144 VITAMINS A AND CAROTENES 



clarified and established the etiology of xerophthalmia and keratomalacia. 

 In the Japanese studies keratomalacia was relatively less common than in 

 the Danish outbreaks. Since the Japanese children were breast-fed and 

 derived limited amounts of vitamin A from the mother's milk, symptoms 

 appeared chiefly during the postweaning period (2 to 5 years of age). The 

 Danish children were mostly bottle-fed with skimmed cow's milk, often 

 boiled with consequent loss of vitamin A; hence, the symptoms appeared 

 earlier and in a more acute form. It is well recognized that, the younger 

 the infant, tbe more rapidly the ocular symptoms develop, and that in very 

 young infants signs of xerophthalmia and keratomalacia appear in rapid 

 sequence. In fact, keratomalacia has been observed in breast-fed infants**- *^ 

 and also in the newborn infant.*^ The incidence of xerophthalmia is low in 

 adults and particularly high in infants and young, actively growing chil- 

 dren. Some investigators consider the cornea of infants especially vul- 

 nerable. 



2. External Manifestations 



The usual sequence of ocular changes, as seen on ophthalmologic examina- 

 tion, is as follows: (1) night blindness; (2) dryness of the conjunctivae and 

 diminution in lacrimal secretions; (3) loss of normal luster of conjunctival 

 surfaces; (4) thickening, roughening, and wrinkling of the bulbar conjunc- 

 tiva; (5) appearance of foam-like, irregular placques on the sclera of the 

 palpebral fissure (Bitot's spots), and similar xerotic patches on the sub- 

 palpebral sclera ; (6) increasing opaqueness and hypoesthesia of the sclera 

 and cornea; (7) impaired vision in bright light; (8) edema, photophobia, 

 leucocytic infiltration, and necrotic softening of the cornea (stage of kerato- 

 malacia) ; (9) marked corneal opacity, corneal perforation, infection of the 

 anterior chamber, prolapse of the iris, and panophthalmitis. Body tempera- 

 ture is said to be increased in adults*^ and children*^ with keratomalacia, 

 returning to normal when other symptoms have regressed following therapy. 



The palpebral conjunctiva, perhaps because of its more protected loca- 

 tion, rarely shows more than a yellowish reddening, with some granulation 

 and thickening in more advanced stages of the ocular lesions; the conjunc- 

 tiva of the fornix and adjacent sclera usually shows yellowish to brownish- 

 grey discoloration in dark-skinned races. '^ Smears of epithelial scrapings 

 from the conjunctivae always contain a great abundance of bacterial organ- 

 isms of a variety of types. These are considered to have no specific relation- 



'3 J. Thalberg, Arch. Augenheilk. 12, 314 (1883). 



" J. H. deHaas, J. H. Posthuma, and O. Meulomans, Indian ./. Pcdicit. 8, 139 (1941). 



IB J. P. Maxwell, ./. Ohstet. Gynaecol. Brit. Empire 39, 764 (1932). 



16 A. Pillat, Arch. Ophthalmol. (Chicago) 2, 256, 399 (1929). 



17 K. L. Hsu, China Med. J. 41, 825 (1927). 



