14 SIR DAVID BREWSTER ON THE CAUSE AND CURE OF CATARACT. 



restored, and by the use of spectacles the vision becomes as perfect as it was 

 before the change. If glasses are not used when the change is completed, the 

 eye must either strain itself, or use a strong light, to produce distinct vision in 

 reading the small type and the imperfect printing which characterises the daily 

 press ; and by both these processes it will, in a greater or less degree, be injured. 

 It is a strange delusion, arising either from ignorance or vanity, which induces 

 most people to put off the use of spectacles as long as possible. From the instant 

 they are required, spectacles of different focal lengths ought to be used for the 

 different purposes for which distinct vision is required, and the eyes should never 

 do any work, unless they can do it with perfect distinctness and satisfaction. 

 There is no branch of the healing art where science comes so directly and imme- 

 diately to the relief of impaired functions as that which relates to vision, and none 

 where science has been so imperfectly applied. When the change in question 

 takes place, the eye requires to be carefully watched, and used with the greatest 

 caution ; and if there is any appearance of a separation of the fibres or lamina?, 

 those means should be adopted which, by improving the general health, are most 

 likely to restore the aqueous humour to its usual state. Nothing is more easy 

 than to determine the condition of the crystalline lens ; and by the examination 

 of a small luminous object placed at a distance, and the interposition of small 

 apertures, and small opaque bodies of a spherical form, we can ascertain the 

 exact point in the lens where the fibres and laminae have begun to separate, 

 and may observe from day to day whether the disease is gaining ground or dis- 

 appearing. 



[Since the preceding paper was read I have seen a remarkable work, entitled 

 "Etudes Cliniques sur V evacuation de VHumeuv Aqueuse dans les Maladies de 

 VCEil" par Casimir Spirino, Turin, 1862. Pp. 500. M. Spirixo had, in the 

 course of little more than a year, operated upon forty-five cases of cataract. In 

 many of these the cataract was perfectly cured, and in others the sight was 

 improved. The first case was that of a lady of eighty-one, who had cataract in 

 both eyes. After thirty-two evacuations of the aqueous humour by the same 

 aperture, and almost always two or three times at the same sitting, both cataracts 

 disappeared, the lady was able to read, without glasses, Nos. 3 and 4 of Jaeger's 

 scale, at the distance of 4 or 5 inches, and even to thread a small needle.] 



