A novel Ocular Anaesthetic Scoring System, OASS, tool to measure both motor and sensory function following local anaesthesia

Abstract

Background/aims: To devise and evaluate a novel Ocular Anaesthetic Scoring System (OASS) for non-topical local anaesthesia.

Methods: In OASS, a score of between 0 (poor) and 14 (excellent) was devised measuring motor (ocular motility, levator and orbicularis function) and sensory functions (digital spear pressure at limbus and topical anaesthetic sting). 40 patients were studied prospectively to analyse interobserver consistency in OASS. A further 100 patients were collected into four groups receiving either sub-Tenon or peribulbar block with 150 or 300 units of hyaluronidase. Patient satisfaction was determined using the Visual Analogue Pain Scale and Iowa Satisfaction with Anaesthesia Scale.

Results: There was no significant difference in OASS scores between two independent observers (p = 0.8910). The sub-Tenon approach achieved significantly better OASS scores than the peribulbar approach (p<0.0004). 300 units of hyaluronidase gave significantly higher OASS scores in both sub-Tenon (p<0.0001) and peribulbar groups (p<0.0001). Spearman rank correlation showed that OASS correlates significantly with VAPS (-0.82, p<0.0001) and ISAS (0.70, p<0.0001). The median satisfaction score was significant in order of magnitude: sub-Tenon with 300 units of hyaluronidase>sub-Tenon with 150 units of hyaluronidase>peribulbar with 300 units of hyaluronidase>peribulbar with 150 units of hyaluronidase.

Conclusion: OASS is a simple and robust system for assessing and comparing non-topical local anaesthetic techniques. Of the techniques evaluated, a sub-Tenon block with 300 units of hyaluronidase gives the best anaesthesia, analgesia and patient satisfaction results.