test is performed and the denominator indicates the distance at which a subject with unimpaired vision can read the same figure.
What are Allen reduced picture cards used for?
Allen reduced picture cards are used to test near visual acuity in children.
What is an optotype?
An individual letter, number, or picture on a testing chart used in visual acuity testing.
What external factors can affect visual acuity measurement?
External factors such as patient distraction, fatigue, age, and psychological influences can affect the results of visual acuity measurements.
What is the Amblyopia Treatment Study (ATS) visual acuity testing protocol?
The ATS visual acuity testing protocol uses isolated HOTV optotypes surrounded by bars and is gaining acceptance for testing young children due to its high testability and excellent test-retest reliability.
How can visual acuity be tested in the presence of latent nystagmus?
In cases of suspected latent nystagmus, the fellow eye may be blurred using a +10.00 to +20.00 diopter lens instead of a standard occluder to obtain the best possible monocular visual acuity.
What is the Snellen fraction?
The Snellen fraction is a notation used to express visual acuity, represented as a ratio of the distance at which a patient can read a specific line on a visual acuity chart to the distance at which a person with normal vision can read the same line.
What is the significance of the number in the denominator of Snellen notation?
The number in the denominator represents the distance at which the target subtends a visual angle of 5 minutes of arc.
What are Teller acuity cards?
Teller acuity cards are large photographic plates used to estimate visual acuity in infants, featuring line gratings that become progressively smaller, allowing the examiner to determine the baby's direction of gaze.
What is the significance of the blink response in newborns?
A consistent blink response to a bright light, even through closed eyelids, is an indicator of normal visual function in newborns.
Why might children prefer different types of visual acuity charts?
Children may prefer different types of visual acuity charts because some respond better to numbers while others prefer letters, and their engagement can affect testing accuracy.
What is the purpose of testing an infant's fixing and following behavior?
To assess the infant's visual tracking and fixation abilities by observing their eye movements in response to a visually stimulating object.
Why do patients with extremely low vision require special testing?
Patients with extremely low vision, including infants, toddlers, illiterate adults, and nonverbal patients, require special testing methods and attention to accurately assess their visual acuity.
What is the significance of testing the right eye first in visual acuity testing?
Testing the right eye first is a convention in visual acuity testing to maintain consistency and avoid confusion in the testing routine.
Fine oscillatory movements with the slow phase going in the direction of the stripes indicate that the baby has a potential for discriminating detail of at least the width of the ___.
stripe
The Jaeger (J) notation is used to express ___ visual acuity.
near
Each individual letter, number, or picture on a testing chart is referred to as an ___.
optotype
The term visual acuity refers to an angular measurement that relates testing distance to the minimal object size resolvable at that ___.
distance
Contrast sensitivity refers to the ability to discern relative darkness and brightness and the ability to see ___, edges, and borders of images.
details
Before the visual acuity test begins, it is important to determine if the patient is familiar with the ___ being used.
optotypes
If a patient misses half or fewer than half the letters on the smallest readable line, record how many letters were ___.
missed
The smallest angle discernible for normal human vision is ___ minute.
1
For patients with low vision, if they cannot resolve the largest optotype, they should stand or sit ___ feet from the test chart.
10
If the patient prefers ___, use that chart for the visual acuity test.
numbers
It is important to ensure that all lenses, projectors, and charts are ___.
clean
If the pinhole improves the patient’s acuity by ___ lines or more, it is likely that a refractive error exists.
2
Record the acuity value for each eye separately, with correction and without correction, as would be done for standard distance acuity testing, recording the distance at which the patient successfully reads the chart as the numerator of the ___ acuity designation.
Snellen
A pinhole no more than ___ mm in diameter should be used for testing.
2.4
The two basic types of vision testing are ___ and ___ visual acuity tests.
distance, near
Patients with neurologic impairments may experience motility problems or central nervous system ___ that can influence acuity measurement.
abnormalities
The NPA is defined as the point where the patient can no longer bring the image into ___ focus.
clear
Severe low vision, defined as legal blindness in the US, ranges from ___ to ___.
