30 PRACTICE OF PHYSIC. 



I have therefore given the advice, that the first and fundamen- 

 tal remedy, in all kinds of ophthalmia, is the avoiding all exer- 

 cise of the eye, and therefore all application or admission of 

 light. 



" I am disposed to believe that the obstinacy of many cases 

 of ophthalmia is merely owing to the admission of light. For, 

 though every body avoids the direct light of the fire or sun, yet 

 patients do the matter only by halves ; and although they slouch 

 the hat, hang before the eye a bit of green silk, &c. they still 

 look upon objects which are strongly illuminated. The same 

 may be said of a skreen between the patient and the fire, and of 

 candle skreens ; they are very imperfect means of avoiding the 

 light. Another way is to tie up the affected eye, but neither is 

 this sufficient, as the motions of the two eyes are necessarily 

 connected together, so that the covered eye constantly follows 

 the other, and is affected so far as motion can operate. Shutting 

 up the eye also accumulates the perspiration and confines the 

 heat, which is considerably increased. There is therefore no 

 effectual means of avoiding the irritation of light and the mo- 

 tion of the eye, but putting the person into a dark chamber ; 

 and I am certain of the good effects of this in many cases. 11 



CCLXXXVIII. These are the remedies of the Ophthalmia 

 membranarum ; and, in the Ophthalmia tarsi, so far as it is pro- 

 duced by the Ophthalmia membranarum, the same remedies 

 may be necessary. As, however, the Ophthalmia tarsi may 

 often depend upon an acrimony deposited in the sebaceous 

 glands of the part, so it may require various internal remedies 

 according to the nature of the acrimony in fault ; for which I 

 must refer to the consideration of scrofula, syphilis, or other dis- 

 eases with which this ophthalmia may be connected ; and, when 

 the nature of the acrimony is not ascertained, certain remedies, 

 more generally adapted to the evacuation of acrimony, such, for 

 instance, as mercury, may be employed. 



CCLXXXIX. In the Ophthalmia tarsi, it almost constant- 

 ly happens that some ulcerations are formed on the tarsus. 

 These require the application of mercury or copper, either of 

 which may by itself sometimes entirely cure the affection ; and 

 these may even be useful when the disease depends upon a fault 

 of the whole system. 



