Localizing the Retinal Hole in the Surgical Treatment of Retinal Detachment.

The application of surface diathermy to the sclera, followed by ophthalmoscopic observation of the choroido-retinal reaction, is a time-honoured technique which may be used with shallow detachments; it fails with deep detachments, as no reaction can then be seen with the ophthalmoscope. Stallard (1958) advocated the focusing of a narrow beam of light from an ophthalmoscope on to the retinal hole; the operator's assistant observes the surface of the sclera and marks the point of transillumination. This technique has obvious limitations, as it is often not possible to position the eye so that both the retinal hole and the corresponding area of sclera can be observed simultaneously. Strampelli (1935) transilluminated the sclera in the opposite direction by means of a narrow curved tube carrying a transilluminating component and a diathermy terminal. The retina is then observed with an ophthalmoscope and, when the point of maximum illumination is over the tear, a diathermy application is made to mark the sclera. Schepens, Okamura, and Brockhurst (1957) advocated the use of a flat-tip diathermy electrode on a curved shank. An assistant indents the sclera with the electrode in the approximate region of the hole, while the operator observes the resulting choroidal indentation with an ophthalmoscope. The operator directs the assistant to move the electrode until the indentation coincides with the retinal hole, and a diathermy application is then made to mark the sclera.