The application of digital pressure to the eye and orbit following retrobulbar injection of local anesthetics prior to cataract surgery has become a routine procedure to many ophthalmic surgeons. The studies of Kirsch1,2 established the efficacy of this maneuver and suggested that the optimal length of time for the application of digital pressure is five minutes. Possibly because of the very fact that this maneuver has become routine, it is often assumed without reservation that ocular hypotony has occurred, unless there is visible evidence of retrobulbar hemorrhage.
The present study of ocular tension following retrobulbar injection of an anesthetic and during the period of digital pressure to the orbit clearly indicates that such an assumption is unwarranted. This evidence is so conclusive that it is felt that an incision in cataract surgery should never be made, even after five minutes of digital pressure, until hypotony has been proven by
HILL HF, LOPEZ E, HILL K. Effect of Retrobulbar Anesthesia Upon Intraocular PressurePreliminary Report on Its Importance in Cataract Surgery. Arch Ophthalmol. 1963;70(2):178-180. doi:10.1001/archopht.1963.00960050180008