Anomalies of Color Vision Flashcards

Question

_Explain why Protans perceive REDS as dim or dark._

Answer 1

* The photopic luminosity curve peaks at approximately 555 nm – it has this shape because there is a disproportionately large input (approximately 2 or 3 to 1) from LWS cones compared to MWS cones & little/no input from SWS cones * Consequently, compared to color normal, one would predict that protanopes (who lack LWS photopigment) and protanomalous trichromats, (who have an LWS photopigment that is more like the normal MWS photopigment), would experience a severe reduction in the relative brightness of RED LIGHTS * Examples proving: * Protans have difficulty seeing automobile REAR TAIL & BRAKE LIGHTS under conditions in which it is easy for color normal to see them * This can lead to delayed reaction times, which has been linked to a higher incidence of rear-end automobile accidents in protans * Protans may also have difficulty seeing RED traffic lights even under normal conditions * Deep-Red (long-wavelength) surface colors may look quite black to protanopes * The red light- emitting dioees on consumer electronic devices can be difficult for protans to see * Deep-red laser pointers can be invisible to protans * Deutans have NO significant relative LOSS of luminosity compared to normal – this is also the case for deuteranomalous trichromats

Answer 2

* Daughters: 100% carriers but color normal * Sons: 100% color deficient (anomalous) * ![]()

Answer 3

* Daughters: 50% carriers, 50% color normal * Sons: 50% color deficient (anomalous), 50% normal ![]()

Answer 4

* Daughters: 100% carriers but color normal * Sons: 100% color normal ![]()

Answer 5

* Daughters: 100% color normal * Sons: 100% color normal ![]()

Answer 6

* Daughters: 50% color deficient (anomalous); 50% carriers but color normal * Sons: 50% color deficient (anomalous); 50% color normal ![]()

Answer 7

* The X-chromosome typically has one copy of the L-cone opsin gene an one or more copies of the M-cone opsin gene * Intergenetic – * Normal * Dichromacy * Intragenetic – * Normal * Dichromacy * Anomalous trichromacy * Hybrid gene – the basis for anomalous trichromacy

Answer 8

* Inherited Color vision anomalies – * Heterozygous female (xX) is a carrier (x to take place of X with the bar over it) * A male with the defect gene has anomalous color vision (xY) * Because the gene is recessive, a female must be homozygous (xx) to express the color vision anomaly * Note: a son (male) always receives the defective gene from the mother * Patients sometimes incorrectly assume that color anomalies are transmitted from father to son * Acquired color vision anomalies – * Secondary to disease or toxicity * May be either red-green or blue-yellow in nature * Because blue-yellow anomalies are so rarely inherited, it must be assumed that such an anomaly is acquired until proven otherwise * Acquired anomalies may be unilateral or asymmetric

Answer 9

* Must be assumed any difference in the color vision of the two eyes, as demonstrated on a color vision test, is due to an acquired anomaly * Because acquired anomalies may be asymmetric, important to perform color vision tests monocularly when screening for these conditions * If a patient with a unilateral anomaly is tested binocularly, the results may be normal, reflecting the performance of the unaffected eye * The test should be first administered monocularly to the eye most likely to harbor disease

Answer 10

* Rare condition where the patient manifests monochromatic vision; fully expressed at birth * Autosomal Recessive Achromatopsias – common * Two types: * Complete AR Achromatopsia – only rods are present * Incomplete AR Achromatopsia – residual L/M cone function * Signs & Symptoms: * No or very poor color discrimination, nystagmus, photophobia and VA ~20/200 * Differential diagnosis is not always straight forward * Dark red lenses * Minimize rhodopsin bleaching * Recommended for bright light conditions

Answer 11

* X-Linked (XL) Achromatopsia – recessive inheritance * Referred to as Blue or S cone monochromacy * Contain only rods & S cone (though sometimes other cone types can be present) * Clinical signs & Symptoms: * Similar to rod monochromacy * Magenta colored lenses * Minimizes rod saturation * Provide light to enable S cones may provide relief to patients

Answer 12

* Cone Monochromacy – * A rare disorder where VA is normal but patients exhibit monochromatic color matching * Appears to involve a defect in postreceptoral processing of color information * Achromatopsias – retina * Cerebral Achromatopsia – Extrastriate cortex

Answer 13

* Chromatopsias – * Not true color vision anomalies * They do not typically produce a decreased ability to discriminate colors * Represent distortion of color vision * 2 conditions where it can be present: * (1) Cataract Extraction * Perception of blueness (cyanopsia) * (2) Can be secondary to drugs/medications * Digitalis may produce – Xanthopsia (yellow vision) * Fluorescein in fluorescein angiography – xanthopsia

