Amsler Grid and Its Function

Amsler Grid

• Used since 1945
• Developed by Marc Amsler, a Swiss ophthalmologist
• Looks like graph paper with multiple small boxes, centered around a dark spot.

Amsler Grid Function

• A diagnostic tool used primarily in screening, detecting, and monitoring macular diseases (e.g., macular degenerations, epiretinal membranes) and optic nerve and visual pathway issues.
• Evaluates the central 20 degrees of the visual field.

Amsler Grid Variations

• Original: Black and white
• Available Versions:
  • Black on white
  • White on black
  • Colour version (blue and yellow grid): More sensitive, tests for a wider variety of visual pathway abnormalities (retina, optic nerve, pituitary gland).

Amsler Grid Procedure

• Patient wears reading glasses, if necessary.
• Holds the chart 16 inches (40 cm) from the eye.
• Patient looks at the central dot with one eye at a time, focusing on the central dot.
• Reports any distortions, breaks, blurred areas, missing areas, dark areas, or abnormalities in the grid lines (corners and sides).
• Mark on the chart any abnormalities and refer to an ophthalmologist.

Amsler Grid Charts

• There are seven different charts, each a 10 cm square
• Chart 1: High contrast white grid on a black background; 400 smaller 5mm squares; each square subtends a 1-degree angle when viewed from about 1/3 of a meter.
• Chart 2: Similar to chart 1, includes diagonal lines, aiding fixation in patients with central scotoma.
• Chart 3: Identical to chart 1 but with red squares, stimulating long-wavelength foveal cones and helps detect colour scotomas. Also useful in diagnosing toxic maculopathies, optic neuropathies, and chiasmal lesions.
• Chart 4: Consists of random dots and used to distinguish between a scotoma and metamorphopsia.
• Chart 5: Consists of horizontal lines along a specific meridian, specifically useful for detecting metamorphopsia in patients experiencing reading difficulties.
• Chart 6: Similar to chart 5, but with a white background and closer together lines for more detailed evaluation.
• Chart 7: Fine grid, each square subtending a degree of angle and more sensitive.

Amsler Grid Examples of Findings

• Macular Edema: Visual distortion or changes in the grid lines
• Tumor: Visual distortion or changes in the grid lines, potentially with a dome-like distortion
• Metamorphopsia: Distortions or warped patterns in the grid
• Scotoma: Missing portion(s) in the grid
• Glaucoma (Peripheral Field Loss): Loss or missing portions of the grid, primarily in the peripheral areas

This quiz covers the Amsler grid, a diagnostic tool for macular diseases developed by Marc Amsler in 1945. It includes variations of the grid, the procedure for its use, and how it helps evaluate vision. Test your knowledge on its history, application, and importance in ophthalmology.