We read with special interest the article by Auriol and associates describing risk factors for development of choroidal detachment after sclera buckling. Some points need to be addressed.
Apposition of the retina to the retinal pigment epithelium may be achieved not only by buckling or intraocular tamponade, but also by drainage of subretinal fluid. Also, the authors refer to scleral buckling and an encircling band interchangeably, whereas most surgeons do not use an encircling band in all scleral buckle cases, often performing segmental buckles without banding. The primary purposes of a band are to provide support to retinal tears in different quadrants by creating a circumferential buckling effect and probably in some cases to relieve vitreoretinal traction circumferentially. Normally, regulation of intraocular pressure after subretinal fluid drainage is not among them.
Reference 14 in the article, which is cited to support a rate of choroidal hemorrhagic and or serous detachment of 23% to 44%, is a review article that cites original references dating from 1975 and 1966 that refer only to serous choroidal detachments. Also, surgical techniques in that era were different from what generally is performed now, so these statistics are not valid today.
The authors lump together serous, serosanguineous, and hemorrhagic choroidal detachments. The pathophysiologic features of serous and hemorrhagic choroidal detachment often are different. Serous detachments generally are related to ocular hypotony or inflammation. Hemorrhagic detachments also may occur as a result of hypotony, but risk factors also include trauma, particularly the surgical trauma of choroidal perforation, systemic hypertension, glaucoma, age, and high myopia.
This series of 69 consecutive rhegmatogenous retinal detachment cases all underwent drainage of subretinal fluid. Many retinal surgeons try not to perform drainage if possible; it is the riskiest maneuver during buckling surgery because choroidal perforation may hemorrhage, and also drainage of subretinal fluid may be accompanied by intraoperative hypotony. Furthermore, the authors do not state how they restored intraocular pressure if the volume of subretinal fluid drained was greater than the buckle volume. Do they simply tighten the band excessively? The authors claim no intraoperative hypotonia was observed, even though all cases were drained; this is ideal, but how was it avoided?
Ten hemorrhagic choroidal detachments from 69 cases is a very high incidence. Further, trans-scleral cryopexy under microscopic visualization was performed in all cases, but this is rarely performed outside of Europe and is a much more difficult technique than cryopexy with indirect ophthalmoscopy. Indirect ophthalmoscopy is the gold standard for sclera buckling in most of the world.
The Discussion states: “The objective of this study was thus to identify conditions leading to the formation of choroidal detachment during sclera buckling surgery . . . .” However, the authors previously state that the principal outcome measure was intraoperative systolic arterial blood pressure. Clearly, the principal outcome measure was selected after analysis of the data and not before, and thus this is not proper statistical procedure.