Epidemiología clínica de la xeroftalmia en el hombre

Abstract

Although in the last decade outstanding research workers have published important reports on their studies, there is still not satisfactory work dealing with the clinical pathology of xerophthalmia

The essential feature of this disease and of hypovitaminosis A in man is xerosis whose ocular manifestations are roughness, rigidity, opacity, pigmentation, dryness, and absence of tearing

After reviewing the clinical and epidemiological evidence on the function of vitamin A in man and leaving aside the arguments provided by the concentrations of retinol and carotene in the serum and the tissues as well as histological studies, it appears that:

The only inequivocable clinical proof is epithelial changes in the external surface of the eye and functional changes of the retina

Epithelial xerosis of the conjunctiva and the cornea are due to keratinizing metaplasia which may be considered a differentiating regression. The exposed parts of the eye socket are especially affected. Hyperpigmentation typical of these parts is a secondary effect

After weaning, the dietetic problem is related to the ingestion and utilization of carotene rather than of retinol

The most commonly affected age group among the poor is children between the ages of 2 and 4; they are affected slightly later than the victims of protein malnutrition

Night blindness and xerophthalmia are often closely related; only during pregnancy ...(AU)