20/200, 20/400
Patients should identify letters or numbers on successively smaller optotypes from ___ to ___.
left, right
The abbreviation HM stands for ___ motion.
Hand
When testing visual acuity, you can ask the child which direction the legs of the letter are pointing—___, to the floor, to me, or to Mommy/Daddy?
to the ceiling
To test near visual acuity, a ___ pocket vision screener or a Lebensohn chart should be used.
Rosenbaum
The easiest letter to recognize is ___, which can be mistaken for few letters other than the letter I.
L
Falsely high or low acuity measurements can occur due to ___ or ___ conditions.
external, internal
In the near visual acuity test, the patient is asked to occlude one eye and read the line with the smallest characters that are ___.
legible
The near test card shows numeric notations alongside each line of ___ .
optotypes
When occluding the left eye, ensure that the occluder does not ___ against the eye.
touch or press
Crowding bars may be used to induce the ___ phenomenon, making the test more sensitive for amblyopia.
crowding
Color vision differences between two eyes may indicate ___ nerve or retinal disease.
optic
The letterform ___ is the hardest for patients to recognize and can be confused with an E or the number 8.
B
The decimal notation converts the Snellen fraction to a decimal; for example, Snellen 20/20 equals decimal ___.
1.0
The younger the patient, the more successful the amblyopia ___ is.
treatment
Nystagmus is characterized by spontaneous oscillatory movements of the ___ .
eyes
By convention, the ___ eye is tested first during a distance visual acuity test.
right
Profound visual impairment is classified as ___ to ___.
20/500, 20/1000
The test for near visual acuity is usually performed at ___ inches.
16
The abbreviation used to precede or follow the Snellen acuity obtained during pinhole testing is ___.
PH
To test for Near Point of Accommodation (NPA), the near testing card is placed at a distance of ___ inches from the patient.
16
Patients with normal color vision can easily detect specific ___ and figures in the dot pattern.
numbers
The 15-hue test is also known as the ___ test.
Farnsworth-Munsell D-15
Toddlers and preliterate children might be tested with a picture chart, Lea symbols, the Landolt C or ___ test.
tumbling E
Causes of unilateral amblyopia include ___, strabismus, and unilateral media opacities.
anisometropia
Optokinetic nystagmus (OKN) can be elicited using any regularly ___ object.
striped
The abbreviation ___ indicates that corrective lenses were worn during the visual acuity test.
cc
The cleanliness of the projector bulb and lens affects the ___ of the letters viewed by the patient.
contrast
Patient ___ or boredom can affect acuity measurements.
fatigue
The use of artificial tear preparations can help minimize the effects of ___ abnormalities.
tear film
For children, near visual acuity can be tested with ___ reduced picture cards.
Allen
When measuring vision without corrective lenses, the abbreviation ___ is used.
sc
Vertical OKN might not be elicited until a child is approximately ___ months of age.
6
Charts with optotypes have achieved almost universal acceptance in the ___.
United States
Glare occurs when light from a single bright source scatters across the visual field, reducing the quality of the visual ___.
image
In low vision testing, the distance is repeatedly halved until the patient identifies half the ___ on a line.
optotypes
Patients with extremely low vision require ___ testing methods.
special
If a patient cannot read the largest line of the visual acuity chart, the examiner should repeat the test at ___ distances.
shorter
Near acuity testing assesses the ability to see clearly at a normal ___ distance.
reading
In the Snellen notation, the number in the ___ position indicates the distance at which a subject with unimpaired vision can read the same figure.
denominator
Lighting conditions must remain ___ for acuity tests to be comparable.
equivalent
During the NPA test, the patient is asked to state when the letters become ___.
blurred
Many amblyopic patients exhibit the '___ phenomenon,' where smaller optotypes are identified more easily when viewed singly.
crowding
Amblyopia is often referred to as ___ eye.
lazy
The normal near point of convergence (NPC) is between ___ cm and ___ cm.
6, 10
The abbreviation NPA refers to the ___ point of accommodation.
