What does tangent screen field testing primarily assess?

Tangent screen field testing primarily assesses the sensitivity of the central 30 degrees of vision as well as the identification of the blind spot. This type of testing is specifically designed to evaluate visual field deficits, which are often crucial for diagnosing various ocular conditions, such as glaucoma, retinal diseases, and neurological issues.

The central 30 degrees of vision is particularly important because this area encompasses key visual tasks, including reading and recognizing faces. By assessing sensitivity in this region, healthcare providers can detect changes in vision that may indicate a problem within the visual pathways. The testing also includes the evaluation of the blind spot, known as the optic nerve head, helping to provide additional insights into a patient's visual health.

This method does not primarily focus on overall visual acuity, which measures sharpness of vision rather than the extent of the visual field. It also differs from testing that isolates peripheral vision alone or color vision, as tangent screen testing requires a broader evaluation of central sensitivity as part of a comprehensive assessment.