ANOMALOSCOPE. User s Manual

Transcription

1 ANOMALOSCOPE User s Manual

2 Foreword Anomaloscope User s Manual This User s Manual shows how to examine red/green colour vision by means of the Rayleigh equation, and blue/green colour vision by means of the Moreland equation, using the OCULUS HMC Anomaloskop. The unit is controlled via PC by means of a graphic user interface. The procedures described here can be adopted for any anomaloscope that meets DOG quality assurance requirements (DOG : Commission for quality assurance of sensory physiology examination methods and equipment: Ophthalmology : ), e.g. the Heidelberg Anomaloscope, the Neitz Anomaloscope, the Spectrum Colour Vision Meter, and the Nagel Anomaloscope. The specific, individual diagnostic situation must be taken into account when implementing the described methods. To adopt skills and practice and to achieve reproducible results, we recommend that you initially examine 10 people with normal colour vision and 10 patients with an already established diagnosis (anomalies and anopias) following the instructions given in the User s Manual. Colour vision examination courses are held, e.g. at the AAD in Düsseldorf, during the Basic Science Course in Ophthalmology in Munich, during the FUN Course in Tübingen, during the Course "Function meets morphology" in Munich, and upon special request, by the company OCULUS. To ensure the correctness of the information, the following text has been carefully reviewed by Dr. Chr. Kahlert, Chemnitz, formerly Mannheim and Heidelberg, by Dipl.-Ing. R. Kirchhhübel, Dipl.-Ing. J. Sapauschke, M.Sc. N. Mothes and Dipl.-Ing. S. Schultze-Lutter, Wetzlar. However, the author and co-workers cannot accept responsibility for errors in application or erroneous conclusions drawn from any result achieved by anomaloscope examinations. We welcome any feedback and questions: Please contact Hermannkrastel@msn.com. For any questions regarding the device technology, software, networking, please contact info@oculus.de Person responsible for the content: Hermann Krastel, Dr.med., Prof.apl., Medicine. University of Heidelberg, Mannheim Medical Faculty, Consultant, Dept. of Ophthalmology, Mannheim, Germany Layout and printing: OCULUS Optikgeräte GmbH, Wetzlar, Germany Vers. March 2015, Copyright 2015 OCULUS Optikgeräte GmbH, Wetzlar, Germany Anomaloscope User s Manual (B/47700/1115/en)

3 Table of Contents Table of Contents 1 HMC-Anomaloskop: Control and Display Functions Rayleigh Equation (Red/Green) Rayleigh Equation: Graphic Presentation in the Pitt Diagram Rayleigh Equation: Results for Congenital Red/Green Deficiencies White Adaptation in the Eyepiece s Optical Path for Better Colour Differentiation: Neutral Adaptation Inside Neutral Adaptation to Determine the Absolute Matching Range Preparing the Examination "Coaching Plate": Patient Training Rayleigh Equation, Standard Examination: Preparation Examination Starting the Examination Rayleigh Equation Flow Chart: Evaluation of Congenital Red/Green Deficiencies Examination: Deuteranomaly Deuteranomaly "DA": Green Deficiency Examination: Protanomaly Protanomaly "PA": Red Deficiency Anomaly Quotient AQ Definition Anomaly Quotient AQ: Pitt Diagram and AQ Examples Absolute Matching Range: From Sharp Setting to Extreme Anomaly Which Matching Range is Significant for the Anomaly Quotients? Examination: Deuteranopia, Protanopia, Achromatopsia Deuteranopia (D): Lack of Middle Wavelength Sensitive Cones Protanopia (P): Lack of Long Wavelength Sensitive Cones Rod Monochromasy (RMC) = Achromatopsia: Lack of All Cones Loss of Brightness in Protan Colour Deficiencies, Cone Disease and Achromatopsia Rayleigh (Red/Green) Documentation of Results Documentation of the Anomaloscope Examination and The Results Acquired Colour Deficiencies Characteristics of Acquired Red/Green Deficiencies Moreland Equation (Blue/Green): Principle Moreland Equation (Blue/Green): Graphic Presentation of the Moreland Diagram...28 Anomaloscope User s Manual (B/47700/1115/en)

