Lea Symbols Test optotypes on a blanket to be used to test the visual acuity of a young child

The LEA Vision Test System is a series of

pediatric Pediatrics ( also spelled ''paediatrics'' or ''pædiatrics'') is the branch of medicine that involves the medical care of infants, children, adolescents, and young adults. In the United Kingdom, paediatrics covers many of their youth until the ...

vision tests An eye examination is a series of tests performed to assess Visual acuity, vision and ability to Focus (optics), focus on and discern objects. It also includes other tests and examinations pertaining to the human eye, eyes. Eye examinations are ...

designed specifically for children who do not know how to read the letters of the

alphabet An alphabet is a standardized set of basic written graphemes (called letters) that represent the phonemes of certain spoken languages. Not all writing systems represent language in this way; in a syllabary, each character represents a syll ...

that are typically used in

eye chart __NOTOC__ An eye chart, or optotype, is a chart used to subjectively measure visual acuity. Eye charts are often used by health care professionals, such as optometrists, physicians or nurses, to screen persons for vision impairment. Ophthalmologi ...

s. There are numerous variants of the LEA test which can be used to assess the visual capabilities of near vision and distance vision, as well as several other aspects of occupational health, such as

contrast sensitivity Contrast is the contradiction in luminance or colour that makes an object (or its representation in an image or display) distinguishable. In visual perception of the real world, contrast is determined by the difference in the colour and brightn ...

visual field The visual field is the "spatial array of visual sensations available to observation in introspectionist psychological experiments". Or simply, visual field can be defined as the entire area that can be seen when an eye is fixed straight at a point ...

color vision Color vision, a feature of visual perception, is an ability to perceive differences between light composed of different wavelengths (i.e., different spectral power distributions) independently of light intensity. Color perception is a part of ...

, visual adaptation,

motion perception Motion perception is the process of inferring the speed and direction of elements in a scene based on visual, vestibular and proprioceptive inputs. Although this process appears straightforward to most observers, it has proven to be a difficult pr ...

, and ocular function and

accommodation (eye) Accommodation is the process by which the vertebrate eye changes optical power to maintain a clear image or focus on an object as its distance varies. In this, distances vary for individuals from the far point—the maximum distance from the eye ...

History

The first version of the LEA test was developed in 1976 by Finnish pediatric

ophthalmologist Ophthalmology ( ) is a surgery, surgical subspecialty within medicine that deals with the diagnosis and treatment of eye disorders. An ophthalmologist is a physician who undergoes subspecialty training in medical and surgical eye care. Followin ...

Lea Hyvärinen, MD, PhD. Dr. Hyvärinen completed her thesis on

fluorescein angiography Fluorescein angiography (FA), fluorescent angiography (FAG), or fundus fluorescein angiography (FFA) is a technique for examining the circulation of the retina and choroid (parts of the fundus) using a fluorescent dye and a specialized camera. S ...

and helped start the first clinical laboratory in that area while serving as a fellow at the

Wilmer Eye Institute The Wilmer Ophthalmological Institute, also referred to as the Wilmer Eye Institute, is a component of the Johns Hopkins University School of Medicine. Ophthalmologist William Holland Wilmer opened the Wilmer Eye Institute in 1925. Its home was co ...

Johns Hopkins Hospital The Johns Hopkins Hospital (JHH) is the teaching hospital and biomedical research facility of the Johns Hopkins School of Medicine, located in Baltimore, Maryland, U.S. It was founded in 1889 using money from a bequest of over $7 million (1873 mo ...

in 1967. During her time with the Wilmer Institute, she became interested in

vision rehabilitation Vision rehabilitation (often called vision rehab) is a term for a medical rehabilitation to improve vision or low vision. In other words, it is the process of restoring functional ability and improving quality of life and independence in an individ ...

and assessment and has been working in that field since the 1970s, training rehabilitation teams, designing new visual assessment devices, and teaching. The first test within the LEA Vision Test System that Dr. Hyvarinen created was the classic LEA Symbols Test followed shortly by the LEA Numbers Test which was used in comparison studies within the field of

occupational medicine Occupational medicine, until 1960 called industrial medicine, is the branch of medicine which is concerned with the maintenance of health in the workplace, including prevention and treatment of diseases and injuries, with secondary objectives ...

