WHAT IS RETINOSCOPY? 
Retinoscopy is a technique used to objectively determine the refractive error of the eye (farsighted, nearsighted, astigmatism) and the possible need for glasses. The test can be quick, easy, reliably accurate and requires minimal cooperation from the patient.  For accurate retinoscopy the child should look at target either hand held or at distance for a time period that only takes few seconds. Most children, including infants, can look at targets long enough to allow successful retinoscopy in the office.

HOW IS IT PERFORMED?
A handheld instrument called a retinoscope projects a beam of light into the eye.  When the light is moved vertically and horizontally across the eye, I observe the movement of the reflected light from the back of the eye. Observing this reflex allows me to estimate the prescription with a certain degree of accuracy.  More exact measurements are made when I introduce lenses in front of the eye... and as the power of the lenses changes, there is a corresponding change in the direction and pattern of the reflection. Using this technique I am able to change the lenses until reaching a lens power that neutralizes the reflex- which indicates the refractive error of the patient.

​WHEN IS RETINOSCOPY USED?
Retinoscopy is used to determine refractive error in children, developmentally delayed adults, or in individuals whose behavior limits the ability to be cooperative with other refraction techniques. It is especially useful in very young children and infants. I make this a routine procedure for my younger patients and is a defining difference between my practice and the majority of my peers. 

ARE DILATING EYE DROPS NECESSARY FOR RETINOSCOPY?
The reflex is easier to see when the pupil is large and most children are naturally gifted with large pupils. Based on the needs of the child I will often NOT dilate if I find a stable and consistent reflex. This allows for a tears-free experience and is a preferred method of mine. Having performed over 20,000 retinoscopy procedures I feel very confident in my ability to determine when and if dilation is necessary.  Children's eyes are typically dilated for retinoscopy when an unstable reflex is noted and compliance with fixation is lacking. Because the drops temporarily limit the eye's ability to accommodate or focus this may allow for a more accurate determination of the DISTANCE refractive error, but also put the eyes in an unnatural state of focus. 

WHAT OTHER TESTS CAN BE USED TO DETERMINE THE REFRACTIVE ERROR OF A CHILD?
Auto-refraction and subjective refraction are other techniques used to determine refractive error. Auto-refraction is a method of refraction that is performed by a computing device. This method can be precise but requires the subject to be still and look at a target for several seconds in order to obtain an accurate measurement. When used as the only "objective" measurement of vision, dilation would be necessary to give an accurate reading in young children. Subjective refraction is a method that can be used to refine the results of retinoscopy or auto-refraction. Subjective refraction requires participation in the process by telling the examiner which of a series of choices of lenses provides the clearest vision. Based on the needs of the patient we may not be able to rely on these other tests.

 A handheld instrument called a retinoscope projects a beam of light into the eye during retinoscopy.