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Clinton Sims, ; Refractive Retinoscopy. Invest. Ophthalmol. Vis. Sci. 2014;55(13):2715.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate the accuracy of Refractive Retinoscopy (RR), an off-axis technique using calibrated converging light and no fogging lens. The basic principles of conventional retinoscopy were used as the patient read the Snellen or animal chart. The clarity of the RR endpoints was compared to conventional retinoscopic endpoints and the retinoscopic accuracy evaluated with subjective refractions..
With calibration formulas a Copeland Optec 360 Streak Retinoscope (Fig. 1) was calibrated for +0.50D RR and conventional infinity retinoscopic endpoints and a 67cm retinoscopic working distance (RWD). Slide locks maintained the alignment of the thumb slide with the two calibrated positions. With a phoropter, thirty normal and abnormal eyes of patients (6-91) with undilated pupils were retinoscoped. As the refractive error was neutralized with retinoscopy, the size of the Snellen letters or animals was decreased as the patient’s visual acuity improved. Without changing the RWD, the +0.50D RR endpoint was compared to an infinity endpoint by adding a +1.50D sphere and elevating the thumb-slide to the calibrated conventional infinity position. Subjective refractions were performed and the results compared to the refractive retinoscopies.
The mean differences between the spherical equivalents (SE) and crossed cylinder (Xcyl) of the retinoscopic and subjective refractions were -0.08±0.14DSE and 0.06±0.15DXcyl. In contrast to the infinity endpoints the +0.50D RR endpoints were defined and easy to evaluate. No patients reported the retinoscopic light blurred their vision or interfered with the retinoscopic examination (Fig. 2).
Results indicate that Refractive Retinoscopy is an accurate technique. Displaced from the visual axis, Refractive Retinoscopy maintains fixation, reduces accommodation and produces clear retinoscopic endpoints and clear vision for the patient. This technique eliminates the fogging lens which blurs vision, the zone of doubt, the undetectable endpoint of conventional retinoscopy and the variable spherical errors of conventional retinoscopes. It also reduces cycloplegia usage which create spherical and astigmatic errors and increase the higher order aberrations. The visible RR endpoint calibrated to the examiner’s technique should make retinoscopy more accurate than conventional retinoscopy, simplify the teaching of retinoscopy and shorten the learning curve.
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