Fototestes

Fototestes, also known as photo tests or photographic tests, are diagnostic tools used primarily in the fields of ophthalmology and optometry to assess visual acuity, eye alignment, and other aspects of eye health. These tests rely on visual stimuli presented in the form of images or patterns, allowing healthcare professionals to evaluate a patient’s vision objectively.

One of the most common types of fototestes is the Snellen chart, which consists of rows of letters or symbols of varying sizes. Patients are asked to read the smallest line they can identify from a standard distance, typically 20 feet (6 meters). The results are recorded as a fraction, such as 20/20, indicating normal vision, where the second number represents the distance at which a person with average eyesight could read the same line. Other variations include tumbling E charts, which are used for non-literate individuals or children, and Landolt C charts, which assess visual acuity by identifying the orientation of broken-ring symbols.

Fototestes can also include tests for eye alignment, such as the cover test, where a small occluder is used to observe how one eye compensates when the other is covered. This helps detect conditions like strabismus (misalignment of the eyes). Additionally, contrast sensitivity tests, such as the Pelli-Robson chart, evaluate a person’s ability to distinguish between shades of gray, which is particularly useful in diagnosing conditions like glaucoma or amblyopia.

These tests are non-invasive, quick, and provide valuable data for diagnosing refractive errors, eye diseases, and visual development issues. While fototestes are widely used in clinical settings, they are not a substitute for a comprehensive eye examination, which may include additional procedures like tonometry (measuring intraocular pressure) or retinal imaging. Proper administration and interpretation of fototestes require training, ensuring accurate assessment and appropriate treatment recommendations.