4 Table of Contents 11 Preparing the Examination "Coaching Plate": Patient Training Moreland Equation, Standard Examination: Preparation Examination Moreland Equation Flow Chart Moreland Equation (Blue/Green): Documentation of Results Moreland Equation (Blue/Green): Blue Colour Vision Deficiencies Form for Documentation of the Anomaloscope Examination and Recording of Results...33 Anomaloscope User s Manual (B/47700/1115/en)

5 1 HMC-Anomaloskop: Control and Display Functions 1 HMC-Anomaloskop: Control and Display Functions Eyepiece for focussing: Range sph. +/- 6 dpt Inside: Colour examination field and white adaptation field Data entry and selection of the examination mode. On the Pitt diagram: Manoeuvring of the red/green mixture and the yellow brightness for determination of matches and matching ranges 5 2 Display of patient and examination data; Results in scale units and anomaly quotients 3 Pitt diagram: The interactive graphic interface guides you through the examination and displays the results. 4 Display of the view seen by the patient: Colour examination field alternating with white adaptation field 6 Response button "match" 7 Control knobs for the red/green mixture (top) and for the yellow reference light (bottom). These can be used by patients with high sensitivity for final matching. 8 Response button "no match" Anomaloscope User s Manual (B/47700/1115/en) 1 / 36

6 2 Rayleigh Equation (Red/Green) 2 Rayleigh Equation (Red/Green) Rayleigh equation: Additive mixture (top): Green (545 nm) + Red (666 nm) = Yellow (589 nm) The mixture can be varied to obtain a match with the yellow shown at the bottom Bottom: Spectrally pure yellow The brightness can be varied to obtain a match with the red/green mixture in the top field. 2 / 36 Anomaloscope User s Manual (B/47700/1115/en)

7 2 Rayleigh Equation (Red/Green) 2.1 Rayleigh Equation: Graphic Presentation in the Pitt Diagram Diagram and graphic interface as the guiding tool for the examination and for documentation of the results X-axis: 73 Scale units of the mixture of pure green (0) via normal midmatch (40) to pure red (73) Y-axis: brightness of the yellow reference field. Anomaloscope User s Manual (B/47700/1115/en) 3 / 36

8 2 Rayleigh Equation (Red/Green) 2.2 Rayleigh Equation: Results for Congenital Red/Green Deficiencies Fig. 2-1: Pitt diagram (Rayleigh equation) View of the settings for the normal observer. For clarity s sake, the coloured examination field presentations with the perceptions of the normal observer are shifted upward on the Y-axis P P Protanopia PA Protanomaly D D Deuteranopia DA Deuteranomaly PA and DA line segments indicate matching ranges of individual subjects RMC Achromatopsia = Congenital total colour blindness (= Rod Mono- Chromasy) M Normal mid-match 40 / 15 Normal matching zone 34 to 46 / 16 to 14 (Red-green mixture / yellow reference field) 4 / 36 Anomaloscope User s Manual (B/47700/1115/en)

9 2 Rayleigh Equation (Red/Green) 2.3 White Adaptation in the Eyepiece s Optical Path for Better Colour Differentiation: Neutral Adaptation Inside Continuous observation through the eyepiece OCULUS Heidelberg Anomaloscope OCULUS HMC-Anomaloskop Automatic alternation between colour field 5 s / and white field 3 s: Achieves neutral adaptation The standard examination during neutral adaptation determines the "absolute matching range". Green/red ratios are calculated from the matches obtained during neutral adaptation: The anomaly quotients (AQ), sect. 7, page 14. The "relative matching range" is determined by observation of the examination field for a longer duration: Observation for 15 s or continuously to check for "Umstimmung" (shifting of the match and possible extension of the matching range due to colour adaptation). Anomaloscope User s Manual (B/47700/1115/en) 5 / 36

10 2 Rayleigh Equation (Red/Green) Neutral Adaptation Outside: Patients must switch from outside observation to inside observation External, white adaptation field Nagel Anomaloscope Neitz Anomaloscope Without neutral adaptation, "Umstimmung" can occur with shifting of the match and extension of the matching range. The result is generally less favourable for the patients. 6 / 36 Anomaloscope User s Manual (B/47700/1115/en)