Answer 14

* A neurological phenomenon in which stimulation of ONE sensory or cognitive pathway leads to automatic, involuntary experiences in a SECOND sensory or cognitive pathway * Cortical modules appear to be abnormally linked to each other such that stimulation of one sense results in the activation of another * Increased cross-talk between regions specialized for different functions may account for the many types of synesthesia * In one form of synesthesia, the presentation of a LETTER or a NUMBER results in the perception of a COLOR * For instance, the patient may report the perception of: * Green whenever he/she is presented with the number 5 * Red when presented with the number 9 * Not only can the effect be elicited by physical presentation of a stimulus, there is evidence that the same perception can result without external presentation of the trigger stimulus * The patient may, for example, experience GREEN when asked to perform a mental calculation whose answer is the trigger stimulus (e.g., 4 + 1)

Answer 15

* Another common form of synesthesia is the association of SOUNDS with colors * For some, everyday sounds such as doors opening, cars honking, or people talking can trigger seeing colors * For others, colors are triggered when musical notes and/or keys are being played * People with synesthesia related to music may also have perfect pitch because their ability to see/hear colors aids them in identifying notes or keys

Answer 16

* According to Kollner’s rule, outer retinal disease and media changes result in blue-yellow color vision anomalies, whereas disease of the inner retina, optic nerve, visual pathawys, and visual cortex results in red-green anomalies * This general guideline is not correct in every instance, and important exceptions have been reported * Post receptoral lesions are more likely to affect both the types of cones opponent neuron channels * It is not uncommon for a blue-yellow anomaly to be presen tin the early stages of an eye disease, and change into a red-green anomaly as the disease progresses (the reverse also may happen) * A pt may manifest a nonselective loss

Answer 17

* Based on the knowledge of confusion lines * Color vision testing is the existence of highly predictable confusion lines that allows for clever diagnostic distinction between color defective types * Goals: * Screening – i.e., congenital vs. acquired * Diagnosis – i.e., type and severity * Vocation or occupational testing * Determining protan vs. deutan congenital deficiencies: inability to detect red (protan) can have greater occupational consequences * Focus also on differentiating red-green vs. blue-yellow acquired defects * Red-green – cone and optic nerve disease * Blue-yellow – retinal and choroidal disease

Answer 18

* Ishihara * Sensitive * Protan and deutan defects * HRR * Sensitive * Protan, deutan, tritan, and severity * CVTME – color vision testing made easy \**patterns of objects, letters, or numbers placed on isoluminant backgrounds*

Answer 19

* Color cap tests * Farnsworth-Munsell 100 * Panel D-15 * Lanthony Desaturated D15

Answer 20

* Anomaloscopes * C100 * CUT

Answer 21

* NAMING * E.g., often PIC, but sometimes tests specifically designed for vocation/occupations (Lantern tests) * OCCUPATIONAL COLOR TESTS * Rabin Cone Contrast Test

Answer 22

1. The target/stimulus is defined by a color difference from the background 2. Color differences of the target/symbol straddle confusion lines 3. If the color differences are aligned on or close to the dichromatic confusion lines, the object is invisible to those with certain color deficiencies 1. It serves to detect both types but not to distinguish them 4. CHROMATICITIES OF A “DISAPPEARING PLATE” FROM ISHIHARA’S TEST: 1. The colors of the figure and the background are in the portion of color space, where there is little difference between protans and deutans 2. The colors straddle both confusion lines and the figure will not be seen by either type of CVD 5. Shortcomings: 1. Slower administration for CVD

Answer 23

1. Design intentions: to provide an alternate response for the color vision defectives 2. Contain colors that can be confused with the background and others that are not 3. Those with – 1. Normal color vision – see one thing 2. Color deficiency – see another thing, generally just slightly altered 4. Confirms that the test is understood 5. Prevents the frustration found with blank plates aka ambiguous or alteration plates\*\*

Answer 24

* Incorporates both disappearing and demonstration figures * Color normal: might report 2 figures * Color deficiency: report 1 figure * These plates are useful because there is always something to which the CVD can respond

Answer 25

1. Design: multiple disappearing plates for different color vision deficiencies 2. These disappearing plates have two figures 3. Example: Ishihara one plate that would disappear (be diagnostic) for protans and one for deutans 1. Normal: should see both the 2 and the 6 2. Deutan: type CVD should see 2 more easily, whereas a protan see the 6

Answer 26

* Ishihara * HRR (Hardy-Rand-Rittler) (????)

