MYOPIA.
When the myopic eye is quite healthy a fair amount of exercise of the ciliary muscle will tend to keep up its normal tone, but the diminution of 37 the angle of convergence at near work by the employment of suitable concave glasses certainly tends to prevent the myopia increasing, and diminishes the danger of the supervention of organic disease so liable to occur in high degrees of shortsightedness.
Even when the myopia is fully corrected the habit of reading in bad light must be guarded against, and the patient should be encouraged to wear his glasses constantly for near work and to keep the print as far from his eyes as possible. The clearest type, the best light and the most suitable form of writing-desk should be selected. Special attention should be paid to the position in which school-work or reading is done, and the common habit of bending over a table corrected. The head should be thrown well back, and all tendency to congestion of the eyes avoided. If more attention was paid to the printing, type and paper entering into the ordinary schoobbooks, and if the result-fee system was done away with, there probably would he less myopia. Where pain or aching follows the use of the eyes all school work should be given up entirely for a short period, and after the complete rest has removed these symptoms, shorter school hours, better print, and clearer light should be provided.
Experience pronounces in favour of a full rather than a partial correc tion of the myopia. Suitable concave lenses fitted in a spectacle frame are preferable to folders or pince-nez. In the higher degrees it is a good plan to disorder the accommodation by instilling Atropine, so as to prevent the otherwise powerful efforts at accommodating. In very mild cases,
resulting from overwork, especially when the eyes have been long and persistently fixed upon minute objects, and where myopia may be said to be commencing, the proper treatment will be to insist upon proper rest to the eyes and the instilling of a drop of weak Eserine solution every night for a couple of months.
In high degrees of myopia, operative cure should be considered. The practice of removing the lens has given satisfactory results, the resulting acuity of vision being greater without the aid of lenses than that attain able by glasses. It causes a lessening of the myopia by from 12 to 20 dioptres, so should only be done in cases where the myopia is over 20 D, except in children with progressive myopia of 12 D or more. In these last cases the best results are obtained. The lens is needled, and after some time what fragments remain unabsorbed can be removed by ex traction. Swanzy advises that, owing to the possibility of the super vention of detachment of the retina, one eye only should be operated upon, this being kept for distant vision, whilst its fellow can be employed for near work. The recent statistics from Leipzig and Giessen demonstrate that detachment of the retina followed in 44 cases out of 400 operated upon for a high degree of myopia, hut considering that in a fair percentage of these cases detachment would have supervened without operation the removal of the lens is more than justified. All authorities agree that the operation should be performed only on otherwise healthy eyes, and that the risk of failure following operation after 3o is very great.