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.

Changes of Transient and Steady VEP by Checkboard Contrast

We measured the changes of each component of YEP by increase in contrast 8%, 30%, 60%, 90%, 98% in small checkerboard pattern stimuli and large checkerboard pattern stimuli in 10 normal subjects (20 eyes) in order to get basic data for utilizing YEP according to changes of contrast in clinical diseases group, N1 latency and P1 latency were notably shortened from 30% to 60%. N2 latency was extremely shortened from 60% to 90%. N1-P1 amplitude and P1-N2 amplitude were remarkably increased from 30% to 60%. The amplitude of steady YEP generally increased as the contrast was increased. Immatured YEP wave was turned to matured YEP wave between contrast 30% and 60%. Threfore, when we apply YEP with to lower contrast of stimuli clinical cases, the appropriate range of contrast is from 30% to 60%.

Clinical Results of Epikeratoplasty for Myopia, Keratoconus and Aphakia

We have performed epikeratoplasty to correct the visual acuity in high myopia who are more than -8.0D and intolerant to the wearing of contract lens, and for the aphakic eyes. It has been also applied to supress the progression of keratoconus. Of 118 eyes performed from january 1989 to july 1992, a total of 90 eyes which could be followed up were subject to the review, including 66 high myopic eyes, 18 keratoconus, and 6 aphakic eyes. In myopic patients, uncorrected visual acuity was stable from a proeperative mean of 0.04 to 0.58 at 4 months. Spherical equivalent was stable from a preoperative mean of -13.99 to -2.01 at 4 months. In keratoconus patients with mean 10.1 months follow-tp, uncorrected visual acuity was changed from 0.05 to 0.33 Corrected viaual acuity was changed from 0.15 to 0.60, keratometry reading was changed from 55.87D to 45.92D. Of 6 aphakic eyes, spherical equivalent of 3 pediatric: aphakic eyes under the age of 3 was changed from +15.0D to +3.41, for the other 3 adult aphakic eyes, spherical equivalent was changed from +9.5D to +1.83D and uncorrected visual acuity was changed from 0.03 to 0.32. Epikeratoplasty is effective surgery applicable to the correction of myopia more than -8.0D, keratoconus, and aphakia.