Skiaskopie

Skiaskopie, also known as skiascopy or retinoscopy, is an objective method used by ophthalmologists and optometrists to estimate a patient’s refractive error. The procedure involves projecting a light into the eye with a retinoscope and observing the movement of the reflex from the retina as the examiner sweeps the light across the pupil. By introducing trial lenses and adjusting the lens power, the examiner identifies the neutralization point where the reflex movement ceases. The powers of the lenses required to achieve neutralization in each principal meridian provide an estimate of the eye’s spherical and cylindrical refractive errors.

The technique is commonly performed for distance vision, though near retinoscopy can be used with the patient focusing on a near target. Cycloplegic drops may be used, especially in children, to temporarily paralyze accommodation and obtain a more accurate measurement. Skiascopy can be performed with a streak or spot retinoscope; the streak orientation helps assess astigmatism along different meridians. The examiner notes the reflex movement relative to the retinoscope's motion, and records the results as diopters of refractive error in each meridian.

Applications include screening and guiding prescription decisions in both adults and children, preoperative assessments, and fitting of contact lenses or visual aids when subjective refraction is unreliable or impractical. While objective and rapid, skiascopy requires skill and cooperation, and its accuracy depends on proper technique, attention to illumination, and sometimes the use of cycloplegia to control accommodation. The method remains a foundational tool in refractive assessment and is frequently performed before subjective refraction.