New Electrode Transilluminator
Andrew Osmond · British Journal of Ophthalmology · 1954
Worthing and BrightonTHE classical operation for retinal detachment, although giving an 80-85 per cent.success rate in skilled hands, appears to have one uncertain feature, namely, the ability of the surgeon to place the diathermy electrode exactly on the point of the sclera corresponding to the hole in the retina.To achieve this, one has been taught to think in terms of meridians and optic disc diameters, and then, by making a tentative " shot" with the diathermy, to look and see if the answer to the calculations is anything like right (Gonin's method).Textbooks make this sound easy, and so indeed it may be, provided the diathermy has made a mark on the retina which is easily recognizable.But so often it has not, either because the current at the electrode was not sufficiently great, or because there was too much inter- vening fluid for the retina to show coagulation.It would be helpful to have a really positive method of marking on the outside of the sclera the exact position of a retinal hole or tear within, and to this end I have reviewed the methods used by surgeons in Britain and else- where.The earlier ones, summarized by Duke-Elder (1934), all depend fundamentally upon the estimation of meridian and latitude.They include the perimetric methods of Lindner (1929) and Klein (1933), the tangential projection method of Cowan and McAndrews (1931), the " thread " method of Imre (1930), and that of Weve (1931), which depended upon the projection of the retinal hole upon an artificial eye.To these must be added the" stud" method of Foster Moore (1931), and that advocated by Vogt (1936), which depended on the production of hydrogen bubbles round a perforating electrode.None appears to offer a completely satisfactory solution to the problem; some because they require elaborate apparatus and others because they depend upon perforating the globe, which not only causes additional trauma, but also makes subsequent diathermy on a collapsed eye much more difficult.The new method of Weve (1940) and Arruga (1936) is a very different matter.The hole is located by indirect ophthalmoscopy, using an extremely powerful light, and the sclera is marked with Chinese ink at the point where the light is seen by translucence.It seems that this is certainly the best method in use to-day, as it provides a way of marking the sclera which is quick and accurate in skilled hands.