Of 43 eyes with retinal detachment reviewed for this slit. lamp biomicroscopic study, 35 eyes (81.4%) were associated with retinal breaks. Most attention has been concerned with the degenerative changes that so frequently occur in the retina : these together with associated degenerations of the vitreous gel, posterior vitreous detachments and the part played by the adherence of mambranes and bands to the retina in determining the origin of a tear in this tissue.
The authors are of the opinion, that total posterior vitreous detachment with collapse, is one of the predisposing factors to lead to a horseshoe tear. In posterior vitreous detachment with collapse, the solid vitreous in the superior part is found only anteriorly next to the vitreous base. In event of trauma and sudden movement of the eyeball, vitreoretinal adhesion, which when located in superior 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. (S.Fig. 9A) On the other hand, in simple total posterior vitreous detachment, a round hole often occurs in the equator as well as in the macular region, because the s3lidification power or the formed vitreous operates as the force on the vitreoretinal adhesion toward the center of the eyeball. (S.Fig. 9 Band C)
With various advantages of the slit lamp biomioroscopic findings of vitreous and retina, retinopexies (diathermies and cryothermies) and vitrectomies could be effectively performed. Postoperative progress of 32 eyes were observed with slit lamp and compared with postoperative findings related with various methods of operations. In emmetropic and slight myopic eyes, only surface diathermy produced sufficient effects for retina surgery; so far there is no mechanical hindrances to the apposition of the retina to its bed caused by retraction bands in the vitreous or fixed retinal folds. In macular break, we prefer to manage by mean of cryopexy; a more dramatic effect could be attained by additional implantation of amniotic tissue in the posterior pole. Dextran, as a vitreous substitute, which was proposed by Won Sik Yoon in his animal experiments, is not suitable, because it has a tendency to retract solid vitreous.
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