Answer 27

* Ishihara – sensitive for screening red-green CVD * Published in 1906 – first PIC test in commercial product * Available as 38- and 24- plate editions * Has HIGH SENSITVITY and SPECIFICITY * Useful in children above 5 years * Can perform acceptably even when it is given under the wrong illumination * The figures on each plate are embedded in a random pattern of variably-sized dots * The test comprises a demonstration plate, disappearing, alteration, hidden, and diagnostic plates * The colors of the figure and background are carefully chosen to lie close to confusion lines * Interpretation of 24-plate edition: * As assessment of the readings of plates 1 to 15 determines the normality or defectiveness of color vision * If 13 or more plates are read normally, the color vision is regarded as NORMAL (up to 6 errors) * If only 9 or less than 9 plates are read normally, the color vision is regarded as deficient * However, in reference to plates 14 to 15, only those who read the numerals 5 and 45 and read them easier than those on plates 10 and 9 are recorded as abnormal readings * It is rare to find a person whose recording of normal answers is 14-16 plates * An assessment of such a case requires the use of other color vision tests, including the anomaloscope

Answer 28

* Ishihara – Performance/sensitivity: * The individual plates of Ishihara’s test have sensitivities (in identifying color defectives) and specificities (identifying color-normal) typically between 0.85 and 0.95 * The test as a whole performs “very close to 1” in both sensitivity and specificity implying its excellent in failing color defectives (sensitivity) and passing color-normals (specificity) * There is a tendency for it to * PASS: very mild deutans * FAIL: some normal with poor discrimination (But without being identifiably protan or deutan) * Ishihara PIC test does not distinguish between dichromats and anomalous trichromates (i.e., protanope from protanamalous, deuteranope from deuteranomalous) * But useful in differentiating protan and deutan

Answer 29

* 2 Major Shortcomings (compared to HRR): * (1) Isharaha has no TRITAN plates * (2) Does NOT provide a severity diagnosis * Other shortcomings: * Relatively mildly affected CVDs (protanamalous, deuteranomalous) may make as many errors like dichromats (protanopes, deuteranopes) * Can be memorized as its always presented the same way * Difficult to administer in children younger than 5 years * Does not distinguish between dichromats and anomalous trichromats (i.e., protanope from protanomalous, deuteranope form deuteranomalous)

Answer 30

1. Using the wrong failure criterion leading to misdiagnosis 2. Assuming that patients who make many errors have a “Severe” color vision deficiency 1. Number of errors on the Ishahara test is NOT a measure of severity, except that a very small number of errors may indicate a mild CVD 3. Diagnosing plates to different protan and deutan CVD that are well designed but DO NOT ALWAYS YIELD A DIAGNOSIS 4. Sometimes the diagnosis is WRONG and in 30-40% of cases – NO diagnosis is possible because both numerals are seen or neither is seen

Answer 31

Demonstration plate 1. Plate has luminous reflectance cues and/or color differences that do not lie on confusion line 2. Ex) Ishihara & HRR demo plates 3. Color vision is not necessary for a correct response 4. Useful for demonstration on how the test symbols look 5. Also useful for picking up on malingerers 1. Malingerer – pretends to exaggerates incapacity

Answer 32

* Quantitative plates * A set of plates with increasing color difference * Confusion with small color difference – mild * Confusion with large color difference – moderate/severe * Example: Hardy-Rand-Rittler (HRR) * Hidden-digit plates * Opposite of a disappearance test * Visible only to those with color deficiency * Normals should not see anything, whereas a CVD should see 5

Answer 33

* Contains demonstration, screening, and diagnostic plates * Demonstration plates = 4 plates * Screening plates = 6 plates (2 blue-yellow, 4 red-green) * Diagnostic plates = 14 plates (10 red-green, 4 blue-yellow) * There are 20 test plates, 4 for screening red-green (protan/deutan) CVD, 2 for blue-yellow (tritan/tetartan) CVD * 10 for classifying and assessing the severity of red-green CVD * 4 for classifying and assessing the severity of blue-yellow CVD * N a few cases where the color defective is very mild, a patient may fail to see correctly some of the symbols in the SCREENING PLATES (5-10), but see correctly all symbols in the DIAGNOSTIC PLATES (11-24) * The screening plates must be given a second time with the test book

