lO 



s. HOLTH AND O. BERNER. M.-N. Kl. 



much reading and line close work under strong convergence and with 

 bent head. She never squinted, and like her brother and sister, she had 

 good muscle balance for the distance of 5 meters and of 25 centimeters. 



Anna's emmetropic twin brother Axel [case b] was until his 30^^ year 

 a country gentleman and did not do much reading or near work during 

 his youth; he never suffered from spa^m of accommodation. 



Treatment. Presbyopes with exclusively indoor life may prefer no 

 treatment at all [e. g. case b) Axel B]. ; they can read for a long time 

 without glasses. But in outdoor life the twilight-blindness is very embar- 

 rassing and can be relieved in two ways: 



i) By daily application of mydriatics to the eyes, when myopic, as 

 long as the pupils by this means can be dilated to 1.5 or 2 mm. diameter; 

 this treatment is also indicated by other refraction anomalies when the 

 miosis is complicated by spasm of accommodation. It appears, however, 

 that a local habitude to or resistance against mydriatics develops after the 

 lapse of many years, so that their dilating power on the pupil gradually 

 decreases [case a) and c)]. It is scarcely age which effects this, for in 

 case b), Axel B. at the age of 52, a single instillation of i per cent 

 homatropine dilated the pupils to 2 and 2.5 mm. as other mydriatics with 

 the sisters at the age of 20 to 30 years. 



2) By optical iridectomy — as a rule upwards; indicated in all re- 

 fraction conditions where the accommodation should be left intact, but also 

 if mydriatics appear to be injurious e. g. by increasing of tension (which 

 I have not yet seen in my cases). Iridectomy may also prove necessary 

 in elderly myopic persons, when the dilating effects of mydriatics after 

 daily applications during many years are at last insufficient or nil [case c)]. 



