M.C. Minasian, A.C. Ionides, et al (Royal Free Hospital, London)
Pain perception with pH buffered peribulbar anaesthesia : a pilot study.
Br.J.Ophthalmol 2000; 84: 1041-1044
This is a prospective randomised controlled double blind pilot study involving 60 consecutive patients, to determine the relation between pH of anaesthetic solutions and patient perception of pain with peribulbar injection of local anaesthesia.
It was found that there was no difference in the reduction in the pain experienced by patients undergoing peribulbar anaesthesia with pH buffered local anaesthetic.
The study also showed that some patients feel considerable pain on instillation of the preoperative dilating drops.
N. Kristin, C. L. Schonfeld, et al (Munich, Germany)
Vitreoretinal Surgery: Pre-emptive Analgesia
BJO, Nov.2001, 85(11): 1328-1331
The authors stress two important concepts:
(1) Analgesia initiated before a nociceptive event will be more effective than analgesia commenced afterwards.
(2) Local anesthesia (LA) (alone) or preoperatively in addition to GA provides the best comfort for the patient in vitreoretinal surgery.
A study was carried out on 90 patients who underwent vitrectomy without buckling. 60 patients underwent GA-(30 without LA, 15 with preoperative LA and 15 with postoperative LA) while 30 received LA alone.
Postoperative pain was less under LA (alone) compared to GA alone. Additional PREOPERATIVE LA resulted in less pain than additional postoperative LA.
Additional postoperative peribulbar anesthesia did not differ from GA alone.
A.S.Ramsay, N.Ray-Chaudhari, et al (West Suffolk Hospital, Bury St. Edmunds. Suffolk, UK)
Quantification of relative afferent pupillary defects induced by posterior sub-Tenon’s, peribulbar, and retrobulbar anaesthetics.
BJO, 2001; 85:1445-1446.
This study compared the depth of induced relative afferent pupillary defect (RAPD) following:
(i) Posterior sub-Tenon’s
(ii) Retrobulbar and
(iii) Peribulbar, local anesthetics using crossed polarising filters before (5 minutes)
cataract surgery, immediately after surgery (42 minutes- average) and again in the ward (107 minutes av).
It was found that all 3 anaesthetic methods caused a similar level of disruption to optic nerve conduction, immediately following injection and at the time of day case discharge.