Answer 34

* Demonstration: * The demonstration plates (1-4) are not scored * Show these demonstration plates in a sequence saying: “I am going to show you some colored symbols. Without touching them, how many do you see? Where are they?” * Unless the patient is malingering or totally color deficient, two colored symbols should be seen on each of the plate 1-2: first demonstration (0X and X∆), one colored symbol (O) on the 3^rd, and no colored symbol on the 4^th demonstration plate * Tell the patient that these symbols may appear in any of the 4 corners of the page * Ask the patient to trace the symbols they see with a small brush * Then say: “The test itself is made up of just three symbols with 2, 1, or 0 on a page. Some of them will be harder for you to see as they may be less strong in color.”

Answer 35

* Interpretation of responses: * A correct response to a plate includes the number, name, and location of all colored symbols on the plate * An error is failure to see all symbols, or an incorrect name of any symbols, or an incorrect location * Normal Color Vision: * A patient who gives correct responses to all 6 screening plates has normal color vision * Testing may be stopped at this point * A patient who makes ONE or MORE errors in the screening plates but NONE in the subsequent diagnostic plates, and upon retesting gives correct responses to all of the screening plates (5-10), has normal color vision in the eye being tested

Answer 36

* Type of Defect: * Red-green deficiency * Protan if the total number of checks in the protan column is greater than in the deutan column * Deutan if the total number of checks in the deutan column is greater than in the protan column * Unclassified as to type of red-green deficiency if the number of checks is the same in the protan an ddeutan columns, or if errors have been made in only the screening plates * Blue-Yellow Deficiency * Tritan if the number of checks in the tritan column is greater than in the tetartan column * Tetartan if the total number of checks in the tetartan column is greater than in the tritan column * Unclassified as to type of blue-yellow deficiency if the number of checks is the same in the tritan and tetartan columns, or if the errors have been made only in the screening series * Extensive scattered errors throughout the various groups of plates may indicate: * Malingnering * Monochromatism – total color blindness * Low color discrimination approaching monochromatism * Extent of Defect: * The HRR test recognizes 3 degrees of extent of defect: * Mild * Medium * Strong * The last group of plates in which error occurs gives the extent of the patient’s color deficiency * For example, in a case of red-green deficiency: * If the last error occurs in either group of plates 7-10 or 11-15 and there are no errors in plates 16-20, the defect is MILD in extent * If the last error occurs in plates 16-18 and there are no errors in plates 19-20, the defect is MEDIUM in extent * If errors occur in plates 19-20, the defect is STRONG * Similarly, in a case of Blue-Yellow Deficiency * If the last error occurs in plates 5-6 and there are no errors in plates 21-24, the defect is MILD * If the last error occurs in plates 21-22 and there are no errors in plates 23-34, the defect is MEDIUM * If errors occur in plates 23-24, the defect is STRONG

Answer 37

* HRR – Screening Plates * When the manufacturer criterion for FAILING, 2 or more errors with the screening plates (i.e., 1 error is allowed) is used: * The Richmond HRR test has a * Sensitivity of 1.00 * In correctly identifying color defectives * Specificity of 0.975 * In correctly identifying color-normal * When the criterion for falling is 3 or more errors with the screening plates * Sensitivity of 0.98 * Specificity becomes 1.0 * HRR – Diagnostic Plate Performance: * Red-Green CVD were * Correctly classified as protan or deutan on 86% of occasions * Unclassified on 11% * Incorrectly classified on 3% * All those graded as having a “mild” defect by the Richmond HRR test – PASSED the Farnsworth D15 test and had an anomaloscope range of 30 or less * Not all dichromats (protanope/deuteranope) were correctly classified as “STRONG” * Those graded as “MEDIUM” and “STRONG” defects – included Dichromats and those who have a mild color vision deficiency based on the results of the Farnsworth 15 test and the anomaloscope range

Answer 38

* Has tritan screening & diagnostic plates * Classifies protan, deutan, tritan and severity * Can be used with very young children because it uses symbols, a circle, a triangle, and a cross * Can often be named or traced by young children before they can read numbers

Answer 39

* Reproduction of plate 20 of the HRR pseudoisochromatic plates (4^th edition) * The circle may not be visible in deuteranopia or deuteranomaly, while the triangle may not be visible in protanopia or protanomaly * Example of a diagnostic plate from the HRR test * The colors of the symbols lie on the Protan and Deutan confusion loci * This means that depending on the saturation fo the color of the symbols and the severity of the color vision deficiency, they MAY NOT BE DISTINGUISHED from the grey dots of the background * They are “Vaninishing” plates (similar to the plates in the Ishihara) * There are also plates where symbols have colors that lie on the TRITAN confusion loci * The tritan plates in the HRR test also have symbols with colors that lie on the so-called Tetartonpia confusion locus but as tetertanopia does not exist, these are not of any value * Does not discriminate dichromacy from anomalous trichromacy