Near
If the patient is unable to resolve the largest optotypes on the chart from a distance of 2.5 feet, display 2 or more fingers of 1 hand and ask the patient to count the number of fingers displayed. Record the longest distance at which counting is done accurately; for example, ___ at 2 ft.
CF
If the patient cannot detect your hand motion, shine a penlight toward the patient’s face from approximately 1 foot and turn it on and off to determine if ___ perception is present.
light
A 20/60 optotype is ___ times as big as the 20/20 optotype.
3
If a child objects when one eye is covered, a difference in vision between both eyes should be strongly ___ .
suspected
Legal blindness typically requires severe visual impairment in both eyes, which is often used to determine eligibility for ___ benefits.
disability
During pinhole testing, the patient is instructed to use small hand or eye movements to align the pinhole to resolve the ___ image on the chart.
sharpest
For near visual acuity testing, the patient should hold the test card at the distance specified on the ___ card.
test
Dirty lenses, whether trial lenses, phoropter lenses, eyeglass lenses, or contact lenses, will decrease acuity and result in falsely ___ measurements.
low
Normal vision at normal reading distance is classified as ___ to ___.
20/12, 20/25
Charts with higher contrast will be seen more easily than those with ___ contrast.
lower
A variety of ___ can be used to cover the eye not being tested.
occluders
Vision is a complex human sense that includes visual acuity, visual field, and ___ sensitivity.
contrast
Impaired vision in amblyopia is due to damage in the ___ and ___ that do not receive proper visual input.
lateral geniculate nucleus, visual cortex
Ophthalmologists typically use ___ acuity as a measure of the resolving ability of the eye.
Snellen
Picture charts can result in over-estimation of visual acuity because the optotypes are not equally ___.
recognizable
Patients with congenital nystagmus often have better visual acuity for ___ than for distance.
near
In most states, visual acuity must be correctable to ___ or better in at least one eye for an unrestricted driver's license.
20/40
When recording acuity values, it is important to do so for each eye ___ in the patient’s chart.
separately
The logMAR notation expresses visual acuity as the logarithm of the minimum angle of ___ (log-MAR).
resolution
Acuity of 20/200 has a logMAR value of ___.
1.0
The nearest point at which the eye can focus clearly is known as the near point of ___.
accommodation (NPA)
For Near Point of Convergence (NPC) testing, the target is held at approximately ___ inches from the patient.
16
The abbreviation VA stands for ___ acuity.
Visual
If a child seems bored or hesitant with one kind of chart, it is recommended to try ___ chart.
another
Avoid glare on the viewing ___ or screen.
chart
The distance at which the acuity measurement is successfully taken is used as the ___ of the Snellen fraction.
numerator
For toddlers, the examiner should allow them to sit with a ___ or familiar caretaker.
parent
For testing an infant’s fixing and following behavior, select a small toy or other attention-attracting object that stimulates sight only; do not use a ___-producing object.
sound
Severe visual impairment is defined as corrected distance VA less than ___ (including 20/200–20/400).
20/160
To test pinhole visual acuity, the patient should hold the pinhole occluder in front of the eye that is to be tested while wearing their ___ correction.
habitual
Corneal or lenticular astigmatism might require the use of special ___ or ___ lenses.
spectacle, contact
Healthy young adults typically have vision better than ___.
20/20
Visual acuity can improve when the patient maintains a head position to decrease the amplitude of the ___.
nystagmus
Amblyopia results from a difference in optically correctable acuity of more than ___ lines between both eyes.
2
Amblyopia can be associated with long-standing uncorrected ___ and nystagmus.
refractive errors
Horizontal OKN should be present by ___ months of age.
3
The ideal testing distance for distance visual acuity is ___ feet from a well-illuminated wall chart.
20
To assess latent nystagmus, the fellow eye may be blurred using a ___ to ___ diopter lens.