Accuracy

Among the array of visual assessment picture tests that exist, the LEA symbols tests are the only tests that have been

calibrated In measurement technology and metrology, calibration is the comparison of measurement values delivered by a device under test with those of a calibration standard of known accuracy. Such a standard could be another measurement device of known a ...

against the

standardized Standardization or standardisation is the process of implementing and developing technical standards based on the consensus of different parties that include firms, users, interest groups, standards organizations and governments. Standardization ...

Landolt C The Landolt C, also known as a Landolt ring, Landolt broken ring, or Japanese vision test, is an optotype: a standardized symbol used for testing vision. It was developed by the Swiss-born ophthalmologist Edmund Landolt. The Landolt C consists ...

vision test symbol. The Landolt C is an optotype that is used throughout most of the world as the standardized symbol for measuring visual acuity. It is identical to the "C" that is used in the traditional

Snellen chart A Snellen chart is an eye chart that can be used to measure visual acuity. Snellen charts are named after the Dutch ophthalmologist Herman Snellen, who developed the chart in 1862. Many ophthalmologists and vision scientists now use an improved ...

. In addition to this, the LEA symbols test has been experimentally verified to be both a valid and reliable measure of visual acuity. As is desirable of a good vision test, each of the four optotypes used in the symbols test has been proven to measure visual acuity similarly and blur equally as well, supporting the test's

internal consistency In statistics and research, internal consistency is typically a measure based on the correlations between different items on the same test (or the same subscale on a larger test). It measures whether several items that propose to measure the same g ...

. A study published in ''Acta Ophthalmologica Scandinavica'' in 2006 showed that the Lea Symbols 15-line folding distance chart is clinically useful in detecting deficiencies in

visual acuity Visual acuity (VA) commonly refers to the clarity of vision, but technically rates an examinee's ability to recognize small details with precision. Visual acuity is dependent on optical and neural factors, i.e. (1) the sharpness of the retinal ...

in preschool children. The study, which compared visual acuity diagnoses from Lea symbols tests to those obtained via

ophthalmological Ophthalmology ( ) is a surgical subspecialty within medicine that deals with the diagnosis and treatment of eye disorders. An ophthalmologist is a physician who undergoes subspecialty training in medical and surgical eye care. Following a medic ...

examination, revealed that the Lea symbols chart provided an accurate and sufficient assessment in 95.9% of the 149 preschool-age children tested. This suggests that Lea tests can be used confidently as an alternative to more costly and time-consuming pediatric tests of visual acuity.

Importance

The unique design of the LEA tests and their special optotypes allow for pediatric low vision to be diagnosed in children at much younger ages than standard vision tests allow. This is especially important in young children who possess other

physical disabilities A physical disability is a limitation on a person's physical functioning, mobility, dexterity or stamina. Other physical disability, disabilities include impairments which limit other facets of daily living skills, daily living, such as respiratory ...

mental disabilities Mental may refer to: * of or relating to the mind Films * ''Mental'' (2012 film), an Australian comedy-drama * ''Mental'' (2016 film), a Bangladeshi romantic-action movie * ''Mental'', a 2008 documentary by Kazuhiro Soda * ''Mental'', a 2014 Od ...

and are entitled to receive early

special education Special education (known as special-needs education, aided education, exceptional education, alternative provision, exceptional student education, special ed., SDC, or SPED) is the practice of educating students in a way that accommodates th ...

benefits. More than half of children who suffer from low vision also have other impairments or disabilities. Most of the LEA tests can also be used on children with significant brain damage and serve as one of the few methods that can accurately assess visual acuity in these situations.

Versions

The LEA Vision Test System currently contains over 40 different tests which target the assessment of many aspects of vision and communication deficiencies in both children and adults.

