title: Intraocular pressure and pulsatile ocular blood flow after retrobulbar and peribulbar anaesthesia.
abstract: OBJECTIVE
  This study investigated the effect of peribulbar and retrobulbar local anaesthesia on intraocular pressure (IOP) and pulsatile ocular blood flow (POBF), as such anaesthetic techniques may adversely affect these parameters.
  
  
  METHODS
  20 eyes of 20 patients who were to undergo phacoemulsification cataract surgery were prospectively randomised to receive peribulbar or retrobulbar anaesthesia. The OBF tonometer (OBF Labs, Wiltshire, UK) was used to simultaneously measure IOP and POBF before anaesthesia and 1 minute and 10 minutes after anaesthesia. Between group comparisons of age, baseline IOP, and baseline POBF were performed using the non-parametric Mann-Whitney test. Within group comparisons of IOP and POBF measured preanaesthesia and post-anaesthesia were performed using the non-parametric Wilcoxon signed ranks test for both groups.
  
  
  RESULTS
  There was no statistically significant IOP increase post-anaesthesia in either group. In the group receiving peribulbar anaesthesia, there was a significant reduction in POBF initially post-anaesthesia which recovered after 10 minutes. In the group receiving retrobulbar anaesthesia, there was a persistent statistically significant reduction in POBF.
  
  
  CONCLUSIONS
  Retrobulbar and peribulbar injections have little effect on IOP. Ocular compression is not needed for IOP reduction when using local anaesthesia for cataract surgery. Conversely, POBF falls, at least for a short time, when anaesthesia for ophthalmic surgery is administered via a retrobulbar route or a peribulbar route. This reduction may be mediated by pharmacologically altered orbital vascular tone. It may be safer to use other anaesthetic techniques in patients with ocular vascular compromise.
authors: Department of Ophthalmology, Norfolk and Norwich University Hospital NHS Trust, West Norwich Hospital, Bowthorpe Road, Norwich NR2 3TU, UK. r.j.watkins@apu.ac.uk
authors: R
authors: R
authors: Watkins
authors: B
authors: B
authors: Beigi
authors: M
authors: M
authors: Yates
authors: B
authors: B
authors: Chang
authors: E
authors: E
authors: Linardos
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000772:Anesthesia, Local / Q000009:adverse effects* / Q000379:methods; D005123:Eye / Q000098:blood supply*; D005260:Female; D006801:Humans; D007429:Intraocular Pressure / Q000187:drug effects*; D008297:Male; D008875:Middle Aged; D018918:Phacoemulsification; D011446:Prospective Studies; D011673:Pulsatile Flow / Q000187:drug effects; D018709:Statistics, Nonparametric