斜視之手術治療 第一篇：共働性內斜視之手術治療

Abstract

The purpose of this study was to understand the complex factors that influence the surgical results for comitant esotropia. A review was taken of the records of my patients who had undergone surgery during the period of Aug. 1976 to July 1982 at Municipal Chung-Hsin Hospital of Taipei. A total of 213 cases, 108 male and 105 female, was included in this study immediately after surgery. The age group at operation ranged from 9 months to 51 years of age with the average age of 10 years. Of these 213 cases, 151 patients were followed up more than 1 year from the date of surgery. The factors we were concerned with were the type of esotropia, the age at surgery, the methods of operation, the refractive conditions and the bi-nocular visual functions. Type of esotropia might he the most important factor that determined the success rate of surgery. The total success rate in accommodative esotropia was 88.6% while in the nonaccommodative type it was only 70.1%. Overcorrection was more frequent in nonaccommodative esotropia (19.4%) than in accommodative (5.1%). Intentional overcorrection produced a good result in accommodative type (success rate 83.8%), but was very dangerous in nonaccommodative esotropia (success rate only 38.5% with 53.8% overcorrection). Monocular esotropia showed itself in this study to be very unstable and tended to be exotropic in the follow up period. Bimedial rectus recession was more effective (success rate 91.7%) in normalizing the high AC/A ratio than one medial rectus recession (success rate 72.7%). The statement that esotropia with high AC/A may be corrected by bimedial recess 4 to 5mm without fear of over-correction at distant in not always true. Two of our 14 patients became exotropic in the follow- up period. But bimedial rectus recession still is the first choice of operation in the management of esotropia with high AC/A ratio, because of its safety, less inflammatory reaction and high success rate. Age group in this study also presented a meaningful effect on the result of surgery. Cases under the age of 4 yrs. tended to be under-corrected immediately after operation and to be esotropic in the follow up period while cases over the age of 5 yrs. tended to be overcorrected and become exotropic. The ratio of under-correction to overcorrection was 6/2 in the former age group and 13/28 in the latter one immediately after operation, and 5/1 to 13/28 in the follow up period. Early surgery of esotropia was recommented in this study to avoid secondary changes in conjunctiva, Tenon's capsule and the horizontal rectus muscles. The result of early surgery was more predictable and stable during the follow up period. The problem on which muscle, how many muscles and how much surgery to do on those muscles has been a difficult decision for most of our surgeons. In this study, one millimeter medial rectus recession for 4∆ correction of esotropia and one millimeter lateral rectus resection for 2.5∆ correction seemed reasonable in two muscle surgery. But in larger deviations in which more than three muscles had to be done, more effect should be estimated per millimeter of recession/resection. The overcorreciton rate in two muscle surgery in our study was 9.6% while in three muscle surgery was 22.4% and in four muscle surgery up to 58.3%. Hyperopia more than +3.25D seemed to have the ability to keep the eye from becoming exotropic, but this was not the cases in monocular esotropia, which tended to be exotropic in spite of any refractive conditions. Binocular visual function was also an important factor in keeping the eye in normal position. Only 57.7% of cases without any stereopsis could keep the eye in normal range while 90.8% of cases with gross to fine stereopsis could do so. Esotropia with vertical deviation could be corrected in one operation with good result (success rate was 82.6%). Surgery on vertical muscles seemed to produce only negligible effect on the horizontal position of eyeball, since in our cases, no special consideration of the effect of vertical muscle surgery was taken in planning the operation.