The Chantres of ERG b-wave and Oscillatory Potential in White Rat during Dark Adaptation

We studied changes of b-wave and oscillatory potential in ERG test during dark adaptation in white rats for the purpose of using it in experimental disease-group and studying difference in man. For this we performed ERG test on normal 14 S-D (Sprague-Dawley) rats (28 eyes) during dark adaptation. The implicit time of a-wave and b-wave was shortend during dark adaptation. The b-wave and oscillatory potential rapidly increased by 20 and 30 minutes during dark adaptation: in b-wave, these values were 425.89 +/- 141.15 micro v, 473.65 +/- 130.35 micro v respectively, and in oscillatory potential, 110.56 +/- 54.82 micro v, 126.27 +/- 48.24 micro v respectively. After then, these were slightly increased. This results reveal that dark adaptatin in ERG test using rats needs sufficient time from 20 minutes to 30 minutes in similar to man. The oscillatory potential in white rat had three components with 1] light stimulus and the increase of amplitude of oscillatory potential was similar to that of b-wave during dark adaptation. But we should consider that the decreased cone function of white rat was different from that of man, that amplitude of b-wave was continously increased without the break point of early 6 minutes, and that the implicit time of b-wave was continously decreased after 10 minute during dark adaptation, when we use rat.

Trephination Effect After Epikeratoplasty

Trephination was performed for the purpose of correction of undercorrection after epikeratoplasty. We classified two group-Delayed regression group represented regression toward myopia more than 3D again after spherical equivalant become stable. Undercorrection group represented remained myopia after epikeratoplasty. Thirteen trephinations were performed on eleven eyes. Mean follow-up period was 22.4 weeks. In skiascopy, totally 1.15D myopia was decreased. In delayed regression group myopia was increased 0.5D, while in undercorrection group, myopia was dereased 3.5D, The results of three eyes in eleven eyse were satisfactory. Those 3 cases were from undercorrection group. The results suggest that trephination might be effective method for correction of remained myopia in undercorrection group.

Variability and application of VEP components in Transient VEP and Steady VEP

Before VEP use in clinics, we studied in statistical significance between borh eyes, intrasubject varciabilty intersubject variability (between incdividul) and changes of VEP cmponents between ignorance and attention in losujects (20eyes). There was no statistically significant difference between both eyes in each component of VEP and the variability of intersubjects was larger than that of intrasubjects. The smallest variability of intersubject was N1, P1 latency and that of intrasubject was PI latency in each component of VEP. When subjects were ignored, N1-P1, P1-N2 and steady VEP amplitude decreased significantly but N1, P1 and N2 latency were no significant difference.