Answer 40

* Holmgren Wool Test – subject is asked to sort colors (e.g., woll yarn, caps) into sequences or groups * Colors have same Munsell values and Chroma and differ by Munsell Hue * 5 Munsell hues: Red, Yellow, Green, Blue and Purple * 5 Hue Subcategories (partitions) – RY, YG, GB, PB, RP, each subdivided into 10 steps (e.g., 1-10 RP), for 100 hues

Answer 41

* The further out from the center, the worse the severity of the CVD

Answer 42

* FM 100 Hue Test in Acquired Color Vision Deficiency * Means of monitoring treatment * Diabetic retinopathy – tritan defect * Retrobulbar neuritis associated with MS * Recovery of red-green defect * Vitamin A deficiency * Recovery of nonspecific hue discrimination loss following oral dose of Vitamin A * The Farnsworth D-15 / Dichotomous D-15 / Panel D-15 / Regular D-15 has been used widely in evaluation of acquired color vision defects * The Lanthony desaturated D15 test is useful for detecting mild acquired color vision deficiencies (where subtle acquired losses occur) * Ex: cataract, glaucoma

Answer 43

* Deuteranomalous error reduction * Recovery of nonspecific hue discrimination loss following oral dose of vitamin A

Answer 44

* The D-15 has been widely used in the evaluation of acquired color vision defect

Answer 45

* The D-15 Test: * Designed to “distinguish the functionally color blind from the moderately color defective and the normal” (hence called dichotomous) * The D-15 has been widely used in the evaluation of acquired color vision defect * Strengths: * Spacing of the colors along confusion lines makes it relatively * Easy test to pass for normal trichromats * Many anomalous trichromats * BUT almost all dichromats fail * The test has good test-retest reliability for pass/fail with a coefficient of reliability of between 0.96 and 1.0 * MOST CLINICALLY USEFUL TEST * Allows to discriminate protan, deutan, and tritan defects * Weakness: * Although it allows to discriminate protan, deutan, and tritan defects, it does NOT allow to discriminate between dichromacy and anomalous trichromacy * Has low sensitivity – hence some subjects with Mild defects (anomalous trichromacy) may pass the test

Answer 46

* Dichotomous pass/fail results, where those with failure may have problems with some day-to-day tasks and occupations * The Farnsoworth D15 test was designed to classify patients into those who are likely to experience difficulties with their color vision and those who are not * A patient arranges 15 colored caps in a tray with a fixed reference cap at one end * Each successive cap is the closest (similar) match to the one that preceded it * Farnsworth D15 categorizes patients with abnormal color vision into one of two categories… Those who: * PASS and have mild color deficiency * FAIL and have a moderate-to-severe deficiency * The primary use of the D15 is categorization into Mild and Moderate/Severe * Failure is based on number of crossings: 2 or more crossings is deemed as FAILURE * The orientation of the diametrical CROSSINGS gives information on the type of CVD * It can be relied on for classification by type when there are diametrical crossings * Was originally designed to set a level of difficulty such that those who passed it would be able to identify the colors of wires used in transformers * Some clinicians presume that hose who pass the Farnsworth D15 test have a mild deficiency that is unlikely to cause significant handicap in everyday color tasks * This is not entirely true! * While many of those who pass the D15 test can recognize the colors of signal lights and recognize complex surface color codes, a good number cannot

Answer 47

* Failing Ishihara = red-green color deficiency * Can be anomalous trichromat or dichromats * But if there are no errors on the Farnsworth D15 test, there is no indication of whether the protan or deutan variety is present * So in this case it indicates anomalous trichromacy (protanamlous/deuteranamalous) * Protanopes and deuteranopes, as well as extreme anomalous trichromats (who are nearly dichromatic or severe), fail both the Ishihara and Farnsworth D15 tests, and their error axes are diagnostic of these conditions

Answer 48

* Standard D15: * Munsell Value: 5 * Munsell Chroma: 4 * VARIES IN HUE * Lanthony Desaturated D15: * Munsell Value: 8 * Munsell Chroma: 2 * VARIES IN HUE * So the color differences are substantially smaller than D15

