Amsler grid and color vision charts

G.SHIRISHA13IMMO20

Amsler grid• Amsler chart is designed to evaluate the central visual field of

20°. • It is a diagnostic tool that is used mainly in screening,

detection and monitoring macular diseases(e.g. Macular degenerations)as well as the optic nerve and the visual pathway.

• Procedure-

Test is done uniocularly Patients pupil should not be dilated Patient should were their full refractive correction Use good illumination on chart Hold the chart at 40cm from patients eye. Ask the patient to fixate on central white dot & tell patient while

looking on central dot give the answers of following questions-

1.Can you see the central white dot in the center of grid? 2.While looking at central dot ,can you see all four quadrants of chart

simultaneously? 3.Does the grid appears to have any missing or distorted area? 4.Are there any area of grid that have an unusual appearance? 5.Are any square blurring/missing? All the observations and information given by the patient

should be noted and can be used for further examination and diagnosis

There are seven charts, each consisting of a 10cm square.CHART 1: Standard Amsler grid It is most commonly used. It

comprises a high contrast white grid on a black background.

To identify various forms of distortion as well as Relative and Absolute scotoma.

Chart 2• Is a similar to chart 1 but has

diagonal lines that aid fixation in patients unable to see the central spot as a result of a central scotoma

Chart 3• Is to identical to chart 1 but has

red squares. The red on black design aim to stimulate long wavelength fovea cones.

• It is used to detect color scotomas and desaturation that may occur in toxic maculopathies , optic neuropathies and chiasmal lesions.

Chart 4• Consisting only of random dots

is used mainly to distinguish scotoma from metamorphosia, as there is no form to be distorted.

Central metamorphosia

Chart 5• This chart consists of 20

evenly spaced white horizontal lines on a black background.

• and is designed to detect metamorphosia along specific meridian.

• It is of particular value in the evaluation of patients with reading difficulties

Chart 6• It a similar to chart 5 but has a

white background and the central lines are closer together enabling more detailed evaluation.

• Metamorphopsia along the reading level may be more easily observed with this chart.

Chart 7• Exhibits a fine central grid ,

each square subtending an angle of a degree and is therefore more sensitive.

• This chart is more useful in cases where there is a subtle visual disturbance from macular disease, especially early in the course of the disease

Color vision charts• Color vision is the ability of the eye to discriminate

between colours excited by lights of different wavelengths.

• Cones are responsible for the color vision .• 6 – 7 millions in number .• Good reactants in photopic condition.

Tests for color vision • Screening tests.• Grading tests.• Classifying tests.• Vocational tests.Color vision and principle function

Pseudoisochromatic plate test

• Most commonly used tests, • Easily and rapidly administered.• Designed to screen for the presence of red-green inherited

color vision defects. Ishihara Plates American Optical Hardy-Rand-Rittler Plates Standard Pseudoisochromatic plates City University test

Ishihara plates • Comes in three different forms: 16 plates, 24 plates, and 38plates.

(10th edition)• Plates should be held at 75 cm under good illumination .• Numerals should be answered in not more than 3 sec• Pathway tracing should be completed within 10 sec.• Designed in four ways

1st plate- for demonstration and malingerers

Transformation plate:• 2-9 plates• A number seen by a color normal

appear different to color deficient subject.

Vanishing plats :• Plate no. 10-17th

• A number is seen by a color normal but cannot be seen by a color deficient subject

(18-21)plate-Hidden-digit plates: normal person does not see a figure(22-25)plate-Diagnostic plates: seen by normal subjects.

• Out of initial 21 plates, if 17 or more plates are read correctly by an individual his color sense should be recorded as normal.

• If 13 or less plates are correctly read then the person has a red-green color defect.

• Plates 22 to25 are for differential diagnosis of Protans and Deutans.

• Disadvantage of this test is that it neither test for tritanope nor grade the degree of deficiency

American optic hardy rand ritter

• There are plates with paired vanishing designs• Contain geometric shapes (circle, cross and triangle)• Shape is in neutral colours on a background matrix of grey

dots.• Six plates for screening (four red-green and two tritan),• 10 plates for grading the severity of protan and deutan

defects• Four plates for grading tritan defects• Ideal for paediatric testing of congenital color blindness

CITY UNIVERSITY COLOR VISION TEST• 10 Plates ,35 cm,daylight,right angle.• Where a centre colored plate is to be matched to its

closest hue from four surrounding color plates.• Three peripheral colors are typical isochromatic

confusions with the central color in color deficiency.• The fourth color is an adjacent color in the D15

sequence and is the intended normal preference• Identifies moderate and severe color deficiency only

FARNSWORTH- MUNSELL 100 HUE TEST

• Very sensitive reliable and effective method of determining color vision defect.

• The test consists of 85 movable color samples arranged in four boxes of 22 colors.

• Subject has to arrange 85 color chips in ascending order.• The color vision is judged by the error score. The results are recorded in a circular graph The Farnsworth-Munsell Hue Test Scoring Software has

been developed to speed up and simplify scoring of the FM 100 Hue test and to provide a powerful set of analytical and administrative tools

FARNSWORTH- MUNSELL D-15 HUE TEST

• Abridged version• Patients are asked to

arrange 15 colored caps in sequential order based on similarity from the pilot color cap

• Intended for screening color vision defects only.

• Used to detect color vision defects such as red-green and blue-yellow deficiencies as opposed to color acuity.

FARNSWORTH- MUNSELL D-15 HUE TEST

• Abridged version.• Patients are asked to arrange 15

colored caps in sequential order based on similarity from the pilot color cap.

• Intended for screening color vision defects only.

• Used to detect color vision defects such as red-green and blue-yellow deficiencies as opposed to color acuity.

Spectral anamaloscope• Accepted as the most accurate for diagnosis• unlike most other tests,they require a fair amount of skill on the

part of the examiner.1. Nagel anomaloscope.2. Oculus HMC (Heidelberg Multi Color) anomaloscope3. Neitz anomaloscope4. Pickford-Nicolson anomaloscope

Nagel’s anomaloscope

• GOLD STANDARD• Extraordinarily sensitive.• In this test the observer is asked to mixed red and green

colors in such a proportion that the mixture should match the yellow color disc.

• Indication of defect is relative amount of red and green required.

Lantern test • The test is performed in a dark room at 6 meters distance• It has five rotating discs• Disc 1 – aperture sizes varies 1.3 to 13 mm.• Disc 2-4 – Eight color filters (2 red, 2 green, white, yellow, blue,

Purple)• Disc 5 – a clear aperture, 5 neutral density filters, a ribbed glass

(simulate rain), frosted glass (simulate mist)• Recommendations of the test state that a candidate should be

rejected if he calls:• Red as Green• Green as Red• White light as Green or Red or vice versa• Red-Green or White light as black

Thank you