SUMMARYThe retinal function of patients with high refractive error was studied eletroretinographically. Thirty-one hypermetropic patients, 7 myopic patients, and 7 patients with either unilateral or bilateral aphakia participated in the study. The ERG responses were measured in the light-and dark-adapted states. It was found that myopic eyes were characterised by subnormal amplitude but normal pattern, expressed by normal relationship between the b-wave amplitude and the a-wave amplitude. In aphakia the ERG responses were of normal amplitude and pattern. However, the hypermetropic patients could be divided into 3 groups. One group included subjects with a subnormal b-wave to a-wave relationship. The second group was characterised by a normal b-to a-wave relationship, while patients belonging to the third group exhibited supernormal b-wave to a-wave relationship. This classification of hypermetropic subjects did not correlate with the axial length of the eye or the refraction of the ocular media.The electrical response of the eye (ERG) to a flash of light is commonly used to evaluate the functional integrity of the retina.12 The a wave of the electroretinogram reflects light absorption by the photoreceptors and their functional integrity.2-5 The b wave is generated in the proximal retina,2-5 and therefore its amplitude depends on that of the a wave and on signal transmission in the retina.6 Thus the relationship between the b-wave amplitude and that of the a wave depends on the functional integrity of the retina. Any extraretinal parameter, such as opacities in the ocular media, resistance of ocular and extraocular tissues, or resistance between the recording electrodes, may affect the size of the electroretinogram but not the b-wave to a-wave relationship. Therefore the b-wave to a-wave relationship may serve as a useful index for the assessment of retinal function.6It has been previously reported that the amplitude of the b wave was proportional to the refraction of the eye, being smallest for high myopia and largest for hypermetropia.7 An inverse relationship was found between the b wave and the axial length of the eye, which was attributed to the increase in the ocular Correspondence to Ido Perlman, PhD,