76 



MICROSCOPY OF THE LIVING EYE 



True flattening of part of the corneal face following injury or 

 disease is possible, but rare. Not infrequently nebulae or scars 

 deep to the surface will simulate flattening of the surface when 

 examined with the wide slit-beam, as shown diagrammatically in 

 Fig. 18, A ; but when they are examined in the thin optical 



B 



Fig. 44. — A, Superficial nebula of the cornea revealed by 

 " sclerotic scatter." B, The nebula by direct illumina- 

 tion. C, The pathological vessels in the nebula by direct 

 illumination and retroillumination. D, Thin optical 

 section of the cornea in the region of the nebulous 

 infiltration. (Drawn by Theodore Harnblin, Ltd.) 



section (Fig. 18, B) the surface contour of the cornea is seen to be 

 normal. 



Localised bullae or blebs of the corneal surface caused by fluid- 

 elevation of the epithelium show by direct-illumination in the 

 thin optical section as in Fig. 18, C ; they are also revealed clearly 

 by retroillumination. 



A permanent superficial scar of the anterior corneal surface 

 due to a grazing blow from a missile, is shown in Fig. 45, A ; in 



