LETTER CONTRAST SENSITIVITY FUNCTION OF THE EYE

Purpose: To provide empirical data of letter CSF for various levels of defocus under controlled conditions of luminance and age. Methods: Co rrected distance visual acuities were tested tit different levels of c ontrast and defocus, An experiment was conducted using the Medmont vis ual acuity tester on 10 young subjects and under normal room lighting. Results: Empirical data of visual acuity were obtained for 7 levels o f contrast (5, 10, 15, 25, 30, 60, 80%) and defocus levels of 0, +1 an d +2D, A mathematical model was derived (R-2=0.995) and this can be us ed to estimate visual acuity at various contrast levels for defocus of less than or equal to+2D. Conclusion: This information is useful for the clinician as normative data and for further development of optical models to predict visual performance of the eye.