Retinoscopy

Retinoscopy is a clinical method used to estimate refractive error by observing the movement of the retinal reflex as light is projected into the eye and swept across the pupil. It provides an objective, rapid assessment of refractive status and is commonly employed by optometrists and ophthalmologists, especially with children or patients who cannot reliably cooperate with subjective refraction.

Principle and concepts: A bright light from a retinoscope enters the eye and the reflected reflex is observed while the examiner moves the instrument. The reflex motion—with, against, or neutral—depends on the subject’s refractive error relative to the working distance. In plane-mirror retinoscopy, a neutral reflex is obtained when the eye’s refractive error matches the inverse of the working distance; with movement suggests hyperopia or low myopia; against movement suggests higher myopia or astigmatism. The final refractive estimate is obtained by combining the lens power needed to neutralize the reflex with a standard correction for the working distance.

Procedure and practice: The patient fixes on a distant or near target while the clinician sweeps the retinoscope in multiple meridians. Streak or spot retinoscopy can be used; the streak aids assessment of astigmatism by aligning with principal meridians. In children or non-cooperative patients, cycloplegia may be employed to temporarily paralyze accommodation. The neutralization point is identified in each meridian, and the results are recorded with appropriate corrections for the working distance.

Indications, interpretation, and limitations: Retinoscopy is used for refractive assessment, screening for anisometropia, and pediatric evaluations. Limitations include dependence on patient cooperation and the influence of accommodation, media clarity, and pupil size. Proper training is essential for accurate interpretation, and results are typically confirmed with subjective refraction when possible.