Amslerin

Amslerin, commonly called the Amsler grid, is a simple diagnostic chart used to detect distortions or blind spots in the central visual field. Named after Marc Amsler, a Swiss ophthalmologist who introduced the method in the mid-20th century, the grid consists of a square array of horizontal and vertical lines with a central fixation point. The typical presentation is printed in black on white, and the patient views it with one eye at a time while the other eye is covered.

How it is used: The patient focuses on the central dot and surveys the grid for any lines that appear distorted, bent, wavy, blurred, or for blank areas. Noting abnormalities in any quadrant may indicate changes in the macula, the central part of the retina. The test is commonly performed at home for ongoing monitoring or in clinical settings as part of an eye examination.

Clinical significance: The Amsler grid helps detect conditions such as age-related macular degeneration, diabetic macular edema, macular holes, or other maculopathies that affect central vision. It is a screening tool rather than a definitive diagnostic test; an abnormal result warrants a professional ophthalmologic evaluation.

Limitations: The test assesses only the central visual field and relies on proper fixation, adequate lighting, and correct refractive correction. Results can be influenced by cataracts, dry eye, small pupils, or user error. False positives and false negatives can occur, and the grid cannot detect peripheral vision loss.

Variations and modern use: Digital adaptations and smartphone applications offer virtual grids and automated guidance, though the traditional paper grid remains widely used in clinics and for patient home monitoring.