Closed branches of conjunctival vessels.

NORMAL conjunctival vessels have been studied with the slit lamp by many observers, including Koeppe (1920-22), Vogt (1930-31), Graves (1934), Berliner (1943), and Meesmann (1927). The conjunctival vessels are capillaries, many of which are seen to be filled with red blood corpuscles; some of these capillaries are fairly large, but others are fine. These capillaries, containing one row of red blood corpuscles, have been traced from artery to vein (Graves, 1934). It is very important that no definite walls have been found in these fine vessels, even with a high-power slit lamp. The normal conjunctival blood vessels can be irritated witlh chemical, traumatic, or bacterial agents, one of the simplest ways being to insert a drop of dionin 2 to 5 per cent. as I have described in a previous communication (Loewenstein, 1944). The dilated conjunctival blood vessels can then be studied, and there is an increase of ten to twenty times the number of small capillaries in eyes so treated. I tried to study the normal area supplied by the capillaries, but it is not easy to examine eyes with the slit lamp when using a high magnification. Finally, I kept my own eye at rest under high power, and our artist, Mr. G. Donald, sketched the conjunctival capillaries (Fig. 1). There were many very fine capillaries containing red cells, but I expected to find some + very fine capillaries apparently empty as had been previously s noted,. and such very fine capillaries were bh. H found in myconjunc-dn tiva, apparently empty and colourless. Some had no red blood cells in them, while others P2 contained various types FIG. 1 Blood free capillaries of the conjunctiva of blood corpuscles seen in high-power slit lamp. *Received for publication April 5, 1951. + This research was sponsored by the W. H. Ross Foundation (Scotland) for the Study of the Prevention of Blindness.