|Ocular anaesthesia: What works best for you?|
|Saturday, 01 January 2011|
Cehajic-Kapetanovic J, Bishop PN, Liyanage S, et al. A novel Ocular Anaesthetic Scoring System (OASS) tool to measure both motor and sensory function following local anaesthesia. Br J Ophthalmol 2010; 94: 28-32. (Clinical Science) Athanasiov P, Henderson T. Ocular anaesthesia and the never-ending story. Br J Ophthalmol 2010; 94: 1. (Editorial)
In a nutshell
A new method of assessing the effectiveness of ocular anaesthesia, the Ocular Anaesthetic Scoring System (OASS) is described. Two studies were carried out: the first to investigate the effectiveness of the scoring system and to analyse inter-observer consistency, and the second to compare the effectiveness of different anaesthetic techniques and to determine whether the OASS score correlated with patient satisfaction, using the Iowa Satisfaction with Anaesthesia Scale (ISAS) and the Visual Analogue Pain (VAP) Scale.
In the second study, a comparison is drawn between peri-bulbar (PB) block and sub-tenon (ST) injection, and two dosages of added hyaluronidase are compared.
Motor function is measured by three objective methods: by scoring the degree of ptosis, estimating lid function, and the extent of extraocular movements. Sensory effect is measured by two methods: by scoring appreciation of digital spear pressure at the limbus, and the sensation of topical anaesthetic sting using one drop of amethocaine 1%.
Athanasiov’s editorial concludes that the OASS provides a ‘useful and reproducible method for ophthalmologists and anaesthetists to monitor their results and tailor their techniques’.
Ocular topical and local anaesthesia have been used since the mid-1800s, but controversy still exists as to the best method in terms of safety, efficacy, and patient comfort. Surgeon preference tends to be coloured by established local practice, personal experience, and subjective feedback from patients.
Although it is generally accepted that topical anaesthesia is the emerging method of choice, it is by no means universally employed and it is interesting that Davidson et al, writing in the Cochrane Database Systematic Review (2007), bluntly concluded that ‘Sub-Tenon anaesthesia provides better pain relief than topical anaesthesia for cataract surgery.’
In order for individuals to choose the best method of ocular anaesthesia for their practice, they need to appreciate prevailing local attitudes to surgery and anaesthesia, what works best in their hands, and to keep up with current trends and research. Cehajic-Kapetanovic et al have provided a useful, cheap, and easy method of determining the best way to judge the effectiveness of local or topical anaesthesia. According to the contributing editor, it is reproducible, has been thoroughly tested, and fully validated.