IRIS AND LENS 



81 



one emerging through the pigment layer posteriorly and one through 

 the stroma anteriorly. These last should not be called tubercles, 

 but nodules, because they are seldom of tubercular origin ; they 

 occur mostly in an unobtrusive, but very chronic and persistent 

 form of iridocyclitis of varying or uncertain aetiology. 



The iris is readily accessible to slit-lamp examination ; Fig. 48 

 shows a striking view of a small angio-sarcoma of the iris in process 



Fig. 48. — Small malignant highly vascular tumour of the iris, with 

 bleeding taking place from crypt-like cavities. 



of bleeding into the aqueous fluid, the patient having given the 

 history that on three or four occasions in the preceding two or 

 three years she had " seen red " with this eye whose sight was 

 otherwise normal. 



Care is required to obtain clear optical sections of the living 

 lens, owing to the distance separating the anterior and posterior 

 surfaces : a sharp section of both regions at the same time is 

 usually not obtamable, this particularly being the case when the 

 7-0 cm. focusing lens is used (see Fig. 11). It is, however, usual in 