+10.00 to +20.00
As people age, their NPA recedes, a condition referred to as ___.
presbyopia
If a patient cannot read the standard chart even at close distances, the examiner can ask them to ___ the fingers held up.
count
If the distance for near testing is not accurate, the measurements will not be equivalent to the ___ acuity.
distance
The distance at which the patient is placed in reference to the chart is the ___ of the Snellen expression.
numerator
If using the Landolt ring chart, you can ask the child to indicate which side of the 'cookie' has a ___ in it.
bite
Possible causes of poorer near acuity than distance acuity include ___ and ___ presbyopia.
presbyopia, premature
Evaluation of color vision is often performed with a book that displays ___ dot patterns.
multicolored
Moderate low vision is classified as ___ to ___.
20/80, 20/160
In latent nystagmus, the unoccluded eye develops nystagmus when ___ eye is occluded.
one
In the NPC test, the patient is asked to tell you when the image ___ .
doubles
Patients with color deficits arrange the chips in the 15-hue test ___ than those with normal color vision.
differently
After testing each eye separately, if desired, retest acuity with both eyes ___ and record acuity ___.
simultaneously, OU
To avoid memorization, present different charts or optotype ___ whenever possible.
sequences
The most commonly recognized color vision abnormalities are the X-linked congenital red-green ___ .
deficiencies
If visual acuity is worse than 20/20, recheck with a ___.
pinhole
A pinhole acuity test can help infer the presence of a ___ error.
refractive
When interacting with patients who have low vision, alert them to your ___ beforehand.
movements
The letters C, D, and O are often confused because their shapes are ___ .
similar
Refrain from using the term '___' when counseling patients with severe visual impairment.
blindness
Infants and young toddlers respond best to a gentle, ___ approach.
gradual
The ___ E and Landolt C tests can be done by matching but involve testing psychophysical components other than vision.
tumbling
If light is perceived from straight ahead, move the light sequentially into each of the 4 quadrants of the visual field. Turn the penlight on and off in each field, and ask the patient to identify when the light comes on. If the patient correctly identifies the direction from which the light is coming, record the response as ___ with projection.
LP
The number in the numerator of the Snellen fraction represents the equivalent of the testing distance from the eye to the ___ being used.
chart
Anomalous head position may improve acuity by allowing patients to maintain that head position while measuring ___ visual acuity.
binocular
The Amblyopia Treatment Study (ATS) visual acuity testing protocol uses isolated HOTV optotypes surrounded by ___.
bars
The Snellen standard of ___ is considered normal vision.
20/20
If a patient misses 2 letters on the 20/40 line, the acuity may be expressed as 20/40 ___ 2.
−
Profound visual impairment is defined as corrected distance VA less than ___ (including 20/500–20/1000).
20/400
If the patient cannot count fingers, move your hand horizontally or vertically before the patient at a distance of approximately 2 feet. Record the distance at which the patient reports seeing your hand move; for example, ___ at 2 ft.
HM
In Snellen notation, / is considered normal visual acuity.
20, 20
In infants, vision should be assessed by testing each eye ___ with the other eye covered.
separately
Moderate visual impairment is defined as corrected distance VA less than ___ (including 20/70–20/160).
20/60
If the patient cannot see the light, dim the room lights and shine the brightest light available toward the patient’s eye again. If the patient cannot see even the brightest light, record the response as ___ (no light perception).
NLP
The letters H, O, T, and V were chosen for testing with young children because they are ___ and can be used for matching.
symmetric
If a patient reads one-half of the letters correctly on the 20/40 line, the vision may be recorded as ___ .
20/40
Newborns should show a consistent ___ response to a bright light.
blink
Watch the infant’s eyes for fixation and following movements. Cover 1 eye and repeat the test. Cover the other eye and repeat again. Observe for any difference between the eyes in the quality of ___ and smooth pursuit.
fixation
If the light can be seen from straight ahead, colored filters can be placed in front of the light and the patient asked to identify the ___ of the light.
color
Teller acuity cards are used to estimate acuity in infants and are large photographic plates approximately ___ feet by ___ foot.
3, 1
The guidelines for issuing noncommercial driving licenses recommend an uninterrupted visual field of ___ horizontal diameter for individuals with 20/40 or better visual acuity.
140°
Certain conventional abbreviations such as C, S, M are used for preverbal or ___ children.
nonverbal
