a rough estimate of the distribution of collagen types in the trabecular meshwork was based on 3-hydroxyproline/4-hydroxyproline ratios , indicating an age-related increase of type i collagen from about 55 to 70 per cent , and of type iv collagen from about 2 to 5 per cent of the total protein present .
C0009325
collagen
C0041455
type i collagen