Effect of Botulinum Toxin Type a Chemodenervation in Esotropia

PURPOSE: To investigate the efficacy of botulinum toxin type A chemodenervation in various types of esotropia(ET). METHODS: Enrolled eleven esotropic patients treated with botulinum toxin type A and examined the amount of esotropic correction and success rate of less than 10 PD (prism diopter) of postinjection deviation at 5 months after injection. RESULTS: Among the eleven esotropic patients, there were 7 cases of infantile ET, 2 cases of partially accommodative ET and 2 cases of basic ET. The mean preinjection deviation was 30.5 +/- 7.3 PD. The amount of correction was 17.7 +/- 4.3 PD and correction rate of deviation was 57.5%. In 6 of 11 cases, the postinjection deviation was within 10 PD and therefore success rate was 54.5%. In 5 patients (45.5%), their ET was undercorrected. In patients with under 20 PD of preinjection deviation, success rate was 75% (3/4) and those with over 20PD, the rate was 42.9% (3/7). In partially accommodative ET, 2 (100%) of 2 cases were aligned within 10PD. CONCLUSIONS: In comitant ET, botulinum toxin chemodenervation shows high undercorrection rate. The effects of botulinum toxin type A chemodenervation were better for relatively small angle and in partially accommodative ET than nonaccommodative one. But further study with more cases is needed.

The Effect of the Amniotic Membrane and Methocel (R) on the Postoperative Adhesion after Strabismus Surgery

PURPOSE: To evaluate the effect of amniotic membrane and additional use of 2% methylcellulose(Methocel(R)) in reducing the postoperative adhesions following strabismus surgery. METHODS: Twenty white rabbits (40 eyes) were divided into 4 groups: control group C (12 eyes), trial group A (12 eyes), trial group B (12 eyes), and normal group N (4 eyes). In group C, the superior rectus was detached and scleral scratching was done to provoke a fibrotic reaction, and then, the superior rectus was reattached to the original insertion site. In group A, the above procedure was done and in addition, the superior rectus was covered with two-folded amniotic membrane. In group B, the same procedure was done as in group A and in addition, Methocel(R) was coated between the muscle and adjacent tissues. Eight weeks later, we divided each group into two subgroups. In one group, we examined the degree of adhesion by the blunt dissection between the muscle and adjacent tissues, and in the other group, the histologic findings with a light microscope between the muscle and adjacent tissues. RESULTS: The adhesion degree on the blunt dissection and histologic examination was significantly reduced in groups A and B. But no statistically significant difference between groups A and B was shown in the postoperative adhesion. CONCLUSIONS: From these findings, it is expected that the use of amniotic membrane may reduce the postoperative adhesion after strabismus surgery and theadditional use of Methocel(R) may not be useful.

Immunohistochemical Findings in the Early Ischemic Retina of Gerbil Model

Gerbil has no Willis circle so we can make the model of cerebral ischemia simply by occluding the common carotid artery. In this study, we occluded the common carotid arteries of the gerbil for 5 minutes, and at the designated reperfusion time (0.5, 3, 6, 12 and 24 hrs), the experimental animals were killed for histopathological and neurofilament 68 kDa immunohistochemical study. At 12 hrs after ischemia the neuronal cell change occurred in inner nuclear layer (INL)and ganglion cell layer (GCL). At 24 hrs after ischemia the disappearance of neurons were observed in GCL and severe edema, pyknotic degeneration were observed in INL and outer nuclear layer (ONL ). On immunohistochemical study, the NF 68 kDa antibody labelled the cell bodies in the GCL and some nerve fibers in nerve fiber layer (NFL). In addition, the processes of horizontal cells also showed the slight NF 68 kDa immunoreactivity. After ischemic insult, the intensity of NF 68 kDa immunoreactivity in GCL and NFL was slightly decreased. But, its intensity in the process of horizontal cells was increased. And the NF 68 kDa immunoreacticity was detected in some neurons of INL and ONL. This represents the neurofilament protein has the important role in the cell death at the ischemic retina as well as at the ischemic brain.