IMPROVEMENTS IN SPECTACLE FRAMES. By HENRY D] NOYES, M.D., New York. THE following contrivances have been made by the optician, Mr. William Hunter, of New York, to meet certain special requirements in spectacle frames. Reversible Frames.-For a person having the use of only one eye and who needs two glasses for different kinds of vision, it has been customary to make a frame whose bridge is on a line with the transverse diameter of the glasses, and which is reversed by turning it over in a plane parallel to the suLrface of the face. This is the kind of frame worn by patients who have had a cataract operation upon only one eye. The inconvenience attending this arrangement is that the bridge is not equally fitted to the use of the glass for distant and for near sight. If the nose be prominent, this may be exceedingly awkward. Moreover, in wearing cataract glasses, the person's comfort is promoted by having the frames light, and by having the arms turned over so as to hook behind the ears. The accomplishment of these objects has been secured by joining, each arm to the body of the frame by two hinges which are close together. Each arm can then be made to sweep through a complete circle, and the glasses reversed by turning the frame in a plane parallel to the ground. This does not reverse the bridge, which may be as concave as needed by the shape of the nose, and permits the arms to hook over the ears. Another device which accomplishes the same object is to use a balland-socket joint for attaching the arms to the frame. This permits the arms to hook over the ears, but compels the employment of a horizontal bridge. Double glasses.-For glasses of short focus a difficulty arises because of the great amount of aberration inseparable from their spherical curvature. If the patient look through the centre of the glass this error is small, but to do this renders fluent reading impossible. The eye cannot glance along the line and anticipate the words. I have been able to abate this annoyance by putting together two planoconvex lenses each of half the needful focus, with their convex sides toward each other. This well-known optical device has been found

357 satisfactory in several instances. The obvious need of making the spectacles as weightless as possible, has been well achieved. One frame is by a simple mechanism made to fasten to the other, and is easily separable from it, so as to permit cleaning. This suggestion of doubling the spectacle glasses permits other applications. For instance, if a cylindric glass is needed and near vision requires a glass of power different from that needed for distance-the glass for most frequent use may be made cylindric, and the one for occasional use may have a spherical curve, either plus or minus. The question is simply one of convenience annd expense.