11 2 Rayleigh Equation (Red/Green) 2.4 Neutral Adaptation to Determine the Absolute Matching Range Absolute matching range: Neutral adaptation. Continuous switching between the white adaptation field (3 s) and the coloured examination field (5 s) Examination principle: Localization. Do a check scan for localization of the match. Then do a fine scan for identification of the match. Refer to the flow chart for more information (example below shows deuteranomaly): Show the normal mid-match (40/15) The first question is an open option one: "Which colour(s) do you see?" The next questions are "forced choice": "Which half looks redder? "Where is it brighter?" Adaptive strategy: The next presentation is changed based on the result, until the patient sees the top and bottom halves to be equal in brightness and colour (page 8 and flow chart page 11). The example below illustrates the time frame of a check scan on a patient with deuteranomaly. Anomaloscope User s Manual (B/47700/1115/en) 7 / 36

12 3 Preparing the Examination 3 Preparing the Examination 3.1 "Coaching Plate": Patient Training Rayleigh Equation White will be shown at intervals. This needs no comment. It helps you to recognize the colours more easily. This page may be copied or scanned for patient training purposes. 8 / 36 Anomaloscope User s Manual (B/47700/1115/en)

13 3 Preparing the Examination 3.2 Rayleigh Equation, Standard Examination: Preparation Choose: Manual examination, absolute matching range Check that the patient is actually using the eye that is to be examined Show a setting of 70 / 30 (R/G mixture / yellow reference field), so that any observer, colour-deficient or not, can recognize the horizontal horizontal line between the two test fields and understands the examination field structure. Sharply focus the horizontal line between the two test fields by turning the eyepiece. If the refractive error exceeds + / - 6 dpt sph, or 1.5 dpt cyl, the patient has to wear his or her own correction lenses. No tinted spectacles, no tinted contact lenses (a tinted IOL is an integral part of the eye and should be noted in the results) Explain the examination procedure and its goal ("coaching plate", page 8) Examine both eyes. Proceed as described in "Starting the Examination" (page 10) and then follow the flow chart (page 11) Anomaloscope User s Manual (B/47700/1115/en) 9 / 36

14 4 Examination 4 Examination 4.1 Starting the Examination Your subject has failed the pseudoisochromatic plates: Start the examination by showing the normal mid-match (40/15): Your first question has an open option response: "Which colour(s) do you see?" All subsequent questions have defined "forced choice" answers, whereby you follow the flow chart sect. 4.2, page 11. Self-setting by the patient is not objective enough. The settings are chosen by the examiner. "Which half of the field is brighter? Top? Bottom?" Which half is redder (orange)? Which half is greener? Top? Bottom?" Then adjust the settings accordingly. Do a check scan in steps of 10 scale units along the mixture axis to get an approx. localization of the matches Then do a fine scan in steps of 1 scale unit to get the exact localization of the match and to demarcate the matching range. If the patient s responses are hesitant, it means that the perceptible differences are minor. Encourage the patient: He or she is getting close to a match. Examine both eyes. Minor side differences may appear in congenital defects too. Significant side differences however, are indicative of an acquired colour vision deficiency. For your information: Acquired colour vision deficiencies may affect both eyes as well. 10 / 36 Anomaloscope User s Manual (B/47700/1115/en)

