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ACCURACY OF EVOKED POTENTIAL REFRACTOMETRY USING BAR GRATINGS
Author(s) -
RENTSCHLER INGO,
SPINELLI DONATELLA
Publication year - 1978
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.1978.tb00468.x
Subject(s) - extrapolation , optics , amplitude , refraction , bar (unit) , astigmatism , refractive index , evoked potential , spatial frequency , phase (matter) , physics , grating , materials science , mathematics , audiology , medicine , mathematical analysis , quantum mechanics , meteorology
We recorded cortical potentials evoked by phase‐alternating square‐wave gratings. Significant effects of varying the refractive power of the eye are obtained only at 5 cycles/degree (cy/deg) and above. The extrapolation to zero amplitude of the evoked response as a function of spatial frequency predicts the psychophysical visual acuity even for the myopic eye. As the sensitivity of meridional refraction using sufficiently fine bar gratings is better than 0.5 D it provides a suitable means for the measurement of astigmatism.