Experimental Xerophthalmia of Rats. 375 



182 (1929) 



Location of the earliest changes in experimental xerophthalmia of 



rats. 1 



By A. M. YUDKIN and R. A. LAMBERT. 



[From the Departments of Pathology and Physiological Chemistry, 

 Yale University, New Haven, Conn.] 



It is generally assumed that the lesions in experimental xer- 

 ophthalmia due to dietary deficiency have their origin in the 

 cornea which, in the advanced stage of the condition, becomes 

 markedly affected. A recent study of the eyes of a series of rats 

 on a diet deficient in fat-soluble A has led us to the conclusion 

 that it is the eyelid rather than the cornea that is primarily 

 affected. 



The following is a summary of the study. Six young rats, 

 weighing from 45 to 50 grams, were placed on a diet consisting of 

 casein, mineral salts, starch, lard, and yeast. After from 45 to 

 60 days, the first evidences of eye changes developed — watery 

 lacrimation with a serosanguineous conjunctival secretion, becom- 

 ing after a short time somewhat viscid. The rats were killed at 

 this stage and the eyes, with the lids attached, were embedded 

 and sectioned. In all cases early focal lesions were found in the 

 epithelial lining of the lids. The changes consisted of localized 

 foci of degeneration of the epidermis with cellular infiltration 

 which, in some cases, extended into the subepidermal tissue. In 

 all these early cases the cornea was found uninvolved, that is, 

 there were no degenerative changes which could be recognized 

 by ordinary stains, and no cellular or vascular reaction. 



These findings suggest that the eye changes resulting from 

 deficiency in fat-soluble A vitamine, which in the advanced stage is 

 characterized by a widespread keratitis, do not begin in the cornea 

 but have their origin in the lids. In this respect the sequence of 

 events is the same as that in some of the severer types of acute 

 and chronic conjunctivitis which are frequently complicated by 

 corneal injury, with infection and ulceration of this structure. 



1 This investigation was made in cooperation with Drs. Thomas B. Osborne and 

 Lafayette B. Mendel, under whose direction the feeding of the experimental animals 

 was conducted. The Connecticut Agricultural Experiment Station and the Carnegie 

 Institution of Washington shared the expenses of the research. 



