Experimenters in animal nutrition have frequently observed the susceptibility of animals on certain deficient diets to an affection of the eye which is variously described as a conjunctivitis,1 a xerophthalmia 2 or a keratomalacia.3 This usually begins with swelling of the eyelids, followed by an inflammation of the conjunctivitae and a haemorrhagic discharge which frequently becomes purulent. Unless treated the cornea eventually becomes involved and total blindness results.

Wason4 sums up the results of a study of the pathology of this eye condition as follows:

1. The primary etiological factor in ophthalmia of rats is lack of the vitamin A.

2. The nature and mechanism of the change in these rats whereby their corneas are rendered susceptible to bacterial invasion is unknown.

3. The type and virulence of the organism of secondary infection determine, in part at least, the course of the disease.

4. The anatomic manifestations of the disease are characterized by hyalinization or necrosis of the outer layer of the corneal epithelium, exudation of serum and cells into epithelium and stroma, and proliferation of the blood vessels and fibroblasts. In advanced cases invasion of the anterior, and occasionally of the posterior chamber result.

5. The degree to which restoration is possible depends on the extent of the secondary injury.

While this disease has been most commonly reported in rats, Nelson and Lamb5 have found that rabbits are also susceptible, although they failed to produce the characteristics in guinea pigs or chickens under the same conditions. Guerrero and Concepcion6 however, report cases of xerophthalmia developing in fowls fed on a polished rice ration. Of five birds on an exclusive diet of polished rice all developed polyneuritis and one became blind. Of 30 more which were given polished rice with the addition of "tikitiki extract" five developed polyneuritis and seven died after developing xerophthalmia, which appeared in some cases as early as the seventh day and in others not until the seventy-ninth day of the experiment.

1 Falta and Noeggerath, Beit. 3, Chem. Physiol, u. Path. 7, 313, 1906. Knapp, Z. f. Exp. Path. 5, 147, 1908; Steenbock, Sci. Mo. 7, 179, 1918.

2 McCollum and Simmonds, J. Biol. Chem. 32, 182, 1917. 3 Stevenson and Clark, Bioch. J. 14, 502, 1920.

4 Wason, J. Am. Med. Ass. 76, 908, 1921. 5 Nelson and Lamb, Sci. 52, 393, 566, 1920.

Symptoms similar to those noted in animals have been described in young children whose diet is known to have been deficient in fat, Mori7 reported over 1400 cases of such a disease in Japanese children, which he believed to be due to fat starvation and which was cured by administration of liver (chicken and fish) or eel fat. Czerny and Keller8 describe what are probably analogous cases of eye disease in children suffering from malnutrition as a result of restriction to a cereal diet, and further instances, all of which appear to be of dietary origin, are given by Monrad9 and Ronne10 and Bloch.11 Bloch describes over fifty cases observed in Copenhagen. The most severe cases occurred in children about twelve months old, who had been fed on separator milk, and were characterized by hardening of the cornea, ulceration, necrosis, and ultimate blindness. External treatment gave little relief and no permanent improvement. As all the patients showed pronounced symptoms of malnutrition Bloch was led to connect the eye disease with this general condition, and investigation into their previous diets suggested that the most serious defect in their nutrition was lack of fat.

The treatment consisted in feeding on whole milk together with as much cod liver oil as could be tolerated, which resulted in the rapid disappearance of the eye trouble together with marked general improvement. On milk alone, without the addition of the cod-liver oil, recovery was much slower, and was frequently too late to save the sight.

A particularly interesting case noted was that of an orphanage in which there were 86 children of various ages up to two years. The inmates were divided into three sections, group I, made up of infants and ailing children, and two groups, Ha and lib, of older children. Eight cases of xerophthalmia appeared in group Ha, while the rest of the institution was free from it. Group I was receiving the whole milk, on which they all made satisfactory progress. Group II received an apparently liberal diet of cocoa, buttermilk, milk foods made with separator milk, various kinds of bread, margarine, cereals, fruit syrups, boiled fish, minced meat, and mashed potatoes. No butter, eggs, or cream was used, and no whole milk except a small amount which was given to group lib with a beer and bread porridge for breakfast. The children in Ha (the group in which the xerophthalmia appeared) breakfasted off rusks and gruel and were given no whole milk. As this small addition of whole milk to the diet of one group was the only variation in the treatment of the older children it would appear that it must have been sufficient to prevent the onset of the disease in group lib.

Local treatments have failed to cure the eye condition (although it was slight in all cases.) Ten gms. of cod-liver oil were administered twice a day, resulting in a complete cure in eight days. Thereafter the separator milk in the diet was partly replaced by whole milk.

6 Guerrero and Concepcion, Phil. J. Soi. 17, 99, 1020. 7 Mori, Jahib. f. Kinderh. 50, 175, 1004.

8 Czerny and Keller, Des Kindes, Leipsic. 1006, pt. 2, p. 67.

9 Monrad, Ugeak. f. Laeger, 70, 1177, 1017.

10 Ronne, Ugeak. f. Laeger, 70, 1470, 1017.

11 Bloch, Ugeak. f. Laeger, 70, 340, 1017; Rigahoap. Boerneaf. Med. 2, 1, 17; 3, 57,1018. Quoted in Rep. 38, Med. Res. Com. p. 76.

On the other hand, von Grocr12 succeeded in maintaining two infants during their first half year of life on a practically fat-free diet, consisting at first of separator milk and sugar alone, and later of a porridge made with skimmed milk and sugar. The children grew at practically normal rate, and no symptoms of eye disease are reported, although there are some indications of lowered nutritive condition. Still more striking is the study reported by Hess13 in which five infants varying in age from five to twelve months were fed for eight or nine months on a diet consisting of 180 gms. of highly skimmed milk ("Krystalak," 0.2 per cent fat), 30 gms. cane sugar, 15 to 30 gms. autolyzed yeast, 15 c.c. of orange juice, 30 gms. of cottonseed oil, and cereal for the older infants. On this diet they are reported to have done well and to have shown no signs of eye trouble.