Amsler Grid PDF

# Amsler Grid ## Overview - Used since 1945 AD. - Developed by Marc Amsler, swiss ophthalmologist. - Looks like a graph paper with multiple small sized boxes on it with a centre dark spot. ## Description - The grid chart evaluates the central 20 degree of the visual field. - It is a diagnostic too...

# Amsler Grid ## Overview - Used since 1945 AD. - Developed by Marc Amsler, swiss ophthalmologist. - Looks like a graph paper with multiple small sized boxes on it with a centre dark spot. ## Description - The grid chart evaluates the central 20 degree of the visual field. - It is a diagnostic tool used in screening, detection and monitoring macular diseases. - ex: Macular degenerations, epiretinal membranes. - It can also be used to test for issues with the optic nerve and visual pathway. ## Dimensions - The Amsler grid measures 10 degrees across and 10 degrees tall. ## Availability - Original grid was black and white. - Available in multiple variations: - Black on white - White on black. - A color version with a blue and yellow grid is more sensitive and can test for a wider variety of visual pathway abnormalities associated with the retina, the optic nerve & pituitary gland. ## Procedure - The patient is made to wear his reading glasses, if any. - The patient holds the chart 16 inches (40cm) away from their eye. - Patient looks at the chart with each eye separately by covering one eye. - The patient is asked to focus on the small dot in the centre of the grid. - The patient reports any abnormalities they see on the grid. - ex: distorted lines, broken lines, blur, missing areas, dark areas. - Mark the area of abnormality on the chart and refer to the ophthalmologist. ## Chart Types There are seven charts, each consisting of a 10cm square. ### Chart 1 - Most commonly used. - High contrast white grid on a black background. - The outer grid encloses 400 smaller 5mm squares. - When viewed about one-third of a meter, each small square subtends an angle of 1 degree. ### Chart 2 - Similar to Chart 1 but with diagonal lines. - Diagonal lines aid fixation in patients unable to see the central spot as a result of a central scotoma. ### Chart 3 - Identical to Chart 1 but has red squares. - Red on black stimulates long wavelength foveal cones. - Used to detect colour scotomas and desaturation that may occur in toxic maculopathies, optic neuropathies and chiasmal lesions. ### Chart 4 - Consists only of random dots. - Used mainly to distinguish scotoma from metamorphopsia as there is no form to be distorted. ### Chart 5 - Consists of horizontal lines. - Designed to detect metamorphopsia along specific meridian. - Of particular value evaluating patients with reading difficulties. ### Chart 6 - Similar to Chart 5. - Has a white background. - Central lines are closer together enabling a more detailed evaluation. ### Chart 7 - Exhibits a fine central grid. - Each square subtending an angle of a degree. - More sensitive than other charts. ## Common Findings - Below are images showing the appearance of the Amsler grid with common conditions: | Condition | Description | |---|---| | Macular Edema | A wavy distortion of the lines in the center of the grid. | | Tumor | A distortion that appears as a bulge or a dip. | | Metamorphopsia | A distortion of the lines into wavy or irregular shapes. | | Scotoma | A blind spot. | | Glaucoma | A loss of vision in the peripheral field of vision. |