Randomised trial of topical versus sub-Tenon's local anaesthesia for small-incision cataract surgery.

Fifty unselected patients undergoing routine cataract surgery were randomised to receive either topical or sub-Tenon's local anaesthesia with 2% prilocaine administered by a blunt cannula. Visual analogue scales were used to assess pain during administration of sub-Tenon's anaesthetic and pain during surgery, and any complications were noted. Sub-Tenon's anaesthesia proved to be entirely comfortable to administer, and allowed for a statistically significantly more pain-free operation, at the expense of some residual eye movement and an inevitable subconjunctival haemorrhage. Both techniques compared well with other studies assessing periorbital or retro-orbital injections, and both have significant safety advantages which are discussed in the context of the joint Royal Colleges report on ophthalmic anaesthesia. It is suggested that a combination of one or other technique could safely cover all requirements for intraocular surgery under local anaesthesia.