Recognised risk factors for developing subconjunctival haemorrhages include:
- Valsalva manoeuvres (coughing, sneezing, straining)
- general anaesthesia
- trauma to the eye
- clotting disorders - (which may also predispose to bruising elsewhere)
- severe conjunctivitis (viral)
- a fragile blood vessel in the conjunctiva
- recent eye surgery
Tetracyclines are known occasionally to cause liver toxicity, and the liver is responsible for manufacturing clotting factors. The connection is a little tenuous and uncommon, but if the subconj haemorrhages occur a week or two after starting the course of antibiotics, it may be worth getting you liver function and clotting function checked at that time.
Tetracyclines can also cause rash and immunological reachions that affect mucosa surfaces such as the conjunctiva. It is just possible that you are experiencing a mild form of such a reaction.
If the subconj haemorrhage always happens in the same place, it is more likely that you just happen to have a fragile blood vessel there... in which case there is probably nothing to worry about.
Given the infrequent nature of these haemorrhages, you should probably not be worried, but if the next one occurs in association with the tetracycline, you will have established a link, and a couple of blood tests may uncover the underlying mechanism of the problem.
I hope these thoughts are helpful. If so kindly click the 'accept' link.
Thanks & best wishes.
Edited by Dr Dansingani on 9/15/2009 at 10:51 PM EST