Srinivasan 2004.
| Methods | Randomized controlled trial Approved by the ethics committee; written informed consent obtained |
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| Participants | 210 participants listed for cataract surgery on a single eye by a single surgeon Exclusion criteria: dementia, deafness, eye movement disorder, combination surgery, excessive anxiety, English not first language, allergy to local anaesthetics | |
| Interventions | Treatment group: topical anaesthesia with proxymetacaine 0.5% 4+2 drops; 5 minutes apart (n = 70) Control group: sub‐Tenon's anaesthesia with poxymetacaine 0.5% 1 drop topically, lignocaine 2% 2 mL + bupivacaine 0.75% 1 mL (n = 140) Surgical technique: clear corneal incision Number of operating surgeons: 1 Oral sedative: none used | |
| Outcomes | Pain during anaesthesia Pain felt intraoperatively (VAS score 0 to 10) Pain felt 30 minutes postoperatively (VAS score 0 to 10) Complications: Three participants (4.3%) in the topical anaesthesia group and 2 (2.1%) in the sub‐Tenon’s group had posterior capsular tear and vitreous loss. One participant (0.5%) in the sub‐Tenon’s group had iris prolapse intraoperatively and required a single interrupted stitch to close the corneal wound |
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| Notes | Surgeon blinded to participant group: yes Pain assessor blinded to participant group: yes |
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| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | "An independent researcher provided the hospital pharmacy with an individual randomization schedule of 250 allocations" |
| Allocation concealment (selection bias) | Low risk | "The randomization schedule was retained in the hospital pharmacy and was not seen by the investigators until the trial was completed" |
| Blinding of participants and personnel (performance bias) All outcomes | Low risk | "A customized pack was prepared from this schedule for each patient. The pack comprised a syringe containing either 3 mL of local anaesthetic lidocaine 2% (2 mL) and bupivacaine 0.75% (1 mL) or placebo, a minims dropper containing either placebo or proxymethocaine 0.5%, and a separate minims dropper containing proxymethocaine 0.5%. These packs were sequentially labelled 1 to 210. All patients received a sub‐Tenon’s injection and topical eyedrops. In this way the patients, the ophthalmologist administering the anaesthetic, the surgeon and the nurse measuring the pain score were fully masked from the identity of the contents of the pack" |
| Blinding of outcome assessment (detection bias) All outcomes | Low risk | "A customized pack was prepared from this schedule for each patient. The pack comprised a syringe containing either 3 mL of local anaesthetic lidocaine 2% (2 mL) and bupivacaine 0.75% (1 mL) or placebo, a minims dropper containing either placebo or proxymethocaine 0.5%, and a separate minims dropper containing proxymethocaine 0.5%. These packs were sequentially labelled 1 to 210. All patients received a sub‐Tenon’s injection and topical eyedrops. In this way the patients, the ophthalmologist administering the anaesthetic, the surgeon and the nurse measuring the pain score were fully masked from the identity of the contents of the pack" |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | Nine participants (5 in sub‐Tenon’s group and 5 in topical anaesthesia group) were excluded from the analysis, as their pain scores were not recorded |
| Selective reporting (reporting bias) | Low risk | No cross‐over |
| Other bias | Low risk | Groups well balanced |