The alteration of intraocular pressure and ocular pulse amplitude by retrobulbar anaesthesia : a search for risk factors for serious complications due to retrobulbar anaesthesia

Abstract

Our goal was to assess the impact of retrobulbar anaesthesia on ocular pressure and perfusion development and to find out if there were systemic or biometric parameters of patients affecting them in order to understand the effect of retrobulbar anaesthesia better. Methods: Changes in intraocular pressure (IOP) and ocular pulse amplitude (OPA) using a dynamic contour tonometer (DCT) were noted before and after retrobulbar anaesthesia (RBA) in combination with five minutes of oculopression at 40 mmHg in 134 patients. Only results with a quality Q 1–3 were considered for further statistical analysis. Systemic and ophthalmic parameters were noted and their impact was tested using linear regression. Results: IOP decreased from 18.9 ± 7.2 mmHg to 15.4 ± 6.3 mmHg (n = 71, p = 0.001) after first RBA. The dosage of midazolam administered during premedication was found to increase IOP significantly after first RBA (B = 3.75; R2 = 0.38). Ocular pulse amplitude decreased significantly from 3.8 ± 1.7 mmHg to 3.0 ± 1.9 mmHg after first RBA (n = 72, p < 0.001). This change was found to be dependent on the presence of diabetes mellitus (n = 68, p = 0.048). Conclusions: IOP and OPA decrease after RBA and oculopression. Caution is needed with midazolam premedication due to potential IOP increase. Patients with diabetes and pre-existing retinal or optic nerve damage should consider alternative anaesthesia methods, such as eye drops or general anaesthesia, due to the observed decrease in OPA after RBA and oculopression.