BLINDNESS. 193 
BLINDNESS. 
In advanced age the sight often becomes much impaired. But rarely, how- 
ever, is it wholly lost in consequence of years; for, as a rule, in blindness of 
long duration some structural change has occurred within the organ to account 
for it, such as opacity of the cornea, failure or paralysis of the optic nerve, 
cataract, or destruction of part of the refracting apparatus by disease. Animal 
parasites may also invade the eyeball and destroy the sight, they or their germs 
having been first acquired by eating infected raw meat. 
In certain diseases, notably of the brain, blindness may occur. There are 
cases in which the causation is very obscure; but it is reasonable to attribute 
them in some instances to reflex irritation from worms in the intestinal canal, 
while in others intense derangement of some important organ, as the liver or 
kidneys, may rightly be held responsible. 
An injury to the eye is always a serious and important matter, and should 
claim immediate attention ; for if the damage is not irreparable at the instant of 
the accident, destructive changes may be set up which are apt to go on until the 
sight is nearly or entirely destroyed. 
The most serious injuries as a rule are those received in fighting ; and while 
some may be entirely recovered from, in the majority of the cases of wounds 
thus received the eye is practically ruined. Nor is this painful result always 
limited to the injured eye. Indeed its fellow eye is often in time as seriously 
affected by sympathetic disease excited therein. 
Judicious treatment, however, will often accomplish great good, and possibly 
save the entire sight. It is evident, therefore, that in all injuries the best medi- 
cal advice available should be obtained, and, if possible, always that of physi- 
cians who make the eye a specialty. 
Excepting those cases in which it is caused by intestinal worms, the chances 
of recovery from blindness are never good, although the cause and duration are 
in some degree influential in forming a favorable prognosis. In blindness of 
recent and quite sudden occurrence due to injury or acute inflammation, partial 
or complete recovery occurs in some cases. On the other hand, in cases of 
several months duration in which the loss of sight was gradual, entire recovery 
is exceedingly rare, for then structural changes beyond repair have almost 
always taken place. : 
Where the indirect cause is intestinal worms the loss of vision is only 
moderate, unless it is of long standing, although it may appear to be quite com- 
plete ; for it is exaggerated by the affection of the nervous system with which it 
is associated. This latter affection is commonly a paralysis of considerable 
degree, especially of the hind parts. 
If the worms are speedily removed, the blindness is generally recovered from. 
