There seems to be a considerable difference of opinion among ophthalmologists regarding the tractability of chronic primary glaucoma to operative treatment. There are those who believe that the disease can be arrested in most cases by well chosen and well executed operation when indicated, and there are others who take a much less optimistic view. Judgment in the choice of the operation and the technic employed do not seem to be the most important factors in this difference of opinion; it rests rather on the time in the course of the disease at which the operation is performed. My own observations have inclined me to the opinion of those ophthalmologists who hold that primary glaucoma is relatively tractable if the patient is operated on in the early stages of the disease when an operation is indicated and relatively intractable if the operation is deferred until the disease has advanced. In