15 4 Examination 4.2 Rayleigh Equation Flow Chart: Evaluation of Congenital Red/ Green Deficiencies Anomaloscope: Manual Mode, Absolute Matching Range Patient failed the pseudoisochromatic chart test Show normal mid match: 40 / 15 Ask what colour the mixing area (top half) is Patient training by coaching plate "Red at top" = reduced perception of the green content of the R / G - mixture: Green deficiency = Deuteranomaly Green at top" = reduced perception of the red content of the R/G mixture: Red deficiency = Protanomaly "Top resembles bottom": No red /green distinction. In Protanopia and Deuteranopia any red + green mixture is accepted including the normal midmatch Check Scan: In steps of 10 increments towards "0" on the mixture scale until patient sees "green at top". Adjust brightness as necessary. Fine Scan: in steps of 1 increment between the last red at top and the first "green at top" to determine the patient s individual match or matching range Convert increments of the match and matching range into AQ values: AQ 2.0 to 20: Deuteranomaly. If the matching range includes the AQ or AQ 1.0 : Extreme Deuteranomaly Check Scan by steps of 10 units towards mixture scale reading 73. Any setting of mixtures requires brightness matching prior to colour rating. Stop with first "red on top" Fine Scan by steps of 1 unit between the last "green on top" and the first "red on top". Any setting of mixture requires a brightness match before asking for colour appearance and assessing of the individual match and matching range Conversion of match and matching range scale units into AQ values: > AQ 0,7 to 0,1: Protanomaly. Range including AQ 0 or AQ 1,0: extreme Protanomaly. Take notice of brightness loss towards red Protanopia is discerned from Deuteranopia by the brightness slope of matches: protans show brightness loss towards red Mixture 73 fits to yellow of appr. 13 Mixture 0 fits to yellow of appr. 17. Deuteranopia: Moderate or none brightness loss Mixture 73 fits to yellow of appr. 4 Mixture 0 fits to yellow of appr. 30. Protanopia: distinct brightness loss towards red In protanopia and deuteranopia obtain exact brightness match first. Thereafter ask for colour match The settings must be made by the examiner, as a matter of principle. When the mixture is sharply focussed, the observer can adjust the yellow brightness. As an exception to the rule, if there is only one turning point (matching range 0), the patient may finely adjust the mixture. If anopia is suspected (colour charts not read, normal mid-match or adjacent match accepted), the acceptance of the two threshold match settings consisting of mixture 0 and mixture 73 is adequate for diagnosis of the anopia. Only the brightness must now be adjusted for each of these mixtures. Patients with anopia tend to refer to differences in brightness as differences in colour. Obtain the exact brightness match first and then ask for the colour match. If, after matching the brightness, only a threshold match setting is accepted, the patient suffers from an extreme anomaly. Then proceed as described in Anomaly. Anomaloscope User s Manual (B/47700/1115/en) 11 / 36

16 5 Examination: Deuteranomaly 5 Examination: Deuteranomaly 5.1 Deuteranomaly "DA": Green Deficiency Fig. 5-1: Settings as observed by deuteranomalous patients For clarity s sake, the colour presentations of the perceptions of the deuteranomalous observer are shifted upward on the Y-axis Deuteranomaly: Deviating, weaker red/green distinction without loss of brightness The red/green mixture (top field) at normal mid-match is seen as "redder" because it s green content is perceived too weakly. (Green deficiency = Deuteranomaly). Sometimes the patient will give complementary colours as his response, i.e. he will say, for example, "greenish at the bottom" instead of "reddish at the top". Patients suffering from deuteranomaly need more green to arrive at their individual match to yellow. The line segments in the DA area indicate the matching ranges of individual patients. 12 / 36 Anomaloscope User s Manual (B/47700/1115/en)

17 6 Examination: Protanomaly 6 Examination: Protanomaly 6.1 Protanomaly "PA": Red Deficiency Fig. 6-1: Settings as observed by protanomalous patients For clarity s sake, the colour presentations of the perceptions of the protanomalous observer are shifted upward on the Y-axis Protanomaly: Deviating, weaker red/green distinction with loss of brightness towards red The red/green mixture (top field) at normal mid-match is seen as "greenish" because it s red content is perceived too weakly. (Red deficiency = Protanomaly). Sometimes the patient will give complementary colours as his response, i.e. he will say, for example, "reddish at the bottom" instead of "greenish at the top". Patients suffering from protanomaly need more red to arrive at their individual match to yellow. The loss of brightness for red is a distinct characteristic of protanomaly. The line segments in the PA area indicate the matching ranges of individual patients. Anomaloscope User s Manual (B/47700/1115/en) 13 / 36

18 7 Anomaly Quotient AQ 7 Anomaly Quotient AQ 7.1 Definition The anomaly quotient AQ indicates the green/red ratio. AQ < 0.7 to 0.1 : AQ > 1.4 (mostly > 2.0) to (mostly up to max. 20): AQ 0.7 to 1.4 : AQ up to or down to 0, or including the normal mid-match: Protanomaly Deuteranomaly Normal matching zone Extreme anomaly In the past: AQ calculation with AQ slide rule, or by means of the formula: AQ = [(73 P) : P] / [(73 M) : M] P = Individual match of the anomalous observer: Mixture scale reading M = Normal mid-match of the anomaloscope, scale units of the mixture (mostly 40) 73 = Mixture scale reading with 0% green content Today: The AQ values are automatically displayed by the device at the end of the examination. The anomaly quotient says nothing about the yellow reference light. The yellow brightness is just supplementary information: The loss of brightness towards red characterizes protanomaly deficiencies. 14 / 36 Anomaloscope User s Manual (B/47700/1115/en)

