4.6.6.2  The Stroma

Nevertheless, the stroma might also have some ability to regenerate the cornea. That is what the Thill and his assistant study [7] seems to demonstrate with the highlighting of a new population of repairing stem cells located inside the adult human corneal stroma. These cells might evolve toward the monocytemacrophage specie or toward the fi broblast specie (keratocytes).

There is a parallel to draw between the Thill and assistant study and the study by Kubota and Fagerlhom [15] who have demonstrated that the importance of the initial corneal edema, resulting from a burn, is correlated to the importance of the sequelar cicatricial leukoma that causes the drop of vision. The stromal lacunae, formed by the edema, will be colonized by the keratocytes. After the resorption of the edema and at the level of these lacunae, the keratocytes form a zone of cicatricial tissue, which is the origin of the leukoma. These keratocytes also produce an unorganized network of collagen fibrillae, thus causing the drop of transparency of the cornea.

This study should be considered in relation with the Jester study [16] on rabbits. The latter suggests that the postnatal development of the corneal transparency of rabbits might be associated with the decline of the density of keratocytes, with their evolution toward resting state and with their excretion of two water soluble­ proteins:­ class 1A1 dehydrogenase aldehyde and transketolase.

At last, we must mention the essential role of vitamin C in the making by keratocytes of an unorganized network of even, uniform and parallel to each other collagen fibrillae [15]. And yet when ocular burns caused by basic aggressors occur, the ascorbic acid rate in aqueous humor remains low during the month following the burn [15].

4.6.7  Action of the Intraocular Pressure

Its action on the corneal transparency only visible in case of pathology, the part played by the intraocular pressure is to be considered separately. Indeed, the big increase of the intraocular pressure may cause a stromal edema and this might happen after a chemical eye burn with lesion at the level of the trabeculum,

occurring in clinical study during the second or third following week.

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