DISEASES OF THE CORNEA 107 



first, a nebula, which is a slightly clouded patch; second, 

 a macula, a somewhat denser patch; and third, a leu- 

 koma, a dense opalescent patch. 



If the opacity is not over the pupillary area it does 

 not materially interfere with the vision, but if it be 

 centrally located vision of the central field is de- 

 stroyed. 



Treatment.— As the opacity is composed of cicatricial 

 tissue quite different in structure from the normal 

 elements of the cornea, it is impossible to reproduce a 

 perfect transparency, though in some cases the results 

 are surprising when proper treatment is employed. 

 The following remedies are useful: Dionin, in solution 

 of 5 to 10 per cent., or in the form of the powder, is 

 probably the best. Begin with 5 per cent, solution and 

 drop into the eye three to five times a day. This at first 

 produces an extreme reaction, and causes the con- 

 junctiva to become very red and edematous. When this 

 takes place, use it less frequently. The reaction subsides 

 in a day or two, and, after using the dionin a few times, 

 it ceases to have this effect, when a stronger solution 

 may be employed. In conjunction with this use the 

 yellow oxid of mercury ointment in the eye three times 

 a day, followed by massage. An ointment of thiosinamin, 

 10 per cent., is also recommended. The results are due, 

 in great part, to massage used with the appHcations. 

 Massage alone has been followed with excellent results. 

 One must have patience in the treatment of opacities, as 



