Amslergrid

Amsler grid is a simple diagnostic tool used to assess the central visual field. Named after Swiss ophthalmologist Marc Amsler, the test consists of a square grid of evenly spaced lines with a small central fixation point. When viewed at a standard distance with the correct refractive correction, the grid should appear with straight lines and a uniformly detailed center.

To perform the test, a person covers one eye and focuses on the central dot while keeping the grid at the appropriate distance. The observer notes whether any lines look bent, distorted, missing, or blurred, or if the center area seems darker. Distortions or blind spots can indicate changes in the macula, the region of the retina responsible for fine central vision, and typically prompt evaluation by an eye care professional. The grid is commonly used for monitoring conditions such as age-related macular degeneration and diabetic macular edema, among others.

Limitations include reliance on steady fixation and proper refractive correction; uncorrected errors, improper lighting, or an inappropriate viewing distance can produce misleading results. It does not assess the entire visual field, and a normal result does not exclude other eye diseases. Digital versions and printed formats exist, and some patients use electronic tests or smartphone apps for periodic self-testing, often under professional guidance.