It will be observed that in the preceding remarks we have dealt with two of the problems which confront us in diagnosis, for the simple reason that it is very difficult to separate them; to do so would mean needless repetition. The discovery of the new position of the lens, and of the degree of fixation, if any, it has undergone, can hardly be divorced from the question of whether a couching has or has not been performed. Our third problem was to decide whether it is advisable to operate in any cases, and if so, in which. The Baron de Wenzel, in his treatise on cataract,[4] records two cases in which his father successfully extracted couched lenses. A number of Anglo-Indian surgeons have had similar experiences, but most of them are reluctant to interfere with these cases oftener than they can help, because, should the operation fail, it is extremely likely that they will unjustly incur the odium for the loss of the patient’s vision. On this subject Maynard wrote (_Ophthalmic Review_, April, 1903): “It may be justifiable to attempt the removal of a recently couched lens. If not recent, and more especially if the lens is fixed, it is wiser to leave it alone, even if the sight is failing.” To the writer’s mind, the one crying indication for removal of a couched lens is that it flaps across and obstructs the pupil. He agrees strongly with Maynard, that if the lens is fixed it is better left alone; but he is doubtful whether the time element is of very great importance, in comparison with the mobility of the cataract; for a study of the fifty-four globes already dealt with has shown him that the fixation or otherwise of the lens is a question of the amount of septic action set up by the operation. If this is small, the lens may continue mobile, even for a very long period; if it is more severe, the latter will soon be tethered. Dealing with this subject five years ago (Proc. of S. Indian Branch of B.M.A., March 13, 1912), the author wrote as follows: [4] Translation by James Ware, surgeon, F.R.S.; London, 1812. “We are extremely reluctant in Madras to undertake further operative procedures on an eye in which couching has been performed. Removal of a lens dislocated into the posterior chamber obviously means a wide opening up of the vitreous; and even if the immediate result appears good, there is little guarantee that the benefit will continue. Of eighteen cases in which the lens was removed, twelve obtained better vision at the time, four remained _in statu quo_, and two were rendered worse. I cannot but think that these statistics would suffer if the cases were followed for some years. On five occasions we undertook the laceration of an after-cataract which blocked the line of sight after couching. In two cases there was considerable benefit, whilst in three vision remained _in statu quo ante_. In four cases an iridectomy was performed for optical purposes. In two vision improved slightly, whilst in the two others it remained as before.