Answer 49

* 100 caps with colored papers, 1.5˚ from eye to desktop * 85 caps – 15 removed to create relatively equal just noticeable differences between caps * 4 trays * Tray 1: 22 caps * Tray 2-4: 21 caps * Form Hue Circle in CIE * Typically used under standard Illuminant C (daylight) * Total Error Score (TEST) plotted in score sheet * Error Score (TES): indicates severity of the defect * Midpoint indicates the type of color vision defect * Cap score (for each cap) – sum oof differences between neighboring caps

Answer 50

* Length of test – time consuming (used rarely) * Doesn’t distinguish dichromacy from anomalous trichromacy (i.e., protanope vs. protanomalous)

Answer 51

* Provides a means of monitoring color vision changes & treatments

Answer 52

* Identical to Farnsworth D15, except the color caps are much less saturated than D15 * Detects anomalous trichromacy (sensitive test) * A higher level of illuminance than any other test (600 to 800 lux) is specified * CVD subjects passing the D15 may, as expected from the smaller color differences, FAIL the lanthony D15 * Small color differences of Lanthony D15 lead to normal making minor transpositional errors * This tends to blue the distinction between normal and abnormal

Answer 53

* ONLY CLINICAL INSTRUMENT that can provide a complete diagnosis of Red-Green color vision anomaly including differential diagnosis of DICHROMACY from ANOMALOUS TRICHROMACY: Nagel Anomaloscope

Answer 54

* Gold Standard: Nagel Anomaloscope * Bipartite field viewed through an eye-piece * Diagnoses the 4 major X-linked color defects

Answer 55

* Mixture field – the upper half: consists of red and green wavelengths * Mixture scale setting 0 to 73 represent various combinations of 546 (green) to 670 (red) * Test field – lower half: consists of a fixed yellow test field * Test field knob setting 0-35 varies test field yellow Brightness/Luminance * Observer: the task of the observer is to adjust the wavelengths of red and green primaries on the Mixture field, to match the brightness and color of the yellow test field so that they both appear identical (Metameric match) * The observer’s red-green balance can be used to distinguish a red-green dichromacy from anomalous trichromacy * Nagel primaries: fall along protan and deutan lines of confusion and it constitutes Rayleigh Equation * New Nagel anomaloscope can detect TRITAN! * Unlike the old Nagel anomaloscope’s, where none of the 3 primaries were absorbed by the S-cones \*\*primary one tested on

Answer 56

* Based on the Rayleigh equation for Protan/Deutan: * Red + Green = yellow * E.g., 670.8 + 546 = 589.3 nm (Nagel) \*\*don’t worry about this equation * Based on Moreland equation for Tritan: * Blue + Green = blue-green

Answer 57

* Mixture Field: * Setting: 0-45 * Appearance in Normal Trichromacy: Green (0) to yellow (45) * Test Field: * Setting: 17 * Appearance in Normal Trichromacy: yellow

Answer 58

* Mixture Field: * Setting: 45-73 * Appearance in Normal Trichromacy: yellow (45) to red (73) * Test Field: * Setting: 10 * Appearance in Normal Trichromacy: dim yellow

Answer 59

* Mixture Field: * Setting: any setting from 0 to 73 will be matched * Appearance in Normal Trichromacy: Green (0) to yellow (45) to red (73) * Test Field: * Setting: 17 * Appearance in Normal Trichromacy: yellow

Answer 60

* Mixture Field: * Setting: any setting from 0 to 73 will be matched * Appearance in Normal Trichromacy: Green (0) to yellow (45) to red (73) * Test Field: * Setting: 35-5 * Appearance in Normal Trichromacy: bright to dim yellow

Answer 61

* When a color-normal views a protanomalous match, the color mixture will look red

Answer 62

* When a color-normal views a deuteranomalous match, the color mixture will look green

Answer 63

* The color will look more red because deuteranomalous trichromats are green deficient

Answer 64

* the initial appearance will look more green because protanomalous trichromats are red deficient

Answer 65

* 0 to 45 = deuteranomalous * 45 to 73 = protanomalous * \*note protanomalous and protanope individuals will also want to adjust the brightness setting of the test field – often lower brightness

Answer 66

* Nagel anomaloscope is capable of determining: * Anomalous trichromats from normal trichromats * Dichromats from anomalous trichromats

