| Posterior Vitreous Detachment and its Relation to Type of Retinal Perforation. |
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Sang Ha Kim, Hwa Sun Jung |
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Department of Ophthalmology Kyung-buk National University, Hospital, Korea. |
| 초자체후박리와 (硝子體後剝離) 망막열공의 (網膜裂孔) 형태 |
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김상하 , 정화선 ( Sang Ha Kim , Hwa Sun Jung ) |
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| Abstract |
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Of 127 consecutive cases of relatively fresh rhegmatogenous retinal detachment, posterior vitreous detachments and their relation to type of retinal perforation were studied using a contact lens or Hruby lens and a biomicroscope for stereoscopic examination of the vitreous cavity and the fundus of the eve. Analysing 127 cases, the authors found a complets posterior vitreous detachment with collapse in 58 cases and a simple total pcsterior vitreous detachment in 69 cases. And posterior vitreous detachment was an indispensable factor for rhegmatogenous retinal detachment. The topographical site of election, however, varies with the type of perforation. Arrow-head tears occur preferentially in the upper half of the retina, particulaly with a predilection for the equatorial zone. Amog 26 horse-shoe shaped tears, 25tears were found in the upper half of the fundus and only one in the lower half. The horse-shoe shaped tears were always accompanied with total posterior vitreous detachment with collapse. In the series of 127 rhegmatogenous retinal detachment, 100 round holes were detected; 48 holes were found in the eyes wth total posterior vitreous detachment with collapse and 52 holes in the eye with simple total posterior vitreous detachment. The distribution of these perforations in the retina is of interest. The teares distributed almost equally in all quadrants. The vast majority occurred in the peripheral retina at equator or anterior to the equator and holes at juxtapapillary and intermedial areas are extremly rare. The authorse are of the opinion, that total posterior vitreous detachment with collapse, is one of the predisposing factors to lead to a horse-shoe shaped tear. In this type of vitreous detachment, the solid vitreous in the upper part is found only antereioly next to the vitreous base. In event of trauma and sudden movement of the eyeball, vitreoretinal adhesion, which located in the upper part of peripheral fundus may be pulled anteriorly and tangentially from the internal surface of the retina and so the base of the operculum deflects toward the ora serrata. The ascension phenomenon of the solid vitreous may also lead tc the formation of retinal tears in th elower part of the fundus. The convexity of the tear is always turned toward the optic nerve, and the concavity face the ora. The appearance of these rents may suggest that they not only are formed by a tearing process of a forward direction due to adhesion of the retina to the vitreous but also depend upon the typical network of retinal fibers. On the other hand, in simple total posterior vitreous detachment, a round hole of en occurrs in the equator as well as in macular, juxta papillary and intermedial region, because the solidification power of the formed vitreous operates as a force on the vitreoretinal adhesion toward the center of the eyeball. |
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