It has been observed that those antibiotics which penetrate into the spinal fluid through the so-called blood-brain barrier also penetrate into the eye through the blood-aqueous barrier. Recent reports in the literature have indicated that tetracycline penetrates into the spinal fluid in animals1 and in humans.2
As no other report concerning the intraocular penetration of tetracycline has been published up to this time, we considered it of value to determine the degree of penetration of this antibiotic into the aqueous humor of rabbits and human beings. It was considered of importance to use human as well as rabbit eyes, for there have been very few reports on the intraocular penetration of antibiotics into human eyes, the supposition having been that rabbit eyes were very similar to human eyes in this respect.
Various modes of administration and dosage schedules were utilized. Also, a small number of assays were performed
ABRAHAM RK, BURNETT HH. Tetracycline and Chloramphenicol Studies on Rabbit and Human Eyes. AMA Arch Ophthalmol. 1955;54(5):641-659. doi:10.1001/archopht.1955.00930020647002