Answer 67

* Macular pigment and crystalline lens variability

Answer 68

* Flicker matching (rapid alternation) of Red (659) and Green (560) using dual light emitting diode * Subject controls luminance ratio of red and green * Reliably distinguishes: protans from normal * Does not distinguish deutans from normal

Answer 69

* Book format (appearance of pseudoisochromatic plate test – but not classified as so) * Because of this design – not strictly/purely a color matching test, but it incorporates D15 hues mimicking an arrangement test (but not classified so) * Task: match the central hue with one of the peripheral hue (which appears similar) * Of the 5 hues, one choice is the adjacent D15 hue, one each lies on each of the protan, deutan, and tritan confusion loci * Forced Choice Procedure test – subject is forced to match a color/response for each plate (as opposed to having nothing visible) * Psychophysical procedure * Similar difficulty to the D15 and can be an alternative

Answer 70

* Neither are commercially available * Farnsworth Lantern – 2 light lantern for US navy, with Red, Green and White * Stereo Optical OPTEC 900 – used in US military, FAA

Answer 71

* D15 * Lantern Tests * The Rabin Cone Contrast Test (CCT)

Answer 72

* D15 * Lantern Tests * The Rabin Cone Contrast Test (CCT)

Answer 73

* Gold standard/sole CV test for US air force and US military * Detects severity of cone deficiency and congenital color deficiencies * Unlike other CV tests: Rabin Cone test measures the severity of cone function loss, and tracks cone function over time, aiding in the detection of disease and monitoring disease progression and efficacy of treatment

Answer 74

* ARMD, Glaucoma, Diabetic Retinopathy, MS, Parkinson’s disease, TBI, Retinal Toxicity due to high-risk meds such as Plaquenil

Answer 75

* Rabin CCT Stimulus * FM-100 Hue Test * Nagel Anomaloscope * Insurance – separate CPT code (92283) $47 technical + 9 professional ~$56 reimbursement * Other CV tests (HRR/Ishihara) – charged with the eye exam

Answer 76

* Light grayish purple (mauve) -\> gray * Pink -\> gray * Green -\> white * Green -\> gray * Light yellowish brown (beige) – green * Dark purplish red (maroon) – brown * Olive – brown * Light green – light yellow * Light green – light orange * Light yellow – light orange * Light yellowish green (chartreuse) – pink * Light purple – light blue * Light orange – light red

Answer 77

* Illuminant C or MacBeth Lamp – not readily available * FM 100, Regular D-15, Lanthony D-15 – strictly Illuminant C * Indirect sunlight * Screening: Ishihara – performs well in room lighting and sometimes even in incorrect illumination * HRR – okay to perform in room lighting – away of variable results that may pass mild color defectives * Non-standard fluorescent tube – Varilux F15T8/BLX – advisable * Not advisable lighting: * Standard fluorescent * Unfiltered incandescent source – patient may perform better due to varying luminance profile * Incandescent source should be used with appropriate (blue) filters

Answer 78

* Practitioners should never rely on a single color vision test regardless of the color vision standard * Lighting/illumination for testing * Lighting should be color temperature (Tcp) 6500 K and color-rendering indices (Ra) should be greater than 90 (Ra \> 90) * Illuminance levels should be between 200 and 30 lux if detection of color vision deficiency is a priority or between 300 and 1000 lux if the need is to tes tat the level where illuminance has minimal influence on performance * Illuminance should be reported when testing color vision * Time limits should be set between 1 and 2 minutes * Repeat testing (beyond the specified test and one retest) should be carried out only with authorization * Initial and repeated results should be reported

Answer 79

* Stable, no threat to vision * Children should be screened at pre-school level * Parents and teachers informed * Parents counseled about career choices (airline pilot, firefighter) * May have difficulties distinguishing colors in dull illumination

Answer 80

* HRR (Richmond 4^th edition) * Standard Pseudoisochromatic Plate Test (SPP-2) * SPP-1 * Tests for red-green defects * SPP-2 * Tests for blue-yellow defects * D-15 Tests * SWAP or Moreland Anomaloscope * These tests are to establish baseline data during first visit and are to be performed monocularly with the worst eye first

Answer 81

* \*\*conditions that are exceptions to Kollner’s Rule * Blue-Yellow acquired anomalies: * Glaucoma \*\* * Diabetes * Retinal detachment * Age-related maculopathy * Chorioretinitis * Central serous retinopathy * Papilledema * Hereditary autosomal dominant optic atrophy * Red-Green Defects: * Optic neuritis * Papillitis * Leber’s optic atrophy * Toxic amblyopia * Lesions of the optic nerve and pathway * Dominant cystoid macular dystrophy \*\* * Hereditary juvenile macular degeneration \*\* * Fundus Flavimaculatus \*\*

