Treating one eye disease may cause another.

A new study showed patients that received seven or more intravitreal injections of Avastin had an increased risk of needing glaucoma surgery.
The study used information from databases supported by the British Columbia Ministry of Health.  Using data from 2009-2013, patients that received their first Avastin injection between these dates were included in the study.
Several other studies have shown that repeated intravitreal injections can cause sustained elevated IOP.  The leading theory is that there is damage to the trabecular meshwork but the mechanism is unclear.  This study further corroborates the elevated IOP results but goes a step further to say seven injections is the magic deleterious number.