19 7 Anomaly Quotient AQ 7.2 Anomaly Quotient AQ: Pitt Diagram and AQ Examples Sport boat navigator s licence: Normal colour vision with AQ and deuteranomaly with AQ up to 6.0 are permitted Pilot s licence, Classification I and II: Normal trichromasy is necessary; deviation from the normal mid-match must not exceed 4 scale units. Classification III: AQ allowed. Anomaloscope User s Manual (B/47700/1115/en) 15 / 36

20 7 Anomaly Quotient AQ 7.3 Absolute Matching Range: From Sharp Setting to Extreme Anomaly Marking of the matching range For protanomaly and deuteranomaly: Turning point: < 1 Scale unit Sharp setting: Precise setting: Extended setting: Inaccurate setting: 1 Scale unit 2 to 5 Scale units 6 to 10 Scale units > 10 Scale units Extreme anomaly: The range includes either 0, or 40, or 73 scale units. 16 / 36 Anomaloscope User s Manual (B/47700/1115/en)

21 7 Anomaly Quotient AQ 7.4 Which Matching Range is Significant for the Anomaly Quotients? Matching range: First to last value of the green/red mixtures, which the patient sees as being equal to yellow. Absolute matching range in neutral adaptation: Significant for AQ. (Absolute matching range: Regular alternation between the coloured field and the white field (5 s/ 3 s) ) Qualification and certification guidelines define anomaly quotient limits, which must not be exceeded (deuteranomaly) or fall below the minimum value (protanomaly). Therefore, to assess qualification or suitability, the AQ that lies farthest from the normal must be stated (threshold value, see example below): The scale units of the red/green mixture (top numerals) correspond to the AQ values of 3.0 to 5.1. The relevant AQ threshold value for qualification/ certification is 5.1. The bottom numerals define the yellow brightness. These do not enter into the anomaly quotients. Anomaloscope User s Manual (B/47700/1115/en) 17 / 36

22 8 Examination: Deuteranopia, Protanopia, Achromatopsia 8 Examination: Deuteranopia, Protanopia, Achromatopsia 8.1 Deuteranopia (D): Lack of Middle Wavelength Sensitive Cones Deuteranopia: Explained graphically in the Pitt diagram Fig. 8-1: For clarity s sake, the colour presentations of the perceptions of the deuteranopic observer are shifted upward on the y-axis In deuteranopia, the colours green, yellow and red appear as yellow with little difference in brightness. For diagnosis, the acceptance of the normal mid-match as well as matches at both threshold mixture settings, namely 0 and 73, is adequate. The brightness adjustment must be done with extreme care, as otherwise, the patients tend to make misleading statements about differences in colour. Obtain the exact brightness match first and then ask for the colour match. 18 / 36 Anomaloscope User s Manual (B/47700/1115/en)

23 8 Examination: Deuteranopia, Protanopia, Achromatopsia 8.2 Protanopia (P): Lack of Long Wavelength Sensitive Cones Protanopia: Explained graphically in the Pitt diagram. Fig. 8-2: For clarity s sake, the coloured presentations of the perceptions of a patient with protanopia are shifted upward on the y-axis In protanopia, the coulours green, yellow and red are all seen as yellow, but with great differences in brightness. - Green as pale yellow, - Yellow as yellow, - Red as dark yellow ("brown"). For diagnosis, the acceptance of the normal mid-match as well as matches at both threshold mixture settings, namely 0 and 73, is adequate. Due to the loss of brightness towards red, every green/red mixture needs an individual brightness match with the yellow of the reference field. The brightness adjustment must be done with extreme care. The patients tend to refer to differences in brightness as differences in colour. Obtain the exact brightness match first and then ask for the colour match. Anomaloscope User s Manual (B/47700/1115/en) 19 / 36

