Examination Techniques for Accuracy and Efficiency Principles of Retinoscopy A VOSH-Florida Presentation

Principles of Retinoscopy Basic concepts Basic technique

Basic Concepts: Retinoscopy is a method of objective refraction that does not require a patient response. A point source of light located at the far point of focus of the eye will have it’s light focused on the retina. The goal is to locate the far point of the eye at the aperture of the retinoscope, using trial lenses, to determine the refractive error of the eye.

Basic concepts: The retinoscope streak beam is moved back and forth across the pupil of the eye being examined. The retinal light reflex motion is observed through the retinoscope, while adding plus or minus power lenses, until a neutral reflex is achieved.

The light reflex will generally move in the opposite direction of the retinoscope beam in myopia and will move in the same direction in hyperopia. The basic rule is “With motion, Add minus” and “Against motion, Add plus”. This is performed for both principle meridians in the case of astigmatism.

Determine your working distance: Sit in front and to the left of your patient, for scoping the right eye. Hold the retinoscope in your right hand and in front of your right eye. Extend your left arm to comfortably reach the spectacle plane of the patient. Have an assistant measure the length of your arm from the plane of the retinoscope to the spectacle plane.

Calculate the dioptric equivalent of the distance that you are scoping. This is your working distance lens and should be consistent from one patient to the next. Examples: 40cm = +2.50 D working lens 50cm = +2.00 D “ 67cm = +1.50 D “ 100cm = +1.00 D “

Spherical refraction using a retinoscope and lens (skioscopy) rack: Place the trial frame on the patient. Place your working distance trial lens over each eye (+1.50D for 65cm). Do not occlude either eye. Viewing through the retinoscope, move the streak back and forth to observe the direction of the light reflex.

Hold up the lens rack (+ or – as needed). Move the lens rack to neutralize the reflex (“with motion” – add minus; “against motion” – add plus) Add the appropriate spherical trial lens to the trial frame. Repeat on other eye. Remove the working distance lenses from the trial frame.