The purpose of this ar- ticle is to review the performance and application of this valuable clinical tool. During retinoscopy, the examiner views the red reflex of the eye through the peephole of the retino- scope while sweeping a linear streak of divergent light across several meridians. When the eye is fo- cused in the plane of the peephole, all light return- ing from the retina passes through the peephole, and the red reflex appears to fill with light neutral- ization, Fig. When the subjects eye is focused beyond the peephole behind the examiner , only a portion of returning light passes through the peep- hole, and the red reflex appears as a band of light the shape of the bulb filament in the same merid- ian as that of the filament, moving in the same direc- tion as the light source with motion, Fig. When the eye is focused in front of the peephole, the band of light moves in the direction opposite the light source against motion.
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Monoocular Estimate Method MEM Book Retinoscopy A simple way of performing Dynamic retinoscopy is by using a near fixation target a small letter chart along with retinoscope.
Make the room dark and direct a dim light reading lamp attached to refraction unit stand to the small letter chart so that patient is able to see it. The patient should wear distance correction, if any. The retinoscope and chart should be held approximately at the normal reading position.
Next ask the subject to fixate on the small letter chart, with. If the neutralization is incomplete, then again ask the patient to fixate on the distant target. Now move closer to patient and ask the patient to maintain fixation at near for a longer period of time. This places more demand on the accommodative system, which helps estimate whether the accommodative effort is sustainable or not.
The results of dynamic retinoscopy can be described as normal rapid, complete, and steady or abnormal incomplete, sluggish, momentary accommodation only, or accommodative lag. This target provides a three dimensional viewing target. Move the ball towards the patient and stop when it reaches the point in front of the nose, then move it backwards.
The observed motions will occur in reverse. The two measurements are recorded as a fraction e. The expected values for Bell retinoscopy are: Inward shift at Lenses which normalize these ranges are considered an acceptable nearpoint prescription. Three things occur when near-point stress is experienced. It initially brightens and then became dull and finally again brightens. As a guideline, in children the stress-point should be 10cm closer to the subject than the Harmon distance.
Consider it as the distance from fist at chin to the elbow on the desk. In adults, the stress point is 20 to As an example an 11 year old child yields a Harmon distance of It is attached on a retractable tape measure. It is viewed at 40 cm in dim illumination.
The target remains stationary and examiner with retinoscope moves back till the reflex is neutralized. The accommodative response is the inverse of the final distance between child and examiner. Most near retinoscopy depends on the insertion of a lens to determine the effect of the lens on performance.
MEM is unique in that lenses are primarily used to verify the observation of the examiner. Case Examples How can we use dynamic retinoscopy to solve a variety of clinical dilemmas? Is a bifocal also necessary to help the amblyopic eye focus at near? An amblyopic eye tends to accommodate poorly, especially when the eye has significant hyperopia. The use of atropine penalization increases the relevance of the question, since the amblyopic eye will be responsible for fine near work.
Dynamic retinoscopy with best distance correction in place and a cycloplegic agent instilled in only the penalized eye can answer this. If the amblyopic eye does not accommodate reliably, a bifocal lens should be prescribed only for the amblyopic eye until later testing reveals improved accommodation in that eye. Are her complaints fictitious? Measurement of normal near acuity alone in this patient does not fully characterize her accommodative status.
Dynamic retinoscopy might reveal rapid, complete, but unsteady or discontinuous accommodation in this low hyperope, confirming the diagnosis of accommodative insufficiency and reinforcing the decision to treat with glasses.
Alternatively, a briskly normal dynamic retinoscopy response is consistent with a nonocular etiology to her complaints. If symptoms persisted in the latter case, a trial of a low-power reading add may be indicated in case of a falsely normal response to dynamic retinoscopy. Science ; — Hunter DG. Dynamic retinoscopy: the missing data. Surv Ophthalmol ; — Apell RJ.
J Am Optom Assoc. WJ Benjamin. WB Saunders Company. Philadelphia, London, Toronto. An evaluation of the monocular estimate method of dynamic retinoscopy. Am J Optom Physiol Opt. Article Options.
Out of which the two important methods are Nott Method: Target: Near target at subjects working distance. Near target is either held in patients hand or A scale containing a self-illuminated cube with pictures held as shown in figure 1 The patient sees the target binocularly Patients must wear their distance correction Retinoscope is kept alongside the target and the movement of the reflex is observed If the movement is against, then the subject is over accommodating. Move the retinoscope towards the kid till you get neutral point while keeping target fixed. The distance between the neutral point and the target will be converted into dioptres. The resultant dioptric value is the magnitude of the lead of the accommodation. If the movement is with, then the subject is under accommodating. Move the retinoscope away from the kid till you get neutral point while keeping target fixed.
Dynamic retinoscopy: the missing data.
Monoocular Estimate Method MEM Book Retinoscopy A simple way of performing Dynamic retinoscopy is by using a near fixation target a small letter chart along with retinoscope. Make the room dark and direct a dim light reading lamp attached to refraction unit stand to the small letter chart so that patient is able to see it. The patient should wear distance correction, if any. The retinoscope and chart should be held approximately at the normal reading position.