24 8 Examination: Deuteranopia, Protanopia, Achromatopsia 8.3 Rod Monochromasy (RMC) = Achromatopsia: Lack of All Cones Rod Monochromasy: Explained graphically in the Pitt diagram Rayleigh matching in rod monochromasy depicts the long wavelength flank of rhodopsine absorption. Deep red stimuli are neither seen as red, nor seen at all, because nm of the visual purple is not absorbed in the rods. In achromatopsia, due to the loss of brightness for red, the red visual field is either missing completely or is greatly limited, depending on the wavelength of the red stimulus in the perimeter in question. 20 / 36 Anomaloscope User s Manual (B/47700/1115/en)

25 8 Examination: Deuteranopia, Protanopia, Achromatopsia 8.4 Loss of Brightness in Protan Colour Deficiencies, Cone Disease and Achromatopsia The loss of brightness for red also shows in the red visual field: In congenital protan colour deficiencies (protanomaly and protanopia), the red visual field is more or less concentrically restricted. The extent to which this constriction is measurable depends on the individual results and on the wavelength of the red stimulus in the perimeter that was used. In achromatopsia, the red visual field is missing completely when the red stimulus was sufficiently longwave to be rod-ineffective. In cone disease, acquired colour deficiency also shows a loss of brightness for red: Pseudo- protanomaly, which gradually progresses and develops into scotopisation. Scotopisation means that the patient no long views the coloured field shown on the anomaloscope with cones, as these have fallen victim to the disease, but rather with the rods. This also means there is a central scotoma in the visual field. In cone disease, red visual fields exhibit central and pericentral scotoma in particular more clearly than those recorded by white perimetry (e.g. Stargardt s disease, and chloroquine maculopathy). The extent of these results also depends on the wavelength of the red stimulus in the perimeter that was used. Anomaloscope User s Manual (B/47700/1115/en) 21 / 36

26 9 Rayleigh (Red/Green) Documentation of Results 9 Rayleigh (Red/Green) Documentation of Results 9.1 Documentation of the Anomaloscope Examination and The Results The next page shows a form for documenting the anomaloscope examination and recording the results. You can copy this form for your consultations. 22 / 36 Anomaloscope User s Manual (B/47700/1115/en)

27 Patient name: Date of Birth: Rayleigh Equation - Patient Record Field diameter 2 : (standard eyepiece only) Matching Range OD: Red/ green mixture scale units: from to Yellow : from to AQ from to OS: Red/ green mixture scale units: from to : from to AQ from to Given name: Date of examination: Yellow [SU] 60 Achromatopsia o Scotopization on Deutan Protan Anomaloscope Green Mixture [scale units] Red Diagnosis: Examiner: :

28 10 Acquired Colour Deficiencies 10 Acquired Colour Deficiencies 10.1 Characteristics of Acquired Red/Green Deficiencies Acquired red/green deficiencies: Explained graphically in the Pitt diagram PsPA Pseudo- protanomaly, e.g. in serous retinopathy, Stargardt s disease, cone dystrophy, chloroquine and hydroxy-chloroquine maculopathy. Red match shifting and loss of brightness towards red. Gradual progression to scotopisation, i.e. rod vision following extensive cone loss. ext. M Extended matching range due to contrast loss in optic neuropathies. Umstimmung Umstimmung (tuning) means match shifting and extension of the matching range due to colour adaptation. Umstimmung occurs more often in acquired than in congenital colour vision deficiencies. 24 / 36 Anomaloscope User s Manual (B/47700/1115/en)

29 10 Acquired Colour Deficiencies cerebr. Achr. Cerebral achromatopsia due to cortical lesions. Virtually all settings of the red / green mixture can be matched to yellow, generally without a loss of brightness. M = Normal mid-match Acquired colour vision deficiencies may develop in diseases of the retina, optic nerve, visual pathways and centres. They accompany the underlying pathology and go hand in hand with: Reduction of visual acuity Visual field scotoma Impairment of contrast sensitivity. Accordingly, acquired colour deficiencies often show up by way of pale, desaturated colours. Unilateral acquired colour vision deficiency occurs in localized diseases, such as optic neuritis, compression, central serous retinopathy; or in association with systemic disease Bilateral acquired colour vision deficiency occurs in hereditary disease (Stargardt s disease, retinitis pigmentosa), as a result of toxic damage (chloroquine, ethambutol, tobacco alcohol), or in bilateral manifestation of systemic disease (diabetes). Progression and sometimes, regression accompanying the underlying pathology. The type and extent of the acquired colour vision deficiency may change as the disease progresses. In congenital colour vision deficiencies, they remain the same. Acquired blue deficiencies are common in all spatial organization impairments in the retina, from the receptors to the ganglion cells. The loss of brightness for blue increases with the severity of the blue colour vision deficiency. Therefore, detection with pseudoisochromatic plates is difficult. Colour arrangement tests (Farnsworth Panel d 15, Lanthony désaturé 15, Roth 28 Hue) or the Moreland equation (blue-green spectral equation) are more suitable. Congenital blue colour vision deficiencies are very rare. Anomaloscope User s Manual (B/47700/1115/en) 25 / 36

