CONJUNCTIVAL CHANGES AFTER SUBCONJUNCTIVAL LIGNOCAINE

Subconjunctival injection of 2% lignocaine at the 12 o'clock position was used as the local anaesthetic in 19 eyes undergoing a primary trab eculectomy for open angle glaucoma. The appearance of the bleb and mea n post-operative intraocular pressure (IOP) were compared with those i n 29 eyes with the same diagnosis undergoing trabeculectomy under gene ral anaesthesia by the same surgeons over the same time period. The tw o groups of eyes were similar with regard to treatment with beta block ers (p>0.1), miotics (p>0.25), sympathomimetics (p>0.25), carbonic anh ydrase inhibitors (p>0.5), or no treatment (p>0.25). Seventy-seven per cent of the local anaesthetic group and 25% of the general anaestheti c group developed avascular, thin-walled drainage blebs (p<0.001). The mean post-operative IOP was significantly lower in the group receivin g local anaesthetic (p<0.001). The reasons for and significance of the se observations are discussed, and the merits and disadvantages of thi n-walled blebs are evaluated.