Comparison on Preoperative Intraocular Pressure Elevation after Performing between Pin Point Anesthesia and Retrobulblar Anesthesia

ABSTRACT

The importance of the preoperative intraocular pressure cannot be overemphasized for cataract operation. We compared the preoperative intraocular pressure between the conventional retrobulbar anesthesia technique and the pin point anesthesia technique with different anesthetic dosage using tono-pen in 23 patients(41 eyes) divided into 4 groups. In the 1st group(10 eyes), after conventional retrobulbar injection was performed using 3ml of 2% lidocaine, digital massage was done for 10 minutes. In 2nd group(13 eyes), 2% lidocaine 1.0ml was injected into subtenon's space(true muscle cone) through the small hole in the superior temporal quadrant 8mm posterior to limbus using specially designed blunt, curved cannula without any method to decrease the intraocular pressure (pin point anesthesia). In the 3rd group(13 eyes), and 4th group(5 eyes), same procedure was performed as 2nd group using 0.75ml and 0.50ml of 2% lidocaine respectively. As a results, in 1st group, average intraocular pressure was decreased around 5.6mm Hg after digital massage. In the 2nd, 3rd, and 4th group, preoperative intraocular pressure increased by 2.2, 0.8, and 0.5mmHg. As comparison of three group of the pin point anesthesia, in the 2nd group, sometimes there were mild chemosis, in the 4th group, often discomfort, in contrast, in 3rd group there were no chemosis, pain or discomfort. As a conclusion we want to recommend a pin poit anesthesia using 0.75ml of 2% lidocaine for the routine cataract operation.