30 10 Acquired Colour Deficiencies Acquired red/green deficiencies follow three patterns: Damage to the macular cones causes a pseudo-protanomaly with a red shift of the Rayleigh match and loss of brightness for red. Both increase as the original disease progresses; the matching range increases. In the course of the disease, pseudo-protanomaly progresses to pseudo-protanopia and to scotopisation. Scotopisation means the complete loss of the central and paracentral cone function. The Rayleigh match is then assessed with the rods. Signal conduction impairments cause an extension of the matching range in the Rayleigh equation, starting from the normal mid-match. Due to the loss of contrast, red and green are less clearly discernible from yellow: This is typical of axial damage in optical neuritis, e.g. retrobulbar neuritis or Leber s optic neuropathy: The relative matching range is even greater than the absolute. Stress on the cardiovascular system (Uhthoff s syndrome) increases the matching range even further (and the red desaturation). Cerebral achromatopsia from strokes: Loss of colour differentiation with preserved brightness perception. The Rayleigh match typically covers the complete matching range, without increased brightness for yellow or green and without loss of brightness for red. 26 / 36 Anomaloscope User s Manual (B/47700/1115/en)

31 10 Acquired Colour Deficiencies 10.2 Moreland Equation (Blue/Green): Principle Moreland equation: Additive mixture (top): Blue (436 nm) + Green (490 nm) = Cyan (480 nm) + Yellow (589 nm) The ratio of the mixture can be varied to obtain the observer s individual match to the monochromatic cyan on the bottom Bottom: Monochromatic cyan with low spectral yellow content for correcting the saturation. The brightness of the combination can be varied to obtain a brightness match with the blue and green mixture in the top field. Anomaloscope User s Manual (B/47700/1115/en) 27 / 36

32 10 Acquired Colour Deficiencies 10.3 Moreland Equation (Blue/Green): Graphic Presentation of the Moreland Diagram Diagram for documenting the examination and recording the results X-axis: 100 scale units of the mixture: From pure blue (0) via normal mid-match "N" (50/50) to pure green (100) Y-axis: brightness of the reference field (cyan) 28 / 36 Anomaloscope User s Manual (B/47700/1115/en)

33 11 Preparing the Examination 11 Preparing the Examination 11.1 "Coaching Plate": Patient Training Moreland Equation White will be shown at intervals. This needs no comment. It helps you to recognize the colours more easily. This page may be copied or scanned for patient training purposes. Anomaloscope User s Manual (B/47700/1115/en) 29 / 36

34 11 Preparing the Examination 11.2 Moreland Equation, Standard Examination: Preparation Choose: Manual examination, absolute matching range. Check that the patient is actually using the eye that is to be examined. Attach the 4 add-on optics, and check by rotation the centering. Show a setting of 80 / 40 (blue/green mixture / cyan reference field) so that any observer, colour deficient or not, can recognize the horizontal line between both test fields and understands the examination field structure. Sharply focus the line between both test fields by turning the eyepiece. If the refractive error exceeds + / - 6 dpt sph, or 1.5 dpt cyl, the patient has to wear his or her own correction lenses. No tinted spectacles, no tinted contact lenses (a tinted IOL is an integral part of the eye and should be noted in the results). Explain the examination and its goal ("coaching plate", page 31). Always examine both eyes because of the lateral differences in the manifestation of acquired colour vision deficiencies. Proceed in accordance with the flow chart, sect. 12.1, page 31. After completing the examination: Remove the 4 add-on optics; readjust the focus to the Rayleigh setting. 30 / 36 Anomaloscope User s Manual (B/47700/1115/en)