LEA Symbols Test

The oldest and most basic form of the LEA test is simply referred to as the "LEA Symbols Test". This test consists of four

optotype __NOTOC__ An eye chart, or optotype, is a chart used to subjectively measure visual acuity. Eye charts are often used by health care professionals, such as optometrists, physicians or nurses, to screen persons for vision impairment. Ophthalmologis ...

s (test symbols): the outlines of an

apple An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple fruit tree, trees are agriculture, cultivated worldwide and are the most widely grown species in the genus ''Malus''. The tree originated in Central Asia, wh ...

, a

pentagon In geometry, a pentagon (from the Greek πέντε ''pente'' meaning ''five'' and γωνία ''gonia'' meaning ''angle'') is any five-sided polygon or 5-gon. The sum of the internal angles in a simple pentagon is 540°. A pentagon may be simpl ...

, a

square In Euclidean geometry, a square is a regular quadrilateral, which means that it has four equal sides and four equal angles (90-degree angles, π/2 radian angles, or right angles). It can also be defined as a rectangle with two equal-length adj ...

, and a

circle A circle is a shape consisting of all points in a plane that are at a given distance from a given point, the centre. Equivalently, it is the curve traced out by a point that moves in a plane so that its distance from a given point is const ...

. Because these four symbols can be named and easily identified as everyday, concrete objects ("apple", "house", "window", and "ring"), they can be recognized at an earlier age than abstract letters or numbers can be. This enables preschool children to be tested for

long before they become familiar with the letter and numbers used in other standard vision charts. The LEA Symbols Test is often used in the form of the

three-dimensional Three-dimensional space (also: 3D space, 3-space or, rarely, tri-dimensional space) is a geometric setting in which three values (called ''parameters'') are required to determine the position of an element (i.e., point). This is the informal ...

(3-D) LEA Puzzle. This puzzle incorporates color along with the four standard optotypes to allow for measurement of visual acuity in children as young as fourteen months of age.

LEA Numbers Test

The "LEA Numbers Test" was the second of the LEA tests that was developed and can be used to test the visual acuity of older children and even adults. This test has a layout similar to a typical

, with lines of numbers decreasing in size towards the bottom of the page. Like the optotypes of the LEA Symbols Test, these numbers are also calibrated against the Landolt C and blur equally.

LEA Grating Acuity Test

This test allows for the assessment of

grating A grating is any regularly spaced collection of essentially identical, parallel, elongated elements. Gratings usually consist of a single set of elongated elements, but can consist of two sets, in which case the second set is usually perpendicul ...

acuity, especially in children who possess severe or multiple visual deficiencies. The "LEA Gratings Test" has also been shown to be successful in vision testing of children with

brain damage Neurotrauma, brain damage or brain injury (BI) is the destruction or degeneration of brain cells. Brain injuries occur due to a wide range of internal and external factors. In general, brain damage refers to significant, undiscriminating t ...

and is the only test that can reveal their limited capacity for the processing of large numbers of

parallel Parallel is a geometric term of location which may refer to: Computing * Parallel algorithm * Parallel computing * Parallel metaheuristic * Parallel (software), a UNIX utility for running programs in parallel * Parallel Sysplex, a cluster of IBM ...

lines.

LEA Contrast Sensitivity Test

Visual information that is presented in low contrast settings is very important to the process of visual communication. It is especially vital to assess a child's

at a young age in order to determine the distance and accuracy with the child can distinguish facial features. A very popular test designed specifically for this reason is the "Hiding Heidi Low Contrast Face Pictures" test (which the LEA Vision Test System produces a version of.) This test uses a series of cards depicting cartoon faces of different contrast levels. The contrast sensitivity assessment obtained from this test is very important in educational settings because children with contrast deficiencies have extreme difficulty receiving visual cues from body language or facial expressions and often can't read the blackboard or projector.Hyvärinen, L. (n.d.). Contrast sensitivity. Retrieved from http://www.lea-test.fi/en/assessme/educearl/part1/contrast.html

References

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External links

Official website
Diagnostic ophthalmology Optotypes