Which method is used to objectively assess refractive error?

Retinoscopy is the method used to objectively assess refractive error because it relies on the observation of how light reflects off the retina. During the retinoscopy procedure, an examiner shines a light into the patient’s eye and observes the movement of the light reflex on the retina. This reflex provides vital information about the refractive status of the eye without requiring the patient to provide feedback about their vision, thus allowing for an objective measurement.

In contrast, subjective testing relies on the patient’s ability to communicate their visual experience, which can introduce personal bias and variability. Self-reported assessments are even less objective, as they depend entirely on the patient's own descriptions of their vision, which can be influenced by numerous factors such as understanding and mood. Visual field testing assesses the range of vision rather than refractive error, making it unsuitable for this specific assessment. Therefore, retinoscopy stands out as the objective and reliable method for determining refractive errors in patients.