DISORDERS IN RELATION TO THE EYE 801 



lack is suggested in the dystrophic lamellar cataract of rickets, and in the 

 trophic disturbances of the cornea and sclera in this disease which are 

 analogous to the changes in the bones throughout the body. Special local 

 conditions, notably intra-ocular secretion and tension, are responsible for 

 reactions which are peculiar to the eye, such as the distention of its patho- 

 logically non-resistant and excessively elastic coverings which result in 

 megalccornea, bouphthalmos, and probably infantile glaucoma, so called. 

 The markedly hereditary character of these structural anomalies is another 

 link in the chain which connects the eye with both hormone and vitamin 

 supply. 



Visual Disturbances. As has already been noted, visual disturbances 

 of a uniform and characteristic nature are seen with certain congenital 

 abiotrophies, and again in apparently normal eyes, under the influence of 

 starvation, exhaustion, or the experimental withdrawal of one or the 

 other vitamin. Hemeralopia is the common symptom in retinitis pig- 

 mentosa, in avitaminosis, and in certain chronic disturbances of hepatic 

 metabolism. The relation of pigment to vision is indicated again by the 

 histological changes in the ocular tissues and by the fact that coloring 

 matter seems to be a characteristic of certain necessary food-elements. 

 Thus Sfeenbock concludes that the fat-soluble vitamin is related to cer- 

 tain yellow pigments found in butter, sweet potatoes, carrots, maize, and 

 spinach. Spoiled maize plays a role in pellagra, and in this disease and in 

 scurvy, degenerative processes with a marked pigmentary relation (nails) 

 are found. 



There are certain endocrin-metabolic implications in therapy, as well, 

 such as the beneficial effect of cod liver oil in starvation hemeralopia, in 

 the cataracts of acidotic hypothyroid states, the interstitial keratitis of 

 rickets and lymphatism, and in tetany. As the administration of calcium 

 itself seems to be of little value, the question arises whether this element 

 or the iodin in cod liver oil, a synthetically produced calcium, or a com- 

 bination of these elements, is the essential, and, finally, whether the reac- 

 tion is purely metabolic or not rather connected with chemical activation 

 of the thyroid. 



Xer ophthalmia and Keratomalacia. This affection has been observed 

 in rats, mice, young rabbits, and children as a result of a deficiency in 

 the diet of so-called fat-soluble vitamin (A). As histological examinations 

 showed no corneal changes in consonance with the name given, the condi- 

 tion is to be referred to simply as ophthalmia. Wason found hyalinization 

 of the corneal epithelium with signs of bacterial invasion and of pro- 

 ductive inflammation and vascularization in Bowman's membrane and 

 in the substantia propria. The corneal degeneration progresses to a gen- 

 erally perforative ulceration which may lead to the protrusion or extrusion 

 of the lens. Simple inanition and infection have been excluded as pos- 

 sible causes of this condition although, of course, there is almost always 