35 12 Examination 12 Examination 12.1 Moreland Equation Flow Chart Moreland Equation Blue + Green = Cyan Use the Moreland coaching plate to demonstrate differences in colour and brightness, and explain that the aim of the test is to find a match Blue Green deficiencies are early indications of diseases of the retina and optic nerve Mount and center the 4 add on optics. Sharply focus the line between the both coloured fields. Select the manual program and the absolute matching range. Carry out the examination steps using Moreland diagram. Show different colour and brightness settings Colour mixture / Brightness = 100 / 60 ( green at top ) or 20 / 30 ( blue at top ) The Moreland equation is more difficult to assess than the Rayleigh equation. Therefore, use the lager test field of 4. Ask suggestive,. forced choice questions: Where is it still greenish? Where is it more bluish? Fine scan downwards from the last green at top to the first blue at top. Asses the range in steps of 2 scale increments along the brightness diagonal line. Check Scan down from 100 / 90 every 20 scale units towards 50 / 50, and from 0 / 10 too, along the brightness diagonal, until the subject`s rating switches from top greenish to top blue > Match position and and matching range are now encircled in first approximation. The match is determined, the matching range ascertained. Remove the 4 add on optics For each blue / green mixture in the top field: Adjust the brightness via bottom field Save when the first brightness and colour match is attained. Fine scan upwards from the last blue at top. Asses the range in steps of 2 scale increments along the brightness diagonal line. Save when the second brightness and colour match is attained. The examination for blue colour vision deficiency using the Moreland equation should be preceded by an examination using pigment colours, e.g. colour arrangement test with the Farnsworth Panel d 15 or Lanthony 15 desaturated, and/or Velhagen/Broschmann/Kuchenbecker Panel 49. Anomaloscope User s Manual (B/47700/1115/en) 31 / 36

36 13 Moreland Equation (Blue/Green): Documentation of Results 13 Moreland Equation (Blue/Green): Documentation of Results 13.1 Moreland Equation (Blue/Green): Blue Colour Vision Deficiencies Congenital defects of the blue system are very rare (less than 1 in 10,000 in Europe), acquired deficiencies, on the other hand, are common. Blue colour vision deficiencies occur when the spatial retinal organization is damaged in the area of the receptors, bipolar cells, transverse neurons and ganglion cells. Blue colour vision deficiencies exhibit a loss in brightness towards blue (with rare exceptions, e.g. blue cone monochromasia). The Moreland equation is more difficult to assess than the Rayleigh equation, due to the small colour difference between green and cyan. Also due to the lack of blue cones in the foveal centre of the retina, the Moreland equation should be assessed on the 4 colour field. Example of results in ganglion cell disease: DIOA (dominant infantile optic atrophy) The net of blue cones and blue ganglion cells is wide-meshed and therefore particularly susceptible to various defects: Stargardt's disease, retinitis pigmentosa, cholorquine maculopathy, diabetic and age-related maculopathies, ganglion cell damage caused by solvents, ethambutol, alcohol, paints, glues, and also genetic defects: The tritan defect is characteristic for DIOA (results shown above). 32 / 36 Anomaloscope User s Manual (B/47700/1115/en)

37 13 Moreland Equation (Blue/Green): Documentation of Results 13.2 Form for Documentation of the Anomaloscope Examination and Recording of Results The next page shows a form for documenting the anomaloscope examination and recording the results. You can copy this form for your consultations. Anomaloscope User s Manual (B/47700/1115/en) 33 / 36

38 13 Moreland Equation (Blue/Green): Documentation of Results Patient name: Date of Birth: Moreland equation - Patient record Recommended field diameter 4 : (supplementary eyepiece) Matching Range OD: Blue/ Green mixture scale units: from to Corresponding cyan scale units: from to TAQ from to OS: Blue/ green mixture scale units: from to Corresponding cyan scale units: from to TAQ from to Anomaloscope Given name: Date of examination: Diagnosis: Examiner: : 34 / 36 Anomaloscope User s Manual (B/47700/1115/en)

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40 OCULUS Optik Geräte GmbH, Münchholzhäuser Str. 29, Wetzlar, Germany Univ. Augenklinik (University Clinic of Ophthalmology) Mannheim, Theodor Kutzer Ufer 1-3, Mannheim, Germany