As indicated above, the success rate depends on case selection, length of follow-up, whose cases they are, who evaluates them, etc. The impetus for change in the latter series was the unavoidable morbidity associated with encircling and drainage. In order to make sure that the overall success rate corresponded to the published norm of 80-90%, modifications occurred gradually - first by tying the band loosely, then by omitting it. Modifications were also made by shortening the circumferential 7-mm explant and finally by just buckling the breaks, preferably in a radial orientation. Fewer and fewer cases were drained, sometimes at the cost of sleep.
This experience somewhat parallels the trend described by Lincoff,who drained 48% of cases in 1963 and only 13% by 1971 , or by Kreissig who drained almost all cases in 1966,6% of cases in 1972  and none in 1992 . The reasons for drainage were (1) giant tears, (2) severe preretinal retraction, (3) uncertain localization of the break, (4) defective choroid, (5) thin sclera, or (6) glaucoma . Reasons 1-3 might be managed by vitrectomy techniques today including encircling with the ubiquitous 3.5-mm band, which reduces indications for drainage.
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