Answer 82

* Red-Green Defects: * Antidiabetics (oral) * Tuberculostatics * Blue-Yellow Defects: * Erythromycin * Indomethacin * Trimethadione * Chloroquine derivatives * Phenothiazine derivatives * Red-Green and/or Blue-Yellow Defects: * Ethanol * Cardiac glycosides (digitalis, digitoxin) * Oral contraceptives

Answer 83

* Yes * Certain non-neutral tints (other than grey) may make it difficult * Tinted lenses should not be recommended to CVD * Protan anomalies have been associated with increased rear-ended automobile accidents

Answer 84

* Determine the type of color vision defect and occupational needs of the patient * Explain the nature of the defect (inherited/acquired) * Seek family history if inherited * Inform probability of their child/grandchild being color vision defective * Depending on defect type, explain the consequences of day-to-day living (like driving) * Explain that CVD cannot be treated, but can be HELPED with filters while performing specific tasks * But the Enchroma Glasses don’t work for everyone * Caution on career choices * Recommend avoidance of driving with sunglasses * Caution them about driving at night in new towns/cities where streetlights may blend into traffic lights

Answer 85

* Inform the teacher * Counsel parents about the career choices

Answer 86

* Filters cannot fully correct CVDs – but some pt’s may benefit from colored filters * If the color defective has well defined and predictable problems with specific colors, it is relatively straightforward to introduce a colored filter that can exaggerate the brightness differences of two colors * Example: red-green confusions can be viewed with a red filter to make the red object become relatively brighter, thereby distinguishable * Selective filtering of the most desaturated colors for color defectives may enhance the appearance of an otherwise dull scene * Colors that fall on the confusion lines of dichromats can be moved off them * However, it should always be assume that the discrimination of some other colors has been reduced by adding this filter * Nonetheless, in an environment or workplace in which a limited number of important colors must be distinguished from each other, there is a good application of filters for color defectives

Answer 87

* There is a theoretical possibility that the brain of the color defective could learn to interpret this differential information in a way that leads to an increase in color discrimination abilities overall * However, this does not occur (or vary rare) in practice

Answer 88

* NO * Use of colored filters to help an individual pass an Ishihara test / HRR cannot be construed as overall improvement in color vision – it is like allowing an individual to stand closer to the acuity chart so that he can read the 20/20 line * The result is misleading

Answer 89

* NO – it could impair depth perception and possible confusion/interference with perceiving traffic lights

Answer 90

* X-chrom lens is a red contact lens worn on one eye * Designed to improve color discrimination in dichromats and anomalous trichromats * It is a long-pass filter, blocks shorter wavelengths and transmits longer wavelengths * There is a deuteranomalous error reduction and recovery of nonspecific hue discrimination loss following oral dose of Vitamin A on F100 Test

Answer 91

* Some patients suppress the eye that has the contact lens, others tend to fuse the image * Based on improved performance on the pseudoisochromatic plate tests, it has been claimed that the x-chrome lens improves color vision * Same claim has been made when viewing binocularly through large colored filter * This does not indicate improved color discrimination * Red contact lens use is questionable * A handheld red filter may be helpful to some patients * Counseling: parents, adults – restrictions in certain occupations, about alternate careers

Answer 92

* Replacement of defective gene in color blindness offers promise to cure color blindness * Animal studies (mice, monkeys) have shown that it is possible to confer color vision by injection a gene of the missing photopigment using gene therapy * Improved color vision in dichromatic monkeys by injecting the virus carrying the opsin gene * Further work needed to demonstrate the efficacy and safety of such an approach in humans

Answer 93

* Recombinant adeno-associated virus (rAAV) = vector * cDNA of opsin gene found in the L or M cones can be delivered to a fraction of cones via subretinal injection * effects lasts until the cones die or the inserted DNA is lost within the cones * not attempted in humans yet – but should be feasible for humans eventually

Answer 94

* SWAP = short wavelength automated perimetry * The S cone (blue-yellow pathway) is more vulnerable to certain pathological conditions like Glaucoma * SWAP has been developed to detect early glaucoma by isolating S-system function * Humphrey visual field apparatus can be adapted by replacing standard white stimulus with a short wavelength stimulus to maximize S cone sensitivity & yellow background to suppress (adapting) L & M cone systems * SWAP – sensitive measure of glaucomatous nerve damage